CN101734698B - Method for preparing aluminum oxide from aluminiferous material - Google Patents

Abstract

The invention provides a method for preparing aluminum oxide and other products from aluminiferous materials such as bauxite, high iron bauxite, alunite, kaoline, alumina, fly ash, coal gangue, aluminum ash, nepheline, clay and the like. The method comprises the following steps: (1) crushing, grinding and mixing the aluminiferous materials with ammonium sulfate and then roasting; (2) dissolving the roasted product (clinker aggregate) in water, and filtering to obtain aluminum ammonium sulfate solution and filter residues; (3) carrying out deferrization, aluminum deposition or recrystallization on the aluminium ammonum sulfate solution with ammonia to prepare aluminum oxide, and meanwhile, recycling the ammonium sulfate; (4) preparing silicon dioxide from the filter residues, and taking the remaining residues containing ferrum as the raw material for ironmaking. The method is suitable for treating various aluminiferous materials, has the advantages of simple technical process, simple equipment, no emission of solid, liquid and gas wastes, and no secondary pollution, and realizes the high-added-value green complex utilization of the aluminiferous materials such as bauxite, high ironbauxite, alunite, kaoline, alumina, fly ash, coal gangue, aluminum ash, nepheline, clay and the like.

Description

A method for preparing alumina from aluminum-containing materials

technical field

The invention relates to a method for processing aluminum-containing materials, in particular to aluminum-containing materials such as bauxite, high-iron bauxite, alunite, kaolin, bauxite, fly ash, coal gangue, aluminum ash, nepheline, and clay Process for preparing ammonium aluminum sulfate, alumina and silica products. the

Background technique

Bauxite, high-iron bauxite, alunite, kaolin, bauxite, nepheline, clay, fly ash, coal gangue, aluminum ash and other aluminum-containing materials are aluminum-containing minerals or aluminum-containing solid waste, usually containing A large amount of silicon dioxide and iron, calcium and other oxides. Among them, the main aluminum-containing minerals in bauxite, high-iron bauxite, and bauxite are gibbsite and gibbsite; the main aluminum-containing minerals in kaolin, nepheline, clay, fly ash, and coal gangue are Aluminosilicate; the main aluminum-containing mineral in alunite is potassium aluminum sulfate; the main aluminum-containing mineral in aluminum ash is metallic aluminum, crystalline alumina and amorphous alumina. The chemical composition of these aluminum-containing materials not only varies according to the origin, but also varies greatly in composition and physical and chemical properties. In particular, aluminum usually forms aluminosilicate with silicon, which increases the cost and difficulty of separating aluminum and silicon. The production of alumina from bauxite or other aluminum-containing raw materials is essentially the process of separating alumina from other impurities in the ore. The methods of producing alumina include alkaline method, acid method and electrothermal method. 1Alkaline production of alumina

The basic principle of the alkali method is to make the alumina and alkali in the ore generate water-soluble sodium aluminate under certain conditions, and separate it from impurities such as silicon dioxide and iron oxide after dissolution, and then separate the pure sodium aluminate solution. Aluminum hydroxide is analyzed, and aluminum hydroxide is calcined at high temperature to obtain finished alumina. the

Alkali production of alumina can be divided into Bayer method, sintering method, combined method and so on. the

1.1 Bayer method

The Bayer method directly treats bauxite with caustic soda solution to make the alumina in the ore generate sodium aluminate, while the silica in the ore becomes an insoluble residue—red mud, which is separated from the sodium aluminate solution. The purified sodium aluminate solution is decomposed, filtered to obtain aluminum hydroxide, and calcined into alumina after washing. The caustic alkali solution that decomposes aluminum hydroxide is called mother liquor, and the mother liquor is evaporated and concentrated before being used to process the next batch of ore for recycling. the

1.2 Sintering method

The sintering method is to mix the ore, soda ash and limestone, and sinter at high temperature, so that the alumina in the ore will form solid sodium aluminate, ferric oxide will form sodium ferrite that can be hydrolyzed, and silicon dioxide and calcium oxide will form insoluble primary silicon. Calcium Oxide 2CaO·SiO ₂ . Then use dilute lye to dissolve the clinker-clinker, so that sodium aluminate enters the solution and separates from the red mud.

