JPS63500655A - Production method of alkali metal aluminate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Production method of alkali metal aluminate [Industrial application field] The present invention relates to the production of inorganic materials, and in particular to the production of aluminum-containing raw materials. It relates to a method of processing lumina, soda, and potash. In particular, the present invention This invention relates to a method for producing an alkali metal aluminate.

Alkali metal aluminates have wide applications, e.g. in the pulp-paper industry. As a substitute for rosin glue, and as a coagulant for purifying sewage and portable water, It is used as a soil stabilizer for the construction of academic buildings, as a binder in casting technology, in oil drilling. It is used as a mud ingredient in machining and in other industries.

[Conventional technology and problems In the manufacturing method of sodium aluminate, alkali lime is used as a raw material for aluminosilicate. Produced from leaching, sodium oxide: aluminum oxide molar ratio N a 20: A l　20　Z　Z　=　7 Aluminate solution is firstly desilicated and Evaporate to 40% Na2O concentration (350-575 g/b Na20), In the evaporated solution, sodium aluminate (N a 20-A l 20x ・Introduce 2.5H20) seeds, cool to a temperature of 20 to 60℃, and remove from the solution. A method for crystallizing sodium ruminate and subsequently separating the crystalline product from the mother liquor. is known (see U.S. Pat. No. 3'998.927, 1977). Although the method can obtain high product yield (80%), it is complicated in terms of evaporation equipment. (this equipment must be constructed of corrosion-resistant material) and the solution High power consumption rates are required to concentrate to g/A Na2O.

Also, the alkali metal oxide to aluminum dioxide ratio in the range of 2.3 to 3.6, Me 2O: Al2O! By leaching aluminum-containing raw materials for alumina production with The aluminic acid solution obtained by A method of producing a product by evaporation to an alkali gold l'X concentration equal to Me2O of is publicly known.

Evaporation of an aluminate solution of the above composition produces corrosion of processing equipment made of ordinary steel. Yes, this is a drawback. During this corrosion, the corrosion index is 8.5 to 34 mII+ (A, 1. Manufacturing method of Reinel' alumina, 1961. Moscow , Publisher °゛Metallurgy, 82, 292, pp. 354-355 [2], Non-ferrous materials for metallurgical engineers Metals Handbook, A.

A. Agranovsky et al., 1970. Moscow, Publisher °° Metallurgy”, p. 91 [ 3]).

Evaporation and crystallization of the aluminate solution to increase the yield and separation of the mother liquor from the desired product Various attempts have been made to improve the manufacturing process of alkali metal aluminates by (All-Federal Aluminum-Magnesium Association proceedings M-Na70°G, A, Panasco ,M,1. Smirnov paper "Sodium caustic alkali from mixed aluminate solution" 1970, Moscow, Publisher “Metallurgy”, pp. 126-135 [4 copies] , and V, S, Sargin°, a new hydrochemical process for alumina production. Cheng, 1979. Narakova Dumka°° Publishing, pp. 125-126, 130, 135 pages, 208 pages [5]).

One of the attempts is to have a M e 20: A 1203 molar ratio of 3.4 or more. desilicated aluminate solution to an M e 20 concentration of 500 to 510 g/Jl. It relates to a method of evaporating and crystallizing a solution in a temperature range of 30 to 90°C.

However, this attempt was not successful. Crystallization of the solution at 30°C results in excessively concentrated This results in a viscous pulp that cannot be separated into solid residue and mother liquor and therefore Alkaline components cannot be recovered from the mother liquor, which is caused during the raw material leaching stage. increases the consumption of alkaline reactants used in High yield of final product Despite this (approximately 80%), this product has a high moisture content and additional water is added for its drying. Requires additional power.

Results of crystallization of an aluminate solution having the above composition at about 90°C.

Product yield is reduced (approximately 60%).

