WO2008100123A1

WO2008100123A1 - Integrated method for processing alumosilicate raw material

Info

Publication number: WO2008100123A1
Application number: PCT/KZ2007/000015
Authority: WO
Inventors: Alexandr Kosmukhambetov; Berik Kaniyev
Original assignee: Alexandr Kosmukhambetov; Berik Kaniyev
Priority date: 2007-02-14
Filing date: 2007-11-19
Publication date: 2008-08-21
Also published as: RU2373152C2; RU2007143435A

Abstract

The invention relates to nonferrous metallurgy, in particular, to the integrated processing of an oxidised raw material containing aluminium and silicon oxides and can be used for producing alumina, silica and for separating heavy nonferrous metals from a complex difficult raw material. Said invention makes it possible to increase the aluminium extraction to a solution during leaching, to extract silica in the form of a saleable material, in particular in the form of amorphous finely dispersed silica, to reduce the consumption chemical agents and energy for sintering and to separate foreign-metal impurities in the form of rich concentrates suitable for integrated processing. The inventive method for processing alumosilicate raw material consists in sintering said raw material together with sodium carbonate and a chemical agent which exhibits basic properties, in leaching the thus obtained cake, in extracting aluminium from a solution and in obtaining silica, wherein the raw material is sintered using sodium hydrate in the form of a chemical agent exhibiting basic properties and the obtained cake is leached by means of a muriatic solution in such a way that a chloride solution and a fixed residue are obtained. Said method also consists in separating from the chloride solution metals which are more electropositive than aluminium, in exposing the chloride solution to heat treatment in such a way that an oxidised aluminium-rich material and a chlorohydric solution are obtained, in dissolving the fixed residue of the leaching process in an alkali solution and in carbonising the thus obtained solution in such a way that a sodium carbonate solution and an amorphous silica precipitate are obtained.

Description

The method of complex processing of aluminosilicate raw materials

The invention relates to non-ferrous metallurgy, in particular, to the technology of complex processing of oxidized raw materials containing aluminum and silicon oxides and can be used to obtain alumina, silica, and the separation of heavy non-ferrous metals from complex refractory raw materials.

The traditional technology of processing aluminosilicate raw materials, mainly bauxites, by the Bayer / Gudima method H. V., Shein Ya. P. Quick reference to the metallurgy of non-ferrous metals. - M .: Metallurgy, 1975, p. 36-38 /, provides for autonomous alkaline leaching of pre-ground raw materials with the dissolution of aluminum and the conversion of impurities into the so-called red mud, the decomposition of the aluminate solution with the release of aluminum hydroxide and the regeneration of the leaching solution, calcining aluminum hydroxide to obtain alumina.

The Bayer method is intended for the processing of high-quality bauxite with a low silica content, silicon module (the ratio of the content of Al ₂ O ₃ to SiOg) for which should be at least 7-8. This limitation is associated with the formation of alkaline leaching of insoluble sodium aluminosilicate (permutite), with which aluminum oxide and sodium oxide are lost.

Closest to the proposed method for processing aluminosilicate raw materials is a method of sintering aluminosilicate raw materials with a high content of silica / A. Liner. Production of alumina. - M .: Metallurgizdat, 1961, p. 362-370 /. The method is intended for processing raw materials with a silicon module of less than 7, consists in converting aluminum oxide into solid sodium aluminate due to its binding to soda and provides for the binding of silica to insoluble dicalcium silicate. The method includes preparing a mixture consisting of feedstock, soda and a reagent having basic properties, which is limestone or lime, firing the mixture at a temperature of 1150-1250 ⁰ C, leaching the obtained cake with reverse soda-alkaline solutions with dissolution of aluminum and transferring impurities into dump sludge, desiliconization of the solution, separation of aluminum hydroxide from the solution and its calcination to obtain alumina. The method is intended primarily for producing alumina and does not provide complex processing of raw materials. In particular, silica in the form of dicalcium silicate is lost in the waste sludge. The method is associated with a high consumption of soda, the need to use a significant amount of limestone or lime, high energy consumption. Extraction of aluminum into the solution from the cake is in the range of 80-85% due to the insufficiently complete formation of sodium aluminate during sintering. The disadvantage of this method is also a significant decrease in technological parameters during the processing of raw materials with a high iron content, which leads to the formation of low-melting iron silicate during sintering, the presence of which reduces the temperature range within which sintering takes place and leads to the formation of crusts in kilns.

