• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention concerns a process for sulfuric acid treatment of clays or aluminiferous minerals to obtain pure aluminum oxide via a basic intermediate. The process finds application in the production of aluminum through fusion electrolysis and for the production of different types of alumina. The process provides a mass production method which is economically and technically superior over the prior art methods. The mechanically and/or thermally pretreated raw material is subjected to a two-step pressure treatment with sulfuric acid solution. The aluminum sulfate solution is treated to reduce the iron with SO2 and hydrolytic precipitation of basic aluminum sulfates. After separation of the salts from the mother liquor, which is returned to the process, the aluminum sulfate is thermally decomposed. The SO2/SO3-containing waste gases from the decomposition are used to renew the treatment acid.
    公开号:SU941291A1
    申请号:SU787770389
    申请日:1978-12-13
    公开日:1982-07-07
    发明作者:Зигфрид Цигенбальд；Герхард Хааке；Гунтер Гейлер
    申请人:Феб Мансфельд Комбинат Вилхельм Пик (Инопредприятие)；
    IPC主号:
    专利说明:

    (S) METHOD OF OBTAINING A CLEAN
    This invention relates to industrial methods for the sulfuric acid leaching of clays or alumina minerals to obtain pure alumina through the main intermediate product. five
    A known method of producing aluminum oxide involves leaching A120-containing sulfuric acid minerals at elevated pressure and temperature, separating the insoluble cake, reducing the iron-containing solution to avoid precipitation, hydrolysis of the aluminum sulfate solution, and thermally decomposing the precipitated basic sulfate. aluminum veil (AS I 179 919).
    In this connection, it is known that the yield of the solid hydrolysis product very strongly depends on the basicity of the solution, as expressed, for example, with respect to the masses SOj: M. To establish a low ratio, it is proposed to add basic aluminum sulphate or active alumina. To do this, use either 25 ALUMINUM OXIDES
    basic sulphate obtained by pressure leaching or active alumina from a thermal decomposition process. As a result of this correction of the mass ratio to 30, the obtained basic sulphate or active alumina is reversed. Such a return of part of the basic sulphate or active alumina greatly loads the turnover of the material. This is reflected in the increase in the cost of energy and equipment, which significantly increases the cost of the process.
    Another known possibility is to increase the basicity of the solution - it is the addition of alkali metal hydroxides or their alloys. The addition of these chemicals for a longer time leads to unacceptable contamination of the final product, i.e. alumina. In order to achieve a product suitable for electrolysis, the corresponding purification steps are outlined, 39 loading the process in instrumental and energy ratios. A method is known for the sulfuric acid leaching of clays and alumina materials, which includes subsequent operations that require high instrumental energy and, at the same time, economic costs. For this reason, this method has not been implemented anywhere in the industry. Other disadvantages of the known process are that the load of the process is inevitable with circulating material, which means unacceptable contamination of the final product and a decrease in its specific weight in the overall yield. The purpose of the invention is to introduce in the technology a number of significant changes to reduce the high technical and energy costs arising from the known method of producing alumina using the sulfuric acid leaching of alumina minerals, as well as to create a technologically simple, cost-effective and feasible in the industry process obtaining alumina of such purity, which is suitable for the production of metallic aluminum according to known methods. The task of the invention is to create a method for producing alumina by two-step leaching of mechanically and / or thermally treated clays or alumina minerals with sulfuric acid under pressure and at elevated temperature, separation, insoluble cake, reduction of iron, hydrolytic precipitation of solid basic aluminum sulphate and its subsequent thermal decomposition. alumina, including the generation of circulating acid from the gases of the decomposition process. The method of obtaining pure alumium oxide consists of several stages and consists in extruding clay to obtain a basic solution of aluminum sulfate, as well as in removing the contaminants with silica cake in just two stages. In the reduction of the initial solution for hydrolysis, in hydrolysis solution and the subsequent crystallization in solid basic aluminum sulfate in one stage. This allows for the first time in the industry to apply the acidic process of alumina production in economically and technologically favorable conditions. The method is characterized by a continuous sequence of individual operations in a cycle, determined by the composition of circulating liquids, pulps and working solutions, characterized by the introduction or selection at certain points of the cycle of important intermediate products, as well as by such reaction conditions as pressure, temperature and exposure. The method includes the following operations. Mechanically and / or thermally treated clay or alumina minerals