Another attempt to improve the yield and obtain the mother liquor is to increase the Me2O:A1zOz molar ratio of about 2.3. 400-450 g of a desilicated aluminate solution with alkali metal The oxide Me2oA is evaporated and the residue is then crystallized at a temperature of 50-70 °C. , held for 1 to 2 hours, and then filtered and separated the mother liquor to produce alkali metal aluminate. It was necessary to carry out the manufacturing process. Is this process a mother liquor of alkali metal aluminate? 450-510, which guarantees the separation of g / Alkali gold of A @ oxide M a Strong evaporation into aluminic acid solution to a concentration of 20 The evaporated solution was crystallized at a temperature of 30°C, and then the aluminate pulp was filtered. Attempts to increase the yield of the desired product by increasing the yield of the desired product were unsuccessful. obtained The resulting product could not be produced in excessive quantities, and the quality of the product obtained was reduced.

of an aluminate solution with a molar ratio of M e 20: A 120 s = 8 Desilicate treatment and 460-540 g/I! - alkali metal oxide M e By Al P, Nie, L, G, Romanoff °° Aluminum by evaporation up to 20 concentrations ``Physical-chemistry of hydroalkali production method'', 1975. Alma Ata, ``Now'' The resulting product is a pasty consistency sheet. and unsatisfactory filterability.

Although the yield reached as high as 70%, the product had an excessive amount of mother liquor and therefore had high water content. This is because the alkali metal oxide and aluminum oxide in the product have a This is proven by the ratio Me20:A120z=2.2. Remove such moisture. Difficult to handle and transport.

Na2O:A120 with a sodium oxide Na20 concentration of 100-350g/p A desilicated aluminate solution having a molar ratio of s = 1.3 to 1.6 was added to a fluidized bed apparatus. The aluminic acid solution was dried and granulated for 3 minutes at a temperature of 250 to 350°C. Methods for producing sodium aluminate are known. As a heating agent in the drying process, Hot air from which carbon dioxide had been removed was used. The product obtained is sodium aluminate. (USSR Inventor's Certificate No. 345767, 1984) Published in 2007 [7]”), this method requires high-power crystallization and dehydration of sodium aluminate. , which is carried out in a drying oven unit that requires large amounts of heat and investment, With the commercial use of this process, a high percentage of Dust release (27%) t: occurs.

Therefore, a simple process guarantees high yields, high quality of solid products and low power consumption. Methods to produce alkali metal aluminates by process are still urgently needed. It is.

[Summary of the invention] The present invention minimizes energy consumption, simplifies the process, increases yield, and maximizes We propose a method for producing alkali metal aluminates that can improve the quality of the final product. This is what we provide.

This purpose is Aluminic acid is produced by leaching starting materials containing aluminum monoxide and alkali metals. producing a solution; and desilicating the -2 aluminate solution.

- an evaporation step of the silicicated aluminate solution; - an evaporated aluminate solution; and crystallizing an alkali metal aluminate from a liquid. in the acid solution '*a', According to the invention.

-1.1 to 1.7 alkali metal oxide vs. aluminum oxide Me 20: A an aluminate solution having a molar ratio of 1 tOs is evaporated, and this evaporation is 12 350-400 g/IL of alkali metal oxide at temperatures ranging from 0 to 150°C a step carried out to a concentration; Transfer the evaporated solution at a temperature of -95 to 150°C to a temperature range of 10 to 95°C. The above-mentioned method can be obtained by sending the product over a type filtration surface, during which the product is crystallized and separated from the mother liquor. crystallizing the alkali metal aluminate from the evaporated solution.

-The step of sending the obtained mother liquor to the leaching step of raw materials and the process are difficult. will be accomplished.

The method according to the invention! It simplifies the manufacturing process and saves energy during the evaporation and crystallization stages. Minimize the amount of ruggy and gR.

Improve product quality and reduce consumption of one reactant.

Preferably, the step of evaporating the aluminate solution is carried out in two stages. 1st stage odor The evaporation of the solution is 225-230g/A of alkali metal oxide at a temperature of 120°C. Me2O concentration is carried out, and in the second stage 360-37 at a temperature of 150 °C. It is carried out at a concentration of said oxide M e 20 of 0 g/A. This two-stage evaporation mode It is more economical, ie the required consumption of heating medium (steam) is lower.

