Improved copper smelting process

专利摘要:
There is disclosed a method for recovering copper from secondary raw materials which comprises, in a feed charge, furnace smelting (100) of a feed material (1, 2) comprising copper oxide and iron to form a concentrated copper intermediate (3) , where heat is generated by the redox reactions that convert iron to oxide and convert copper oxide to copper, where copper collects in a molten liquid metal phase and iron oxides collect in a supernatant liquid slag phase, where at the end of the charge the liquid phases separate and can be removed from the furnace as smelting furnace slag (5) and as concentrated copper intermediate (3), characterized in that, during the smelting step, an excess of iron is kept in the furnace, in proportion to the amount required to carry out the redox reactions. complete, and an additional heat supply is provided by injecting an oxygen-containing gas for the oxid honor of excess iron.
公开号:BE1027795B1
申请号:E20205840
申请日:2020-11-20
公开日:2021-06-23
发明作者:Niko Mollen；Steven Smets；Jan Dirk A Goris；Walter Guns；Andy Breugelmans；Charles Geenen；Bert Coletti
申请人:Metallo Belgium；
IPC主号:

专利说明:

,Ç BE2020/5840 Improved copper smelting method
FIELD OF THE INVENTION The present invention relates to the recovery of copper (Cu) together with other non-ferrous metals such as tin (Sn), lead (Pb), nickel (Ni) and zinc (Zn), mainly from secondary feed materials, by means of pyrometallurgical process steps. The present invention preferably relates to secondary feed materials, also known as recyclable materials. For example, recyclable materials can be by-products from metal producers, waste materials and materials at the end of their use cycle.
BACKGROUND OF THE INVENTION The present invention mainly relates to a known pyrometallurgical step in the production of copper, namely the smelting step. Depending on the source of the feed materials, the smelting step may be further specified as a primary or secondary smelting step. Smelting is a process in which heat and chemical agents, usually in a primary smelter, are applied to metal ore to extract a base metal. In more technical detail, smelting is a process in which metallic solids are liquefied using a chemical reaction that produces metals as a result. It is used to extract many metals from the inert gangue component of the ore, including silver, iron, copper, and other base metals. It is a form of extractive metallurgy that uses chemical reactions to remove other elements in the form of gases or slag, leaving behind a liquid bath containing metal in elemental or in a chemically bonded form, such as bonded with sulfur, known as a "matte". The elemental metal is recovered in a separate molten metal phase. Also, the matte usually forms a separate liquid phase. Most ores are impure, and often it is necessary to use a flux, such as limestone or silica, to remove the entrained gangue as part of another separate liquid phase that forms the typical by-product called “slag”.
Also in the recovery of copper from secondary materials, smelting can be used as a first step to recover a concentrated copper phase from secondary raw materials that may be too contaminated, and/or whose copper content may be too low to be directly suitable as feedstock to be refined to anode copper grade. Such secondary feedstocks are generally richer in copper than the primary copper sources, such as copper ore or even as the copper concentrate intermediate usually first derived from the ore, for example by mineral flotation upstream of the smelting step. Part of the copper in the secondary material may also already be present in the elemental form, and thus not chemically bonded. For those reasons, the operating conditions in a copper smelting step applied to secondary raw materials are markedly different from those in a primary copper smelting step applied to a copper concentrate, or sometimes a copper ore.
In a primary copper smelter, the typical starting materials are copper-containing sulfides such as chalcopyrite (CuFeS), bornite (CusFeS4) and chalcocite (Cu2S). Their reaction with oxygen (oxidation) drives off S as SO2 in the off-gas, forming a “matte phase” (CuzS.FeS) together with a slag phase (FeO.SiO2), the latter being formed by the reaction with added silicon dioxide. In a second step, usually also in the smelting furnace, FeS is driven off by an additional reaction with oxygen and silicon dioxide to form more slag and more SOO: gas, leaving behind a so-called “white metal” (CuzS), usually with less than 1% residual Fe. The latter is then oxidized with an oxygen-deprived gas, preferably air, according to the reactions CuzS + O2 — 2CU + SO: CuzS + 3/2 O2 — CuzO + SO:
CuzS + 2 Cu2zO — 6 Cu + SO: This primary copper smelting process is usually performed in a so-called “Pierce-Smith” converter, to form so-called “blister copper”, which contains Ni and precious metals, a slag that contains most of the Fe , contains Zn together with 2-15% Cu, furnace dust (which contains most of the Sb, As, Bi, Cd, Pb), and exhaust gas (which again contains SO:). The large amount of S released in those process steps is expelled as SO: and is recovered in the form of sulfuric acid.
Thus, the primary copper smelting step is usually and primarily a strong oxidation step. A primary copper smelting process is described, for example, in JPS61531 (A) or its assigned version, JPH0515769 (B2). Processing of the copper frosted phase is described, for example, in patents CN101871050 A and GB2462481 A. US 3,954,448 describes a process for the further processing of the copper frosted or a slag from a primary copper smelting step.
JP 2003253349 discloses a primary copper smelting process in which the matte raw material also contains iron sulfide. In a first step, that iron sulfide is selectively oxidized to iron oxide using oxygen-enriched air. The iron oxide and the added silicon dioxide end up in a separate slag phase which is removed from the furnace before the copper sulfide is further processed in a second step. The amount of iron sulfide available and its reaction to FeO may not be sufficient to generate the heat of reaction required to maintain the furnace temperature during that first step, especially when cold feedstocks are to be processed. In the first step, an amount of extra metallic iron is added per ton of processed matte to counteract the further oxidation of iron to magnetite (FezO3), which would otherwise increase the viscosity of the slag and the subsequent phase separation and slag removal at the end. hinder the first step. Under the usual oxidizing conditions in the primary copper smelting step, the additional metallic iron is oxidized, and that reaction generates additional heat.
The metals in the typical raw materials for a secondary copper smelting step are mainly present as oxides, although small amounts of sulfides may also be present.
An important difference from a primary copper smelting step is therefore the absence of copper matte as an intermediate.
Some of the copper in the raw materials may already be present in its elemental form, but in too low a concentration or in a form that is less suitable for pyrometallurgical copper refining, and even less for hydrometallurgical recovery (leaching + electro-extraction). The copper in the oxides is then reduced in the smelting step by adding a reducing agent, e.g. a source of carbon, such as coke, and/or metallic iron, usually in the form of iron scrap.
Another important difference from a primary copper smelting step is thus the reducing conditions in which the smelting step is performed on secondary raw materials.
US Patent US 3,682,623 (Ludo Dierckx et al) describes a copper refining process starting from secondary raw materials, the first step of which is a smelting step, i.e. a reduction step, which is carried out in a smelting furnace in which copper-containing materials are heated together with solid material metallic iron, under an oxygen-enriched neutral flame, and with light agitation, a bath comprising a slag phase is produced from that charge.
A small amount of basic or neutral flux may be added to optimize the specific gravity and viscosity of the slag formed.
Also, additional silicon dioxide can be added to absorb iron compounds produced in the reduction reactions.
As the temperature of the molten pool in the furnace increases, chemically combined copper, lead, tin, or nickel in the charge is reduced with solid-state metallic iron, forming a molten metal called "black copper" and molten slag. containing iron silicate.
The typical process reactions, it is stated, include:
MeO + Fe > FeO + Me (MeO);SiO2 + x Fe > (FeO}),SiO2 + x Me x FeO + SiO2 > (FeO)xSiO2 These reactions confirm that the so-called 5 “melting step” of US 3,682,623 can be considered as a "melting step" in the context of the present document.
The reactions are exothermic, and it is indicated that the heat of reaction rapidly increases the temperature of the charge.
Once the material has melted to the extent that it flows smoothly along the vessel wall, agitation of the vessel can be intensified.
At the end of the reduction step, a black copper and a slag are formed, which can be separated from each other by gravity and removed separately from the furnace.
During the course of the reduction process, the temperature is kept as low as possible, consistent with maintaining a fluid slag.
The fuel supply must be adjusted to prevent the reaction mass temperature from exceeding about 1300°C for a significant period of time during the melter cycle.
Preferably, the temperature should not be kept much higher than the temperature at which the slag becomes substantially fluid.
A bath temperature of about 1180°C is indicated as suitable for normal charge materials, but lower temperatures can be used if borax is used as the flux.
A low temperature not only keeps the evaporation of lead and tin as low as possible, but also limits the dissolution of solid iron in the molten copper produced.
It is stated essential that a significant amount of iron be present in the solid state to provide rapid and complete reduction of the slag.
Iron dissolution should also be minimized to maintain a solubility of lead and tin in the black copper produced.
As the reduction reactions proceed and the material comprising solid iron gradually dissolves in the molten metal, additional solid material containing metallic iron may advantageously be added after the melting is completed to effect a final reduction of copper, tin, lead and zinc that remain in the slag. Generally, an excess of iron is used which remains in the furnace, at least a portion of which is dissolved in the black copper. Zinc is vaporized from the furnace, but a significant amount of zinc also remains in the black copper at the end of the smelting step.
At the end of the so-called smelting step, when the final reduction step was completed, as indicated by further analysis of the slag, the molten slag was poured from the top of the furnace and pelletized. After the slag was cast from the furnace, the resulting black copper was then pre-refined in the same furnace, along with additional secondary raw materials already quite rich in copper, and this pre-refining used a strong oxidizing flame. Thus, this pre-refining step is no longer part of the upstream smelting step, which is a reduction step characterized by a reducing environment.
In Example 1 of U.S. Pat. No. 3,682,623, the charge for the smelter is melted "under a neutral oxygen-enriched flame" (col. 15, lines 1-2), which is understood as a neutral flame utilizing oxygen-enriched sky. After an additional amount of copper/iron scrap was added, the slag was further reduced under a slightly reducing flame (col. 15, r. 33-35). Most of the zinc present was evaporated and recovered as dust in the exhaust system. The slag was then poured off at the top and processed into granules.
DE 10 2012 005 401 A1 describes a bath smelting furnace in which a copper-containing substance, preferably a secondary raw material containing copper, is subjected to a smelting process using oil and/or gas as fuel together with air and/or oxygen, which are injected into the bath by means of a submerged injection lance. The smelting step yields a primary slag containing relatively few impurities which is discharged from the process, and also a second slag for further processing which is transferred from the bath smelting furnace to a rotary drum furnace. The rotary drum furnace is fitted with a burner at one end, which can be fed with oil or gas and optionally also with oxygen from an oxygen reservoir. The further processing takes place step-by-step and successively yields anode-grade copper, black copper, a raw tin mixture that can be further treated with silicon, and a final slag. In each of the process steps, coal is introduced into the rotary drum furnace. In each step of the method according to DE 10 2012 005 401 A1, the furnace is heated by burning a fuel with air and/or oxygen.
Patent EP 0185004 describes a process in which an oxidative smelting step, applied to secondary materials, in an attempt to increase the yield of valuable metals, results in a liquid bath from which tin and zinc are successively removed in two steps. by fumigation, after which a copper-containing slag is tapped off and a copper-containing metal phase remains. That metal phase is further treated to first separate a lead silicate slag, a low nickel blister copper, and a copper-nickel oxide bath which can then be reduced to form a copper-nickel alloy.
US Patent US 2017/0198371 A1 concerns the potentially large variations in the organic components in feedstock for a smelter, and their effects on the throughput of the process. The document proposes to remove, in batch mode, organic components in a first stage, while already producing a so-called “black copper”, which in a subsequent stage can be converted to blister copper by further oxidation. The other product of the first step is a final slag that is low in metal. The document states that “a duly adjusted amount of oxygen is blown into the process chamber”. In this method, “the composition of the slag and the content of valuable metals still present in it are monitored during the melting process by taking samples and analyzing them quickly”.
The disadvantage of the smelting step of US 3,682,623 is that during the majority of the smelting step a significant part of the heat input is provided by the neutral flame, which is fed by oxygen-enriched air. This requires a large source of fuel, air, and pure oxygen, which entails complexity, additional equipment and operational burdens.
The heat supply from the flame above the furnace to the molten bath leaves something to be desired, because the heat has to be transferred from the combustion gases to the liquid bath. The heat transfer from gas to liquid is quite slow, and the surface area of contact surface between the burner in the top of the furnace and the liquid bath remains limited. With a submerged burner, gravity causes the gas to rise rapidly and leave the liquid phase. There is thus relatively little contact time between the combustion gases and the molten bath. The heat supply from the flame to the bath therefore takes place mainly by radiation. As a result, the heat input by the flame is not very efficient and a large portion of the potential heat input from the flame is lost from the furnace with the exhaust gases, where that heat is an additional burden on the exhaust gas cooling system.
The large volumes of flue gases generated by the flame also require the installation and use of a large exhaust gas treatment system.
The inventors have determined that there is still a need for a more convenient and efficient heat supply in a secondary copper smelting furnace, while still maintaining or even improving the means for controlling the temperature in the smelting step.