The solution containing part of silicon dioxide is desiliconized to obtain a sodium aluminate solution refined solution, and carbon dioxide gas is introduced to decompose it to obtain aluminum hydroxide and mother liquor. After the mother liquor is evaporated, appropriate soda ash is added to sinter with the next batch of ore and lime ingredients. The washed aluminum hydroxide is calcined to obtain alumina. the

Generally speaking, the Bayer method has the advantages of simple process, less investment, high product quality and low production cost. However, it has poor advantages in dealing with low-grade ore, and consumes expensive caustic soda. the

The advantage of the sintering method is that it can process lower-grade ores, and only consumes cheap sodium carbonate. Compared with the Bayer method, the low-grade ore is processed under the same conditions, the alkali consumption of the sintering method is lower, and the total recovery rate of alumina Higher, but the process is complicated, the investment is large, the quality of the product alumina is poor, and the cost is high. the

Therefore, Bayer method is used for high-quality bauxite with low silicon content, and sintering method is generally used for aluminum ore with high silicon content and low aluminum-silicon ratio. the

1.3 Joint law

In order to make full use of mineral resources and integrate the advantages of the two methods to increase the total recovery rate of alumina, improve product quality and reduce production costs, the two methods are used in combination, thus resulting in the combined method. The joint method is further divided into series, parallel and hybrid methods. the

The parallel method uses the Bayer method to process high-grade ore, and the sintering method to process low-grade ore; in the series method, the sintering method only processes Bayer red mud; adding some low-grade ore to Bayer red mud at the same time can improve the operation of the large kiln , this method of combining series and parallel is called the hybrid method. the

2. Production of alumina by acid method

The acid method is to treat aluminum-containing raw materials with inorganic acids such as nitric acid, hydrochloric acid, and sulfuric acid to obtain an acidic aqueous solution of the corresponding aluminum salt. Then these aluminum salts or hydrate crystals (crystallization by evaporation) or basic aluminum salts (hydrolysis crystallization) are precipitated from the solution, and the aqueous solution of these aluminum salts can also be neutralized with alkali, so that aluminum is precipitated as aluminum hydroxide. Alumina is obtained by calcining aluminum hydroxide, hydrates of various aluminum salts or basic aluminum salts. the

It is theoretically reasonable to treat widely distributed high-silicon bauxite with acid method to produce alumina, and the prepared aluminum products contain less silicon impurities. However, expensive acid-resistant equipment is required, and the acid used is difficult to recover, so it is difficult to carry out large-scale industrial production. In recent years, the research on the acid method has made progress, but it cannot compete economically with the alkali method for processing high-quality bauxite. the

3. Production of alumina by electrothermal method

The electrothermal method is used to process high-iron aluminum ore, and the ore and carbon reducing agent are made into a charge for high-temperature reduction and smelting in an electric arc furnace. The silicon oxide and iron oxide in the ore are reduced to ferrosilicon alloy, while the alumina floats up in the form of molten calcium aluminate slag, and is stratified due to different specific gravity. The obtained alumina slag is treated with alkali method to extract alumina, and the obtained ferrosilicon alloy is the finished product. At present, the production of alumina by electrothermal method is still in the research stage. the

4. Production of alumina by blast furnace method

The blast furnace method is used to process high-iron bauxite. The ore and coke are added to the blast furnace, the iron oxide is reduced to iron, the alumina, silica and the added lime form slag, and the silica and lime form calcium orthosilicate. The slag is dissolved by alkali, filtered to obtain sodium aluminate solution, obtained by carbon or seed separation to obtain aluminum hydroxide, and calcined to obtain alumina. the

So far, many methods of extracting alumina from aluminum ore or other aluminum-containing raw materials have been proposed, but due to various technical and economic reasons, some have been eliminated, some are in the experimental stage, and almost all of them are in the industry. Alkaline production. the

Contents of the invention

At present, domestic reserves of high-quality bauxite are less and less, and other aluminum-containing resources have not been effectively utilized. Therefore, it is urgent to find a new process and technology that can process all aluminum-containing minerals to produce alumina. Aiming at the current situation that these aluminum-containing materials cannot be rationally utilized, the present invention provides a high-value-added green comprehensive utilization of bauxite, high-iron bauxite, alunite, kaolin, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay and other aluminum-containing materials. the

The process of the invention includes two parts, one is to extract alumina; the other is to process aluminum slag. the