Preferably, after the second evaporation step, the aluminate solution is heated at 95-105 ml for 2-3 hours. (385-395 g/A alkali metal oxide M e 20 concentration), this technology improves the crystallization conditions of the product and increases the yield. let

The crystallization stage is carried out on a moving filter surface at a temperature of 20-50°C. this temperature This is because it can be most easily maintained in industrial conditions. On this filter surface , rapid crystallization of the alkali metal aluminate and its separation from the mother liquor occurs.

The filtration surface can be woven polyamide, woven metal screens, or other suitable materials. material can be used.

The following is a process for producing an alkali metal aluminate according to the present invention and its best embodiment. will be explained in detail.

[Example code] Crushing aluminum-containing raw materials such as nepheline and limestone to a particle size of 80-95μm Ru. Molar ratio of oxides in the charge Cab: 5i02 = 2.1: 1 and M e20: (A1203 + Fa20!) = 0.95-1 at the rate of obtaining nepheline 5 The charge was prepared by blending limestone and alkaline solution. M here e is Na, and the charge thus prepared is placed in a rotary kiln. Sinter at a temperature of 1°150-1,250°C. The obtained sintered product is crushed and then Molar ratio M e20: A 120 m = 1.

Al2O with 63-4.2! 14~s　o　g　/　1. -1M a 2 0-35-36, 5 g/JL, a solution containing SiO20, 5-0.7 g/A Leached by liquid. In this way, aluminum oxide and alkali metal containing In the aluminate solution obtained by leaching raw materials, alkali metal oxides and The molar ratio of aluminum oxide M e 20: Al2O3 is equal to 1.1-1.7 , this aluminic acid solution was filtered to separate the mucilage, and 0.05~0゜07g Desilication treatment was performed to a content of /A of 5ift. White viscous substance resulting from desilication treatment The material was separated and circulated to the preparation stage of Japanese loading.

The majority of aluminate solutions purified from silica contain alumina, potash, and soda. Another part of this solution is used in the production of alkali metal aluminates. It will be done.

The aluminate solution sent to the production of alkali metal aluminate is Molar ratio of compound to aluminum oxide, MezO:A-1203=1. i-1,7 The molar ratio of this alkali metal oxide and aluminum oxide must be , the above composition, namely A1 203-14-30 g/j2. , Met O -35-36,5g/12.5i02-0.5-0.7g/11 with molar ratio M Leaching the raw material with a solution having e20:A1203=1.63-4.2 It can be obtained at the stage of

According to the invention, aluminum having a molar ratio Ma2O:Al2O3 of 1°1-1.7 The acid solution has an alkali content of 350 to 400 g/A at a temperature range of 120 to 150°C. The metal oxide is evaporated to Me2O concentration. Evaporated aluminum @ solution is normal steel No corrosion of evaporation equipment consisting of

This allows the use of inexpensive steel evaporators, which constitutes one advantage of the invention. , because it reduces the cost of producing the desired product. Such evaporated water The non-corrosive nature of aluminate solution is due to the fact that alkali metal oxides in the solution cause aluminate ions to form. Due to being chemically bonded to a shape.

Aluminic acid solution having a molar ratio of M e 20: Al 203 of 1.7 or more It is undesirable to use an aluminate solution with such a composition. At temperatures between 0 and 150°C, M et OA l 203-Ha O system is in the stable region. This is because it is difficult to recover the product by crystallization.

Aluminic acid having a M e 20: A l 20: i molar ratio of 1.1 or less The use of solutions is also undesirable, because solutions with such compositions At a temperature of 150°C, M e 20-A supersaturated with respect to alkali metal oxides This is because it is within the range of 203 H2O system. Production from such solutions This is because crystallization of the product occurs very rapidly and can lead to blockage of the evaporator by precipitated products. be.