The present invention aims to eliminate or at least alleviate the problem described above, and/or to provide improvements in general. SUMMARY OF THE INVENTION
According to the invention there is provided a method as defined in any of the appended claims.
In one embodiment, the present invention provides a method for recovering copper from secondary raw materials comprising the step of smelting, in at least one feed batch, a feedstock comprising the raw materials in a furnace for the recovery from the furnace of a concentrated copper intermediate, wherein the feedstock is gradually introduced into the furnace, the feedstock comprising copper, and optionally at least one metal which is more noble than copper under the operating conditions of the furnace, at least in part as an oxide, the feedstock furthermore being iron and optionally at least one metal or compound which is at most as noble as iron or zinc in the conditions of the furnace, the iron and metal at most as noble as iron or zinc being at least partially present in the elemental form, where heat is generated in the furnace by the redox reactions that element converting iron and metals or compounds no more than as noble as iron or zinc into oxides, and converting oxides of copper and of metals more noble than copper into elemental metal, the elemental metals accumulating at least partially in a molten liquid metal phase and the oxides at least partially collect in a supernatant liquid slag phase, the liquid phases being capable of separating and at the end of the smelting step at least one of the liquid phases is at least partially removed from the furnace as a smelting slag and/or as the concentrated copper intermediate, characterized in that during the smelting step an excess of the elemental form of iron and of metals or compounds which in the conditions of the furnace are at most as noble as iron or zinc in the furnace is kept, in proportion to the amount required to complete the redox reactions,
and an additional heat input into the furnace is provided during the smelting step by injecting an oxygen-containing gas to oxidize the excess iron present and any metals or compounds which are at most as noble as iron or zinc in the furnace and optionally for the combustion of a combustible source of carbon and/or hydrogen which may additionally be introduced into the furnace.
Preferably, the excess of iron and possibly of metals or compounds which in the furnace conditions are at most as noble as iron or zinc is maintained by deliberately adding, as part of the feedstock, at least one additional raw material to the furnace. rich in iron and/or at least one metal or suitable compound.
The applicants have found that maintaining excess iron and any other metals and/or compounds at most as noble as iron or zinc in the furnace provides a very convenient method of controlling a highly controllable part of the heat input, and thereby the temperature in the smelting furnace, ie by controlling the injection of the oxygen-containing gas into the furnace, because the oxygen in that gas is what is made available to oxidize the excess elemental iron and/or other metals or compounds which are at most as noble as iron or zinc.
The applicants have found that this method allows direct, precise and correct metering of the oxygen feed to generate part of the heat of reaction, and more advantageously a part which is made readily, directly and completely available in the liquid bath. in the furnace at the level where it is most desired, ie the interface between the metal phase and the slag phase, where the redox reactions and the phase changes are supposed to take place.
The heat resulting from the oxidation of iron and other metals and/or compounds that are at most as noble as iron or zinc, through the reaction with oxygen from the oxygen-deprived gas, is generated in the bath itself, requiring no additional step of heat transfer. This heat of reaction is completely and immediately dissipated in the molten bath.
The applicants have found that the temperature control in the melting furnace, thanks to the present invention, is easy and very sensitive. This is very beneficial because as the temperature in the molten liquid bath increases, more iron dissolves in the molten liquid metal and is made available for oxidation with the available oxygen, which in the presence of oxygen would generate even more heat and enable to cause an uncontrolled rise in temperature.
The present invention is able to avoid that risk of an uncontrolled temperature rise because in the method according to the present invention the supply of oxygen as part of the oxygen-containing gas is highly controllable. If at any given time the feedstock introduces a greater amount of oxygen to be made available to participate in the redox reactions, and if the heat generated by those additional redox reactions would lead to an increase in the temperature of the molten bath, the temperature of the the melt bath can be brought under control without any problems by reducing the injection flow rate of the oxygen-containing gas, and any risk of an uncontrolled rise in temperature is easily avoided or at least significantly reduced.
Another advantage of the present invention is that the oxidation of iron and other metals or compounds that are at most as noble as iron or zinc generally does not produce large amounts of waste gas, unlike the combustion of natural gas or other fuel containing carbon and/ or hydrogen, and that the furnace exhaust gas treatment system associated with the smelting equipment in which the method of the present invention is carried out can be designed smaller, thereby requiring lower investment costs, and in addition, consuming lower operating costs in operation. Another advantage of the lower volume of exhaust gas is that usually less of the valuable tin, lead and zinc is also evaporated and these elements therefore do not have to be collected in the exhaust gas treatment system.
The applicants have therefore found that the heat generation by the oxidation of, for example, the excess iron to iron oxide by injecting oxygen gas into the molten bath is much more effective, and also much more efficient, than burning a flame based on a combustible source of carbon. and/or hydrogen in the oven. Applicants have estimated that approximately 80% of the injected oxygen reacts with compounds in the liquid bath of the furnace, and that the heat generated by these reactions remains in the liquid bath, which is a very high yield compared to the heat which can be contributed by the combustion of a hydrocarbon fuel such as natural gas, even if that combustion is powered by pure oxygen or oxygen-enriched air. The applicants argue that this difference arises because the conversion of iron to iron oxide takes place in the liquid bath itself, while the combustion of natural gas takes place in the gas phase and the heat of combustion then still has to be transferred to the liquid phase to contribute to the enthalpy content of the liquid bath. Moreover, such combustion does not necessarily take place completely.
The Applicants have also found that suitable sources of elemental iron, and of metals or compounds no more than as noble as iron or zinc, are readily available from a wide variety of sources and can be readily obtained on economic terms that make this process of heat supply economical. more economical than heat supply by means of a neutral flame, based on operating costs alone. In addition, the carbon consumption footprint of the process of the present invention is smaller as compared to the prior art process described above.
While falling within the scope of the present invention, applicants preferably do not use the option of providing a portion of the total heat input to the furnace from the combustion of a combustible source of carbon and/or hydrogen in the furnace.
The applicants have found that in certain economic circumstances it may be advantageous to use this option, but the applicants always prefer, even when this option is used, to control the temperature of the furnace by injecting the oxygen- gas, due to its greater ease of use, easier controllability and less risk of uncontrolled temperature rise.
Another advantage of the present invention associated with the excessive presence of iron dissolved in the molten liquid metal layer in the furnace is that a layer of solid iron and/or iron oxide forms around submerged blowpipes through which the oxygen-containing gas can be introduced and a additional protection of those blowpipes against wear, because the blowpipes are cooled by the gas flow, which is usually cooler than the melt bath.
This protective layer generally takes the form of a hollow mushroom and is formed because the blowpipes themselves are colder, and the molten liquid metal around the blowpipes becomes cooler, reducing the solubility of iron in the concentrated molten liquid copper phase, iron precipitating and adheres to the external surfaces of the blowpipe, except for the outlet opening through which the gas is injected.
The high sensitivity of the temperature control is advantageous because in the event that the temperature of the molten liquid increases, the protective layer may redissolve and the blowpipe may lose its protective layer, leading to potentially serious damage and production losses.
The high sensitivity of the temperature control system entails the effect that the risk of such blowpipe damage, and the associated production loss, can be greatly reduced, and preferably eliminated.
Applicants have found that the beneficial effects of the present invention lead to a more stable and reliable smelting step. The smelting step is usually a very early step in a more complex global pyrometallurgical process.
For example, the process as a whole can further process the products from the smelting step into derivatives according to the process according to the main claim.
The slag resulting from the smelting step can preferably be further treated, e.g. by fumigation, to produce a slag which is not only less problematic when dumped as backfill, and/or when used in higher end end applications, as below. described in this document.
The concentrated copper intermediate, preferably after being separated from the smelting slag formed in the smelting step, may be further treated, e.g. by refining, to produce a more concentrated refined copper product suitable for higher end uses, optionally by casting copper anodes as feedstock for electrolysis, which can ultimately yield high purity copper cathodes that meet many, if not all, of the prevailing industry standards for the more demanding copper end-uses.
The further treatment of the concentrated copper intermediate and/or the slag resulting from the smelting step can lead to other valuable by-products of the refined copper product.
Such a valuable by-product can be, for example, a raw solder stream which can be derived from the copper refining slag that can result from the refining of the concentrated copper intermediate. Such raw solder may be further refined and/or upgraded, i.e. cleaned by removing elements that could affect downstream processing and/or hinder or disable certain uses of the final products derived from the solder flow. For example, those valuable by-products may include at least one of the products included in the list consisting of a high-quality soft lead product, a high-quality hard lead product, a silver-rich anode slime product, and a high-quality, high-quality tin product, as described later in this document. explained.
Applicants believe that the beneficial effects offered by the present invention do continue to manifest downstream into the production of the derivatives of the products of the smelting step listed above. The improved stability and reliability of the smelting step brings the advantage that the downstream processes by which those derivatives are produced are assured of a more stable and reliable feed stream resulting from the smelting step, also making their own operation more stable and reliable. This enables the production of end products with more stable and reliable quality. It also makes it possible to reduce the burden of process monitoring and/or the required operator attention, and increases the possibilities for electronically monitoring and controlling each step in those processes and the process as a whole.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a process flow diagram comprising the process of the invention as part of an overall process for the recovery of non-ferrous metals from secondary feed materials.
DETAILED DESCRIPTION The present invention will hereinafter be described in specific embodiments and with possible reference to specific drawings; however, it is not limited thereto, but is determined solely by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some elements may be exaggerated for illustrative purposes and not drawn to scale. The dimensions and relative dimensions do not necessarily correspond to actual practical embodiments of the invention.
Furthermore, the terms first, second, third, and the like are used in the specification and claims to distinguish between like elements, and not necessarily to describe a sequential or chronological order. The terms are interchangeable in appropriate circumstances, and the embodiments of the invention may function in orders other than those described or illustrated herein. Furthermore, the terms top, bottom, top, bottom, and the like are used in the specification and claims for descriptive purposes, and not necessarily to describe relative positions. The terms so used are interchangeable in appropriate circumstances, and the embodiments of the invention described herein may function in orientations other than those described or illustrated herein.
The term "comprising" used in the claims is not to be construed as being limited to the means listed in its context. He does not exclude other elements or steps. The term should be interpreted as meaning the required presence of the stated properties, numbers, steps or components, but does not exclude the presence or addition of one or more other properties, numbers, steps or components, or groups thereof. Thus, the scope of the expression "an item comprising means A and B" should not be limited to an article composed solely of components A and B. It means that for the subject matter of the present invention, A and B are the only relevant are components. Accordingly, the terms "comprise" or "enclose" also include the more restrictive terms "consist essentially of" and "consist of." Thus, when "comprise" or "contain" is replaced by "consist of", these terms represent the basis of preferred, but narrowed embodiments, which are also provided as part of the contents of this document with respect to the present invention.
Unless otherwise indicated, all values reported herein include the range up to and including the endpoints indicated, and the values of the ingredients or components of the compositions are expressed in percent by weight, or percent by weight, of each ingredient in the composition.
Terms such as "% by weight," "% by weight" "% by weight" "percent by weight," "% by weight," "ppm by weight.", "ppm by weight," "ppm by weight," "weight -ppm" or "ppm" and variations thereof, as used herein, refers to the concentration of a substance as the weight of that substance divided by the total weight of the composition and multiplied by 100 or by 1000000, as appropriate. case, unless otherwise noted It should be understood that the terms "percent," "%," used herein are intended to be synonymous with "percent by weight," "% by weight," etc.
It should further be noted that, in the present specification and the appended claims, the singular forms "a", "the" and "the" may also refer to plural matters unless the content clearly indicates otherwise. For example, a reference to a composition comprising "a compound" also includes a composition having two or more compounds. It should also be noted that the term "or" is generally used to mean "and/or" unless the content clearly indicates otherwise.
Furthermore, any compound used herein may be interchangeably discussed by its chemical formula, chemical name, abbreviation, etc.
Metals and compounds which are at most as noble as iron or zinc are compounds which, under the furnace conditions, have at least the same affinity for oxygen as, or even a higher affinity for oxygen than iron or zinc, and thus also compared to copper, nickel, tin and lead. In this definition, reference is made to “iron or zinc” because the relative positions of zinc and iron in their affinity for oxygen are very close to each other under the furnace conditions and can even change with the furnace conditions. Thus, in order for the definition to be correct and inclusive, it is necessary to refer to both metals. In the furnace conditions, those selected metals or compounds quite readily participate in the oxidizing side of the redox reactions as part of the present invention.
Suitable metals are, for example, elemental zinc and iron itself, aluminum, silicon and calcium.
Suitable compounds may be, for example, metal silicides, preferably silicides of metals which are suitable in themselves, such as iron silicide (FeSi), but also bimetallic or multimetallic compounds may be suitable, including mixtures, such as SnAl, CuFe, FeSn, or alloys, such as brass (ZnCu). Additional suitable compounds may be metal sulfides such as FeS, ZnS and/or sulfides of other metals whose sulfides or metals are at most as noble as iron or zinc.
