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    • 专利摘要:
    The present invention relates to the use of a compound including magnesium as a binder for producing fluxed pellets of metal ore, particularly fluxed iron ore pellets, said compound including magnesium having semi-hydrated dolomite in accordance with the present invention. general formula aCa (OH) 2bMg (OH) 2.cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight; weight relative to the total weight of said semi-hydrated dolomite.
    公开号:BE1025149B1
    申请号:E2017/5875
    申请日:2017-11-30
    公开日:2018-11-20
    发明作者:Marc Pelletier；Costa Eduardo Da
    申请人:S.A. Lhoist Recherche Et Developpement；
    IPC主号:
    专利说明:

    (30) Priority data:
    11/30/2016 EP PCT / EP2016 / 079338 (73) Holder (s):
    S.A. LHOIST RESEARCH AND DEVELOPMENT 1342, OTTIGNIES-LOUVAIN-LA-NEUVE Belgium (72) Inventor (s):
    DA COSTA Eduardo 4031ANGLEUR Belgium
    The present invention relates to the use of a compound including magnesium as a binder for producing fluxes pellets of metal ore, in particular fluxes pellets of ore ore iron, said compound including magnesium comprising semi-hydrated dolomite corresponding to the general formula aCa (OH) 2.bMg (OH) 2.cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    BELGIAN INVENTION PATENT
    FPS Economy, SMEs, Middle Classes & Energy Publication number: 1025149Deposit number: BE2017 / 5875 Intellectual Property Office International Classification: C22B 1/24 C22B 1/243 Date of issue: 20/11/2018
    The Minister of the Economy,
    Having regard to the Paris Convention of March 20, 1883 for the Protection of Industrial Property;
    Considering the law of March 28, 1984 on patents for invention, article 22, for patent applications introduced before September 22, 2014;
    Given Title 1 “Patents for invention” of Book XI of the Code of Economic Law, article XI.24, for patent applications introduced from September 22, 2014;
    Having regard to the Royal Decree of 2 December 1986 relating to the request, the issue and the maintenance in force of invention patents, article 28;
    Considering the patent application received by the Intellectual Property Office on 30/11/2017.
    Whereas for patent applications falling within the scope of Title 1, Book XI of the Code of Economic Law (hereinafter CDE), in accordance with article XI. 19, §4, paragraph 2, of the CDE, if the patent application has been the subject of a search report mentioning a lack of unity of invention within the meaning of the §ler of article XI.19 cited above and in the event that the applicant does not limit or file a divisional application in accordance with the results of the search report, the granted patent will be limited to the claims for which the search report has been drawn up.
    Stopped :
    First article. - It is issued to
    S.A. LHOIST RESEARCH AND DEVELOPMENT, Rue Charles Dubois 28, 1342 OTTIGNIES-LOUVAINLA-NEUVE Belgium;
    represented by
    GEVERS PATENTS, Holidaystraat 5, 1831, DIEGEM;
    a Belgian invention patent with a duration of 20 years, subject to payment of the annual fees referred to in article XI.48, §1 of the Code of Economic Law, for: PELLETS DE MINERAI METALLIQUE.
    INVENTOR (S):
    DA COSTA Eduardo, Avenue des Cerfs 18, 4031, ANGLEUR;
    PELLETIER Marc, Rue de l'Alouette 3bis, 94160, SAINT-MANDÉ;
    PRIORITY (S):
    11/30/2016 EP PCT / EP2016 / 079338;
    DIVISION:
    divided from the basic request:
    filing date of the basic application:
    Article 2. - This patent is granted without prior examination of the patentability of the invention, without guarantee of the merit of the invention or of the accuracy of the description thereof and at the risk and peril of the applicant (s) ( s).
    Brussels, 20/11/2018,
    By special delegation:
    BE2017 / 5875
    Metallic ore pellets
    The present invention relates to fluxes of metal ore, in particular to fluxes of iron ore.
    According to the present invention, the terms "pellets flowed from metal ore" are understood to mean pellets consisting of metal ore coming from metal ore mines. The term "metallic" is a general term that includes ferrous metal ore, also called iron, and non-ferrous metal ore. Non-ferrous metal ore commonly contains metals such as chromium, manganese, nickel, lead, tin, copper, etc.
    Iron ore (ferrous) contains mainly iron, around 60% by weight or more, but may also contain other metals such as titanium and manganese in combination with iron.
    Metallic ore pellets are produced from a fine metallic concentrate containing at least 60% by weight of metals. Metallic ore concentrate, also known as simply concentrate, is the product obtained by finely grinding raw ore in a grinding operation, after which the gangue (impurities) is removed. The product obtained is therefore a concentrate of metallic component. The remaining impurities which may be present in the concentrate are, for example, silicates, aluminates, phosphates and sulfates.
    Iron ore pellets consist of magnetitic, hematitic, limonitic and sideritic concentrates containing at least 60% by weight of iron.
    The fine metal concentrate is first granulated in a tank (container) such as a drum or a disc (bowl) during an agglomeration process to form what are called raw pellets (in English "Green pellets") which are in fact raw pellets. These raw pellets are then hardened by heating in a
    BE2017 / 5875 hardening which is typically divided into three zones, the drying zone at approximately 300 ° C, the cooking zone at approximately 1300 ° C and the cooling zone. After the curing process, the pellets can be referred to as cooked pellets and are suitable for bulk processing and loading in a metallurgical reactor, for example, a blast furnace (abbreviated to “blast furnace”) or a direct reduction reactor. (abbreviated DR for “direct reduction”), the direct reduction reactor being used before an electric arc furnace in a factory.
    It is known to use naturally available minerals such as olivine, dunite, pyroxenite, limestone or dolomite, as flux, also known as fluxing agents to improve the metallurgical properties of cooked pellets. It is in fact known that the properties and chemical composition of raw pellets have an impact on the quality of cooked pellets when used in a metallurgical reactor. Metallic ore pellets containing fluxes are also called fluxed metallic ore pellets or just fluxed pellets. The properties of fluxed pellets depend on the nature of the above-mentioned fluxes which are physically and chemically different and which contain different types and quantities of gangue materials, in particular silica and / or alumina, etc., which are considered to be impurities in the pellets.
    In the production of fluxed pellets, carbonates and / or silicates are commonly used. Carbonates have the disadvantage for the pellet producer of consuming energy for their calcination as well as the emission of carbon dioxide. In the production of calcitic flux pellets, the use of calcium carbonate (limestone) as flux is common. In the production of fluxed magnesium pellets, magnesium silicate, in particular olivine or pyroxenite, has been favored as flux.
    BE2017 / 5875
    Binders are used in the production of fluxed pellets in order to allow the formation of raw pellets by agglomeration and then to withstand the mechanical and thermal stresses of handling in their production process, in particular in the induration furnace (in the areas of drying, baking and cooling).
    Bentonite, a type of clay, has been the binder of choice since the advent of the production of fluxed pellets of metal ore. An existing substitute for bentonite is the use of organic binders such as those based on carboxymethylcellulose or a polyacrylamide, which are however more expensive and prevent good mechanical properties from being achieved in the final pellets.
    The present invention aims to focus on the use of other binders for the manufacture of fluxes pellets of metal ore, in particular fluxes pellets of iron ore.
    The document by J. Pan et al. Concerns the laboratory production of fluxed calcite pellets made from the mixture of fine pretreated iron ore, binder and limestone as flux (refer to Iron Ore conference / Perth, WA, 11 -13 July 2011, J Pan, DQ Zhu, M Emrich, TJ Chun and H Chen, "Improvement of performance of pellets fluxed by hydrated lime instead of bentonite as binder"). The binders which are compared in this document are bentonite and hydrated lime and the mechanical properties of the fluxed pellets obtained are analyzed. This paper concludes that replacing bentonite with hydrated lime as a binder improves the physical properties and compressive strength of cooked pellets and also plays a role in improving the metallurgical performance of cooked pellets.
    However, this document also describes that, in order to observe the improvement in the compressive strength of the pellets cooked in the presence of hydrated lime, the preheating temperature at
    BE2017 / 5875 during the hardening process of raw pellets should be set and raised to 1100 ° C. In fact, the compressive strength of cooked pellets made from preheated pellets with bentonite is higher than that made from preheated pellets containing hydrated lime when the preheating temperature was below 1050 ° C .