The objective of the invention is to develop a method for the complex processing of complex refractory oxidized raw materials, mainly aluminosilicate raw materials containing, along with aluminum and silicon, metals such as copper, lead, zinc, tin, etc.

The technical result achieved by using the invention is to increase the extraction of aluminum into the solution during leaching, the extraction of silica in the form of marketable products, in particular in the form of amorphous highly dispersed silica, the reduction of the consumption of reagents and energy costs during sintering, the separation of related metals in the form of rich concentrates suitable for complex processing.

The specified technical result is achieved by the fact that in the method of processing aluminosilicate raw materials, including sintering with sodium carbonate and a reagent having the basic properties, leaching of cake, extraction of aluminum from the solution, followed by obtaining alumina, it is envisaged to sinter the raw materials using sodium hydroxide as a reagent, having basic properties, and the resulting cake is leached with a hydrochloric acid solution to obtain a chloride solution and a solid residue. More electropositive metals than aluminum are isolated from the chloride solution, after which the chloride solution is subjected to heat treatment to obtain an aluminum-rich oxide product and hydrochloric acid solution, and the solid leach residue is dissolved in an alkaline solution and the resulting solution is carbonized to obtain sodium carbonate solution and sediment of amorphous silica. The ratio of sodium carbonate to caustic soda in the sintering mixture is in the range (2.5-3.5): 1 at a total flow rate of 40-50% in May. from the amount received for sintering raw materials.

Sinter leaching is carried out with a hydrochloric acid solution with an initial concentration of at least 4.4 geq / dm ³ at a ratio W: T of at least 10: 1 for 30-60 minutes at a temperature of 40-80 C, after which the solution is separated from solid residue, replenish with a solution of hydrochloric acid to a concentration of not less than 4.4 g-eq / dm ³ and used to leach a new portion of cake, repeating these operations until the aluminum concentration in the solution is not less than 70-80 g / dm ³ in terms of Al ₂ O ₃ . A special case of cake leaching is continuous leaching, which is carried out with a solution of hydrochloric acid with a concentration of 4.4 g-equiv / dm for 30-60 minutes at a temperature of 40-80 ⁰ C, after which the solution is separated from the solid residue, some of it is returned for leaching of cake, and the rest of the solution is sent to subsequent processing. More electropositive metals as a collective product are isolated from the solution obtained by leaching the cake, and this operation can be carried out, in particular, by electrolysis in an electrolyzer with a separated anode and cathode space at a cathode current density of at least 500 A / m ² . The chloride solution purified from metals that are more electropositive than aluminum is subjected to heat treatment by evaporating the solution to obtain aluminum chloride hexahydrate in the first stage, calcining it at 400-600 ⁰ C to obtain an oxide product in the second stage, and condensing the hydrochloric acid solution from heat-treated gases . The solid cake leach residue is washed with water and leached with a solution containing at least 150 g / dm ³ NaOH for 30-40 minutes at a ratio of W: T = (5-6): 1 to obtain a solution of sodium silicate and a solid residue returned to the operation sintering