Therefore, according to the present invention, M e 20: A l 20 s = 1.

An aluminate solution with a molar ratio of 1 to 1.7 is evaporated. Under the above conditions Evaporation of this solution forms a solution saturated by the alkali metal aluminate. do. This solution at a temperature of 95-150°C is passed through a mobile filtration surface at a temperature of 10-95°C. It is crystallized by charging it to the top.

This crystallization technique allows the aluminate solution to solidify virtually instantaneously on the filter surface. It is separated into alkali metal aluminate as a body component and mother liquor. Aluminic acid solution As the liquid is sent onto the filter surface at a temperature of 95-150°C, this filter surface is heated. . In order to maintain the filter surface within the temperature range of 10 to 95 degrees Celsius, it must be cooled. This cooling is achieved by delivering a refrigerant, primarily water, to the non-working surface. administered. Cool the filtration surface temperature to 10℃ by sending cold water (+5℃). It is possible to

If the filter surface is heated above 95°C, the crystallization rate will decrease and the product crystallization process will be delayed. This will be the disability rate.

If the filter surface is cooled to below 10°C, the viscosity of the aluminium[76] liquid will increase, and therefore ! A "glue"-like residue is formed on the surface, which interferes with the crystallization process. Filter like this Failure to observe the surface temperature limits will disturb the crystallization process and may not yield the desired result. do not have.

As mentioned above, rapid crystallization occurs on the filter surface at a temperature of 10 to 95 °C, and the mother liquor Separate alkali metal aluminate from.

The mother liquor recovered in the process of the invention is sent to the raw material leaching stage. This technology Recovers alkaline components and thus reduces the amount of components consumed in the leaching step can be done.

The filtration surface is made of polyamide fiber woven fabric, and the filtration surface is made of a woven metal woven fabric. Refrigerant to maintain the filtration surface temperature within the range of 10 to 95℃. Energy consumption can be significantly reduced by supplying tap water as Ru.

The alkali metal aluminate obtained is a commercial product.

This is an alkali metal corresponding to the formula Met0-AI=03・2.5H20. It is a homogeneous white crystalline solid in the form of a salt with aluminic acid. Here, Me is Na or It is K. This product is readily water soluble and when stored in air, the JA acid salt (coated with a layer of solid carbonate alkali), easy to cake, 1 , 280 to 1,320 kg/m3, and is hygroscopic. this life The product has high purity and its chemical composition: M in weight %, e 20-25~38 , A 1203-37.5 to 44.5.5 iO2-0.1 or less, F e 20 s　O-02 or less - Moisture - 20 to 25 constant. alkali metal oxides and The molar ratio of aluminum oxide, Me20:Al203, is 1.1 to 1.7. equal.

In comparison with the prior art described in Cited Documents C4, 5, 6].

The method according to the invention has the following advantages.

- This method reduces the power consumption rate by 5.5-8%.

- Increase the yield of desired product by 8.5-26%.

- The processing equipment in the crystallization stage and evaporation stage is simplified and used in the leaching stage. The alkaline reactants are recovered in small amounts from the mother liquor.

[BEST MODE FOR CARRYING OUT THE INVENTION] Crushing aluminum-containing raw materials such as limestone and nepheline into particles of 80 μm size. do. The molar ratio of oxide CaO and SiO2 in the charge becomes 2.05, and the mole The front By mixing the rag material with an alkaline solution.

The charge was prepared. This charge is sintered in a rotary kiln at a temperature of 1200℃. did. Crush the sintered cake.

g/! Composition: A1203 14-30. M8a 0 35-35.5.5i02 0.5-0.7 and 1 molar ratio Me2O: A 1203 = 1.63-4.2 It was leached with a solution containing Contains oxides of alkali metals and aluminum As a result of the leaching of the sinter, the molar ratio Mp of the tympanic material ranges from 1.1 to 1.7, 2C):Δ] ? An aluminate solution with 0.03 was obtained.