Metals and compounds more noble than copper are compounds that have a lower affinity for oxygen than copper in the furnace conditions.
Those raw materials quite readily participate in the reducing side of the redox reactions as part of the present invention and lead to the release of the corresponding metal in its elemental form.
Suitable are, for example, silver, gold, other precious metals, including platinum group metals, alloys and mixtures thereof, including those comprising other metals.
In the context of the present invention, the terms "smelter", "smelting", "smelting" or similar derivations of "smelting" mean a process that encompasses much more than the mere change in the state of matter of a compound from solid to liquid.
In a pyrometallurgical smelting step, various chemical processes take place that convert certain chemical compounds into other chemical compounds.
Important conversions can be oxidations, possibly coupled with the formation of an oxide, or reductions, which change the oxidation state of some of the atoms.
In this document, the terms "melter", "melter furnace", and "melter furnace" are used interchangeably, and all mean the furnace in which this process step takes place.
In the context of the present invention, the terms "scratch" or "scratches" mean a substance that is often a pulpy mass, formed as a result of an operating step, and which separates from another liquid phase, usually under influence of gravity, which usually floats to the surface. The scratch or scratches can usually be scraped off or removed from the liquid underneath.
By the term "solder" in the context of the present invention is meant a metal composition which is rich in tin and/or lead, but which may also contain other metals. Solder is characterized by a relatively low melting temperature, which makes the composition suitable, after being heated to a relatively low temperature, to form a metal connection between two other metal parts after cooling, the so-called “soldering”.
In this document, unless otherwise indicated, amounts of metals and oxides are expressed in accordance with common practice in pyrometallurgy. The presence of any metal is usually expressed as its total presence, regardless of whether the metal is present in its elemental form (oxidation state = 0) or in a chemically bonded form, usually in an oxidized form (oxidation state > 0). For the metals which can be relatively easily reduced to their elemental form, and which can exist as molten metal in the pyrometallurgical process, it is quite common to express their presence in terms of their elemental metal form, even when the composition of a slag is or scratch is indicated, where the majority of such metals may in fact be present in an oxidized form. Therefore, in the composition of a slag, such as the slag obtained in the method of the present invention, the content of Fe, Zn, Pb, Cu, Sb, Bi as elemental metals is expressed. Less precious metals are more difficult to reduce under non-ferrous pyrometallurgical conditions and largely exist in an oxidized form. These metals are usually expressed in terms of their most common oxide form. Therefore, in slag compositions, the content of Si, Ca, Al, Na is usually expressed as SiO2, CaO, Al2O3, NazO, respectively.
A metallurgical slag is usually not a pure substance but a mixture of many different components. As a result, a metallurgical slag has no apparent melting temperature. It has become common in the art to use the term "liquidus temperature", which is the temperature at which the slag is completely liquid.
In an embodiment of the method of the present invention, the feedstock further comprises at least one second metal selected from the group consisting of nickel, tin and lead. Raw materials that include at least one second metal selected from this list are very interesting for recovering copper therefrom, but the presence of the second metal can present additional burdens or difficulties compared to raw materials that do not include the second metal. The applicants have found that the smelting step is an extremely suitable process step for adding a raw material comprising at least one such second metal. The applicants have found that this at least one second metal may also be present in the feedstock as its oxide, or in any other form capable of participating in redox reactions under the furnace conditions and releasing the metal. give in its basic form. Applicants prefer the oxide form in this context, because of its higher availability in favorable conditions, because of the heat of reaction generated by the redox reactions in which it participates, and because of the oxygen it contributes in the furnace, increasing the amount of oxygen should be injected is reduced. The reduction in the need to inject oxygen also reduces the gas flow through the smelting step, which is advantageous because the reaction rate is not limited by the flow rate of the external supply of oxygen gas, but only by the reaction kinetics. Less gas input can also mean that the furnace emits less exhaust gases that need to be treated, as well as less solid particles entrained in those gases.
In an embodiment of the method of the present invention wherein the feedstock comprises the at least one second metal, the concentrated copper intermediate further comprises the at least one second metal. Applicants have found that the smelting step can be carried out such that most of the second metal is also recovered as part of the concentrated copper intermediate, most conveniently by, among other things, driving the redox reactions in the smelting furnace to the appropriate degree. Applicants have found that this feature has the advantage that also the at least one second metal can be recovered further downstream as part of a high quality product of a desirably high quality.
In an embodiment of the method according to the present invention, the feedstock comprises scrap iron, silicon, zinc and/or aluminum, more preferably scrap iron. Applicants have found that this scrap material can be easily dosed with sufficient precision by admixing appropriate amounts with the other raw materials as part of the feed charge. Applicants may also add this scrap material as an additional raw material stream into the furnace. The applicants have found that scrap materials such as scrap iron and aluminium, but also silicon scrap to a certain extent, are readily available in suitable quantities and at economically favorable conditions. The applicants have also found that a separate addition of the scrap material as an additional feedstock feed stream into the furnace, preferably scrap iron, has the advantage that the excess of the elemental form of iron and/or of metals and/or compounds the furnace are at most as noble as iron or zinc, can be regulated and maintained in a very practical way.
In an embodiment of the method according to the present invention, the method further comprises the step of at least partially removing the slag from the furnace. Applicants prefer to remove at least some of the scotch from the furnace before starting the next feed charge. If the feedstock available at the time of the new feed charge includes a significant fine portion, Applicants prefer to maintain a layer of slag in the furnace because that layer forms a suitable blanket under which the fine portion of the feedstock, or the feedstock comprising the significant fine portion, can be introduced without creating an undue risk of feedstock fines being entrained by the furnace exhaust gases and creating an additional burden and/or hindrance to the furnace exhaust gas treatment system. If the available feedstock includes a significant coarse portion, Applicants prefer to remove substantially all of the slag formed from the furnace before starting the next feed charge. This entails the advantage that more furnace volume can be made available for the next feed charge, and is consequently beneficial to the throughput and/or productivity of the smelting furnace. Applicants have found that the step of removing slag from the furnace can be performed multiple times during the same furnace feed charge.
In an embodiment of the method of the present invention, the method comprises the step of removing at least a portion of the concentrated copper intermediate from the furnace, preferably at most a portion. Applicants prefer to ensure appropriate physical presence of molten metal in the furnace when starting a subsequent feed batch or campaign comprising a series of feed batches. That molten metal is then readily available at the start of the new feed charge or complete campaign as a hot liquid for absorbing and moistening the solid feed material and, if necessary, additional amounts of the elemental form of iron and of metals or compounds contained in the furnace conditions are at most as noble as iron or zinc, which may be desirable or necessary for trouble-free creation and/or maintenance of the excess of those additives for the process in accordance with the present invention. The iron dissolved in that molten metal is readily available to react with oxygen injected into the liquid bath, thus generating instant heat of reaction. An added benefit is that solid iron that can be added to the furnace at the start of the new feed charge will float on the molten metal phase, precisely the location where it is able to fully contribute to the redox reactions used in the process. intended. The applicants have found that keeping a portion of the concentrated copper intermediate in the furnace when a new furnace feed charge is started significantly reduces the time before the furnace can again operate at high capacity as part of that next feed charge, and therefore a significant improvement over effect on the productivity of the smelting step. Applicants prefer to remove some of the molten metal formed during the previous feed charge before starting a new furnace feed charge. Applicants have found that the step of removing a portion of the concentrated copper intermediate from the furnace can be performed even multiple times during the same furnace feed charge.
Applicants prefer to carry out the smelting step in an almost semi-continuous mode as much as possible, with suitable material continuously added to the furnace until the usable furnace volume is fully utilized. When the slag and the metal phases have reached the desired quality, at least a major part of the slag can then first be removed from the furnace, for example via an overflow through the feed opening, which is made possible by tilting the furnace, and a substantial portion of the liquid molten metal phase can then also be removed, in the same way if all the slag has been removed, or by being tapped through a “podemtap” hole at a suitable location in the wall of the furnace. An appropriate portion of the molten metal is preferably retained in the furnace when the introduction of the next feed charge into the smelting furnace is initiated, for the reasons set forth above. The applicants have found that this process can be continued for a very long time and may only need to be interrupted or stopped for external reasons or when a maintenance intervention in the smelter is deemed necessary. Applicants have found that this process can be further improved by preparing suitable premixed feedstock batches in composition and size of the solids in the batch. Applicants have found that this can bring the advantage of much more stable operation in the timing in the sequence of steps, and in the quality of the concentrated copper intermediate each time the main product is removed from the furnace. In one embodiment of the method according to the present invention, the iron and compounds which are at most as noble as iron or zinc introduced together with the feedstock contain solid iron, solid silicon, solid zinc and/or solid aluminum, preferably scrap. containing copper/iron, scrap containing silicon, scrap containing zinc and/or scrap containing aluminium. The applicants have found that these sources of iron, silicon, zinc and aluminum are readily available from various sources. In addition, they may include small amounts of other metals which may be recoverable and which are worthy of recovery in their elemental form in and downstream of the smelting step. Such other metals may include tin, lead and nickel. They can also include traces of more precious metals and even precious metals ("precious metals" or PMs) such as silver or gold, and even platinum group metals (PGMs) such as ruthenium, rhodium, osmium, palladium, iridium and platinum itself, of which very small quantities may be worth recovering because of their scarcity and high economic value.
In one embodiment of the process of the present invention, the feedstock is at least partially in solid form and the solid feedstock is fed into the furnace gradually, preferably continuously, preferably during the majority of the smelting feed charge, and more preferably during the majority of a complete meltdown campaign, preferably by means of at least one conveyor belt and/or vibrating conveyor. As set forth elsewhere in this document, Applicants prefer to feed portions of the coarse portion of the available feedstock at the early stage of a furnace feed charge and/or campaign until a sufficiently thick layer of metallurgical slag is formed as a blanket on the molten metal phase in the furnace. If that layer of slag is made available from the start of the feed charge, or once it has been formed by operating the furnace on the coarse portion of the available feedstock, Applicants prefer to also include amounts of the fine portion of the available feed material into the furnace, and Applicants prefer to introduce that fine portion pneumatically through a lance which is immersed in the liquid bath and which feeds the fine material portion approximately at the interface between the molten metal phase and releases the supernatant molten slag phase, because it has the advantage of a low risk of feedstock fines being lost with the furnace exhaust gases.
In one embodiment of the method of the present invention, the feedstock feed rate is kept below the rate at which the heat generation would become insufficient to melt the solid feedstock and/or bring the feedstock to the desired furnace temperature. The applicants prefer to avoid as far as possible the risk of disturbing the enthalpy equilibrium of the furnace due to the heat generation being insufficient to heat and melt the feed material being introduced, thereby risking the temperature in the furnace drops. The applicants have found that it is advantageous to control the feed rate of the feed material, and that, for example, iron can be added at a rate sufficiently high so that the excess of the elemental form of iron and of metals and compounds produced in the furnace conditions are at most as noble as iron or zinc would remain high enough that, combined with a sufficiently high supply of oxygen, they are capable of generating sufficient heat of reaction to provide smooth heating and melting of the feed material being introduced.
In one embodiment of the method of the present invention, at least a portion of the feedstock is in the form of a finely divided feedstock portion, and the finely divided feedstock portion has an average particle size of at most 10mm, the material of the finely divided feedstock portion preferably has an average particle size of at most 3.36 mm.
The applicants have found that finely divided raw materials containing copper and other metals of interest for the process according to the present invention are generally difficult to process in alternative processes, and can therefore be found in considerable quantities and at economically attractive conditions.
Applicants have found that such materials can be easily processed without error in the method of the present invention.
Applicants prefer not to introduce such portions of finely divided feed material into the furnace until a continuous layer of molten slag has become available in the furnace, which floats on top of the molten metal phase below.
Applicants prefer to introduce the finely divided feedstock portion approximately at the interface between molten metal and molten slag, such that the slag layer can act as a blanket capable of entrapping all small particles before they are able to reach the gas phase of the furnace and there is a risk that they will be entrained with the exhaust gases and not participate in the process in the furnace.
In an embodiment of the method of the present invention wherein the feed comprises the finely divided feedstock portion, the material from the finely divided feedstock portion is pneumatically conveyed and injected into the furnace.
Applicants have found that this is a very practical method for introducing such a finely divided feed material portion, and that this method offers the possibility of introducing the portion at the most advantageous location, ie close to the interface between liquid metal and liquid. slag, which usually also contains any elemental iron present, such as iron scrap, and where the majority of the chemical reactions take place. In an embodiment of the method of the present invention wherein the feed comprises the finely divided feed material portion, the material of the finely divided feed material portion is injected into the liquid slag phase and above the metal phase of the liquid bath. The applicants have found that the slag phase floats close to the interface between liquid metal and liquid slag, where elemental iron, such as iron scrap, is usually also present. It is the location where the majority of the chemical reactions take place and where the majority of the heat of reaction is also generated.