The solution obtained by alkaline dissolution of the solid cake leach residue is subjected to carbonization with a gas containing carbon dioxide, followed by separation of the precipitate of amorphous silica, washing and drying it at 300-400 ⁰ C. In a particular case of the application of the invention in the processing of raw materials containing increased the iron content, the initial aluminosilicate raw material is pre-treated with a solution of hydrochloric acid with a concentration of at least 250 g / dm ³ with the ratio W: T = (2.5-3): 1, temperature 75-85 ⁰ C for 4-6 hours, after which the chloride solution is separated from the solid residue, which is washed with water and served as a wet cake in the sintering mixture and the chloride solution is processed to obtain an iron-containing product. To increase the completeness of dissolution of iron during the processing of raw materials with hydrochloric acid, an additional gas containing chlorine, for example, the anode gas of a chlorine membrane electrolyzer, can be added to the pulp. Concentrated hydrochloric acid is introduced into the chloride solution to a concentration of 6.5-7.5 g-eq / dm ^3, after which iron is isolated from the solution by extraction with a solution of tributyl phosphate in kerosene with the number of extraction stages not less than three. The raffinates obtained during the subsequent re-extraction are used in the leaching of cake, and the re-extracts are used to obtain an oxide-containing iron-containing product and regeneration of hydrochloric acid. The strips are treated with iron scrap and then evaporated by 85-90%, after which they are subjected to heat treatment in an oxidizing medium at 580-650 ⁰ C to obtain an iron oxide product, and the hydrochloric acid is regenerated by condensation of the gases obtained during evaporation and heat treatment.

The proposed sequence of operations and their conditions are due to the fact that the set of essential features of the invention allows to extract aluminum from complex refractory raw materials in the form of industrial alumina suitable for processing by known methods, silica in the form of pure finely dispersed amorphous silica, heavy non-ferrous metals in the form of rich products also suitable for processing by known methods. An important advantage of the proposed technology is the ability to regenerate the reagents used in the scheme.

In contrast to the known method of sintering aluminosilicate raw materials, it is proposed to use not limestone or lime, which binds silica into poorly soluble dicalcium silicate, but caustic soda, which forms sodium silicate with silica, as a reagent with basic properties.

The ratio of sodium carbonate to caustic soda in the mixture fed to sintering, in the range (2.5 - 3.5): 1 at a total flow rate of 40-50% in May. of the amount supplied to the sintering of raw materials, provides the binding of aluminum and silica to the corresponding compounds by reactions

Al ₂ O ₃ + Na ₂ CO ₃ = Na ₂ O-Al ₂ O ₃ + CO ₂ SiO ₂ + 2NaOH = Na ₂ SiO ₃ + H ₂ O

Replacing limestone (lime) with sodium hydroxide in the composition of the mixture allows to reduce the consumption of reagents and energy costs in the sintering process. Leaching of cake in hydrochloric acid makes it possible to separate aluminum and non-ferrous metals passing into the solution from the precipitate of silicic acid, which is poorly soluble in an acidic solution and which forms upon reaction with acid.

Na ₂ O-Al ₂ O ₃ + 8HCl = 2AlCl ₃ + 2NaCl + 4H ₂ O Na ₂ SiO ₃ + 2HCl = J, SiO ₂ ^• H ₂ O + 2NaCl

It was experimentally determined that when the ratio W: T is less than 10: 1, a colloidal solution of silicic acid is formed, which complicates the subsequent separation of liquid and solid during sedimentation and filtration of pulps, while the presence of aluminum and sodium chlorides in the solution does not significantly affect the viscosity solutions. In this regard, it was proposed to conduct the leaching of the cake stepwise at a ratio W: T of at least 10: 1 with separation of the solid residue from the solution after each stage, replenishing the solution with hydrochloric acid and using it at the subsequent stage of leaching a new portion of cake to obtain an aluminum concentration in the solution ( in terms of A12O ₃ ) not less than 70-80 g / dm ³ . Sinter leaching can also be carried out continuously using a mixture of hydrochloric acid solution with part of the solution obtained by separating it from the solid leach residue as a solvent in an amount that provides an initial W: T ratio of at least 10: 1. The remaining part of the solution, containing 70-80 g / dm ³ Al ₂ O ₃ , is withdrawn for subsequent processing. Various technological methods can be used to clean the chloride solution from non-ferrous metals that have leached into it, however, the proposed method for their separation by electrolysis in an electrolyzer with a separated anode and cathode space at a cathode current density of at least 500 A / m allows you to quickly and completely clean the solution with obtaining a concentrate of heavy non-ferrous metals, suitable for complex processing.