The aluminic acid solution is separated from the resulting sticky substance and subjected to a desilicating treatment to remove silica. and other contaminants. This desilication treatment is performed to remove residual SiO2 in the solution. It was carried out up to 110°07g/g. When removing silicic acid from aluminic acid solution The white viscous material obtained was separated and sent to the raw material charge preparation stage. The resulting purification Evaporation treatment is performed on the aluminate solution. The evaporation process is carried out in two stages.

The first stage is 225-230g/! at a temperature of 120℃! Me2O11!1 degree The second stage of evaporation is carried out at a temperature of 360 -370 g/J! , up to a concentration of M=20. Two-stage implementation of the evaporation process is preferred because evaporation occurs more efficiently and productively.

The result of the defect-free process is an aluminate solution saturated with respect to the alkali metal aluminate. produced. This saturated aluminic acid solution was kept at a temperature of 95-105°C for 2-3 hours. With this, an alkali metal concentration in solution of 385-395 g/I is obtained. in this way The solution is then supersaturated with respect to the alkali metal aluminate and concentrated into a pulp. Consistency is obtained, and the molar ratio of alkali metal oxide and aluminum oxide is 2. ．． 05. The pulp thus obtained is subjected to crystallization treatment. Ru. The process is carried out using a 50"C surface temperature sliding filter consisting of a woven metal shaving screen. It is carried out on the surface. with rapid crystallization on this filter surface.

Separation of the product from the mother liquor occurs. This crystallization technique shortens the crystallization time and the product improve the recovery and separation from the mother liquor.

The obtained mother liquor is subjected to the leaching step of the sintered material. This technique is used for leaching Reduces consumption of alkaline reactants.

Preferred features of this embodiment of the invention for producing alkali metal aluminates Let's discuss gender in more detail. In the one-stage evaporation process, the product precipitates It has the potential to deposit on the walls of the evaporator and impair the thermal properties of the evaporation process.

In the first stage of the two-stage evaporation process, carried out at 120°C, the alkali in the solution Metal oxide concentration is 225-230g/, f1? , the Me2o concentration is reached. this The solution is still unsaturated and the product is in solution.

In the second stage, carried out at 135-150 °C, the concentration of alkali metal oxides is It is made to M e 20 of 360-370 g/A. Evaporation temperature 135-150" C, a lower solution viscosity is obtained and therefore the alkali metal aluminum increases the solubility of phosphate salts. Therefore, precipitation as a solid phase is almost impossible; The possibility of deposits on the walls of the device is therefore excluded. More preferably, The alkali gold Fit oxide concentration in a saturated viscous solution is 385. -3 Hold this solution at a temperature of 9D to 105°C for 2 to 3 hours until it reaches 95 g/I. do. In this state, crystallization of the product is observed. This technology uses 10 to 95 tons. It has a good effect on the crystallization carried out on the mobile filtration surface at temperatures of . this surface Temperature control is performed by cooling with tap water.

The embodiment of the evaporation stage described above does not require a high consumption rate of the heating medium - water vapor.

Examples illustrating specific embodiments of methods for producing alkali metal aluminates are described. do.

Example 1 Me in weight% 20-20.8. Al20w1 34.2, Fa20s-1~ 278.4 kg of nepheline ore containing the main component of 3.5.8i○2-43 and the remaining impurities and Cao 54. in weight%. Limestone 490k consisting of SiO22, residual impurities g was crushed into particles with a size of 85 μm.

278.4 kg of crushed nepheline and 490 g of crushed limestone were mixed with 33 QkH of water. It matched. The obtained charge was (': a O: Si O2 = 2.05/; Me It has a molar ratio of 2O:(A1203+Fc203)=1. In this way The resulting charge was sintered in a rotary kiln at a temperature of 1200°C. sintered The resulting cake was crushed and had a molar ratio of M e 20: A 1203 = 1.93. A solution containing e 20 35 g/11 and A1203-30 g/A It leached out with liquid.