are leached in the first stage of the process together with the filtrate of the second stage leach at a temperature of IIO-ISO C for 15-60 minutes. The first leaching stage is carried out under the condition that iron is precipitated corresponding to the amount of iron leached during the process, as an insoluble ferric sulfate complex compound with the highest degree of clay dissolution possible. For the first leaching stage (neutral leaching), the required temperature range compared to the known should be reduced to 115-125 seconds in order to prevent a decrease in yield and an increase in the content of impurities in the main sulphate. The operating pressure corresponding to this temperature range is only 2-3 atm. The cake from the first leaching stage is filtered and washed with water, and the soluble fraction of Al2O3 contained therein is almost completely transferred to the solution with a circulating solution containing 10-15 free sulfuric acid, during SO-HO with a leaching time of 15-60 minutes. In the second leaching stage, it is possible to operate at normal pressure, with no significant changes in the recovery of Al 2 O 3 and the composition of the solution. Below are the working conditions and results of the first and second leaching stages: Leaching time in each stage, min 15-60 Temperature in the first stage, s115-125 Temperature in the second stage, s100-T40 Concentration., In the first stage in the second stage 10-15 Extraction (in the first and second stages together), from the content of A1203 in the starting material Up to 30 Under such operating conditions of both leaching stages, a simpler instrumentation of the process can be used. At the subsequent stage of hydrolysis, co-precipitation of the gel in the form of He is necessary. For this, the reduction of Fe to Fe is carried out before hydrolysis. with the help of reducing l, mainly SOj, introduced at a temperature of 20-60 ° C to the solution entering the hydrolysis. In another case, ferric iron is precipitated under hydrolysis conditions under pressure in the form of basic sulphate, similar to aluminum. The filtrate of the first leaching stage, which is fed to the hydrolysis, contains 50-110 g / l A1203 and hydrolyzes at a temperature of 2 AO with exclusion of oxygen in order to avoid reverse oxidation of ferrous iron. The temperature required for the hydrolysis process is significantly determined by the material of the apparatus used, as well as the economic results. From this it can be concluded that the operating temperature range is preferably 220-280 ° C. The main conditions and results of hydrolysis under pressure are given below. Duration of hydrolysis, min 30 Weight ratio 50z: A120z2.0-2.8 Temperature, s 220-280 Yield during hydrolysis,% 50-70 Composition of basic sulphate,%: AGHOz 38.5- 38.7 ,, 0 Fe203. 0.01-0.03 Ti020.01-0.02, 01-0.015 0.01-0.02 40.01 0.01 0.1-0.2 The fact that it is possible to achieve a high recovery of Al-, 0 by hydrolysis under the specified conditions without the addition of active alumina or other chemicals, which by methods known before was considered necessary. It is found that magnesium ions to a concentration of 30-90 g / l MSW lead to a strong increase in yield during hydrolysis, without contaminating the solid basic aluminum sulphate formed during the hydrolysis, as the above composition of basic aluminum sulphate proves. Therefore, it is possible to refuse the use of additives that increase the basicity of the hydrolyzable solution. In practice, this greatly simplifies the process, since the load on the material turnover by the return of active alumina or basic aluminum sulphate is eliminated, thereby significantly reducing equipment and energy costs. In contrast to the alkaline components of the starting material, which is removed from the cake as sparingly soluble compounds, the magnesium contained in the raw material remains predominant in solution. Therefore, the processing of magnesium-containing raw materials does not require the addition of magnesium compounds, and that to achieve a high yield during hydrolysis. When processing materials that do not contain magnesium, a sufficient supply of magnesium is sufficient to establish the optimum Mg content. The increase in magnesium level resulting from the processing of magnesium-containing raw materials can be corrected by the withdrawal of insignificant quantities of the solution, followed by its separate processing. It is found that, under unfavorable conditions for cooling, up to 25 precipitated basic aluminum sulphate is back dissolved in the hydrolysis pulp. As a result, the yield during hydrolysis is significantly reduced, the AlgO content in the reverse solution increases, and the release of Al2O3 per unit volume of the equipment decreases. Studies show that it is necessary to go through the temperature range of SHO-ZO C when cooled very quickly, the back-dissolution effect of 7g was possibly low. The effect of reverse dissolution is more than 18 minutes longer than 90 minutes of cooling, and less than k in terms of the amount of basic aluminum sulphate formed during cooling for less than 10 minutes. The method allows the length of the hydrolysis stage under pressure to achieve very low cooling times, preferably 10 minutes. Filtered after hydrolysis under pressure, the basic aluminum sulphate undergoes a stepwise decomposition and then calcination