In an embodiment of the method of the present invention wherein the feed comprises the finely divided feedstock portion, the average composition of the finely divided feedstock portion fed over the entire fed smelting charge in the furnace satisfies at least one and preferably all of the following conditions, after being heated to 1150°C: ° comprising at least 5% by weight of the total metal, preferably at least 5% of the total of copper, nickel, tin, lead and zinc, preferably at least at least 6% by weight, more preferably at least 7% by weight, even more preferably at least 8% by weight, preferably at least 9% by weight, more preferably at least 10% by weight of the total metal, preferably of the total of copper, nickel, tin, lead and zinc, comprising at most 70.0 % by weight copper (Cu), preferably at most 65.0 % by weight, more preferably at most 60 .0 wt% even more preferably at most 55.0 wt%, even more preferably at most 50.0 wt%, preferably at most 48.0 wt% copper, and optionally at least 10 wt% copper, preferably at least 15% by weight, more preferably at least 20% by weight, even more preferably at least 25% by weight, even more preferably at least 30% by weight, preferably at least 35% by weight more preferably at least 40% by weight and even more preferably at least 42.0% by weight copper, comprising at most 2.00% by weight nickel (Ni), preferably at most 1.50% by weight -%, more preferably at most 1.00% by weight nickel, o comprising at least 0.50% by weight and at most 10.00% by weight lead (Pb), preferably at least 1.00% by weight %, more preferably at least 1.50 % by weight, and optionally at most 9.00 % by weight, preferably at most 8.00 % by weight lead, ° comprising at most 15.00 % by weight time n (Sn), preferably at most 14.00 wt%, more preferably at most 13.00 wt%, even more preferably at most 12.00 wt% tin, comprising at most 2, 00 wt% antimony (Sb), preferably at most 1.50 wt%, more preferably at most 1.00 wt% antimony, ° comprising at most 7.0 wt% iron (Fe), preferably at most 6.0 wt%, more preferably at most 5.0 wt%, even more preferably at most 4.0 wt%, even more preferably at most 3.50 wt% iron and ° comprising at most 55 wt% zinc (Zn), preferably at most 50 wt%, more preferably at most 45 wt%, even more preferably at most 43 wt%, even more preferably at most 40 weight %, even more preferably at most 35.0 weight % zinc.
The applicants have found that the finely divided feedstock portion as indicated is extremely suitable for the process of the present invention, due to the presence of metals of interest to be recovered in high quality products downstream of the process, and/or due to the presence of metals that can contribute heat of reaction as part of the process of the present invention, while at the same time the finely divided feedstock portion has a sufficiently low content of the metals in question that the portion would not be economically interesting enough for alternative processes for the recovery of metals from primary and/or secondary raw materials, and the feedstock can therefore be found at economically attractive conditions that yield a significant upgrade when incorporated in the process of the present invention. Furthermore, respecting the upper limit for the sulfur content as part of one of the conditions in the above list avoids the formation of a separate copper matte phase, thus clearly distinguishing the process of the present invention having this feature from copper smelting processes in which a matte phase is formed. as one of the products or intermediates.
In an embodiment of the method according to the present invention, the feed material comprises at least one return material from the processing of the molten liquid metal phase and/or from the liquid slag phase formed by the method. Applicants have found that the smelting step is a very convenient step for recycling by-products that may have formed from the further processing of the molten liquid metal phase and/or of the liquid slag phase formed in the smelting step. Such further processing can take place after the smelting step in the same furnace, but preferably downstream of the smelting step and in other equipment. Examples of such downstream processing are discussed later in this document.
In an embodiment of the method of the present invention wherein the feed material comprises at least one return material, the at least one return material comprises at least one material selected from rejected anodes or other products comprising copper, tin and/or lead, a metal oxide or sulfide, preferably of copper, nickel, tin, lead and/or zinc, including scribe comprising the metal as oxide or sulfide and formed in and removed from a downstream treatment step, a metal silicide, preferably a silicide of a metal selected from copper, zinc, nickel, iron, lead and tin, and a crust or other solid form formed against a wall of a crucible or ladle used for transferring a molten metal and /or a molten slag that has been removed from a furnace. The Applicants have found that the smelting step is a very suitable process site for recycling by-products that may not be as well defined in content, such as some of the materials in the above list, or of by-products that may contain various target metals, such as zinc oxide dust may be collected by filtering the exhaust gases from furnaces carrying out a wide variety of pyrometallurgical process steps, or from furnace slags containing recoverable metals at levels that would burden or prevent their more typical exit, and/or that require an additional passage through the entire metal recovery process.
In one embodiment of the method of the present invention, the feed material is introduced centrally into the liquid bath in the furnace. This has the advantage that the solid feedstock, due to the buoyancy it exhibits when immersed in the molten metal phase, is usually able to float to the surface of the molten metal phase without coming into contact with the refractory lining in the oven. Therefore, it reduces the wear that the solid feedstock can cause to the refractory lining, thereby improving the service life of the refractory lining, and thus the time between two maintenance interventions for restoring the refractory lining.
In an embodiment of the method according to the present invention, the feed material comprises a coarse portion, the raw feed material portion preferably having an average particle size of at least 5 mm, preferably at least 10 mm, even more preferably at least 15 mm, and the average composition of the raw feedstock portion fed over the entire fed fusion charge in the furnace satisfies at least one and preferably all of the following, after being heated to 1150°C: ° including at least 20 weight percent % of the total metal, preferably at least 20% of the total of copper, nickel, tin, lead and zinc together, preferably at least 30% by weight, more preferably at least 40% by weight, even more preferably at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight and optionally at most 95% by weight of the total metal, preferably of the total of copper, nickel, tin, lead and zinc,
° comprising at least 10.0 wt% and at most 70.0 wt% copper (Cu), preferably at least 15.0 wt%, more preferably at least 17.0 wt%, with even more preferably at least 18.0 wt%, even more preferably at least 19.0 wt%, and optionally at most 65.0 wt%, preferably at most 60.0 wt%, with more preferably at most 55.0 wt%, even more preferably at most 50.0 wt%
and even more preferably at most 45.0 wt% copper, comprising at least 0.50 wt% and at most 2.00 wt% nickel (Ni), preferably at least 0.60 wt% -%, more preferably at least 0.70% by weight, even more preferably at least 0.80% by weight, even more preferably at least 0.90% by weight, and optionally at most 1.90% by weight %, preferably at most 1.80 % by weight, more preferably at most 1.70 % by weight, even more preferably at most 1.60 % by weight
and even more preferably at most 1.50 wt% nickel, comprising at least 1.00 wt% and at most 8.00 wt% lead (Pb), preferably at least 1.10 wt% %, more preferably at least 1.25 % by weight, even more preferably at least 1.50 % by weight, even more preferably at least 1.60 % by weight, and optionally at most 7.50 % by weight %, preferably at most 7.00 wt%, more preferably at most 6.50 wt%, even more preferably at most 6.00 wt%
and even more preferably at most 5.50 wt% lead, comprising at least 0.50 wt% and at most 2.50 wt% tin (Sn), preferably at least 0.60 wt% -%, more preferably at least 0.70% by weight, even more preferably at least 1.00% by weight, even more preferably at least 1.20% by weight, and optionally at most 2.40% by weight %, preferably at most 2.30 % by weight, more preferably at most 2.20 % by weight, even more preferably at most 2.00 % by weight and even more preferably at most 1.90 % by weight % tin, ° comprising at most 0.10 % by weight antimony (Sb), preferably at most 0.08 % by weight, more preferably at most 0.06 % by weight antimony, ° comprising at most at least 10.0 wt% and at most 35.00 wt% iron (Fe), preferably at least 11.0 wt%, more preferably at least 12.0 wt%, even more preferably at least 13.0 wt%, with even more for preferably at least 14.0 wt%, and optionally at most 34.5 wt%, preferably at most 34.0 wt%, more preferably at most 33.0 wt%, even more preferably at most 32.0 wt% and even more preferably at most 31.0 wt% iron, and ° comprising at least 2.00 wt% and at most 15.00 wt% zinc (Zn), at preferably at least 2.50% by weight, more preferably at least 3.00% by weight, even more preferably at least 3.50% by weight, even more preferably at least 4.00% by weight, and optionally at most 14.00 wt%, preferably at most 12.00 wt%, more preferably at most 11.00 wt%, even more preferably at most 10.00 wt% and with even more preferably at most 9.00 weight % zinc.
Applicants have found that the raw feedstock portion is highly suitable as feedstock for the process of the present invention. The portion includes sufficient amounts of the target metals to make the portion as a whole interesting, but the levels of valuable metals are not high enough to make the coarse portion interesting for alternative processes for the recovery of some of these metals. Applicants have found that the coarse portion as indicated is not rich enough in copper and/or tin plus lead to make the portion a suitable feedstock for the pyrometallurgical refining of copper, as described, for example, in WO 2019/115533 A1. Respecting the upper limit for sulfur content as part of one of the conditions in the above list furthermore helps to prevent the formation of a separate copper matte phase, and thus clearly distinguishes the process of the present invention having this feature from copper smelting processes in which a matte phase is formed as one of the products or intermediates.
Applicants have further found that relatively low levels of sulfur can be readily accepted in the coarse portion of the feedstock. This entails the advantage that a wider choice of raw materials can be accepted in the smelting step, including raw materials that would not be acceptable or would be less desirable in alternative processes for processing such raw materials.
In an embodiment of the method according to the present invention, the content of iron and/or metals and compounds which are at most as noble as iron or zinc dissolved in the molten metal in the furnace is at least 1.0 wt. %, preferably at least at 1.5% by weight, whereby the concentration of the metals and compounds that are at most as noble as iron or zinc is converted to an equivalent concentration of iron, the equivalent concentration of iron being a concentration of iron capable of contributing the same amount of reaction heat as the metal or compound which is at most as noble as iron or zinc when reacting with oxygen under the furnace conditions. The applicants have found that respect for this condition is very practical to follow and enforce, and readily provides a sufficient excess of the elemental form of iron and of metals or compounds which are at most equally noble under the furnace conditions. as iron or zinc. Respecting the condition also ensures that there is always a sufficient excess in the furnace of the iron and/or other metals or compounds that are at most as noble as iron or zinc, such that, with sufficient oxygen injection, the temperature can be easily maintained in the oven. An additional advantage is that this condition ensures the protection of the blowpipe by solid iron and/or iron oxide described elsewhere in this document.
In one embodiment of the process of the present invention, the content of iron and/or metals and compounds which are at most as noble in the furnace conditions as iron or zinc dissolved in the molten metal in the furnace is at most at 10.0% by weight, preferably at most 9.0% by weight, more preferably at most 8.0% by weight, even more preferably at most 7.0% by weight, even more preferably at at most 6.0 wt%, preferably at most 5.0 wt%, more preferably at most 4.0 wt%, even more preferably at most 3.5 wt%, even more preferably at at most 3.0 % by weight, preferably at most at 2.5 % by weight, the concentration of the metals and compounds which are at most as noble as iron or zinc being converted to an equivalent concentration of iron, the equivalent concentration concentration of iron is a concentration of iron that is able to Contribute the same amount of heat of reaction as the metal or compound which is at most as noble as iron or zinc when reacted with oxygen under the furnace conditions. Respecting this condition reduces the risk that iron would come out of solution at the colder spots in the furnace, such as against the furnace walls, where it would reduce the available furnace volume and cause agitation of the liquid bath in the furnace. hinder.
In one embodiment of the process of the present invention, elemental iron is introduced into the smelting step at a rate that maintains an excess of iron, above its solubility in the metal bath under the furnace conditions, in the molten bath during the process. Applicants have found that to be a very practical way of providing sufficient iron in the furnace to achieve the desired excess thereof.
In one embodiment of the method of the present invention, the amount of excess iron present in the furnace is maintained by at least periodically taking a sample of the molten metal phase in the furnace and analyzing the sample for iron content. Preferably, the amount of excess iron is limited to limit the amount of solid iron particles moving in the liquid bath of the furnace, in order to limit the possible damage and wear that can be caused by such floating particles to the refractory lining in the furnace. oven.
In one embodiment of the method of the present invention, the combustible source of carbon and/or hydrogen is selected from the group consisting of coke, charcoal, carbon black, a hydrocarbon, natural gas, methane, ethane, propane, butane, a hydrocarbon is, in standard conditions, a polymer containing a hydrocarbon, a plastic, plastic waste, grease, oil, paint, varnish, rubber, preferably waste thereof, and combinations thereof. Applicants have found that a wide range of sources are suitable, and some of these sources are readily available at attractive delivery terms.