The pulp resulting from the leaching was filtered and the Me2O obtained after filtration was 72,5 g/g. -A1203-109g/, full:, Contains SiO2-0,6g/A, M Dequessing an aluminate solution with a molar ratio of e20:A1203=1.1. Treated with icic acid. The obtained white mucilage is separated by concentration and filtration, and is used in the raw material preparation stage. It was circulated to Me2O-72.5g/! , AI 20s -109g / It has a composition of A,5iO3-0,05g/11, Me2O:A1203=1 ．． 1 m3 of desilicated aluminate solution with a molar ratio of 1 was added to the flow-through filter. 350 g / 11 M e 20 at a temperature of 120 °C in a steam-type evaporator. evaporated to a degree.

0.206 m' of evaporated solution at a temperature of 120°C was fixed on a irrigation filter. The filter was passed through an evaporator onto a mobile filter fabric made of polyamide fibers. The filtration fabric is Cooled to a temperature of 10℃ by continuously sending cold water at a temperature of 5℃ to the inactive side of the It was done. Instantaneous crystallization of alkali gold disaluminate and its Mother liquor of Me2O-35g/, Ig,,A1zOs-30g/ A, molar ratio 5Ae20:Ala03=1.93. body aim’ this solution The sinter was sent to the leaching stage.

Product yield was 63 kg (68.5% of theory).

The product had the following chemical composition 1% by weight: M e 20-25, Al2 O337,5,5iOz-0,05, Fe203-0.02; the remainder is the bonded type H2O; Molar ratio Me 20: A120wl"1.1; Moisture -25゜This The product was a commercially pure, rosy white solid material.

Actual #i example 2 Weight%: Me2O-20,8, A1203-34.2, Fe2O33,5, S 280.3 kg of nepheline ore mainly composed of iO2-43 and weight %: CaO-54 , 521.7 kg of limestone whose main component is 3iO2-2 was crushed into particles of 80 μm. Shattered.

280.3 kg of crushed nepheline and 521.7 kg of crushed limestone to 335, mixed with water. The obtained charge had a molar ratio C, aO: 5iOa = 2.1. M g20: (A120x + F In203) = 1.1. like this The resulting charge was sintered in a rotary kiln at a temperature of 1250°C. Sintering The resulting cake was ground and Mc20:A120s had a molar ratio of 4.1 and M6 20-35 g/! And A 120! -14g/, a solution containing A It leached out. The resulting pulp from the leaching was filtered and the Me2O obtained after filtration was -72.5g/i, A1203-70g/J &, 5in2 Contains 0.1g/A Then, 8 liquids of aluminate having a molar ratio of %1c20:A1□03=1.7 were dequested. Treated with icic acid. The obtained white mucilage is separated by concentration and filtration, and is used in the raw material preparation stage. It was circulated to

Mg20-72.5g/A-A 120s-70g/J3゜5iO2-0,0 It has a composition of 5g/A and a molar ratio of Me20:A1zOi=1.7. 1 m' of desilicated aluminate solution in a falling film evaporator. It was evaporated at a temperature of 150° C. to a concentration of 400 g/A M e 20.

0.182 m' of evaporated solution at a temperature of 150"C was solidified on a irrigation filter. from the evaporator onto a mobile filter fabric of coated polyamide fibers. The filtration fabric is , by continuously sending cold water at a temperature of 30°C to the inactive side.

It was cooled to a temperature of 95°C.

On the mobile decreasing surface, alkali metal alumin'rIJ! Instant crystallization of salt separation from the mother liquor occurred. The resulting mother liquor had the following composition. M e z　O-35g　/　A, A　203-14　g/A, molar ratio M　e　2 0: A l 203=1.7. This mother liquor was sent to the sinter leaching stage. Generate The product yield was 56 kg (80.0% of theory).

The product had the following chemical composition. Weight %: Me20 36.5. A120 3-43.5i02-0.07, Fe203-0.02; the remainder is bound H20 ; Molar ratio M e 20: A 120. =1.4 ;Moisture -21゜This raw The product was a liquid white solid material of commercial purity.