Evaporation of the purified chloride solution and subsequent calcination of the mixture of sodium and aluminum chlorides in an oxidizing atmosphere in the presence of water vapor makes it possible to obtain an oxide product containing aluminum and sodium oxides, which can be processed into alumina using standard Bayer method technology. Condensation of the heat treatment gases makes it possible to obtain a hydrochloric acid solution suitable for reuse in the leaching of cake.

The solid cake leach acid leach residue, consisting predominantly of silicic acid, is leached after a water wash with a soda-alkaline solution. In this case, silicon passes into the solution in the form of sodium silicate SiO ₂ ^• H ₂ O + 2NaOH = Na ₂ SiO ₃ + 2H ₂ O SiO ₂ ^• H ₂ O + Na ₂ CO ₃ = Na ₂ SiO ₃ + H ₂ O + CO ₂ , and the impurities in the form of insoluble hydroxides remain in the solid the residue returned to the sintering operation. When a sodium silicate solution is treated with a gas containing CO ₂ , the solution is carbonized, accompanied by the precipitation of amorphous silica from the solution

Na ₂ SiO ₃ + CO ₂ = Na ₂ CO ₃ + | SiO ₂ which, after separation from the solution, washing and heat treatment, is a high-quality commercial product.

In the particular case of processing the initial aluminosilicate raw material containing an increased amount of iron compounds that impede the sintering process due to the formation of low-melting iron silicates during sintering, it is proposed that the raw material be purified from iron before the sintering process. This process was proposed to be carried out by leaching in a concentrated solution of hydrochloric acid, and to intensify the process and increase the extraction of iron into the solution, it was proposed to additionally supply gaseous chlorine to the leaching pulp, which can be obtained, for example, by electrolysis of a solution of sodium chloride in a chlorine membrane electrolyzer. From the solution obtained by leaching, iron is extracted by extraction after acidification of the solution with hydrochloric acid. The extraction is carried out, for example, with a solution of tributyl phosphate in kerosene in several stages (as a rule, at least three stages are required), followed by re-extraction. The raffinate obtained during extraction contains 4.5 - 5 g-eq / dm ³ hydrochloric acid and non-ferrous metals that are converted into solution by hydrochloric acid leaching. This solution can be used for leaching cake. The re-extract is treated with iron scrap to cement a small amount of non-ferrous metals that have passed into it during the extraction process, after which it contains up to 40-45 g / dm ^{3 of} iron, which is extracted by evaporation of the solution and heat treatment of the iron-containing product in an oxidizing medium at 580 - 650 ⁰ C. The heat treatment produces iron oxide and gases, upon condensation of which hydrochloric acid is obtained.

An experimental verification of the method was carried out on a semi-industrial scale with the sequential implementation of technological operations included in the method. AT A sample of oxidized polymetallic ore was used as the feedstock, containing,% May: Fe ₂ O ₃ - 13.7; Al ₂ O ₃ - 22.0; SiO ₂ 40.3; TiO ₂ -1.3; Sn 0.21; Cu - 0.08; Pb - 0.54; Bi - 0.10; W - 0.07, crushed to a particle size of 95% -0.074 mm.

Due to the increased iron content in the initial ore, the raw material was purified from iron by leaching it with a solution of hydrochloric acid with a concentration of 320 g / dm ³ at W: T = 2.5: 1, a temperature of 75-80 ⁰ C, intensive mechanical stirring and feeding into the pulp a chlorine-containing anode gas obtained in a membrane electrolyzer during the electrolysis of a solution of sodium chloride. When leaching for 6 hours, 98% of iron, 94-96% of copper, lead and bismuth, 60-65% of tungsten, 20-25% of tin and titanium were extracted into the solution. The solubility of aluminum does not exceed 10-1 1%, silica - not more than 2%.