through jf 8 oc-AljO-j at l 100-1. To regenerate the acid leaching, gases containing a mixture of S02 / S02, formed during the thermal decomposition of basic aluminum sulphate in alumina, are allowed to react with the hydrolysis mother liquor containing iron ions as a catalyst, at a temperature of 60-80 ° C, preferably 70 ° C, with vigorous stirring and air supply. These low concentrated acids, obtained in such an advantageous way in apparatus and technology, are suitable for leaching raw materials under the conditions specified. I Silica cake obtained in the second leaching stage, after proper processing, can be used, for example, in the manufacture of glass containers as raw glass, in the building industry for the production of building materials, in the foundry industry, as a foundry crepe, and also as a filler for the production of various inorganic and organic materials and for other purposes. The method is described in more detail by example and scheme. The above data for substances relate to the equilibrium state in which solutions and cakes that are in circulation do not change in their composition. As sir, 1 t is mechanically loaded (1) and thermally (2) under prepared clay of the following composition in the first leaching stage (3), to AI OS362.0 FejOo23.0 MgOk, i N3200.5 CaO1, 2 Ti0220.9 soa1 , 7, 0.3 S i02 and others 551.1. About 80 is in the form of a metakaolin, well leachable. Clay is suspended under stirring into a mixture of solutions from the second (acidic) leaching stage (5), consisting of 3.9 m of filtrate and 0.5 m of wash water of the following composition, kg: AlaOa233.0 SOj -, 0 fesOs47.8 MgO129.8 NajO0.5 K20 .1.6 and treated under pressure at 120 ° C for 0.5-1 h. Thus, it succeeds 61.3% contained in the clay soluble translate into solution. The impurities contained in the clay (iron, potassium, and sodium) are converted into insoluble basic sulphates with a small amount of dissolved aluminum and filtered together with the insoluble part of Si02 and TiOj in the clay, which is converted into cake. The composition of the cake after washing in 1 water, kg: A1., 0z187, i SOa85.5 FejOa OJ MgOk, S Ti0226.0 This cake is sent to the second stage of leaching with circulating acid in a volume of k m of the following composition, kg: Al Oa152.1 SOa1330.5 FegOji 3.0 MgO126.2 where, similar to the first leaching stage under pressure at 130 ° C, 38.7 of the soluble part is leached from clay. After filtration and washing the cake with 4 m of water (some of it has already been used to wash the hydrolysis product) 4, m of the solution, which (as already described) is sent to the first leaching stage, and, 7 kg of silica cake following leave kg which may be employed in the construction industry naprime. The remaining volume in 3.5 m of wash water containing, kg: A120З16,2 50з50.0 MgO2.8 is used to wash the cake from the first leaching stage, as well as to supplement the water loss resulting from the regeneration of 50 of the hydrolysis product decomposition exhaust gases in the process wet catalysis specified later (10). By filtering the pulp from the first leaching stage (k) and washing the cake, "7 m of the main solution of aluminum sulphate containing kg: +07.6 115.1 30.7 MgO129.0 S i 022.1 TiOi0.1 VjOyO, This the final solution, i.e. The hydrolysis stock solution has a weight ratio of SO: A1203 of 2.8. The hydrolysis solution thus obtained is added at a temperature of 40 ° C. CO2 to the three-fold amount necessary for the stoichiometric reduction of the trivalent ions to bivalent iron ions, and subjected to hydrolysis in suitable equipment conditions with complete exclusion of oxygen for 30 minutes at a pressure of 30 atm. As a result, a solid oxonium alumite crystallisate is obtained, which is easily amenable to filtration, which is cooled rapidly to prevent the reverse dissolution effect from being filtered off from the hydrolysis mother liquor. After washing the hydrolysis product with water with a volume of 3 m and drying at 150 ° C, 692.9 kg of crystallisate of the following composition are separated, kg: 268.00, 00 0.08 0.06 0.07 0.1i "0.0 0.09 This fairly pure intermediate product is decomposed and calcined at 110O-HZOO C, after which, as a high-C alumina, it can be sent directly to electrolysis to produce aluminum. To the waste gases from decomposition containing 3 SOj, air is added in a volume ratio of 02: SO. Then it is saturated with washing water from filtration processes (6) and (8) in accordance with a partial vapor pressure of 0.32 atm and in the approach At a temperature of 70-80 0, the apparatus (10) is vigorously mixed with the mother liquor from hydrolysis in a volume of 2 m, containing, kg: Al20a123, SOa8i 8.3 Pe20z30.3 MgO126.2 Ti020.1 V2050.2 Oxidation of S02 to sulfuric the acid is carried out by almost 100. In order to avoid a further increase in the content of impurities, in particular MgO, in the obtained circulating acid, 3.3 mother liquors are separated from hydrolysis; they are treated separately, which leads to a decrease in the total recovery of 120z by this method as little as 1. Sulfur losses resulting from the separation of the mother liquor and crema cake are replenished by burning sulfur during the decomposition of alunite window or by addition to circulating acidic sulfuric acid. The total recovery of A1303 for this method is 82%, and the yield for hydrolysis is 66.