Example 3 Weight%: Me2O20.8, A1203-34.2, F e203-1 to 3.5 , 280.3 kg of nepheline ore containing the main component of SiO2-43 and residual impurities. , limestone consisting of Ca　O-54+　Si　O2-2 in wt%, balance impurities 490 kg was crushed into particles of 85 μm size.

Mix 280-3 kg of crushed nepheline and 490 kg of crushed limestone with 330 kg of water. It matched. The obtained charge was CaO:Si○2=2.05:MezO:(A120 It has a molar ratio of FQ203)=1.05. The charge thus obtained was sintered in a rotary kiln at a temperature of 1200"C. The sintered cake was broken. Crushed, M e 20-35 with a molar ratio of M 620: A1203 = 1.63 A solution containing 5 g/A and A 1203-21, 5 g/11 was also prepared. It oozed out. Filter the pulp resulting from the leaching and obtain M e 20 after filtration. -72, 5 g / A, A l 203-Bog / A, S L O1 1-0, 0g / J! / containing -MezO:A1□03 = 1.5 molar ratio An aluminic acid solution containing the following was desilicated. Filter the obtained white mucilage with fA cotton. It was separated by filtration and recycled to the raw material preparation stage.

Thus obtained M 820-72-5 g/! -A l 203- 80 g/! , S i○2-0, has a composition of 05 g / 4, M e 1 m3 of desilicated aluminum with a molar ratio of 20:A120s = 1.5 The minic acid solution was heated to 375 g/! in a falling film evaporator at a temperature of 135°C. M of e Evaporated to a concentration of 20. 0.195m3 of evaporated water at a temperature of 135℃ The solution is evaporated onto a mobile filter fabric of polyamide fibers fixed onto a flow-through filter. Sent from the generator. The filtration fabric is continuously heated with cold water at a temperature of 20°C on its inactive side. The mother liquor obtained by feeding at a temperature of 50° C. had the following composition: Me 2O-35g/A, A1203-21.5g/A, molar ratio Me 20:A12 o3=l, 63. This solution was sent to the sinter leaching stage. Product yield is 58. 5 kg (73% of theory), the product had the following chemical composition: Amount %: MeaO-30,5, A120s-39-5iO2-0,06, Fe2 03-0.015; The remainder is bound H2O; Molar ratio M e 20: A l 203 = 1,3; Moisture -22,5, this product is commercially pure crystalline It was a loose white solid alkali metal aluminate.

Example 4 Weight %: Mg20 20.8, A1203-34.2, Fe203-3.5. 5　280.3 kg of nepheline ore containing the main component of i○2-43 and residual impurities. , weight + i%: Limestone 521 consisting of Cao-54, SiO□-2, and remaining impurities ．． 7 kg was crushed into particles of 85 μm size.

280', 3 kg of crushed limestone 521, 7 kg of crushed limestone and 33 Mixed with 5 kg of water. The obtained charge is CaO:S1o2=2.1; The molar ratio of Mez0: (A1203 + Fe203) is 1.1. child The charge obtained as above was sintered in a rotary kiln at a temperature of 1250°C. Ta. The sintered cake was crushed and had a molar ratio of M e 20: A1203 = 4.2. Shi M e 20-36.5g/! and A1203-14.5g/A. The solution was also leached. The bulb resulting from the leaching was filtered and the Me obtained after filtration was z 0-72.5 g/A, A l 203-70 g/i, S i 02-0. Al containing 1 g/A and having a molar ratio of Me2O:Al10g = 1.7 The minic acid solution was desilicated. The obtained white viscous substance was concentrated and separated by filtration. R-R? + Circulated to the preparation stage.

M14120-72.5 g/A, AI 20s-70g/A-5i 02-0.05 g/A, M820: A120, = 1.7 Evaporate in two stages 1 m3 of desilicated aluminate solution with molar ratio I let it happen.