As a result of the iron removal operation, an average cake was obtained containing, wt.%: Fe ₂ O ₃ - 0.15; Al ₂ O ₃ - 26.0; SiO ₂ 53.1; TiO ₂ -1.35; Sn 0.21; Cu - 0.001; Pb - 0.002; Bi - 0.004; W - 0.04 and an average chloride solution containing, g / dm ³ : Fe ₂ O ₃ - 60.7; Al ₂ O ₃ - 12.0; SiO ₂ - 3.5; TiO ₂ -1.7; Sn 0.26; Cu 0.42; Pb - 2.3; Bi - 0.48; W - 0.21 (hereinafter, in the composition of the solutions, the contents of iron, aluminum and titanium are given in terms of the corresponding oxides).

The iron chloride solution was supported by concentrated hydrochloric acid to 7 g-equiv / dm ³ and was subjected to three-stage extraction with a 30% solution of tributyl phosphate in kerosene. Reextraction was carried out in countercurrent water. The raffinate obtained by extraction with an acidity of 4.7 geq / dm ^J contained, g / dm ³ : Fe ₂ O ₃ less than 0.005; Al ₂ O ₃ - 1 1.6; SiO ₂ - 3.4; TiO ₂ -1, 6; Sn 0.22; Cu - 0.3; Pb 2.2; Bi - 0.45; W - 0.17 and was sent to the subsequent operation of the leaching cake.

The re-extract with an acidity of 2.4 g-equiv / dm ³ contained, g / dm ³ : Fe ₂ O ₃ - 60.0; Al ₂ O ₃ - 0.33; SiO ₂ - 0.1; TiO ₂ -0.03; Sn 0.05; Cu - 0.12; Pb - 0.07; Bi - 0.03; W - 0.004 and from it after treatment with iron scrap, an iron-containing product was released. The re-extract was subjected to preliminary evaporation to obtain a solution with an iron concentration of 370–380 g / dm and subsequent heat treatment at 580–620 ^° C, as a result of which chlorine was completely transferred to the gas phase in the form of hydrochloric acid vapor and an iron oxide concentrate containing, wt.% Was obtained : Fe ₂ O ₃ - 97.3; Al ₂ O ₃ - 0.44; SiO ₂ 0.14; Sn - 0.033; Cu - 0.084; Pb - 0.048; Bi - 0.027; CaO - 1, 21; MgO - 0.43; Na ₂ O - 0.007, S _total -0.12. The extraction of iron in the concentrate was 95.2%.

The cake obtained as a result of acid treatment was mixed with sodium carbonate and concentrated sodium hydroxide solution, taken in an amount of 40% of the amount cakes at a ratio of soda to alkali 3: 1, until a homogeneous wet mass is formed, after which the mass is dried at 250-300 ⁰ C and sintered in crucibles at a temperature of 880 ⁰ C for 2 hours. The resulting spec had a composition in May. %: Fe ₂ O ₃ - 0.12; Al ₂ O ₃ - 20.75; SiO ₂ 42.35; TiO ₂ -0.04; Sn - 0.165; Cu 0.0008; Pb - 0.0016; Bi - 0.003; W - 0.04, was crushed to a particle size of 100% -0.074 mm and was leached in a hydrochloric acid solution.

Leaching was carried out in batch mode at a ratio of W: T = 10: 1 with a solution of hydrochloric acid at a concentration of 4.7 geq / dm ³ (iron stripping raffinate) at a temperature of 60 ⁰ C for no more than 60 minutes. The resulting pulp was filtered on a vacuum filter and the filtrate after reinforcing with hydrochloric acid to 4.4 geq / dm ³ and bringing to the initial volume was fed to leach a new portion of spec and this operation was repeated three times. The composition of the solution obtained after each leaching step is shown below.