    The document by Cribbes and Kestner (see Research Engineer, Dravo Corporation, Pittsburgh, Pennsylvania, chapter 16, pages 272-285, 1977 "Certain factors influencing the quality of cooked iron ore pellets" by James D. Cribbes and Daniel W. Kestner) shows that it is possible to use hydrated lime as a substitute for limestone as a flux and bentonite as a binder and to obtain more pellets with reasonable physical properties. In this document, fluxed pellets containing bentonite and hydrated lime are compared to fluxed pellets containing only hydrated lime. They noted that, at the optimum agglomeration humidity for pellets containing bentonite plus limestone, pellets formed only with hydrated lime produced, after the curing process, cooked pellets with a diffuse uneven surface. They also discovered that it was necessary to reduce the humidity of raw pellets for pellets containing only hydrated lime compared to pellets containing bentonite to obtain cooked pellets having good resistance to cooking after the process of hardening. These results showed that the adjustment of the agglomeration parameters such as the humidity of the raw pellets was more difficult with the use of hydrated lime as flux and as binder and that the properties of the raw pellets when they are not well controlled. can have an impact on the quality of cooked pellets.
    BE2017 / 5875
    Gielen's document refers to the industrial production of pellets prepared from hematitic concentrate (refer to the Society of mining engineers of aime, Colorado, 1983, "Improving quality and saving energy in the formation of pellets of iron ore ”by HH Gielen, HS Heep, MR Hohensee, HG Papacek, VV Arnim). In this document, it has been established that hydrated lime is in no way a good substitute for bentonite as a binder in fluxed pellets. Raw pellets containing hydrated lime as a binder had a strong tendency to stick, causing great difficulty with clogged sieving trays. We have highlighted the fact that, with the improvements obtained in the filtration section (filtration cake) during a filtration stage of the concentrated fines and at the same time a partial substitution of the hydrated lime by limestone in the composition of the raw pellets, the difficulties during the agglomeration stage were reduced.
    Due to the above mentioned difficulties encountered when other binders than bentonite were tested, over time, bentonite has proved to be the binder of choice in the production of fluxed pellets, in particular because it improves the agglomeration process by controlling the moisture content of the raw pellets. In fact, the agglomeration process and, more specifically, the agglomeration rate are, among other things, controlled by the moisture content of the raw mixture used to produce raw pellets. Bentonite has been shown to more easily regulate the moisture content during the agglomeration process.
    However, although bentonite seems to be the go-to for producing metallic flux pellets with good physical properties, it has the disadvantage of bringing more impurities, mainly silica and alumina, to the raw pellets. These impurities resist the hardening process and can be found in cooked pellets. Addition of impurities such as silica
    BE2017 / 5875 or alumina with cooked pellets then leads to an increase in the quantity of slag in the metallurgical furnace (in particular the blast furnace or the electric arc furnace), which is not desirable.
    The present invention further relates to metal ore flux pellets, in particular iron ore flux pellets containing a compound including aluminum as a binder.
    By the expression “compound including magnesium”, is meant in the present invention a compound based on magnesium such as magnesium hydroxide, calcium and magnesium tetrahydroxide, calcium and magnesium (di) hydroxide and their mixtures.
    In addition, the alkalinity of the cooked pellets must be checked by controlling the fraction between the Ca and / or Mg compounds (expressed as oxides of CaO and / or MgO) on one side and SiO 2 and / or AI2O3 on the other side. The quantity of these compounds is however governed by the chemical composition of the raw pellets which is itself controlled by the composition of the compounds initially used to produce them.
    Metallic flux pellets must meet critical criteria for use in metallurgical reactors, such as a blast furnace or a direct reduction reactor. The mechanical and metallurgical properties of the baked pellets must be adequate, for example, to avoid decrepitation or swelling at high temperatures inside the metallurgical reactor.
    Raw (raw) pellets must also have adequate physical properties to withstand the curing process without being degraded by increased temperature and compressive stresses in the curing oven.
    In addition, it is important to control the humidity of raw flux pellets. The ratio of solid components to water added to
    BE2017 / 5875 during the agglomeration process is crucial for having pellets having the exact size and also exhibiting good behavior in the subsequent stages of the process, especially inside the curing oven. The relationship between the different components of the starting powder composition is therefore crucial for treating raw pellets having the appropriate physicochemical properties during the hardening process as well as subsequently in the form of cooked pellets, inside the metallurgical reactors. .
    In addition, in fact, in particular due to the depletion of the metal ore, it is also quite often necessary to be able to process the raw pellets starting from the metal concentrate in the form of a slurry (i.e. suspension, in particular an aqueous suspension) of metal concentrate. Controlling the moisture content during the agglomeration process is therefore a greater challenge in this case.
    On the other hand, the cooked pellets obtained must also have satisfactory physical and metallurgical properties to be used subsequently in metallurgical reactors.
    Physical properties are essential, for example, because breaking and abrasion of cooked pellets leads to loss of material during storage and transport. In addition, it is preferred that the cooked pellets have good mechanical strength, also called crushing or compression resistance, to avoid any loss of permeability in the metallurgical reactor when they are loaded therein. The mechanical resistance of the pellets can be measured, for example, by standard ISO 4700 "Determination of the resistance to grinding".
    The metallurgical qualities of the cooked pellets are also an important criterion which is characterized by the reducibility, swelling and rupture at low temperature of the cooked pellets, in particular according to the
    BE2017 / 5875 ISO 7215 standard "Determination of reducibility by the final degree of reduction index" or according to ISO 4695 standard "Determination of reducibility by the rate of reduction index", ISO 4698 standard "Determination of l 'free swelling index' and ISO 4696 standard 'Determination of reduction-disintegration indices at low temperature by the static process'.
    The document by J. Pan et al, which was cited previously (refer to Iron Ore conference / Perth, WA, July 11-13, 2011, J Pan, DQ Zhu, M Emrich, TJ Chun and H Chen, "Improvement of the performance of pellets fluxed by hydrated lime instead of bentonite as binder "also mentions that, in the production of fluxed pellets, the MgO content appreciably affects the combustion performance of fluxed pellets and that a higher content of MgO leads to lower compressive strength of cooked pellets made from preheated pellets (see Zhang, 2009 and Wang, Liu and Chen, 2004).
    Although it has been discovered that 0.9% pure MgO in a pellet can reduce the Reduction Degradation Index (RDI) to as low as 7.5%, it also shows deterioration of the compressive strength of cooked pellets (see Transactions of the Indian Institute of Metals, August 2016, volume 69, Issue 6, pp. 1141-1153, Role of MgO and its various minerals on the properties of pellets iron ore, Md. Meraj, Susanta Pramanik, Jagannath Pal). This document mentions that when magnesium additives are added, the resistance of the cooked pellets will be reduced due to the oxidation of magnetite which is delayed by the presence of MgO in the pellets.
    Other fluxes based on MgO have been tested and provide good resistance properties to a higher cooking temperature.
    BE2017 / 5875 low, but cannot reduce the degradation index to a sufficiently low level.
    Due to these sensitive requirements, it is not easy to change the composition of metal ore fluxed pellets without completely disturbing the sensitive physicochemical properties of raw pellets and cooked pellets. Since the quality of the cooked pellets depends on the properties of the raw pellets, it is also necessary to control the quality of the raw pellets in order to obtain suitable cooked pellets suitable for use in metallurgical furnaces.
    Despite its drawbacks, bentonite is currently recommended to meet all of the above requirements which are essential for obtaining adequate metallic flux pellets suitable for withstanding a hardening process when in the form of pellets raw and then for use in direct reduction reactors or blast furnaces when in the form of cooked pellets.
    However, there is a need to provide other fluxes of metal ore pellets, in particular fluxes of iron ore pellets having controlled alkalinity, controlled humidity and enhanced mechanical and metallurgical properties while reducing the volume of slag in the metallurgical furnace.
    To this end, the invention relates to the use of a compound including magnesium as a binder for producing fluxed pellets of metallic ore, in particular fluxed pellets of iron ore, characterized in that the compound comprising magnesium comprises dolomite or semi-hydrated dolomitic lime corresponding to the general formula aCa (OH) 2.bMg (OH) 2 .cMgO, a, b and c being weight fractions in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolimia.