In one embodiment of the method according to the present invention, the amount of combustible source of carbon and/or hydrogen is kept below the level at which slag foaming would adversely affect the operation of the smelting step, preferably significantly below that level, such that also the risk on slag foaming remains acceptably low. Applicants have found that the highest acceptable level depends on the source chosen, but can be easily determined experimentally. An additional advantage of respecting this precaution is that the temperature of the furnace flue gas remains acceptable, as does the carbon monoxide content of that flue gas. Alternatively, the amount of combustible source of carbon and/or hydrogen is limited below the level at which the temperature of the furnace flue gas remains acceptably low, or below the level where the content of carbon monoxide in that flue gas remains acceptably low.
In one embodiment of the method of the present invention, at least a portion of the oxygen-requiring gas is introduced into the supernatant slag phase, preferably as close as practicable to the interface between the metal phase and the supernatant slag. Applicants prefer to introduce at least a portion of the oxygen-requiring gas into that target site where the oxygen is most readily consumed by oxidizing elemental metals, such as iron, dissolved in the metal phase, and from where it is oxide formed by the oxidation reaction can easily move to the supernatant slag phase with a minimum diffusion distance to be bridged.
In an embodiment of the method according to the present invention, at least part of the oxygen-requiring gas is introduced by means of at least one metal lance, the end of which is immersed in the liquid slag phase. Applicants have found that this is a very practical method for introducing the oxygen-deprived gas to the target site. The lance can be inserted through a specially provided opening in the oven wall, or can be inserted through the filling opening of the oven through which feed material can also be introduced.
In an embodiment of the method of the present invention wherein the at least one metal lance is used, the gas injected through the metal lance comprises at least 30% by volume oxygen, preferably at least 40% by volume, more preferably at least 50% by volume, even more preferably at least 75% by volume, and even more preferably the gas is high purity oxygen. This has the advantage that, compared to the use of air as the oxygen-requiring gas, the formation of additional furnace exhaust gases is reduced and preferably prevented. The exhaust gas treatment system can therefore be made smaller or operated more efficiently. An additional advantage is that the furnace exhaust gases contain less nitrogen oxides and are therefore more environmentally friendly.
In an embodiment of the method of the present invention using the at least one metal lance, the gas flow through the metal lance provides sufficient cooling to prevent the lance from corroding and/or melting under the conditions of being immersed in the liquid bath of molten slag. Applicants prefer to introduce the gas lance into the furnace from above the liquid bath, and to immerse the lance only in the supernatant slag phase, but into the molten metal bath. The applicants have observed that, due to the sufficiently strong cooling effect of the gas flowing through it as prescribed, the lance withstands prolonged exposure to the hot slag phase, but would dissolve fairly quickly in the underlying molten metal phase.
In an embodiment of the method of the present invention, at least a portion of the oxygen-requiring gas is introduced into the bottom of the furnace through at least one blower pipe, preferably a plurality of blower pipes, more preferably the plurality of blower pipes distributed evenly. are over the bottom of the oven. This entails the advantage of vigorous stirring of the liquid bath in the oven.
In an embodiment of the method of the present invention using the blowpipe, the gas introduced through the at least one blowpipe is an oxygen-deprived gas comprising at most 50 volume % oxygen, preferably at most 40 volume %, more preferably at most 30 volume %, even more preferably at most 25 volume %, even more preferably the gas introduced through the blowpipe is air. The gas must overcome the hydrostatic pressure caused by the height of the liquid contents of the furnace. The gas must therefore be pressurized to allow for introduction through the blowpipe. Thus, if the gas comprises air, that air is pressurized before it is introduced.
In an embodiment of the method of the present invention using the blowpipe, the gas introduced through the at least one blowpipe is cooler than the molten liquid metal phase surrounding the blowpipe. The molten liquid metal phase around the blowpipe is thereby cooled and its solubility to iron is thereby reduced, and when the molten liquid metal phase is saturated with iron at the higher temperature, it causes iron and/or ferrous compounds, such as iron oxides, to precipitate and form a deposit around the blowpipes, usually in the shape of a hollow mushroom, which provides welcome protection of the blowpipes against corrosion caused by the high oxidation heat of iron in the vicinity of the blowpipes.
In an embodiment of the method according to the present invention, the smelting slag produced by the method comprises at least 20% by weight iron (Fe), preferably at least 22.5% by weight, more preferably at least 25.0% by weight %, even more preferably at least 27.50 % by weight, even more preferably at least 30.00 % by weight iron. In this context, the content of iron is the sum of the iron present in all its valence states, and thus the sum of all the iron present as elemental iron and the iron present in a chemically bonded form, usually in the form of an oxide. This entails the advantage of a higher fluidity of the slag, i.e. a lower viscosity at the same temperature.
In an embodiment of the method according to the present invention, the composition of the produced smelting slag satisfies at least one and preferably all of the following conditions: • comprising at most 1.00% by weight copper (Cu), preferably at most 0.90 % by weight, more preferably at most
0.80 wt%, even more preferably at most 0.70 wt%, even more preferably at most 0.60 wt% copper, comprising at most 0.20 wt% nickel (Ni ), preferably at most 0.17 wt%, more preferably at most 0.15 wt%, even more preferably at most 0.12 wt% and even more preferably at most 0.10 wt% % nickel, comprising at most 2.00 wt% lead (Pb), preferably at most 1.50 wt%, more preferably at most 1.00 wt%, even more preferably at most 0 .95 wt% and even more preferably at most 0.90 wt% lead, comprising at most 1.00 wt% tin (Sn), preferably at most 0.80 wt%, with more preferably at most 0.60 wt%, even more preferably at most 0.40 wt% and even more preferably at most 0.25 wt% tin, comprising at most 22.50 wt% % zinc (Zn), preferably at most to 20.00 % by weight, more preferably at most 17.50 % by weight, even more preferably at most 15.00 % by weight and even more preferably at most 12.50 % by weight zinc.
Respecting the upper limits indicated for copper, nickel, tin and lead brings the advantage of limited rejection of valuable metals from the process. Since the invention is directed to a copper recovery method, the limitation of copper loss in the smelting slag entails the advantage of high copper recovery from the available raw materials.
The applicants have found that many copper-containing raw materials, in particular the secondary materials in that group, also contain significant amounts of mainly tin, but possibly also lead, nickel and zinc. Applicants have found that most of these metals other than copper can be recovered from the same raw materials by pyrometallurgical process steps, provided that those metals are not allowed to escape into the smelting slag. Respecting the upper limits for the other metals, mainly for tin and nickel but also for lead and to a certain extent also zinc, entails the advantage of a high recovery of these metals from the available raw materials.
The presence of zinc in the smelting slag can be left higher in the event that an additional slag fumigation step is provided in which the smelting slag is fumigated to reduce its zinc content, and optionally also the lead content. Applicants prefer to add such an additional fumigation step to remove more zinc from the smelting slag, and preferably also additional traces of lead, preferably as described in WO 2016/156394 A1.
The applicants have found that the above characteristics of low losses of valuable metals in the smelting slag can be controlled and obtained by suitably conducting the smelting step in terms of furnace temperature, furnace agitation, and oxygen addition, of reducing agents and the selection thereof, and of flux materials ("flux materials" or slag formers, as they may also be called) and the selection thereof.
In one embodiment of the method of the present invention, the concentrated copper intermediate composition as the high value product of the smelting step satisfies at least one and preferably all of the following conditions: ° including at least 50.0 wt% copper ( Cu), preferably at least 55.0% by weight, more preferably at least 60.0% by weight, even more preferably at least 65.0% by weight, even more preferably at least 70.0% by weight %, preferably at least 72.5 % by weight, more preferably at least 75.0 % by weight, even more preferably at least 77.0 % by weight, even more preferably at least 78.0 % by weight % or even 79.0 % by weight of copper (Cu), and optionally at most 97.0 % by weight, preferably at most 95.0 % by weight, more preferably at most 90.0 % by weight, with even more preferably at most 85 wt%, even more preferably at most 82.0 wt%, preferably at most 80 wt%, more preferably at most 79.0 wt%, even more preferably at most 78.0 wt%, even more preferably at most 77.0 wt% copper (Cu),
° comprising at least 0.01 wt% nickel (Ni), preferably at least 0.05 wt%, more preferably at least 0.10 wt%, even more preferably at least 0.50 wt% %, even more preferably at least 1.00% by weight, preferably at least 1.10% by weight, more preferably at least 1.25% by weight, even more preferably at least 1.40% by weight %, even more preferably at least 1.50 % by weight or even 1.70 % by weight nickel (Ni), and optionally at most 15.00 % by weight, preferably at most 12.50 % by weight more preferably at most 10.00 wt%, even more preferably at most 7.50 wt%, even more preferably at most 5.00 wt%, preferably at most 4.00 wt% more preferably at most 3.00 wt%, even more preferably at most 2.50 wt%, even more preferably at most 2.40 wt% nickel (Ni), comprising at least 0.10 wt% lead (Pb), preferably ur at least 0.50 wt%, more preferably at least 1.00 wt%, even more preferably at least 2.00 wt%, even more preferably at least 3.00 wt%, at preferably at least 3.50 wt%, more preferably at least 4.00 wt%, even more preferably at least 4.50 wt%, even more preferably at least 5.00 wt% or even 5.50 wt% lead, and optionally at most 15.00 wt%, preferably at most 14.50 wt%, more preferably at most 14.00 wt%, even more preferably at most 13, 50 wt%, even more preferably at most 13.00 wt%, preferably at most 12.50 wt%, more preferably at most 12.00 wt%, even more preferably at most 11, 50 wt%, even more preferably at most 11.00 wt%, preferably at most 10.50 wt%, more preferably at most 10.00 wt%, even more preferably at most 9 50% by weight, with self fs even more preferably at most 9.00 wt.% lead (Pb), ° comprising at least 1.00 wt.% tin (Sn), preferably at least 1.25 wt.%, more preferably at least 1.50 wt%, even more preferably at least 1.75 wt%, even more preferably at least 2.00 wt%, preferably at least 2.25 wt%, more preferably at least 2.50% by weight, even more preferably at least 2.75% by weight, even more preferably at least 3.00% by weight or even 3.25% by weight tin (Sn), and optionally at most 12.00 wt%, preferably at most 10.00 wt%, more preferably at most 8.00 wt%, even more preferably at most 7.00 wt%, even more preferably at most 6.00 wt%, preferably at most 5.50 wt%, more preferably at most 5.00 wt%, even more preferably at most 4.50 wt%, even more preferably at most
4.00 wt% tin (Sn),
° comprising at least 0.05 wt% iron (Fe), preferably at least 0.10 wt%, more preferably at least 0.30 wt%, even more preferably at least 0.50 wt% %, even more preferably at least 0.60 % by weight, preferably at least 0.70 % by weight, more preferably at least 0.80 % by weight, even more preferably at least 0.90 % by weight %, even more preferably at least 1.00 wt% or even 1.10 wt% iron (Fe), and optionally at most 5.00 wt%, preferably at most 4.00 wt% more preferably at most 3.00 wt%, even more preferably at most 2.50 wt%, even more preferably at most 2.00 wt%, preferably at most 1.75 wt% more preferably at most 1.50 wt%, even more preferably at most 1.25 wt%, even more preferably at most 1.00 wt% iron (Fe), comprising at least 0.10 weight % zinc (Zn), preferably at least at least 0.50 wt%, more preferably at least 1.00 wt%, even more preferably at least 2.00 wt%, even more preferably at least 2.50 wt%, preferably at least at least 3.00% by weight, more preferably at least 3.50% by weight, even more preferably at least 4.00% by weight, of zinc (Zn), and optionally at most 10.00% by weight, preferably at most 9.50 wt%, more preferably at most 9.00 wt%, even more preferably at most 8.50 wt%, even more preferably at most 8.00 wt%, preferably at most 7.50 wt%, more preferably at most 7.00 wt%, even more preferably at most 6.50 wt%, even more preferably at most 6.00 wt%, preferably at most 5.50 weight %, more preferably at most 5.00 weight % zinc (Zn), comprising at most 5 weight % sulfur (S), preferably at most 4.5 weight % -%, more preferably at most 4.0 wt weight %, even more preferably at most 3.5% by weight, even more preferably at most 3.0 % by weight, preferably at most 2.5% by weight, more preferably at most 2.0 wt%, preferably at most 1.5 wt%, more preferably at most 1.0 wt%, even more preferably at most 0.5 wt%, even more preferably at most 0.1 weight percent sulfur, and optionally at least 5 ppm by weight, preferably at least 50 ppm by weight, more preferably at least 100 ppm by weight, even more preferably at least 500 ppm by weight, even more preferably at least at least 1000 ppm by weight, preferably at least 0.5% by weight, more preferably at least 1.0% by weight sulfur.