As a result of sinter leaching, a solid residue was obtained containing, in terms of dry weight, wt.%: SiO ₂ - 81.0; Al ₂ O ₃ - 14.3; CaO - 0.7; MgO - 0.5; Fe ₂ O ₃ -0.04; Na -2.8; Cl is 0.09. As a result of a two-stage water washing of the solid residue, at least 90% of the impurity components were washed from it, as a result of which the silica content in terms of dry weight increased to 94-96%.

The washed wet precipitate of silicic acid was subjected to alkaline leaching in a solution containing 200 g / dm ³ sodium hydroxide at W: T = 6: 1 for 30-40 minutes. As a result of leaching, silica passed into solution in the form of sodium silicate SiO ₂ —H ₂ O + 2NaOH = Na ₂ SiO ₃ + 2H ₂ O, at the same time, non-washed impurity components, the amount of which did not exceed 1.5–2.8% in the form of hydroxides, remained in the solid residue.

The filtered alkaline solution with a content of SiO _{2 of} 98 g / dm ^{3 was} treated with carbon dioxide, as a result of which the solution was neutralized and silicic acid was released from it

2NaOH + CO ₂ = Na ₂ CO ₃ + H ₂ O Na ₂ SiO ₃ + CO ₂ + H ₂ O = j SiO ₂ ^• H ₂ O + Na ₂ CO ₃

The thickened pulp was filtered, the cake was washed on the filter and subjected to heat treatment at 380-400 ° C until the moisture was completely removed, resulting in amorphous silica with a specific surface area of 120 m ² / g (phenol) containing, wt.%: SiO ₂ - 98.5; Al ₂ O ₃ -0.08; CaO 0.14; MgO - 0.2; Na - 0.05; Cl is 0.008.

From the solution obtained by hydrochloric acid leaching of cake, the non-ferrous metals present in it were extracted by electrolysis in a two-chamber mom> polar membrane electrolyzer at a cathodic current density of 760 A / m. As a result of electrolysis, a cathode precipitate was obtained containing, wt.%: Sn - 19.3; Bi -12.3; Cu - 6.4; Pb -47.3; Fe - 1.1; Ti - 0.35, which is a collective concentrate of heavy non-ferrous metals, the processing of which by known methods does not present technical difficulties.

Obtained by electrolysis, the purified solution contained, g / dm ³ : Al ₂ O ₃ - 75.1; Fe ₂ O ₃ - 1.5; SiO ₂ 0.7; Sn is 0.02; TiO ₂ -3.9; Cu - 0.07; Pb - 0.026; Bi was 0.008, W was 0.03 and was evaporated until the aluminum chloride hexahydrate was completely crystallized, which was calcined at 400-600 ⁰ C, as a result of which an oxide product was obtained containing max. %: Al ₂ O ₃ - 56.8; Fe ₂ O ₃ - 1.9; SiO ₂ 0.2; Sn is 0.02; TiO ₂ -1.3; CaO - 2.1;

MgO - 2.5; Na - 25.5; Mn - 0.8; Cl is 0.18. The oxide product can be processed into commercial alumina using the Bayer method, the condensation of gases obtained by heat treatment of a chloride solution and calcination of aluminum chloride allows us to regenerate hydrochloric acid and reuse it in the process.

The results obtained indicate the possibility of complex processing of complex aluminosilicate raw materials with the achievement of through extraction into the corresponding commercial products of aluminum by 96-97%, silica by 97-99%, iron by 95-96%, non-ferrous metals into collective concentrate by 75-90 %

Claims

CLAIM

1. A method for the complex processing of aluminosilicate raw materials, including sintering with sodium carbonate and a reagent with basic properties, leaching of cake, extraction of aluminum from a solution, followed by obtaining alumina, characterized in that caustic is fed as a reagent with basic properties sodium, leaching of cake is carried out with a hydrochloric acid solution, the pulp obtained by leaching is separated to obtain a chloride solution and a solid residue, more electric is isolated from the chloride solution positively compared to aluminum metals, after which the chloride solution is subjected to heat treatment to obtain the oxide product, and the hydrochloric acid solution; the solid leach residue is dissolved in an alkaline solution and the resulting solution is carbonized to obtain a solution of sodium carbonate and a precipitate of amorphous silica.