    BE2017 / 5875
    This compound is a dolomite or dolomitic limestone derivative which will be referred to as semi-hydrated dolomite in the present invention, obtained by calcination, then by partial hydration (extinction by water) of a natural dolomite or of a dolomitic limestone. .
    Semi-hydrated dolomite can therefore contain the same impurities as those of the dolomite from which it is produced.
    The semi-hydrated dolomite according to the present invention may contain impurities such as sulfur oxide, SO 3 , silica, SiO 2 or even alumina AI 2 O 3 , the sum of which is at a level of one certain weight percentage. Impurities are expressed here in their oxide form, but, of course, they could appear in the form of different minerals. The semi-hydrated dolime generally also contains a certain percentage by weight (up to 10%) of unburned residual residues, namely magnesium and / or calcium carbonates, MgCO 3 and / or CaCO 3 (usually essentially CaCO 3 ). In some cases, a certain amount of unreacted calcium oxide CaO (not quenched) could appear at a level of 1% by weight or less.
    As can be seen, the present invention describes the use not of physical mixtures, but in fact of a single compound providing both magnesium and calcium compounds, namely Mg (OH) 2 , Ca (OH ) 2 and MgO. The use of a single compound instead of physical mixtures of multiple compounds has a considerable practical advantage, since the process for producing the pellets will be easier using a single binder instead of several. In addition, the homogeneity of the dispersion of the Ca and Mg compounds in the composition of the pellets is also improved when these two components are supplied via a single binder which is itself perfectly homogeneous.
    On the other hand, this has the advantage, compared to fully hydrated dolomite, of being a product which is much more
    BE2017 / 5875 easy to obtain. In fact, fully hydrated dolomite, which can be represented by a weight formula of the type xCa (OH) 2 .yMg (OH) 2 and containing non-hydrated residues of CaO and / or MgO only in traces (less than 1% ) is difficult to obtain, because it requires complete hydration of calcined dolomite, generally carried out under a pressure of up to 1 MPa (10 bar) and at high temperature up to 180 ° C. The fully hydrated dolomite of general formula xCa (OH) 2 .yMg (OH) 2 therefore remains at present a specialized product.
    In the present invention, semi-hydrated dolomite is used as a binder to be able to form fluxed pellets of metallic ore in an appropriate manner and to resist the hardening process, then giving good quality baked pellets, i.e. say good mechanical and metallurgical properties.
    In fact, it was not surprisingly observed in the present invention that it was possible to replace the commonly used binder, namely bentonite, by a binder composed of semi-hydrated dolomite containing between 0.5 and 19.5% by weight of Mg (OH) 2 without degrading the physicochemical properties of the pellets flowed from metallic ore against all odds.
    In the semi-hydrated dolomite used as a binder in the present invention, the proportion of Mg (OH) 2 is maintained between 0.5 and
    19.5% by weight in order to control the moisture content of the composition during the production process of raw pellets and to improve the mechanical properties of the raw pellets obtained.
    Advantageously, the weight fraction b of Mg (OH) 2 is greater than or equal to 1%, in particular greater than or equal to 1.5%, better still greater than or equal to 2%, preferably greater than or equal to 5% and less or equal to 18%, in particular less than or equal to 15% relative to the total weight of said semi-hydrated dolimia.
    BE2017 / 5875
    It has been demonstrated in the present invention that it is possible to completely replace bentonite or any organic product as a binder and olivine (or another silicate) as flux with semi-hydrated dolime.
    Another advantage of using semi-hydrated dolomite as a binder leads to a reduction in the consumption of carbonates as a flux, if used, which results in a reduction of CO 2 emissions during the hardening process.
    In addition, when the semi-hydrated dolomite according to the present invention replaces compounds comprising silicates, this allows the reduction of slag levels in the blast furnace.
    Preferably, according to the present invention, the weight ratio of said binder is between 0.5% and 5%, preferably between 0.5% and 1.5% by weight relative to the total weight of the pellets.
    As a variant, according to the present invention, the weight fraction of semi-hydrated dolime is between 80% and 100%, preferably between 90% and 100%, better still between 95% and 100%, advantageously between 97% and 100%. , preferably between 98% and 100% by weight relative to the total weight of the binder. In a particular embodiment of the invention, the semi-hydrated dolomite is 100% by weight relative to the total weight of the binder.
    Advantageously, the weight fraction c of MgO is greater than or equal to 5%, preferably greater than or equal to 10%, advantageously greater than or equal to 15%, preferably greater than or equal to 20% by weight of MgO relative to the total weight. of said semi-hydrated dolime and is less than or equal to 41%, preferably less than or equal to 30% by weight of MgO relative to the total weight of said semi-hydrated dolomite.
    In this particular embodiment of the invention, if higher MgO contents are envisaged, it is possible to add oxide of
    BE2017 / 5875 magnesium as a complementary flux. More preferably, the weight fraction a of Ca (OH) 2 is greater than or equal to 15%, preferably greater than or equal to 30%, advantageously greater than or equal to 40%, preferably greater than or equal to 45% by weight of Ca (OH) 2 relative to the total weight of said semi-hydrated dolime and is less than or equal to 85%, preferably less than or equal to 65%, advantageously less than or equal to 60%, more preferably less than or equal to 55% in weight of Ca (OH) 2 relative to the total weight of said semi-hydrated dolomite.
    Preferably, the semi-hydrated dolomite is in powder form.
    Alternatively, the semi-hydrated dolomite is in the form of an aqueous suspension of said compound based on said semi-hydrated dolomite.
    In addition, in a preferred embodiment, the semi-hydrated dolomite comprises particles having a BET specific surface obtained from nitrogen adsorption of between 5 and 25 m 2 / g, in particular between 10 m 2 / g and 20 m 2 / g.
    By the term "particles" in the sense of the present invention, is meant the discontinuity of the smallest solids of the mineral charge that can be observed with a scanning electron microscope (SEM).
    By the expression “BET specific surface”, is meant within the meaning of this specification the specific surface measured by manometry with nitrogen adsorption at 77 K after degassing under vacuum at a temperature between 150 and 250 ° C, in particular at 190 ° C for at least 2 hours, and calculated according to the BET multipoint process as described in standard ISO 9277: 201 OE.
    Advantageously, the semi-hydrated dolomite comprises particles having a total volume of pores BJH consisting of pores
    BE2017 / 5875 having a diameter less than 1000 Å obtained by nitrogen desorption of between 0.05 and 0.15 cm 3 / g.
    The term “BJH pore volume” according to the present invention means the pore volume as measured by manometry with nitrogen adsorption at 77 K after degassing under vacuum at a temperature between 150 and 250 ° C., in particular at 190 ° C for at least 2 hours, and calculated according to the BJH process using the desorption curve with the assumption of a cylindrical pore geometry.
    By the term "total pore volume" in this specification is meant that the BJH pore volume consists of pores having a diameter less than or equal to 1000 Å.
    Preferably, the semi-hydrated dolomite comprises particles having a d w greater than or equal to 0.5 μm, in particular approximately 1 μm.
    In addition, the semi-hydrated dolomite advantageously comprises particles having a d 5 o of between 4 μm and 8 μm.
    In particular, the semi-hydrated dolomite comprises particles having a d 97 of between 40 μm and 95 μm.
    The notation dx represents a diameter expressed in μm and measured by granulometry with a laser in methanol after sonication with respect to which X% by volume of the particles measured are less than or equal.
    In another embodiment of the present invention, the fluxed pellets of metal ore, in particular the fluxed pellets of iron ore, contain a concentrate of metallic ore, in particular a concentrate of iron ore, having particles having fineness Blaine between 1,500 cm 2 / g and 2,500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    BE2017 / 5875
    By the expression "Blaine fineness" is meant within the meaning of this specification a fineness measured according to the standard ASTM C204-07 using an air permeability apparatus and the test method A. Blaine finesse of particles is the specific surface expressed as the specific surface in square centimeters per gram of particles.
    In a particularly preferred embodiment according to the invention, the fluxed pellets of metallic ore, in particular the fluxed pellets of iron ore, have a size distribution characterized by 90% to 98% of the pellets which have a diameter of between 8 and 16 mm.