Applicants have found that the above features of the invention can also be controlled and obtained by properly performing the smelting step as described above, including the selection of the feed materials. Furthermore, respecting the upper limit for the sulfur content as part of one of the conditions in the above list avoids the formation of a separate copper matte phase, thus clearly distinguishing the process of the present invention having this feature from copper smelting processes in which a matte phase is formed. as one of the products or intermediates. The applicants have further found that the metal phase as indicated above is highly suitable for the recovery of the listed valuable metals by pyrometallurgical process steps, as described further in this document.
The applicants have also found that the large amount of copper in the metal phase can be used as an extractant for other valuable metals, such as nickel, tin and lead, from the slag phase, and therefore also contributes in itself to a high recovery of these metals other than copper .
The applicants have further found that respecting the lead content as indicated has advantages in the recovery of the economically even more advantageous metal tin, because the tin and lead can be recovered as a solder-type by-product stream which, thanks to the lead content, can be advantage can be upgraded and then distilled to recover a high purity high purity tin product along with various grade lead-containing by-products which are also valuable.
In an embodiment of the method according to the present invention, the liquid bath in the oven has a temperature in the range of 1100-1300°C, preferably at least 1120°C, more preferably at least 1140°C or even 1150°C and optionally at most 1250°C, preferably at most 1200°C, more preferably at most
1180°C. The applicants have found that this temperature range can bring the advantage of sufficient slag fluidity and already sufficient fumigation of zinc from the smelting step while maintaining a low fumigation rate of tin and/or lead from the smelting step, thus contributing to a high recovery of tin and/or lead and/or zinc and a high operability of the smelting step. Applicants prefer to allow the contents of the furnace to cool to a maximum of 1140°C before removing metal from the furnace. The applicants have found that this precaution contributes to a longer life of the containers in which the molten metal is received and transferred to the next process step.
In one embodiment of the method according to the present invention, the exhaust gases from the furnace are collected and treated by cooling and/or filtering. Applicants have found that the exhaust gases from the smelting step contain valuable metals worthy of recovery, and that the treatment as indicated also reduces the environmental problems associated with releasing exhaust gases from the smelting step into the atmosphere.
In an embodiment of the method according to the present invention, secondary exhaust gases from around the furnace are also collected and treated by filtration, optionally in combination with cooling. Applicants have found that this feature further reduces the environmental problems that may be associated with the operation of the furnace in accordance with the present invention.
In one embodiment of the method according to the present invention, the smelting is performed in a smelting furnace.
A melting furnace offers the advantage that it is simple to use and in terms of equipment, and thus economically advantageous. A smelting furnace has the added advantage of being tolerant in terms of raw material quality. A smelting furnace is capable of absorbing raw materials that are highly diluted and/or contaminated with a wide variety of components, such as a wide variety of organic substances. The metals are melted in a smelting furnace,
and organic matter and other combustible materials are burned away. Because there is hardly any other end application for such mixed and/or contaminated raw materials, they can be supplied at economically very attractive conditions. The ability to process such raw materials and to upgrade the valuable metals therein is therefore of interest to the practitioner of the method according to the present invention.
A smelting furnace is a relatively simple and inexpensive device consisting of a large cylindrical furnace that only needs to be able to tilt over part of a full circle about its longitudinal axis. That determination entails the advantage of a low capital investment and/or operating costs for performing the smelting step.
In one embodiment of the method according to the present invention, the walls of the furnace are at least partially cooled over the wall surface of the furnace. This entails the advantage of reduced wear of the furnace wall, and in particular for the movable parts provided as part of the means for moving the furnace so that the liquid bath can be stirred, and for strengthening and/or controlling agitation of the bath.
In an embodiment of the present invention, the method further comprises the step of fumigating the slag phase formed in the fusing step to obtain a fumigated slag, wherein the fumigation is preferably performed in a fumigation furnace. The fumigation step produces a fumigated slag along with at least one substance containing the majority of the metals fumigated from the fumigated slag, usually in their oxidized form. The applicants have found it advantageous to provide that additional process step, because it broadens the acceptance criteria for the raw materials of the smelting step to include raw materials containing more zinc, and possibly also lead. Such raw materials are often difficult to process in alternative processes, where they can represent a process load and/or an economic burden, and therefore can be offered in greater quantity and at more attractive economic conditions.
A zinc fumigation step can be performed as described by Michael Borel! in “Slag — a resource in the sustainable society”, during the congress “Securing the Future.
An International Conference on Mining and the Environmental Metals and Energy Recovery”, which took place in Skellefteâ, Sweden, in 2005, pp. 130-138 of the Congressional Publication.
However, the applicants prefer to perform an additional fumigation step as disclosed in WO 2016/156394 A1. In an embodiment of the method according to the present invention, the slag is pelletized when it is removed from the smelting step or from the fumigation step.
Preferably, the slag from the fumigation slag and/or the slag from the fumigation step is removed from the respective furnaces as liquid.
The advantage is that the furnace can be released for further production and/or treatment of slag while the resulting slag is cooling.
The slag can be cooled and/or cured by bringing the slag into contact with a cooling medium, such as air, possibly ambient air.
In an embodiment of the method according to the present invention, the cooling of the slag is carried out by bringing the liquid slag into contact with water.
Applicants have found that water cooling is very effective and can be performed in a variety of ways, resulting in relatively well controlled cooling rates.
In an embodiment of the method of the present invention, the method further comprises the step of using the produced slag in an end use selected from providing a wear layer and/or coating for roof tiles or shingles, as a component of sandblasting sand or blasting grit, as a component of foam tiles as a black colorant, preferably in construction products, more preferably in black tiles, as black hard lumps, preferably for decorative purposes, and as a high-density ballast material, preferably for underwater applications, more preferably for hydraulic engineering applications, and for combinations thereof.
In an embodiment of the method according to the present invention for producing an article for the construction industry, the method further comprises the step of adding the produced slag as aggregate and/or as a binder during the production of an article for the construction industry, preferably as a binder for aggregates, preferably as an active binder, more preferably as a binder with pozzolanic action, even more preferably as a Portland cement substitute, even more preferably as a partial Portland cement substitute.
In one embodiment of the method according to the present invention, the produced slag is added as a binder in an inorganic polymer composition, preferably in combination with a base, more preferably as the main binder! in an inorganic polymer composition, even more preferably as the sole binder in an inorganic polymer composition.
In an embodiment of the method of the present invention wherein the produced slag is added during the production of an article for the construction industry, the method further comprises the step of foaming the inorganic polymer composition.
In an embodiment of the method according to the present invention for producing an object for the construction industry, the object for the construction industry is a construction element, the construction element preferably being selected from the list of a tile, a paving stone, a block, a concrete block, and combinations thereof.
In one embodiment of the method of the present invention for producing a construction industry article, the construction industry article has a foamed structure.
In an embodiment of the method according to the present invention for producing an article for the construction industry, the method further comprises the step of using the article for improving heat and/or sound insulation, for shielding against X-rays, and combinations of that.
In an embodiment of the method of the present invention, the method further comprises the step of refining the concentrated copper intermediate to obtain a refined copper product along with at least one copper refining slag. The applicants have found that this refining step can be carried out adequately as described in WO 2019/115543 A1.
In an embodiment of the method of the present invention wherein the concentrated copper intermediate further comprises tin and lead, the method further comprises recovering a raw solder metal composition from the concentrated copper intermediate. This recovery of a raw solder metal can be carried out adequately as described in WO 2019/115524 A1.
In an embodiment of the method of the present invention comprising the recovery of a raw solder metal composition, the method further comprises the step of recovering from the raw solder metal composition at least one of a purified soft lead product, a purified hard lead product and a purified tin product. The applicants have found that the raw solder metal composition is a highly suitable feedstock for recovering at least one of the listed products, preferably at least the purified tin product, more preferably also one of the purified lead products, and even more preferably both purified lead products.
In an embodiment of the method of the present invention comprising the recovery of a raw solder metal composition, the method further comprises the step of pre-refining the raw solder metal composition to produce a pre-refined solder metal composition.
The raw solder metal composition obtainable as a by-product of the refining of the concentrated copper intermediate obtained from the process of the present invention can be further pre-refined or treated to remove more of the impurities therein, especially copper.
This can be done by contacting the raw brazing metal composition, as a molten liquid, with elemental silicon and/or aluminum, elements which bond with Cu, Ni and/or Fe under the operating conditions and form a separate silicide and/or aluminide alloy phase. .
Applicants preferably use silicon and/or scrap containing aluminum.
Preferably, the added material further comprises Sn and/or Pb, because those metals are easily upgradeable to the respective high value products when introduced at this stage of the process.
Due to the typical presence of Sb and As in the raw solder metal composition, Applicants prefer to use silicon and avoid aluminum, although the latter is generally more readily available and reactive.
This avoids the formation of H2S, a toxic gas, as well as more exothermic reactions in the treatment vessel, and also avoids that the resulting alloy phase could generate as a by-product, in contact with water, stibine and/or arsine, which are highly toxic gases. .
The applicants have found that the silicon feed for this treatment step may contain a limited amount of iron (Fe), without problems more than 1% by weight and without problems up to 5% by weight or even up to 10% by weight Fe.
The process can therefore be performed using Si products that are unacceptable to other silicon consumers, such as rejects from the production line, and may therefore be more readily available.
The applicants have found that the burden of handling this additional Fe, which also binds with Si, is usually easily offset by the favorable conditions for supplying the silicon source.
This pre-refining can be carried out adequately as described in WO 2019/115524 A1, and yields a so-called "cupro-phase" by-product, which, preferably after being
"rinsed" as described can advantageously be recycled to the smelting step of the process of the present invention.
In an embodiment of the method of the present invention comprising the recovery of a raw solder metal composition, the method further comprises the step of updating the raw solder metal composition or the pre-refined solder metal composition to produce an updated solder metal composition. That updating step is capable of further preparing the solder to make it suitable for vacuum distillation, a technically demanding process step that is sensitive to the excessive presence of certain metal impurities. Such updating and distillation can be performed adequately as described in WO 2018/060202. A1. In an embodiment of the method of the present invention which produces an updated solder composition, the method further comprises the step of a first distillation to distill the updated solder composition wherein lead is removed from the solder by evaporation and an overhead from the first distillation and a bottom product from the first distillation is obtained. Such a first distillation can be carried out adequately as described in WO 2018/060202. A1.
In an embodiment of the process of the present invention which produces the overhead of the first distillation, the process further comprises the step of removing at least one impurity selected from the metals arsenic, antimony and tin from the overhead of the first distillation to obtain a purified soft lead product. Preferably, the purified soft lead product is produced as described in WO 2020/157165 A1.
In an embodiment of the method of the present invention comprising the first distillation step, the bottoms of the first distillation of the first distillation step contains lead and silver, and the method further comprises the step of separating the bottoms of the first distillation step by fractional crystallization into a first silver-enriched liquid wicking product at the liquid end of the crystallization step and a first tin-enriched product at the crystallization end of the crystallization step. Applicants prefer to carry out this separation as described in WO 2020/157167 A2.
In an embodiment of the method of the present invention comprising the step of fractional crystallization, the method further comprises the step of separating the first silver-enriched liquid wick product into a product rich in lead plus tin and a product rich in is to silver, preferably by electrolysis wherein the anode slime represents the product rich in silver. Applicants prefer to carry out this separation as disclosed in WO 2020/157167 A2.
In an embodiment of the method of the present invention which produces the first tin-enriched product, the first tin-enriched product further comprising lead and antimony, the method further comprises the step of a second distillation before distilling the first tin enriched product, mainly evaporating lead and antimony to give a top product from the second distillation and a bottom product from the second distillation.
In an embodiment of the method of the present invention comprising the second distillation step, the method further comprises the step of a third distillation for distilling the overhead product of the second distillation, whereby lead is vaporized and an overhead product of the third distillation and a bottoms from the third distillation are obtained, wherein the bottoms from the third distillation are at least partially preferably recycled to the feed of the second distillation step and/or the feed of the fractional crystallization step.
In an embodiment of the process of the present invention comprising the third distillation step, the process further comprises the step of removing at least one impurity selected from the metals arsenic and tin from the overhead of the third distillation to obtain a purified hard lead product.
Applicants prefer to carry out this step as described in WO 2020/157168 A1.
In an embodiment of the process of the present invention comprising the second distillation step, the process further comprises the step of refining the bottoms of the second distillation to obtain a purified tin product. Applicants prefer to carry out this step as described in WO 2020/157168 A1.
In an embodiment of the method of the present invention comprising refining the concentrated copper intermediate to obtain a refined copper product, the method further comprises the step of casting the refined copper product to produce refined copper anodes. The applicants have found that the refined copper product in the form of copper anodes makes the product highly suitable for a further electrolytic process step for the production of high purity copper cathodes, together with anode slimes which can be further processed to recover the metal values contained therein. Applicants prefer to carry out this process step of electrolytic purification as described in WO 2019/219821 A1.