2. The method according to claim 1, characterized in that in the mixture fed to sintering, the ratio of sodium carbonate to caustic soda is in the range (2.5 - 3.5): 1 at a total flow rate of 40-50% in May. from the amount received for sintering raw materials.

3. The method according to p. 1, characterized in that the leaching of cake is carried out with a solution of hydrochloric acid with an initial concentration of at least 4.4 g-equiv / dm ³ with the ratio

W: T at least 10: 1 for 30-60 minutes at a temperature of 40-80 ⁰ C, after which the solution is separated from the solid residue, replenished with hydrochloric acid to a concentration of at least 4.4 g-equiv / dm ³ and used for leaching a new batch of cake, repeating these operations until the aluminum concentration in the solution is at least 70-80 g / dm in terms of Al ₂ O ₃ .

4. The method according to claim 1, characterized in that the cake is leached with a hydrochloric acid solution with an initial concentration of at least 4.4 g-equiv / dm ³ continuously for 30-60 minutes at a temperature of 40-80 ⁰ C, after why the solution is separated from the solid residue, part of it is returned to the leaching of cake, and the rest of the solution is sent for further processing.

5. The method according to p. 1, characterized in that from the solution obtained by leaching the cake, more electropositive metals as compared to aluminum are isolated as a collective product.

6. The method according to p. 5, characterized in that more electropositive metals as compared to aluminum are isolated from a solution in an electrolytic cell with a separated anode and cathode space at a cathodic current density of at least 500 A / m ² .

7. The method according to claim 1, characterized in that the chloride solution, purified from more electropositive metals than aluminum, is subjected to heat treatment by evaporating the solution and obtaining aluminum chloride hexahydrate in the first stage, calcining it at 400-600 ⁰ C to obtain oxide product in the second stage and the condensation of a solution of hydrochloric acid from heat treatment gases.

8. The method according to p. L, characterized in that the solid cake leaching residue is washed with water and leached with a solution containing at least 150 g / dm NaOH for 30-40 minutes at a ratio of W: T = (5-6): 1 s obtaining a solution of sodium silicate and a solid residue returned to the sintering operation.

9. The method according to p. L, characterized in that the solution obtained by alkaline dissolution of the solid cake leaching residue is subjected to carbonization with a gas containing carbon dioxide, followed by separation of the precipitate of amorphous silica, washing and drying it at 300-400 C.

10. The method according to claim 1, characterized in that the initial aluminosilicate raw material is pre-treated with a solution of hydrochloric acid with a concentration of at least 250 g / dm ³ with a ratio of W: T = (2.5-3): 1, temperature 75-85 ⁰ C within 4-6 hours after which the solution is separated from the solid residue, which is washed with water and fed into the sintering mixture, and the chloride solution is processed to obtain an iron-containing product.

1 1. The method according to claim 10, characterized in that the processing of the feedstock is carried out with the additional supply to the pulp of a gas containing chlorine, for example, the anode gas of a chlorine membrane electrolyzer.

12. The method according to claim 10, characterized in that concentrated hydrochloric acid is introduced into the chloride solution separated from the solid residue to a concentration of 6.5-7.5 geq / dm ^3, after which iron is extracted from the solution by extraction with a solution of tributyl phosphate in kerosene with the number of extraction stages of at least three, with after- reextraction and the use of raffinates in the leaching of cake, and reextracts to obtain an iron oxide product and the regeneration of hydrochloric acid.

13. The method according to p. 12, characterized in that the strips are evaporated by 85-90%, and then subjected to heat treatment in an oxidizing medium at 580-650 ⁰ C, to obtain an iron oxide product and condensation of a solution of hydrochloric acid from heat treatment gases.

14. The method according to p. 12, characterized in that before evaporation, the re-extract is treated with iron scrap.