    In a particularly preferred embodiment according to the invention, the fluxes of metal ore pellets are fluxes of iron ore pellets comprising a concentrate of fine iron ore chosen from the group consisting of magnetite, hematite and their mixtures.
    In another embodiment of the present invention, the fluxed pellets of metal ore, in particular the fluxed pellets of iron ore, further comprise a flux selected from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    Preferably, said flow is between 0.5% and 15% by weight relative to the total weight of the pellets.
    Advantageously, according to the present invention, fluxed pellets of metallic ore, in particular fluxed pellets of iron ore, are fluxed pellets of raw metallic ore, in particular fluxed pellets of raw iron ore.
    BE2017 / 5875
    The moisture content of the pellets is controlled even in the absence of bentonite and the mechanical and metallurgical properties of the pellets are improved.
    The fluxed pellets of raw metallic ore are characterized by a resistance to grinding before drying (“wet pellet”) which is between 10 and 30 N per pellet and after drying (“dried pellet”) which is between 30 and 90 N by pellet.
    The fluxed pellets of raw metallic ore according to the present invention have an impact temperature equal to or greater than 250 ° C.
    By the expression "impact temperature" is meant according to the present invention the minimum temperature at which cracks occur in wet raw pellets when they are placed inside a hot muffle, directly from room temperature . For this purpose, various samples of raw pellets are individually subjected to a gradually increased temperature. Typically, a first sample will be subjected to 200 ° C, a second to 250 ° C, ..., until cracked pellets are observed in a sample. These cracks appear very quickly (after a few minutes) in the pellets after submission to the setting temperature.
    Alternatively, the metal ore flux pellets, in particular the iron ore flux pellets according to the present invention, are baked metal ore flux pellets, in particular baked iron ore flux pellets.
    Thanks to the semi-hydrated dolime used as a binder in the present invention, the cooked pellets also have better mechanical properties after the hardening process. The resistance to grinding of the pellets cooked according to the present invention
    BE2017 / 5875 measured according to the ISO 4700 standard is between 2,000 and 5,000 N / pellet, preferably between 2,500 and 5,000 N / pellet.
    In addition, the quality of the pellets cooked according to the present invention is improved, because the replacement of the minerals contained in the bentonite allows, for example, the reduction of the volume of slag in the blast furnace or in the electric arc furnace after the reactor. direct reaction.
    Preferably, the pellets cooked according to the present invention contain less than 10%, in particular less than 5% by weight of SiO 2 relative to the total weight of the pellets.
    The total metal content, in particular of iron, in the cooked pellets is preferably equal to or greater than 55%, in particular equal to or greater than 60%, advantageously equal to or greater than 65% by weight relative to the total weight of the pellets .
    The metallurgical properties of the cooked pellets obtained according to the present invention have a reducibility above 0.70% / minute, according to standard ISO 4695 "Determination of the reducibility by the rate of reduction index", below a 20% swelling (by ascending force), according to ISO 4698 standard "Determination of the free swelling index" and a crushing resistance after reduction above 150 N / pellet, according to ISO 4696 standard "Determination of 'low temperature reduction / disintegration indices by a static process'. The use of semi-hydrated dolomite containing magnesium hydroxide in a proportion of between 0.5 and 19.5% by weight as a binder in fluxes pellets of metallic ore therefore allows the production of fluxes pellets of metallic ore having adequate mechanical properties in conjunction with a suitable chemical composition for use in an electric furnace or blast furnace.
    BE2017 / 5875
    Other embodiments of the use according to the invention are mentioned in the appended claims.
    The invention also relates to a process for manufacturing fluxed pellets of metallic ore, in particular fluxed pellets of iron ore, comprising the steps consisting in:
    - convey a concentrate of fine metallic ore, in particular an iron ore concentrate in a container;
    - conveying a binder in said container;
    - adjust the humidity in said container to form a wet mixture;
    - Agglomerate and sift said wet mixture into fluxes of raw metal ore pellets, in particular fluxes of raw iron ore pellets;
    characterized in that said binder is a compound comprising magnesium comprising semi-hydrated dolomite corresponding to the general formula aCa (OH) 2.bMg (OH) 2.cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    The agglomeration and sieving step is preferably carried out in a granulation tank such as a drum or a disc (bowl) which may or may not be the container.
    The residence time of the wet mixture to form the pellets inside the granulation drum is between 50 and 200 s for pellets with a diameter between 8 and 16 mm.
    Preferably, the method according to the present invention further comprises the step of hardening fluxed pellets of raw metal ore, in particular flux pellets of raw iron ore in a hardening furnace.
    BE2017 / 5875
    Said hardening step advantageously comprises the steps consisting in:
    - drying the raw pellets at around 300 ° C for a predetermined period of between 5 min and 15 min to form dried raw pellets;
    - preheat the dried raw pellets to a temperature equal to or higher than 800 ° C during a predetermined period of between 5 min and 20 min to form preheated raw pellets;
    - bake raw pellets preheated to a temperature equal to or higher than 1200 ° C during a predetermined period of between 5 min and 20 min to form pellets with fluxes of cooked metal ore, in particular pellets with fluxes of iron ore cooked.
    Advantageously, according to the present invention, the humidity adjustment step is a step of adding an aqueous phase to form said wet mixture.
    The step of adding an aqueous phase is preferably a gradual addition of the aqueous phase to the powder mixture.
    Preferably, the aqueous phase is water.
    Advantageously, according to the invention, the humidity adjustment step is carried out until said mixture has a moisture content of between 5% and 15% by weight relative to the total weight of said mixture.
    In another embodiment of the method according to the invention, the fluxed pellets of raw metal ore, in particular the fluxed pellets of raw iron ore, have a size distribution characterized by 90% to 98% of the pellets which have a diameter between 8 and 16 mm.
    Preferably, the method according to the invention further comprises a step of supplying a flow before the humidity adjustment step, the flow preferably being selected from the group
    BE2017 / 5875 consisting of calcium carbonate, olivine, pyroxenite, other magnesium silicates and their mixtures.
    Preferably, the weight fraction c of MgO is greater than or equal to 5%, preferably greater than or equal to 10%, advantageously greater than or equal to 15%, preferably greater than or equal to 20% by weight of MgO relative to the weight total of said semi-hydrated dolomite and is less than or equal to 41%, preferably less than or equal to 30% by weight of MgO relative to the total weight of said semi-hydrated dolomite, the weight fraction a of Ca (OH) 2 is greater than or equal to 15%, preferably greater than or equal to 30%, advantageously greater than or equal to 40%, better still greater than or equal to 45% by weight of Ca (OH) 2 relative to the total weight of said semi dolomite -hydrated and is less than or equal to 85%, preferably less than or equal to 65%, advantageously less than or equal to 60%, better still less than or equal to 55% by weight of Ca (OH) 2 relative to the total weight of said semi-hydrous dolomite atée.
    Advantageously, in the process according to the invention, the binder is added in an amount of between 0.5% and 5%, preferably between 0.5% and 1.5% by weight relative to the total weight of the pellets.
    Alternatively, according to the present invention, the weight fraction of semi-hydrated dolomite is between 80% and 100%, preferably between 90% and 100%, better still between 95% and 100%, advantageously between 97% and 100% , preferably between 98% and 100% by weight relative to the total weight of binder. In a particular embodiment of the invention, the semi-hydrated dolomite is 100% by weight relative to the total weight of the binder.
    In the process according to the invention, said concentrate of fine metallic ore, in particular iron ore concentrate advantageously has a Blaine fineness of between 1,500 cm / 2 and
    500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    BE2017 / 5875
    Other embodiments of the method according to the invention are mentioned in the appended claims.
    The present invention also relates to a composition of fluxed pellets of metallic ore, in particular of fluxed pellets of iron ore, comprising:
    - a concentrate of fine metal ore, in particular an iron ore concentrate in an amount between 80% by weight and% by weight relative to the total weight of the composition of pellets flowed from metal ore;
    a compound including magnesium as binder in an amount of between 0.1% by weight and 5% by weight, in particular between 0.5% by weight and 1.5% by weight relative to the total weight of the composition of pellets metallic ore streams;
    a moisture content of between 5% by weight and 15% by weight relative to the total weight of the composition of pellets streamed from metal ore;
    characterized in that the compound including magnesium comprises a semi-hydrated dolomite corresponding to the general formula aCa (OH) 2 .bMg (OH) 2 .cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    Alternatively, according to the present invention, the weight fraction of semi-hydrated dolomite is between 80% and 100%, preferably between 90% and 100%, better still between 95% and 100%, advantageously between 97% and 100% , preferably between 98% and 100% by weight relative to the total weight of the binder. In a particular embodiment of the invention, the semi-hydrated dolomite is
    100% by weight relative to the total weight of the binder.