In an embodiment of the method according to the present invention, at least part of the method is monitored and/or controlled electronically. Applicants have found that electronically controlling steps of the method according to the present invention, preferably by a computer program, brings the advantage of much better processing, with results that are much more predictable and closer to the process objectives. For example, based on temperature measurements, and if desired also measurements of pressure and/or content, and/or in combination with the results of chemical analyzes of samples taken from process streams and/or analytical results obtained in online , controlling the equipment with regard to the supply or withdrawal of electrical energy, the supply of heat or of a cooling medium, regulation of flow and/or pressure. The applicants have found that such monitoring or control is particularly advantageous for steps performed in continuous mode, but may also be advantageous for steps performed in batch or semi-batch mode. In addition, the monitoring results obtained during or after performing steps in the method according to the present invention are preferably also useful for monitoring and/or controlling other steps as part of the method according to the present invention, and/or of processes carried out upstream or downstream of the process of the present invention, as part of an overall process of which the process of the present invention is only a part. Preferably, the entire process as a whole is monitored electronically, more preferably by at least one computer program. Preferably, the method as a whole is electronically controlled as much as possible.
Applicants prefer that the computer controller also provides for data and instructions to be passed from one computer or computer program to at least one other computer or other computer program or other module of the same computer program, for monitoring and/or controlling other processes, including, but not limited to, the methods described herein.
The claimed invention is further illustrated by Figure 1, which shows a process flow diagram of an overall process as a preferred embodiment comprising the method steps of claim 1 for the recovery of a concentrated copper intermediate.
In Figure 1, the following reference numbers refer to the following process steps or flows:
100. Smelting Step or Smelting Plant
200. Copper Refining
300. Casting copper anode
400. Snail smoke step
500. Recovery lead/tin
1. Raw Feed Material Section
2. Finely divided feed material portion or dust
3. Black copper as the concentrated copper intermediate
4. Melting plant dust as a by-product from the smelting furnace
5. Fusing slag
6. Refining slag
7. Raw solder as a by-product from copper refining
8. Refined Copper
9. Copper Anode Product
10. Soft Lead Product
11. Hard lead product
12. Refined Tin Product
13. Smoked Snail
14. Fumigation plant dust as a by-product from the fumigation furnace. Figure 1 shows that the raw feed material portion 1 and the finely divided feed material portion 2 are fed to the melting furnace 100, where the oxygen-containing gas (not shown) is injected to control the reactions in the furnace and therefore also the temperature in the oven. The furnace exhaust gases are cooled and filtered, collecting smelter dust 4 . Fume slag 5 is removed from the furnace and fed to the fumigation stage 400 to recover smelter dust 14 and to produce final slag or so-called "clean slag" 13 as the second slag.
Black copper 3 as the concentrated copper intermediate is fed to the copper refining 200, which produces a refined copper product 8, a raw solder by-product 7 and a refining slag 6 . The refining slag 6 may be fed to the fumigator 400 to increase the amount of final slag 13 and smelter dust 14 . The refined copper 8 is fed to the copper anode casting step 300 to produce copper anodes 9. The raw solder 7 is sent to the lead/tin recovery step 500, where a soft lead product 10, a refined tin product 12 and optionally a hard lead product 11 are produced. Applicants have found that the beneficial technical effects of the present invention, not only but in particular the more stable and reliable operation of the smelting step 100, manifest themselves smoothly downstream, and all the way to the production of the derivatives 9, 10, 11 12, 13 and 14 shown in Figure 1. Thanks to the present invention, derivative steps receive a more stable and reliable feed stream resulting from the smelting step, enabling them to produce end products of more stable and reliable quality. An additional advantage is that the present invention reduces the burden of process monitoring and the operator attention required to perform the downstream process steps as well as the process as a whole.
EXAMPLE In a rotary drum furnace with an internal diameter of 3 meters, a level of about 1.00 meters of liquid black copper intermediate concentrated copper was left over from the previous feed charge, representing an amount of about 113 tons.
The furnace was operated in semi-continuous mode during an operating period lasting approximately 16 consecutive months, using a repeated sequence of the following operating modes, during which each cycle involved different premixed feed charges that were compounded and collected by selecting packages from a large stock of available raw materials: Mode 1: From a suitable feed charge, coarse solid raw materials are gradually fed to the furnace. This mode is included if necessary, until a continuous layer of slag is obtained which floats to the surface on the liquid metal phase,
Mode 1+2: If a continuous layer of slag is present in the furnace, from another suitable premixed feed charge formulated for this purpose, finely divided feed material, also called “dust”, is pneumatically conveyed and injected into the liquid slag phase and above the metal phase of the liquid bath, usually also gradual over time, while the gradual feed of coarse solids is also preferably continued, Mode 3: Typically, but only as needed, as part of the process after the feed charges are completed and/or the furnace is considered full, provide a period during which the conditions in the furnace are maintained and the chemical reactions are allowed to proceed, and that the desired composition of slag and metal is obtained.
Mode 4: Slag is poured out of the furnace by tilting the rotating drum until the supernatant slag phase at least partially overflows through the furnace feed opening.
The slag was preferably transferred in liquid form in a suitable container to a fumigation furnace for the further recovery of zinc and optionally also lead by fumigation, and optionally also copper as part of a metal phase as a by-product of the fumigation step.
The slag obtained from this fumigation step, and if the fumigation step was not available, the slag resulting from the fusing step was cooled, cured and pelletized by contacting the hot liquid slag with a large stream of water. .
Mode 5: Metal is partially removed from the furnace, if practicable, until, again, a minimum level of approximately 1.00 meters of liquid metal plus any liquid slag, if any, remains in the furnace.
The removal, if the slag is completely removed, is carried out by also allowing the metal phase to overflow through the feed port, and if only a portion of the slag phase has been removed, the metal is tapped through a tap hole at a suitable location in the furnace wall.
After the slag and/or metal removal in Mode 4 and/or Mode 5, i.e. when more space is freed up again in the kiln, the feed of raw materials is restarted depending on the presence of slag in the kiln as above in Mode 1 or in Mode 1+2, and if the previous feed charge is completed, starting with a next feed charge.
If the downstream processing of the concentrated copper intermediate required more feedstock, a portion of the liquid metal phase was intermittently removed from the furnace before or without removing any of the supernatant slag phase, just before or after the metal removal.
Additional flux material, sometimes referred to as "slag formers" as a translation of the common German term, usually sand, was added to the furnace as needed to ensure sufficient fluidity of the slag. Before pelletizing the slag from the furnace or from the downstream fumigation unit, additional silicon dioxide was added as necessary to achieve a correct Fe/Si ratio, such that the risk of hydrogen formation during casting and pellet processing of the slag, and the associated risk of explosions, was kept under control. Over the time required to process the feed charge, an average total of 11.5 tons of sand per feed charge was introduced into the kiln.
During Modes 1, 1+2 and 3, when needed to maintain the oven temperature, pure oxygen gas was injected through a lance inserted through the feed port. During those modes of operation, the drum furnace was reciprocated whenever possible to agitate its liquid contents.
During all modes of operation, compressed air at a pressure of 10 bar gauge was supplied to the 4 blowpipes provided at suitable locations in the furnace wall below the liquid level, and injected into the furnace, mainly for the purpose of agitating the bath, but also for introducing additional oxygen into the bath to participate in the intended chemical reactions.
During the time period considered, a total amount of about 924 tons of coarse solid raw materials, including an amount of return materials, was introduced into the furnace per feed charge, and a total amount of about 23.2 tons of finely divided raw materials was introduced into the furnace. The coarse solid raw materials and the finely divided raw materials had the average composition indicated in Table |. Sufficient additional solid iron scrap was provided as part of the premixed feed batches of coarse solid raw materials, and fed to the furnace as part thereof, to maintain a presence of solid iron floating on the metal phase. That added amount of extra iron scrap is therefore included in the composition of the coarse solid raw materials of Table |. Table |
B SE B 3 | 98 | AS a. | 08] aa
LEI Be 0 | | 5 Over the entire operating period considered, each feed charge averaged a total of approximately 6.6 tons of oxygen, approximately at ambient temperature, as compressed air injected into the bottom of the furnace through 4 nozzles, and as oxygen gas through the lance close to the interface between the metallic phase and its supernatant slag phase. The temperature in the oven could be maintained very conveniently and precisely in the narrow range of 1150-1180°C. Most importantly, controlling the injection of oxygen made it possible to avoid temperature swings beyond that range, such that evaporation of tin and/or lead could be minimized. Controlling the feed rates of the raw materials, including the coarse solids as well as the injection of dust, made it possible to avoid temperature drops below the desired level, and the injection of oxygen made it possible to recover easily from a temporary temperature drop if such a decline occurred. Before removing metal from the furnace, the temperature was allowed to drop to about 1140°C to reduce the risk of damage to the containers into which the molten metal was transferred.
The exhaust gases from the furnace were cooled and filtered to recover the solids in the cooled gases as smelter dust.
Averaged over the entire operating period, per feed batch, the amounts of products and compositions shown in Table 11 were obtained and removed from the smelting furnace.
Table Il ee OW TM | B | Lo 080] 880 | 1088 M 004] NME | 008 Fe | 85851) 192 | 080 — 8,000] 000 | 000 — Aa 000] 000 | 000 — 8,000] 008 | 000 | B | em | 0th | 0m Be | mrs] |E pe | GE |E AS] | aa |E] | [| 8 | The sulfur content of the metal phase obtained as concentrated copper intermediate from the method in the example was determined and found to be well below 2% by weight, and rather in the range of at most 0.25% by weight, for each feed charge. For each feed charge, the sulfur content in the slag was at most 0.33% by weight and in the dust at most 0.21% by weight. Having fully described the present invention, it will be apparent to those skilled in the art that the invention can be practiced with a wide range of parameters within the scope of the claims, without departing from the scope of the invention as defined by the claims.

权利要求:
Claims (62)
[1]
A method for recovering copper from secondary raw materials comprising the step of smelting, in at least one feed batch, (100) a feedstock (1, 2) comprising the raw materials in a furnace for the recovery from the furnace of a concentrated copper intermediate (3), wherein the feedstock is gradually introduced into the furnace, the feedstock comprising copper, and optionally at least one metal which is more noble than tin under the operating conditions of the furnace, at least in part as an oxide, wherein the feed material further comprises iron, and optionally at least one metal or compound which is at most as noble as iron or zinc in the furnace conditions, the iron and the metal which is at most as noble as iron or zinc at least partially present in their elemental form, where heat is generated in the furnace by the redox reactions containing elemental iron and metals or compounds are as noble as iron or zinc, convert to oxides, and convert those oxides of copper and of metals more noble than tin into elemental metal, wherein the elemental metals collect at least partially in a molten liquid metal phase and the oxides at least partially collecting in a supernatant liquid slag phase, wherein the liquid phases are capable of separating and at the end of the smelting step at least one of the liquid phases is at least partially removed from the furnace as a smelting slag (5) and /or as the concentrated copper intermediate (3), characterized in that during the smelting step an excess of the elemental form of iron and of metals or compounds which under the conditions of the furnace are at most as noble as iron or zinc is introduced into the furnace maintained in proportion to the amount required to complete the redox reactions, and an additional heat input is provided in the furnace. aft during the smelting step by injecting an oxygen-containing gas to oxidize the excess iron present and metals or compounds no more than as noble as iron or zinc in the furnace and possibly for the combustion of a combustible source of carbon and /or hydrogen which may additionally be introduced into the furnace.
[2]
The method of claim 1 wherein the feedstock further comprises at least one second metal selected from the group consisting of nickel, tin and lead.
[3]
The method of the preceding claim wherein the concentrated copper intermediate (3) further comprises the at least one second metal.
[4]
The method of any preceding claim wherein the feedstock (1, 2) comprises scrap iron, silicon, zinc and/or aluminum.
[5]
The method of any preceding claim further comprising the step of at least partially removing the smelting slag (5) from the furnace.
[6]
The method of any preceding claim further comprising the step of removing at least a portion of the concentrated copper intermediate (3) from the furnace.
[7]
The method according to any one of the preceding claims wherein the iron and compounds which are at most as noble as iron or zinc introduced together with the feed material (1, 2) are solid iron, solid silicon, solid zinc and/or solid aluminum, preferably scrap containing copper/iron, scrap containing silicon, scrap containing zinc and/or scrap containing aluminum.
[8]
The method according to any of the preceding claims, wherein the feed material (1, 2) is at least partially in solid form and wherein the solid feed material is fed gradually, preferably continuously, into the furnace.
[9]
The method of any preceding claim wherein the feedstock feed rate is maintained below the rate at which the heat generation would become insufficient to melt the solid feedstock and/or bring the feedstock to the desired furnace temperature.
[10]
The method according to any one of the preceding claims wherein at least a portion of the feed material (1, 2) is in the form of a finely divided portion (2), and the finely divided feed material portion (2) is an average has a particle size of not more than 10 mm.