    权利要求:
    Claims (2)
    [1]
    Claim
    1. A method for producing pure alumina by sulfuric acid leaching of mechanically and / or heat-treated clays or aluminous minerals using pressure and elevated temperature, separating insoluble cake, reducing iron, hydrolyzing an aluminum sulfate solution into solid basic aluminum sulfate, decomposing the hydrolysis product into aluminum oxide, characterized in that the mechanically and / or heat-treated starting material is partially dissolved in the first leaching stage at a temperature of 115 _ 125 ° C in those 15 ~ b0min with a filtrate from the second leaching stage containing 5 _ 7% free sulfuric acid, the cake of the first leaching stage is leached in the second stage, in which the soluble part is almost completely leached at a temperature of 100-140 C25 for 15 ~ b0 min at pressure of 1-3 atm with a circulating solution containing 10-15% free sulfuric acid, S0 2 is predominantly added to the filtrate of the first leaching stage, mainly 30 at a temperature of 20 -0 ° C in a hermetically sealed apparatus and is heated mainly : to a hydrolysis temperature of 240 ° C , the obtained basic aluminum sulfate is calcined at a temperature of 35 1100-1300 ° C in alumina, the resulting mixture of S0 2 and SOj is allowed to interact in air at a temperature of b0-80 ° C, mainly at 70 ° C, with a hydrolysis filtrate, and 40 radiated sulfuric acid is used to replenish the losses of S0 2 and SO3 as a circulating solution for the second leaching stage.
    [2]
    2. A method according to Claim. 1 of t n and h a- 45 w ni I and D with that in the first stage leach with starting materi- 'load excess scarlet A1 2 0 3, is 60-120%, preferably 80 %
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    同族专利:
    公开号 | 公开日
    DE2849555A1|1979-12-06|
    DD140737A1|1980-03-26|
    HU184166B|1984-07-30|
    CS215886B1|1982-09-15|
    DE2849555C2|1987-01-29|
    US4244928A|1981-01-13|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2476979A|1945-08-21|1949-07-26|Erwin C Hoeman|Process for preparing alumina from clays and other silicates of aluminum|
    US2566143A|1947-03-18|1951-08-28|State College Of Washington Re|Production of aluminum compounds|
    US2958580A|1955-05-17|1960-11-01|Harvey Machine Co Inc|Process for the production of aluminum sulfate|
    DE1179919B|1958-08-21|1964-10-22|Commw Scient Ind Res Org|Process for the production of aluminum oxide|
    GB883311A|1958-08-21|1961-11-29|Commw Scient Ind Res Org|Improvements in and relating to the production of alumina|
    ES251629A1|1958-08-21|1960-03-16|Commw Scient Ind Res Org|Production of alumina|
    US3079228A|1960-01-12|1963-02-26|American Cyanamid Co|Production of aluminum sulfate|
    FR1558347A|1967-10-25|1969-02-28|US4394368A|1981-12-04|1983-07-19|The United States Of America As Represented By The Secretary Of The Interior|High temperature hydrolysis of aluminum sulfate solutions|
    US5997828A|1998-09-30|1999-12-07|Rendall; John S.|Process for production of alumina from ore bodies containing aluminum|
    US6468483B2|2000-02-04|2002-10-22|Goldendale Aluminum Company|Process for treating alumina-bearing ores to recover metal values therefrom|
    US6447738B1|2000-08-24|2002-09-10|Solv-Ex Corporation|Coproducing alumina, iron oxide, and titanium-dioxide from aluminum ore bodies and feedstocks|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DD20321078A|DD140737A1|1978-01-13|1978-01-13|METHOD FOR PRODUCING PURE ALUMINUM OXIDE|
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