    Advantageously, the composition according to the invention also comprises from 0.5% by weight to 15% by weight of additives as
    BE2017 / 5875 that flux relative to the total weight of the composition of pellets fluxed from metallic ore.
    Preferably, in the composition according to the invention, the weight fraction c of MgO is greater than or equal to 5%, preferably greater than or equal to 10%, advantageously greater than or equal to 15%, preferably greater than or equal to 20% by weight of MgO relative to the total weight of said semi-hydrated dolomite and is less than or equal to 41%, preferably less than or equal to 30% by weight of MgO relative to the total weight of said semi-hydrated dolomite, the fraction by weight of Ca (OH) 2 is greater than or equal to 15%, preferably greater than or equal to 30%, advantageously greater than or equal to 40%, better still greater than or equal to 45% by weight of Ca (OH) 2 by relative to the total weight of said semi-hydrated dolomite and is less than or equal to 85%, preferably less than or equal to 65%, advantageously less than or equal to 60%, better still less than or equal to 55% by weight of Ca (OH ) 2 compared to total weight of said semi-hydrated dolomite.
    In another embodiment of the composition according to the invention, the semi-hydrated dolomite comprises particles having a BET specific surface obtained by nitrogen adsorption of between 5 and 25 m 2 / g, preferably between 10 m 2 / g and 20 m 2 / g.
    Preferably, the semi-hydrated dolomite of the composition according to the invention comprises particles having a total pore volume BJH consisting of pores having a diameter less than 1000 Å, obtained by desorption of nitrogen of between 0.05 and 0 , 15 cm 3 / g.
    Preferably, the semi-hydrated dolomite comprises particles having a size characterized by a d w equal to or greater than 0.5 μm and / or a d 5 o comprised between 4 μm and 8 μm and / or a d 97 comprised between 40 μm and 94 μm.
    BE2017 / 5875
    As a variant, the metal ore concentrate, in particular the iron ore concentrate, has particles having a Blaine fineness of between 1,500 cm 2 / g and 2,500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    Preferably, the fine iron ore concentrate is selected from the group consisting of magnetite, hematite and their mixtures.
    In a preferred embodiment, the composition according to the invention further comprises a flux selected from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    Other embodiments of the composition of fluxes of metal ore pellets, in particular of fluxes of iron ore pellets according to the invention are mentioned in the appended claims.
    The present invention also relates to fluxed pellets of raw metallic ore, in particular fluxed pellets of raw iron ore comprising:
    - a concentrate of fine metal ore, in particular an iron ore concentrate in an amount between 80% by weight and 99% by weight relative to the total weight of the pellets fluxed of raw metal ore;
    a compound comprising magnesium as binder in an amount of between 0.1% by weight and 5% by weight, in particular between 0.5% by weight and 1.5% by weight relative to the total weight of the pellets streamed from ore raw metal;
    - a moisture content of between 5% by weight and 15% by weight relative to the total weight of the pellets streamed from raw metallic ore;
    BE2017 / 5875 characterized in that the compound comprising magnesium comprises a semi-hydrated dolime corresponding to the general formula aCa (OH) 2.bMg (OH) 2.cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite, of said pellets fluxed with raw metallic ore.
    Alternatively, according to the present invention, the weight fraction of semi-hydrated dolomite is between 80% and 100%, preferably between 90% and 100%, better still between 95% and 100%, advantageously between 97% and 100% , preferably between 98% and 100% by weight relative to the total weight of the binder. In a particular embodiment of the invention, the semi-hydrated dolomite is 100% by weight relative to the total weight of the binder.
    In particular, said fluxed pellets of raw iron ore also have a grinding resistance of between 10 and 30 N / pellet.
    Advantageously, the fluxed pellets of raw metallic ore, in particular the fluxed pellets of raw iron ore, further comprise from 0.5% by weight to 15% by weight of additives as fluxes relative to the total weight of the fluxed pellets of raw metal ore.
    Alternatively, according to the present invention, the fluxed pellets of raw metal ore, in particular the fluxed pellets of raw iron ore, have an impact temperature equal to or greater than 250 ° C.
    Preferably, said fluxed pellets of raw metallic ore, in particular said fluxed pellets of raw iron ore further exhibit a grinding resistance between 30 and 90 N / pellet after drying.
    This means that the raw pellets have a crushing resistance of between 10 and 30 N / pellet before drying when this
    BE2017 / 5875 are wet raw pellets, and have a crushing resistance between 30 and 90 N / pellet after drying when they consist of dried raw pellets.
    The drying step is carried out at approximately 105 ° C during a predetermined period typically between 12 hours and 24 hours.
    Advantageously, the fluxed pellets of raw metallic ore, in particular the fluxed pellets of raw iron ore according to the invention have a size distribution in which 90% to 98% of the pellets have a diameter of between 8 and 16 mm.
    The fluxed pellets of raw metal ore, in particular the fluxed pellets of raw iron ore according to the invention advantageously comprise a concentrate of fine iron ore selected from the group consisting of magnetite, hematite and their mixtures.
    Preferably, the fluxed pellets of raw metallic ore, in particular the fluxed pellets of raw iron ore according to the invention additionally comprise a flux selected from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    Advantageously, the raw pellets according to the invention contain a metal ore concentrate, in particular an iron ore concentrate having particles having a Blaine fineness of between 1,500 cm 2 / g and 2,500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    Other embodiments of fluxes pellets of raw metal ore, in particular of pellets fluxes of iron ore raw according to the invention are mentioned in the claims appended hereto.
    The present invention also relates to fluxed pellets of cooked metallic ore, in particular fluxed pellets of cooked iron ore comprising:
    BE2017 / 5875
    - a metal content of 55% or more, in particular 60% or more, advantageously 65% or more by weight relative to the total weight of the pellets, characterized in that the pellets have a Ca / Mg ratio between 0.8 and 2, in particular between 0.8 and 1.7, better still between 0.8 and 1.2 and have a grinding resistance measured according to ISO 4700 standard between 2,000 and 5,000 N / pellet , preferably between 2,500 and 5,000 N / pellet.
    In another embodiment of the cooked pellets according to the invention, said cooked metallic ore fluxed pellets, in particular the cooked iron ore fluxed pellets contain less than 10%, in particular less than 5% by weight of SiO 2 per relative to the total weight of the pellets.
    The fluxed pellets of cooked metal ore, in particular the fluxed pellets of iron ore cooked according to the invention advantageously comprise a concentrate of fine iron ore selected from the group consisting of magnetite, hematite and their mixtures.
    Preferably, the fluxed pellets of cooked metallic ore, in particular the fluxed pellets of iron ore cooked according to the invention further comprise a flux selected from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    In a particularly preferred embodiment according to the invention, the fluxed pellets of baked metal ore, in particular the fluxed pellets of baked iron ore have a size distribution, in which 90% to 98% of the pellets have a diameter between 8 and 16 mm.
    Other embodiments of baked metal ore flux pellets, in particular baked iron ore flux pellets according to the invention are mentioned in the appended claims.
    BE2017 / 5875
    EXAMPLES
    A composition containing the binder according to the invention has been used and has the characteristics presented in Table 1. In Table 1, the percentages by weight are expressed 5 relative to the total weight of the pellets.
    BE2017 / 5875
    Table 1
    Alkalinity expressed as (CaO / SiO 2 ) 0.75 Mg expressed as MgO (% by weight) 1.3 Magnetite (% by weight) 57.4 Hematite (% by weight) 36.6 Limestone (% by weight) 1.2 Dolomite (% by weight) 2.8 Semi-hydrated dolomite (% by weight) 1.5 Bentonite (% by weight) 0 Anthracite (% by weight) 0.5
    The quantity of elementary Mg expressed as MgO represents the quantity of elementary Mg in the mixture of the various components forming the composition of the pellets.