[11]
The method of the preceding claim wherein the material of the finely divided feed material portion (2} is pneumatically conveyed and injected into the furnace.
[12]
The method according to the preceding claim wherein the material of the finely divided feed material portion (2) is injected into the liquid slag phase and above the metal phase of the liquid bath.
[13]
The method according to any one of claims 10-12, wherein the average composition of the finely divided feedstock portion (2) fed over the entire melt charge fed into the furnace satisfies at least one and preferably all of the following conditions after being heated to 1150°C: ° comprising at least 5% by weight of the total metal, preferably at least 5% of the total of copper, nickel, tin, lead and zinc, ° comprising at most 70.0 % by weight copper (Cu), ° comprising at most 2.00 % by weight nickel (Ni), ° comprising at least 0.50 % by weight and at most 10.00 by weight % lead (Pb), ° including at most 15.00 % by weight tin (Sn), ° including at most 2.00 % by weight antimony (Sb), ° including at most 7.0 by weight % iron (Fe), and ° comprising at most 55.00 % by weight zinc (Zn).
[14]
The method according to any one of the preceding claims, wherein the feed material (1, 2) comprises at least one return material from the processing of the molten liquid metal phase and/or of the liquid slag phase formed by the method.
[15]
The method according to the preceding claim wherein the at least one return material comprises at least one material selected from rejected anodes or other products comprising copper, tin and/or lead, a metal oxide or sulfide, preferably of copper, nickel tin, lead and/or zinc, including scribe comprising the metal as oxide or sulfide and formed in and removed from a downstream treatment step, a metal silicide, preferably a silicide of a metal selected from copper, zinc, nickel, iron, lead and tin, and a crust or other solid form formed against a wall of a crucible or ladle used to transfer molten metal and/or molten slag that has been removed from a furnace.
[16]
The method according to any one of the preceding claims, wherein the feed material (1, 2) is centrally introduced into the liquid bath in the furnace.
[17]
The method of any preceding claim wherein the feedstock (1,2) comprises a coarse portion (1) and the average composition of the raw feedstock portion fed over the entire smelting charge fed into the furnace is at least at least one and preferably all of the following after being heated to 1150°C: comprising at least 20% by weight of the total metal, preferably at least 20% of the total copper, nickel, tin, lead and zinc, ° comprising at least 10.0 % by weight and at most 70.0 % by weight copper (Cu), ° comprising at least 0.50 % by weight and at most 2.00 % by weight % nickel (Ni), ° comprising at least 1.00 % by weight and at most 8.00 % by weight lead (Pb),
° comprising at least 0.50 % by weight and at most 2.50 % by weight tin (Sn), ° comprising at most 0.10 % by weight antimony (Sb), ° comprising at least 10 0.0% by weight and at most 35.00% by weight iron (Fe), and o comprising at least 2.00% by weight and not more than 15.00% by weight zinc (Zn).
[18]
The method of any preceding claim wherein the content of iron and metals or compounds which are at most as noble as iron or zinc dissolved in the molten metal in the furnace is at least 1.0 by weight % is kept, preferably at least at 1.5% by weight, whereby the concentration of the metals and compounds that are at most as noble as iron or zinc is converted to an equivalent concentration of iron, whereby the equivalent concentration of iron is a concentration of iron capable of contributing the same amount of reaction heat as the metal or compound which is at most as noble as iron or zinc when reacting with oxygen under the furnace conditions.
[19]
The method of any preceding claim wherein the content of iron and/or metals and compounds which are at most as noble in the furnace conditions as iron or zinc dissolved in the molten metal in the furnace at most 10.0 % by weight, preferably at most 9.0 % by weight, the concentration of the metals and compounds which are at most as noble as iron or zinc is converted to an equivalent concentration of iron , wherein the equivalent concentration of iron is a concentration of iron capable of contributing the same amount of reaction heat as the metal or compound which is at most as noble as iron or zinc when reacted with oxygen under the conditions of the oven.
[20]
The method of any preceding claim wherein elemental iron is introduced into the smelting step (100) at a rate which causes an excess of iron, above its solubility in the metal bath under the furnace conditions, into the molten bath. is held during the process.
[21]
The method of the preceding claim wherein the amount of excess iron present in the furnace is maintained by at least periodically taking a sample of the molten metal phase in the furnace and analyzing the sample for iron content.
[22]
The method of any preceding claim wherein the combustible source of carbon and/or hydrogen is selected from the group consisting of coke, charcoal, carbon black, a hydrocarbon, natural gas, methane, ethane, propane, butane, a hydrocarbon which is liquid under standard conditions, a polymer containing a hydrocarbon, a plastic, plastic waste, grease, oil, paint, varnish, rubber, preferably waste thereof, and combinations thereof.
[23]
The method of the preceding claim wherein the amount of combustible source of carbon and/or hydrogen is kept below the level at which slag foaming would adversely affect the operation of the smelting step, preferably significantly below that level, such that also the risk of slag foaming remains acceptably low.
[24]
The method of any preceding claim wherein at least a portion of the oxygen-containing gas is introduced close to the interface between the metal phase and its supernatant slag phase.
[25]
The method of any preceding claim wherein at least a portion of the oxygen-containing gas is introduced by means of at least one metal lance the end of which is immersed in the liquid slag phase.
[26]
The method of the preceding claim wherein the gas injected through the metal lance comprises at least 30% by volume oxygen, and more preferably the gas is high purity oxygen.
[27]
The method of any of claims 25-26 wherein the gas flow through the metal lance provides sufficient cooling to prevent the lance from corroding and/or melting.
[28]
The method according to any one of the preceding claims, wherein at least a portion of the oxygen-containing gas is introduced into the bottom of the furnace through at least one blowpipe, preferably a plurality of blowpipes, the blowpipes of the plurality of more preferably evenly distributed over the bottom of the oven.
[29]
The method according to the preceding claim, wherein the gas introduced through the at least one blowpipe is an oxygen-containing gas comprising at most 50% by volume oxygen, preferably air.
[30]
The method of any one of claims 28-29 wherein the gas introduced through the at least one blowpipe is cooler than the molten liquid metal phase surrounding the blowpipe.
[31]
The method according to any one of the preceding claims, wherein the smelting slag (5) produced by the method comprises at least 20% by weight of iron (Fe).
[32]
The method according to any one of the preceding claims wherein the composition of the produced fusion slag (5) satisfies at least one and preferably all of the following conditions: ° comprising at most 1.00% by weight copper (Cu), ° including not more than 0.20 wt. % nickel (Ni), ° comprising not more than 2.00 wt. % lead (Pb), ° comprising not more than 1.00 wt. % tin (Sn), and ° comprising at most 22.50 weight % zinc (Zn).
[33]
The method of any preceding claim wherein the concentrated copper intermediate composition (3) as the high value product of the smelting step (100) satisfies at least one and preferably all of the following conditions: ° including at least 50.0 wt% copper (Cu),
° comprising at least 0.01 wt. % nickel (Ni), ° comprising at least 0.10 wt. % lead (Pb), ° comprising at least 1.00 wt. % tin (Sn) , ° comprising at least 0.05 wt. % iron (Fe), ° comprising at least 0.10 wt. % zinc (Zn), and ° comprising at most 5 wt. % sulfur (S) .
[34]
The method of any preceding claim wherein the liquid bath in the oven has a temperature in the range of 1100-1300°C.
[35]
The method according to any one of the preceding claims, wherein the exhaust gases from the furnace are collected and treated by cooling and/or filtering.
[36]
The method of the preceding claim, wherein also secondary exhaust gases from around the furnace are collected and treated by filtration, optionally in combination with cooling.
[37]
The method of any preceding claim wherein the smelting (100) is performed in a smelting furnace.
[38]
The method of any preceding claim wherein the walls of the furnace are at least partially cooled over the wall surface of the furnace.
[39]
The method according to any one of the preceding claims, further comprising the step of fumigating (400) the slag phase formed in the fusing step (100) to obtain a fumigated slag (13), wherein fumigating preferably carried out in a fumigation oven.
[40]
The method of any preceding claim wherein the slag (5, 13) is pelletized when removed from the smelting step (100) or from the fumigating step (400).
[41]
The method of any preceding claim further comprising the step of using the produced slag (5, 13) in an end use selected from providing a wear layer and/or coating for roof tiles or clapboards, as a component of sandblasting sand or blasting grit, as a component of foam tiles as a black colorant, preferably in construction products, more preferably in black tiles, as black hard lumps, preferably for decorative purposes, and as a high-density ballast material, preferably for underwater applications, more preferably for marine engineering applications, and for combinations thereof.
[42]
The method according to any one of the preceding claims further comprising the step of adding the produced slag (5, 13) as aggregate and/or as binder during the production of an article for the construction industry, preferably as binder for aggregates, preferably as an active binder, more preferably as a binder with pozzolanic effect, even more preferably as a substitute for Portland cement, even more preferably as a partial substitute for Portland cement.
[43]
The method according to the preceding claim wherein the produced slag (5, 13) is added as a binder in an inorganic polymer composition, preferably in combination with a base, more preferably as the main binder in an inorganic polymer composition, even more preferably as the sole binder in an inorganic polymer composition.
[44]
The method of the preceding claim further comprising the step of foaming the inorganic polymer composition.
[45]
The method according to any one of claims 42-44, wherein the object for the construction industry is a building element, the building element preferably being selected from the list of a tile, a paving stone, a block, a concrete block, and combinations of that.
[46]
The method of any one of claims 42-45 wherein the construction industry article has a foamed structure.
[47]
The method of any one of claims 42-46 further comprising the step of using the article for improving heat and/or sound insulation, for shielding against X-rays, and combinations thereof.
[48]
The method of any preceding claim further comprising the step of refining (200) the concentrated copper intermediate (3) to obtain a refined copper product (8) together with at least one copper refining slag (6) .
[49]
The method of the preceding claim wherein the concentrated copper intermediate (3) further comprises tin and lead, the method further comprising recovering a raw solder metal composition (7) from the concentrated copper intermediate (3).
[50]
The method of the preceding claim further comprising the step of recovering (500) from the raw solder metal composition (7) at least one of a purified soft lead product (10), a purified hard lead product (11) and a purified tin product (12). ).
[51]
The method of any one of claims 49-50 further comprising the step of pre-refining the raw braze metal composition (7) to produce a pre-refined braze metal composition.
[52]
The method according to any one of claims 49-51 further comprising the step of updating the raw braze composition (7) or the pre-refined braze metal composition to produce an updated braze metal composition.
[53]
The method of the preceding claim further comprising the step of a first distillation to distill the updated solder composition wherein lead is removed from the solder by evaporation and a top product from the first distillation and a bottom product from the first distillation are obtained.
[54]
The method of the preceding claim further comprising the step of removing at least one impurity selected from the metals arsenic, antimony and tin from the overhead of the first distillation to obtain a purified soft lead product (10).
[55]
The method of claim 53 or 54, wherein the bottoms of the first distillation of the first distillation step contains lead and silver, the method further comprising the step of separating the bottoms of the first distillation step by fractional crystallization in a first containing silver-enriched liquid drainage product at the liquid end of the crystallization step and a first tin-enriched product at the crystallization end of the crystallization step.
[56]
The method of the preceding claim further comprising the step of separating the first silver-enriched liquid wicking product into a lead plus tin-rich product and a silver-rich product, preferably by electrolysis wherein the anode slime represents the product rich in silver.
[57]
The method of claim 55 or 56, wherein the first tin-enriched product further contains lead and antimony, the method further comprising the step of a second distillation to distill the first tin-enriched product, wherein mainly lead and antimony are extracted. evaporated and a top product from the second distillation and a bottom product from the second distillation are obtained.
[58]
The method of the preceding claim further comprising the step of a third distillation to distill the overhead of the second distillation, whereby lead is vaporized to obtain an overhead of the third distillation and a bottoms of the third distillation, wherein the bottoms of the third distillation is preferably at least partially recycled to the feed of the second distillation stage and/or the feed of the fractional crystallization stage.
[59]
The method of claim 57 or 58 further comprising the step of removing at least one impurity selected from the metals arsenic and tin from the overhead of the third distillation to obtain a purified hard lead product (11).
[60]
The method of any one of claims 57-59 further comprising the step of refining the bottoms of the second distillation to obtain a purified tin product (12).
[61]
The method of any one of claims 48 to 60 further comprising the step of casting the refined copper product (8) to produce refined copper anodes (9).
[62]
The method of any preceding claim wherein at least a portion of the method is monitored and/or controlled electronically.

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同族专利:

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公开号 | 公开日

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TW202130824A|2021-08-16|

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WO2021099538A1|2021-05-27|

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法律状态:
2021-07-19| FG| Patent granted|Effective date: 20210623 |

优先权:

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申请号 | 申请日 | 专利标题

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EP19210921|2019-11-22|

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