In the first stage, 230 g/g/kg was added at 12 p’C in a falling film evaporator. MQ of A 20. Evaporated to a concentration of SiO2 of 0.16 g/A. 1st stage The 0°315 m' solution exiting from is sent to the second evaporation stage, which At 150℃ humidity, Me2O of 370g/A, S i02 concentration of 0.25g/A It was carried out in a falling evaporator at temperatures up to 135-150"C. The solution coming out of the second stage at 0.195 m'°C was transferred from the evaporator to a crystallizer equipped with a stirrer. It was discharged into the dispenser. among them.

The solution was heated at 95 to 1 The temperature was maintained at 05°C for 2-3 hours. Therefore, the solution was heated to 105℃ by self-evaporation. Allow to cool to temperature, then 390g/A of Me2O, 0.26g/pu of 5iOz After evaporation to a concentration of , a bulb was formed. Aluminic acid obtained in this way The salt valve is 0° 185℃ + M e 20-360 g / A and - A120, -290g/A and 1 molar ratio Me20: Al2O, = It was 2.05. This valve is heated to a temperature of 105°C and the rotary drum filter Sent on a mobile woven metal screen fixed to a pallet. filtration metal screen The screen was cooled to a temperature of 95° C. by sending cold water to the non-working side of the screen. Living The crystallization of the product, its separation from the mother liquor, and its circulation to the leaching stage were performed as described in Examples 1 to 3. It was carried out in the same way.

The product profile was 60 kg (86%), the product obtained had the following chemical composition: 0% by weight with: M Q 20-38, A120s-44,5,5in20 ．． 06, Fe2O, 0.01, the remainder is bound water, molar ratio M e20: A120. = 1.4, moisture is 20. The product was a commercial quality rosy white solid product. .

industrial use The method according to the invention can be applied to aluminum-containing ores such as nepheline, bauxite, etc. metallurgical and other aluminum-containing industrial wastes to alumina, soda and potash. It can be used when processing.

Aluminic acid obtained during the leaching stage of yK material (sintered material) during the production of alumina A significant portion of the salt solution is sent to the production of alkali metal aluminates. This product is , valve-gi paper industry, crude oil drilling, mining, foundry industry, water conservancy technology building construction. It is being used more and more.

1 cabinet string ill referee

Claims (5)

[Claims] 1. Aluminic acid is produced by leaching raw materials containing aluminum monoxide and alkali metals. producing a salt solution; desilicating the aluminate solution; evaporation step of the desilicated aluminate solution; - evaporated aluminate; crystallizing the alkali metal aluminate from the solution. In the mate production method, -1.1 to 1.7 alkali metal oxide to aluminum oxide Me2O:Al2 An aluminum solution with an O3 molar ratio is evaporated, and this evaporation is between 120 and 150 carried out up to an alkali metal oxide concentration of 350 to 400 g/l at concentrations in the range of °C. the stage of Transfer the evaporated solution at a temperature of -95 to 150°C to a temperature range of 10 to 95°C. The above-mentioned method can be obtained by sending the product over a type filtration surface, during which the product is crystallized and separated from the mother liquor. crystallizing an alkali metal aluminate from the evaporated solution; - recycling the obtained mother liquor to the raw material leaching stage. 2. The aluminate solution evaporation step is carried out in two stages, in the first stage , the solution evaporates at a temperature of 120°C and contains 225-230 g/l of alkali metal oxide. concentration and in the second stage at a temperature of 135-150°C. Claim 1, characterized in that the method is carried out up to said oxide concentration of 370 g/l. Method by term. 3. After the evaporation step, the aluminate solution is kept at a temperature of 95-105°C for 2-3 hours. to obtain an alkali metal oxide concentration in solution of 385 to 395 g/l. A method according to either claim 1 or 2, characterized in that: 4. The crystallization step is carried out on a movable filter surface at a temperature of 20 to 50°C. A method according to any one of claims 1 to 3. 5. Features the use of polyamide woven fabric and woven metal screen as the filtration surface A method according to any one of claims 1 to 4.