    Limestone and dolomite appear as flux. Water is added to the composition according to Table 1 in order to agglomerate and to sieve the wet mixture obtained in raw pellets.
    The raw pellets are dried at about 300 ° C to form dried raw pellets. The dried raw pellets are preheated to 800 ° C to form preheated raw pellets. The preheated raw pellets are baked at 1280 ° C to form cooked pellets. The total cycle time from the drying step to the end of the cooking step is
    22.4 minutes and the height of the bed between the raw logs and the hearth layer is 300/100 mm.
    The cooked pellets have 64.2% by weight of Fe and 4.2% by weight of SiO 2 based on the total weight of the cooked pellets.
    The crushing resistance of the cooked pellets measured according to the ISO 4700 standard is 3,320 N / pellet.
    The cooked pellets are subjected to a swelling test according to standard ISO 4698 and then the grinding resistance of the pellets is measured according to standard ISO 4700.
    BE2017 / 5875
    Then, the cooked pellets are subjected to a reducibility test according to standard ISO 4695, then the grinding resistance of the pellets is measured according to standard ISO 4700.
    Finally, the cooked pellets are subjected to a disintegration test according to standard ISO 4696 and, thereafter, the grinding resistance of the pellets is measured according to standard ISO 4700.
    The results of these measurements are illustrated in Table 2.
    Table 2
    Resistance to grinding according to ISO 4700 on pellets after a swelling test according to ISO 4698 (N / pellet) 180 Resistance to grinding according to ISO 4700 standard on pellets after a reducibility test according to ISO 4695 standard (N / pellet) 420 Resistance to grinding according to ISO 4700 standard on pellets after a disintegration test according to ISO 4696 standard (N / pellet) 260
    A composition containing a binder according to the invention has been used and has the characteristics shown in Table 3. In Table 3, the percentages by weight are expressed relative to the total weight of the pellets.
    Table 3
    Alkalinity expressed as (CaO / SiO 2 ) 0.2 Mg expressed as MgO (% by weight) 1.22 Magnetitre (% by weight) 49.5 Hematite (% by weight) 49.5 Binder comprising semi-hydrated dolomite (% by weight) 1
    BE2017 / 5875
    The quantity of elementary Mg expressed as MgO represents the quantity of elementary Mg in the mixture of the various components forming the composition of the pellets.
    The above composition comprises 0.6% by weight of coke and 1.52% by weight of olivine both expressed relative to the sum of the weight of hematite and magnetite.
    The binder composition comprising semihydrated dolomite is presented in Table 4, in which the weight percentages are expressed relative to the total weight of the binder.
    Table 4
    Mg (OH) 2 (% by weight) 1.24 Ca (OH) 2 (% by weight) 57.41 CaCO 3 (% by weight) 2.84 CaO (% by weight) 4.2 MgO (% by weight) 33.1 Fe 2 O 3 (% by weight) 0.42 Other impurities (% by weight) 0.79
    Water is added to the composition to agglomerate and sift the wet mixture obtained into raw pellets.
    The raw pellets are dried at about 300 ° C to form dried raw pellets. The dried raw pellets are preheated to 800 ° C to form preheated raw pellets. The preheated raw pellets are baked at 1,270 ° C to form cooked pellets. The total cycle time from the drying step to the end of the cooking step is
    27.4 min and the height of the bed of raw beads relative to the hearth layer is 300/100 mm.
    The cooked pellets have 66% by weight of Fe and 2.95% by weight of SiO 2 based on the total weight of the cooked pellets.
    The grinding resistance of the cooked pellets measured according to the ISO 4700 standard is 2,920 N / pellet.
    BE2017 / 5875
    The cooked pellets are subjected to a swelling test according to standard ISO 4698 and then the grinding resistance of the pellets is measured according to standard ISO 4700.
    The cooked pellets are subjected to a reducibility test according to the ISO 4695 standard and then the grinding resistance of the pellets is measured according to the ISO 4700 standard.
    Finally, the cooked pellets are subjected to a disintegration test according to standard ISO 4696 and, thereafter, the grinding resistance of the pellets is measured according to standard ISO 4700.
    The results of these measurements are illustrated in the table
    5.
    Table 5
    Resistance to grinding according to ISO 4700 standard on pellets after a swelling test according to ISO 4698 standard (N / pellet) 300 Resistance to grinding according to ISO 4700 standard on pellets after a reducibility test according to ISO 4695 standard (N / pellet) 310 Resistance to grinding according to ISO 4700 standard on pellets after a disintegration test according to ISO 4696 standard (N / pellet) 210
    BE2017 / 5875
    COMPARATIVE EXAMPLE
    A composition containing bentonite as a binder was used and has the characteristics presented in Table 6. In Table 6, the percentages by weight are expressed relative to the total weight of the pellets.
    Table 6
    Alkalinity expressed as (CaO / SiO 2 ) 0.75 Mg expressed as MgO (% by weight) 1.3 Magnetite (% by weight) 56.1 Hematite (% by weight) 36.3 Limestone (% by weight) 1.8 Dolomite (% by weight) 4.7 Semi-hydrated dolomite (% by weight) 0 Bentonite (% by weight) 0.6 Anthracite (% by weight) 0.5
    The quantity of elementary Mg expressed as MgO represents the quantity of elementary Mg in the mixture of the various components forming the composition of the pellets.
    Limestone and dolomite appear as flow. Water is added to the composition according to Table 6 in order to agglomerate and to sieve the wet mixture obtained in raw pellets.
    The raw pellets are dried at about 300 ° C to form dried raw pellets. The dried raw pellets are preheated to 800 ° C to form preheated raw pellets. The preheated raw pellets are baked at 1280 ° C to form cooked pellets. The total cycle time from the drying step to the end of the cooking step is
    22.4 minutes and the bed height between the raw logs and the hearth layer is 300/100 mm.
    The cooked pellets have 63.7% by weight of Fe and 3.5% by weight of SiO 2 based on the total weight of the cooked pellets.
    BE2017 / 5875
    The grinding resistance of cooked pellets measured according to the ISO 4700 standard is 2410 N / pellet.
    The cooked pellets are subjected to a swelling test according to standard ISO 4698 and then the grinding resistance of the 5 pellets is measured according to standard ISO 4700.
    Then, the cooked pellets are subjected to a reducibility test according to standard ISO 4695 and, then, the grinding resistance of the pellets is measured according to standard ISO 4700.
    Finally, the cooked pellets are subjected to a disintegration test according to standard ISO 4696 and, thereafter, the resistance to grinding of the pellets is measured according to standard ISO 4700.
    The results of these measurements are illustrated in the table
    7.
    Table 7
    Resistance to grinding according to ISO 4700 standard on pellets after a swelling test according to ISO 4698 standard (N / pellet) 110 Resistance to grinding according to ISO 4700 standard on pellets after a reducibility test according to ISO 4695 standard (N / pellet) 260 Resistance to grinding according to ISO 4700 standard on pellets after a disintegration test according to ISO 4696 standard (N / pellet) 150
    As can be seen in Tables 2, 5 and 7, the grinding resistances of the cooked pellets made from the composition according to the present invention are much higher than those of the pellets containing bentonite as binder.
    BE2017 / 5875
    权利要求:
    Claims (47)
    [1]
    Claims
    1. Use of a compound including magnesium as a binder for producing fluxed pellets of metal ore, in particular fluxed pellets of iron ore, characterized in that the compound including magnesium comprises semi-hydrated dolomite responding to the general formula aCa (OH) 2.bMg (OH) 2 .cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    [2]
    2. Use according to claim 1, wherein the weight fraction of said binder is between 0.5% and 5%, preferably between 0.5% and 1.5% by weight relative to the total weight of the pellets.
    [3]
    3. Use according to claim 1 or claim 2, in which the weight fraction of semi-hydrated dolomite is between 70% and 100%, preferably between 75% and 100%, better still between 80% and 100%, advantageously between 85% and 100%, better still between 90% and 100% by weight relative to the total weight of the binder.
    [4]
    4. Use according to any one of claims 1 to
    3, in which the weight fraction c of MgO is greater than or equal to 5%, preferably greater than or equal to 10%, advantageously greater than or equal to 15%, preferably greater than or equal to 20% by weight of MgO relative to the total weight of said semi-hydrated dolomite and is less than or equal to 41%, preferably less than or equal to 30% by weight of MgO relative to the total weight of said semi-hydrated dolomite.
    [5]
    5. Use according to any one of claims 1 to
    4, in which the weight fraction a of Ca (OH) 2 is greater than or equal to 15%, preferably greater than or equal to 30%, advantageously greater than or equal to 40%, better still greater than or equal to 45% by weight of Ca (OH) 2 relative to the total weight of said
    BE2017 / 5875 semi-hydrated dolomite and is less than or equal to 85%, preferably less than or equal to 65%, advantageously less than or equal to 60%, better still less than or equal to 55% by weight of Ca (OH) 2 per relative to the total weight of said semi-hydrated dolomite.
    [6]
    6. Use according to any one of claims 1 to 5, wherein the semi-hydrated dolomite is in powder form.
    [7]
    7. Use according to any one of claims 1 to 5, in which the semi-hydrated dolomite is in the form of an aqueous suspension of said semi-hydrated dolomite.
    [8]
    8. Use according to any one of claims 1 to
    7, in which the semi-hydrated dolomite comprises particles having a BET specific surface obtained by nitrogen adsorption of between 5 and 25 m 2 / g, preferably between 10 m 2 / g and 20 m 2 / g.
    [9]
    9. Use according to any one of claims 1 to
    8, in which the semi-hydrated dolomite comprises particles having a total pore volume BJH consisting of pores with a diameter less than 1000 Å, obtained by nitrogen desorption of between 0.05 and 0.15 cm 3 / g.
    [10]
    10. Use according to any one of claims 1 to 9, in which the semi-hydrated dolomite comprises particles having a d w greater than or equal to 0.5 μm.
    [11]
    11. Use according to any one of claims 1 to 10, in which the semi-hydrated dolomite comprises particles having a d 5 o of between 4 μm and 8 μm.
    [12]
    12. Use according to any one of claims 5 to 11, in which the semi-hydrated dolomite comprises particles having a d 97 of between 40 μm and 95 μm.
    [13]
    13. Use according to any one of the preceding claims, in which the streamed ore pellets
    BE2017 / 5875 metallic, in particular fluxed iron ore pellets, contains a metallic ore concentrate, in particular an iron ore concentrate having particles having a Blaine fineness of between 1,500 cm 2 / g and 2,500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    [14]
    14. Use according to any one of the preceding claims, in which the fluxes of metallic ore pellets, in particular the fluxed pellets of iron ore have a size distribution in which 90% to 98% of the pellets have a diameter of between 8 and 16 mm.
    [15]
    15. Use according to any one of the preceding claims, in which the fluxes of metal ore pellets are fluxes of iron ore pellets comprising a concentrate of fine iron ore chosen from the group consisting of magnetite, hematite and of their mixtures.
    [16]
    16. Use according to any one of the preceding claims, in which the fluxes pellets of metal ore, in particular the flux pellets of iron ore further comprise a flux selected from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates, such as dunite, and their mixtures.
    [17]
    17. Use according to any one of the preceding claims, in which the fluxes of metal ore pellets, in particular the fluxes of iron ore pellets are fluxes of raw metal ore pellets, in particular of the fluxes of raw iron ore pellets.
    [18]
    18. Use according to any one of the preceding claims 1 to 16, in which the metal ore fluxed pellets, in particular the iron ore fluxed pellets are
    BE2017 / 5875 Flaked pellets of baked metal ore, in particular pellets of baked iron ore.
    [19]
    19. Method for manufacturing fluxes of metal ore pellets, in particular fluxes of iron ore pellets, comprising the steps consisting in:
    - convey a concentrate of fine metallic ore, in particular an iron ore concentrate in a container;
    - conveying a binder in said container;
    - adjust the humidity in said container to form a wet mixture;
    - Agglomerate and sift said wet mixture into fluxes of raw metal ore pellets, in particular fluxes of raw iron ore pellets;
    characterized in that said binder is a compound including magnesium comprising a semi-hydrated dolomite corresponding to the general formula aCa (OH) 2.bMg (OH) 2.cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    [20]
    20. The method of claim 19, further comprising a baking step to harden the fluxed pellets of raw metal ore, in particular the fluxed pellets of iron ore raw in an induration furnace.
    [21]
    21. The method according to claim 20, wherein said curing step comprises the steps consisting in:
    - drying the fluxed pellets of raw metal ore at around 300 ° C for a predetermined period of between 5 min and 15 min to form dried raw pellets;
    - preheat the fluxed pellets of dried raw metallic ore to a temperature equal to or higher than 800 ° C during a
    BE2017 / 5875 predetermined period between 5 min and 20 min to form preheated raw pellets;
    - baking the fluxed pellets of raw metallic ore preheated to a temperature equal to or greater than 1200 ° C during a predetermined period of between 5 min and 20 min to form fluxed pellets of cooked metallic ore, in particular fluxed pellets cooked iron ore.
    [22]
    22. Method according to any one of claims 19 to 21, in which the humidity adjustment step is a step of adding an aqueous phase to form said mixture.
    [23]
    23. Method according to any one of claims 19 to 22, in which the humidity adjustment step is carried out until said mixture has a moisture content of between 5% and 15% by weight per relative to the total weight of said mixture.
    [24]
    24. The method according to any one of claims 19 to 23, in which said fluxes of raw metallic ore pellets, in particular the flux of raw iron ore pellets have a size distribution, in which 90% to 98% of the pellets have a diameter between 8 and 16 mm.
    [25]
    25. Method according to any one of claims 19 to 24, further comprising a step of conveying a flux before the humidity adjustment step, the flux preferably being chosen from the group consisting of carbonate calcium, olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    [26]
    26. Method according to any one of claims 19 to 25, in which the weight fraction c of MgO is greater than or equal to 5%, preferably greater than or equal to 10%, advantageously greater than or equal to 15%, preferably greater or equal to 20% by weight of MgO relative to the total weight of said semi-dolomite
    BE2017 / 5875 hydrated and is less than or equal to 41%, preferably less than or equal to 30% by weight of MgO relative to the total weight of said semi-hydrated dolomite, the weight fraction a of Ca (OH) 2 is greater or equal to 15%, preferably greater than or equal to 30%, advantageously greater than or equal to 40%, better still greater than or equal to 45% by weight of Ca (OH) 2 relative to the total weight of said semi-hydrated dolomite and is less than or equal to 85%, preferably less than or equal to 65%, advantageously less than or equal to 60%, better still less than or equal to 55% by weight of Ca (OH) 2 relative to the total weight of said semi dolomite -hydrated.
    [27]
    27. Method according to any one of claims 19 to 26, in which the weight fraction of said binder is between 0.5% and 5%, preferably between 0.5% and 1.5% by weight relative to the weight total pellets.
    [28]
    28. Method according to any one of claims 19 to 27, in which said concentrate of fine metallic ore, in particular iron ore concentrate has a Blaine fineness of between 1,500 cm 2 / g and 2,500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    [29]
    29. Composition of fluxes of metallic ore, in particular of fluxes of iron ore, comprising:
    - a concentrate of fine metallic ore, in particular an iron ore concentrate in an amount between 80% by weight and 99% by weight relative to the total weight of the composition of pellets flowed from metallic ore;
    a compound including magnesium as binder in an amount of between 0.1% by weight and 5% by weight, in particular between 0.5% by weight and 1.5% by weight relative to the total weight of the composition of pellets metallic ore streams;
    BE2017 / 5875
    a moisture content of between 5% by weight and 15% by weight relative to the total weight of the composition of pellets streamed from metal ore;
    characterized in that the compound including magnesium comprises a semi-hydrated dolomite corresponding to the general formula aCa (OH) 2 .bMg (OH) 2 .cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    [30]
    30. A composition of fluxed metal ore pellets, in particular a composition of fluxed iron ore pellets according to claim 29, further comprising from 0.5% by weight to 15% by weight of additives as flux relative to the total weight of the composition of metal ore streamed pellets.
    [31]
    31. Composition of fluxes of metallic ore pellets, in particular composition of fluxes of metallic ore pellets according to claim 29 or claim 30, in which the weight fraction c of MgO is greater than or equal to 5%, preferably greater than or equal to 10%, advantageously greater than or equal to 15%, preferably greater than or equal to 20% by weight of MgO relative to the total weight of said semi-hydrated dolomite and is less than or equal to 41%, preferably less than or equal to 30 % by weight of MgO relative to the total weight of said semi-hydrated dolomite, the weight fraction a of Ca (OH) 2 is greater than or equal to 15%, preferably greater than or equal to 30%, advantageously greater than or equal to 40 %, better still greater than or equal to 45% by weight of Ca (OH) 2 relative to the total weight of said semi-hydrated dolomite and is less than or equal to 85%, preferably less than or equal at 65%, advantageously less than or equal to 60%, better still less than or equal to 55% by weight of Ca (OH) 2 relative to the total weight of said semi-hydrated dolomite.
    BE2017 / 5875
    [32]
    32. Composition of fluxes of metallic ore pellets, in particular composition of fluxes of iron ore pellets according to any one of claims 29 to 31, in which the semihydrated dolomite comprises particles having a BET specific surface obtained by adsorption of nitrogen. between 5 and 25 m 2 / g, preferably between 10 m 2 / g and 20 m 2 / g.
    [33]
    33. Composition of fluxes of metallic ore pellets, in particular composition of fluxes of iron ore pellets according to any one of Claims 29 to 32, in which the semihydrated dolomite comprises particles having a total BJH pore volume consisting of pores of '' a diameter less than 1000 Å, obtained by nitrogen desorption of between 0.05 and 0.15 cm 3 / g.
    [34]
    34. Composition of fluxes of metallic ore pellets, in particular composition of fluxes of iron ore pellets according to any one of claims 29 to 33, in which the semihydrated dolomite comprises particles having a size characterized by a dw greater than or equal to 0.5 μm and / or d 5 o between 4 μm and 8 μm and / or d 97 between 40 μm and 95 μm.
    [35]
    35. Composition of fluxed metal ore pellets, in particular composition of fluxed iron ore pellets according to any one of Claims 29 to 34, in which the metal ore concentrate, in particular the iron ore concentrate, has particles having a Blaine fineness of between 1,500 cm 2 / g and 2,500 cm 2 / g, preferably between 1,800 cm 2 / g and 2,200 cm 2 / g.
    [36]
    36. Composition of fluxes of metallic ore pellets, in particular composition of fluxes of iron ore pellets according to any one of Claims 29 to 35, in which the concentrate of fine iron ore is chosen from the group consisting of magnetite, hematite and their mixtures.
    BE2017 / 5875
    [37]
    37. Composition of fluxes of metallic ore pellets, in particular composition of fluxes of iron ore pellets according to any one of Claims 29 to 36, further comprising a flux chosen from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    [38]
    38. Fluxed pellets of raw metallic ore, in particular fluxed pellets of raw iron ore comprising:
    - a concentrate of fine metal ore, in particular an iron ore concentrate in an amount between 80% by weight and 99% by weight relative to the total weight of the pellets fluxed of raw metal ore;
    a compound including magnesium as binder in an amount of between 0.1% by weight and 5% by weight, in particular between 0.5% by weight and 1.5% by weight relative to the total weight of the pellets streamed from ore raw metal;
    - a moisture content of between 5% by weight and 15% by weight relative to the total weight of the pellets streamed from raw metallic ore;
    characterized in that the compound including magnesium comprises a semi-hydrated dolomite corresponding to the general formula aCa (OH) 2.bMg (OH) 2 .cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite, pellets fluxed from raw metallic ore.
    [39]
    39. Fluxed pellets of raw metal ore, in particular fluxed pellets of raw iron ore according to claim 38, further comprising from 0.5% by weight to 15% by weight of additives as flow relative to the total weight of the pellets streamed of raw metallic ore.
    BE2017 / 5875
    [40]
    40. Fluxed pellets of raw metal ore, in particular fluxed pellets of raw iron ore according to claim 38 or claim 39, in which said fluxed pellets of raw metallic ore, in particular said fluxed pellets of raw iron ore an impact temperature of 250 ° C or more.
    [41]
    41. Flux pellets of raw metal ore, in particular flux pellets of raw iron ore according to any one of claims 38 to 40, in which said flux pellets of raw metal ore, in particular pellets flux of raw iron ore have a distribution of sizes, in which 90% to 98% of the pellets have a diameter of between 8 and 16 mm.
    [42]
    42. Fluxed pellets of raw metal ore, in particular fluxed pellets of raw iron ore according to any one of claims 38 to 41, in which the fluxed pellets of raw metal ore, in particular the fluxed pellets of raw iron ore a concentrate of fine iron ore chosen from the group consisting of magnetite, hematite and their mixtures.
    [43]
    43. Flux pellets of raw metallic ore, in particular flux pellets of raw iron ore according to any one of claims 38 to 42, further comprising a flux chosen from the group consisting of calcium carbonate, dolomite, l olivine, pyroxenite, other magnesium silicates, such as dunite, and mixtures thereof.
    [44]
    44. Flaked pellets of baked metal ore, in particular pellets of baked iron ore comprising:
    - a metal content of 55% or more, in particular 60% or more, advantageously 65% or more by weight relative to the total weight of the pellets, characterized in that the pellets have a Ca / Mg ratio between 0.8
    BE2017 / 5875 and 2, in particular between 0.8 and 1.7, better still between 0.8 and 1.2 and have a grinding resistance measured according to ISO 4700 standard of between 2,000 and 5,000 N / pellet, preferably between
    2,500 and 5,000 N / pellet.
    [45]
    45. Flux-cured metal ore pellets, in particular flux-cured iron ore pellets according to claim 44, wherein said flux-cured metal ore pellets, especially flux-cured iron ore pellets contain less than 10%, especially less than 5% by weight of SiO 2 relative to the total weight of the pellets.
    [46]
    46. Flux-cured metallic ore pellets, in particular flux-dried iron ore pellets according to any one of claim 44 or claim 45, in which flux-burned metallic ore pellets, in particular fluxed ore pellets of cooked iron comprises a concentrate of fine iron ore chosen from the group consisting of magnetite, hematite and their mixtures.
    [47]
    47. Flux-capped pellets of cooked metal ore, in particular flux-dried pellets of iron ore cooked according to any one of claims 44 to 46, further comprising a flux selected from the group consisting of calcium carbonate, dolomite, l olivine, pyroxenite, other magnesium silicates such as dunite and their mixtures.
    BE2017 / 5875
    SHORT
    Metallic ore pellets
    The present invention relates to the use of a compound including magnesium as a binder for producing fluxed pellets of metal ore, in particular fluxed pellets of iron ore, said compound including magnesium comprising semihydrated dolomite corresponding to the formula general aCa (OH) 2.bMg (OH) 2.cMgO, a, b and c being weight fractions, in which the weight fraction b of Mg (OH) 2 is between 0.5 and 19.5% by weight relative to the total weight of said semi-hydrated dolomite.
    PATENT COOPERATION TREATY
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    同族专利:
    公开号 | 公开日
    FR3059338A1|2018-06-01|
    PH12019501147A1|2019-08-19|
    US20200190623A1|2020-06-18|
    AU2017367143A1|2019-06-27|
    MX2019006058A|2019-07-10|
    WO2018099559A1|2018-06-07|
    KR20190090815A|2019-08-02|
    WO2018100064A1|2018-06-07|
    EP3548642A1|2019-10-09|
    BR112019010832A2|2019-10-01|
    ZA201903755B|2020-12-23|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    GB990672A|1963-02-01|1965-04-28|Kennedy Van Saun Mfg & Eng|Improvements in method of pelletizing finely divided solid materials|
    EP1659190A2|2004-11-17|2006-05-24|ISM Inc.|A slag conditioner composition, process for manufacture and method of use in steel production|
    FR3008405A1|2013-07-15|2015-01-16|Lhoist Rech & Dev Sa|COMPOSITION COMPRISING CALCO MAGNEI COMPOUNDS IN THE FORM OF COMPACTS|
    法律状态:
    2018-12-13| FG| Patent granted|Effective date: 20181120 |
    优先权:
    申请号 | 申请日 | 专利标题
    EPPCT/EP2016/079338|2016-11-30|
    PCT/EP2016/079338|WO2018099559A1|2016-11-30|2016-11-30|Metallic ore pellets|
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