1. Extraction of alumina

1.1 Ore containing aluminum as oxide

Crush aluminum-containing materials such as bauxite, high-iron bauxite, kaolin, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay, etc., and grind them to less than 80 μm. Massage alumina and ammonium sulfate in the materials Mole ratio 1:4-1:10, add water ball mill and mix evenly. The mixed material is dried and dehydrated below 200°C, roasted at 200-700°C, and kept for 1-8h. The ammonia produced in the reaction process is absorbed by water to prepare ammonia water, or pressurized to make liquid ammonia. Add water to dissolve the roasted clinker, filter, the filtrate is aluminum ammonium sulfate solution; the filter residue is aluminum extraction slag, the main components are silicon dioxide, ferric oxide, etc. the

The chemical reactions involved are:

xAl ₂ O ₃ ·ySiO ₂ +(NH ₄ ) ₂ SO ₄ →NH ₄ Al(SO ₄ ) ₂ +SiO ₂ +NH ₃ ↑+H ₂ O↑

Al ₂ O ₃ +4(NH ₄ ) ₂ SO ₄ ＝2NH ₄ Al(SO ₄ ) ₂ +2SiO ₂ +6NH ₃ ↑+3H ₂ O

NH ₃ +H ₂ O＝NH ₃ ·H ₂ O

4FeSO ₄ +O ₂ +2H ₂ SO ₄ ＝2Fe ₂ (SO ₄ ) ₃ +2H ₂ O

Fe ₂ (SO ₄ ) ₃ +6NH ₃ +6H ₂ O＝2Fe(OH) ₃ ↓+3(NH ₄ ) ₂ SO ₄

For the aluminum ammonium sulfate solution prepared from high-iron bauxite as a raw material, an oxidizing agent, ferrous oxide ion, is added to remove iron by the jarosite method; and then the pH value of the solution is adjusted to 3.5-4.5 to prepare aluminum hydroxide. the

4FeSO ₄ +O ₂ +2H ₂ SO ₄ ＝2Fe ₂ (SO ₄ ) ₃ +2H ₂ O

3Fe ₂ (SO ₄ ) ₃ +2NH ₃ +12H ₂ O＝(NH ₄ ) ₂ Fe ₆ (SO ₄ ) ₄ (OH) ₁₂ +5H ₂ SO ₄

NH ₄ Al(SO ₄ ) ₂ +3NH ₃ +3H ₂ O=Al(OH) ₃ ↓+2(NH ₄ ) ₂ SO ₄

If the raw material is not high-iron bauxite, then the obtained filtrate-ammonium aluminum sulfate solution is purified by recrystallization to obtain higher purity ammonium aluminum sulfate crystals, and then the following four schemes are used for processing:

Option One:

Dehydrate pure aluminum ammonium sulfate crystals at 200-400°C, heat to 500-700°C and decompose for 2-6 hours to obtain aluminum sulfate, and then heat up to 800-1300°C for calcination to prepare alumina products, by-products sulfur trioxide and ammonia, Absorb with water to prepare ammonium sulfate solution. The chemical reactions involved are:

NH ₄ Al(SO ₄ ) ₂ ·12H ₂ O＝NH ₄ Al(SO ₄ ) ₂ +12H ₂ O

2NH ₄ Al(SO ₄ ) ₂ ＝Al ₃ (SO ₄ ) ₂ +(NH ₄ ) ₂ SO ₄

Al ₂ (SO ₄ ) ₃ ＝Al ₂ O ₃ +3SO ₃

(NH ₄ ) ₂ SO ₄ ＝2NH ₃ +SO ₃ +H ₂ O

2NH ₃ ·H ₂ O+SO ₃ =(NH ₄ ) ₂ SO ₄ +2H ₂ O

Option II:

Dissolve pure ammonium aluminum sulfate crystals in water, then add ammonia to the solution, and control the initial concentration of [Al ³⁺ ] in the solution at 0.05- 0.2mol·L ^-1 , the pH value is 3.4-4.5, to prepare aluminum hydroxide. Among them, the temperature of 40°C-60°C is the best. The solution after filtering out the aluminum hydroxide is an ammonium sulfate solution, which is returned to the batching process after evaporation and concentration. The chemical reactions involved are:

3NH ₃ +NH ₄ Al(SO ₄ ) ₂ +3H ₂ O＝Al(OH) ₃ ↓+2(NH ₄ ) ₂ SO ₄

2Al(OH) ₃ ＝Al ₂ O ₃ +3H ₂ O↑

Scheme 3: Dissolve pure aluminum ammonium sulfate crystals in water, then add urea to it, and control the concentration of [Al ³⁺ ] in the solution at 50°C-100°C to 0.05-0.2mol·L ^-1 , [Al ³⁺ ]/ The molar ratio of [CO(NH ₂ ) ₂ ] is 0.04-0.06 to prepare aluminum hydroxide. The solution after filtering out the aluminum hydroxide is ammonium sulfate solution, which is evaporated and concentrated and then returned to the batching process; the carbon dioxide released in the process of preparing aluminum hydroxide with urea and the ammonia gas released by roasting ammonium sulfate are recovered to prepare urea. Aluminum hydroxide is decomposed to produce alumina. The chemical reactions involved are:

CO(NH ₂ ) ₂ +3H ₂ O＝CO ₂ ↑+2NH ₄ OH

NH ₄ Al(SO ₄ ) ₂ +3NH ₄ OH＝Al(OH) ₃ ↓+2(NH ₄ ) ₂ SO ₄

2Al(OH) ₃ ＝Al ₂ O ₃ +3H ₂ O↑

Solution 4: Dissolve pure aluminum ammonium sulfate crystals with water, add to ammonium bicarbonate solution to prepare aluminum ammonium carbonate precipitation, and control the initial concentration of [Al ³⁺ ] in the solution at 20°C-60°C to 0.4mol·L ^-1 Above, the initial concentration of NH ₄ HCO ₃ is above 1.5 mol·L ^-1 , the pH value is 8.0-10.0, and the precipitation of ammonium aluminum carbonate is prepared. The solution after filtering out ammonium aluminum carbonate is an ammonium sulfate solution, which is returned to the batching process after evaporation and concentration. The ammonium aluminum carbonate precipitate is calcined and decomposed at 800°C-1200°C to prepare alumina, the mixed gas of ammonia and carbon dioxide obtained by calcining and the ammonia released by roasting ammonium sulfate are absorbed with water to prepare ammonium bicarbonate solution; the filtrate after filtering ammonium aluminum carbonate It is an ammonium sulfate solution, which is returned to the mixing process after evaporation and concentration. The chemical reactions involved are:

NH ₄ Al(SO ₄ ) ₂ +4NH ₄ HCO ₃ ＝NH ₄ AlO(OH)HCO ₃ ↓+CO ₂ ↑+2(NH ₄ ) ₂ SO ₄ +H ₂ O

2NH ₄ AlO(OH)HCO ₃ ＝Al ₂ O ₃ +2NH ₃ ↑+2CO ₂ ↑+2H ₂ O↑

NH ₃ +CO ₂ +H ₂ O＝NH ₄ HCO ₃

1.2 Ore containing aluminum as sulfate

Alunite is a naturally occurring sulfate mineral of aluminum and potassium. Its chemical formula can be written as: K ₂ SO ₄ ·Al ₂ (SO ₄ ) ₃ ·4Al(OH) ₃ . In addition to alunite minerals, alunite ore mainly contains a large amount of quartz and kaolinite. Therefore, the preparation of alumina from alunite ore is not only to separate the aluminum sulfate combined with potassium sulfate, but also to separate the alumina combined with sulfate. In addition, aluminum must be separated from the silica in the mineral. Therefore, the scheme is modified as follows:

Firstly, calcining and dehydrating the alunite mineral at 500-750°C, the reaction is:

K ₂ SO ₄ ·Al ₂ (SO ₄ ) ₃ ·4Al(OH) ₃ ＝K ₂ SO ₄ ·Al ₂ (SO ₄ ) ₃ +2Al ₂ O ₃ +6H ₂ O↑Then mix with ammonium sulfate at 400-550℃ Mixed roasting, the reaction is:

K ₂ SO ₄ Al ₂ (SO ₄ ) ₃ +2(NH ₄ ) ₂ SO ₄ ＝K ₂ SO ₄ +2NH ₄ Al(SO ₄ ) ₂ +2NH ₃ ↑

Al ₂ O ₃ +4(NH ₄ ) ₂ SO ₄ ＝2NH ₄ Al(SO ₄ ) ₂ +6NH ₃ ↑+3H ₂ O↑

xAl ₂ O ₃ ·ySiO ₂ +(NH ₄ ) ₂ SO ₄ →NH ₄ Al(SO ₄ ) ₂ +SiO ₂ +NH ₃ ↑+H ₂ O↑

The roasted clinker is dissolved and filtered to obtain filtrate and slag. The filtrate is a solution containing aluminum sulfate, potassium sulfate, and ammonium sulfate. Adjust the pH value to precipitate aluminum hydroxide. The remaining substances in the solution are potassium sulfate and ammonium sulfate. Evaporate and crystallize to obtain a nitrogen-potassium mixed fertilizer. The slag obtained after the roasted clinker is dissolved and filtered is aluminum extraction slag, which mainly contains silicon dioxide. the

2. Aluminum slag treatment

This part adopts the following two schemes according to the composition of the aluminum slag:

2.1 High silicon slag

If the aluminum extraction slag contains few impurities such as iron, mainly SiO ₂ , the aluminum extraction slag can be treated with acid to remove impurities, including sulfuric acid leaching and sulfuric acid roasting. The sulfuric acid leaching method is to mix the aluminum extraction slag with the sulfuric acid solution with a concentration of 20%-90% according to the mass volume ratio (g:ml) of 1:3-1:6, and react at a temperature of 60-200°C and stirring 0.5-3h. The sulfuric acid roasting method is to mix the aluminum extraction slag with the sulfuric acid with a concentration of more than 90% at a mass volume ratio (g:ml) of 1:0.5-1:2, and react at a temperature of 200-300°C and stirring for 0.5-3h . After acid leaching or acid roasting, lower the temperature of the system to below 100°C, add 2-5 times the volume of water to dilute, continue stirring at 80-90°C for 20-40min, and leach the formed sulfate. Separation by filtration, washing the filter cake, drying, burning and dehydroxylation at 800-1300°C, mainly silicon dioxide, the filtrate is a sulfuric acid solution containing iron and other ions, and iron can be recovered. The main chemical reactions involved are:

Fe ₂ O ₃ +3H ₂ SO ₄ ＝Fe ₂ (SO ₄ ) ₃ +3H ₂ O

2.2 High iron slag

If the aluminum extraction slag contains a lot of iron, the method of alkali treatment to extract silicon is mainly divided into leaching method and roasting method. The leaching method is to mix the aluminum extraction slag with sodium hydroxide with a concentration of 20%-90% according to the mass volume ratio (g:ml) of 1:2-1:6, and mix it at a temperature of 60°C-280°C and stirring After reacting for 0.5-3h, the temperature of the system drops below 100°C, add 2-5 times the volume of water to dilute, and continue to dissolve at 80-90°C for 20-40min. Sodium silicate solution and slag were obtained after filtration and separation. Sodium silicate solution can be used both as a product and as a carbon fraction to prepare silica. The obtained slag mainly contains iron and can be used as raw material for ironmaking. The roasting method mixes the aluminum extraction slag with sodium hydroxide or sodium carbonate in a mass ratio (g:ml) of 1:0.5-1:8, at a temperature of 350°C-600°C (sodium hydroxide) or 800°C-1200°C ( Sodium carbonate) for 0.5-3h, then add 2-5 times the volume of water and stir at 80-90°C for 20-40min. Sodium silicate solution and slag were obtained after filtration and separation. Sodium silicate solution can be used both as a product and as a carbon fraction to prepare silica. The obtained slag mainly contains iron and can be used as raw material for ironmaking. The main chemical reactions are:

SiO ₂ +2NaOH=Na ₂ SiO ₃ +H ₂ O

Fe ₂ O ₃ +NaOH+3H ₂ O＝2Fe(OH) ₃ ↓+NaOH

Na ₂ SiO ₃ +CO ₂ ＝SiO ₂ ↓+2Na ₂ CO ₃

The method of the invention has simple technological process and convenient equipment, and the products of aluminum ammonium sulfate, alumina and silicon dioxide are prepared at a relatively low cost, and high value-added synthesis of aluminum and silicon-containing mineral resources such as fly ash and bauxite is realized Utilization, the entire process forms a closed loop, which will not cause secondary pollution to the environment, and meets the requirements of green industrial production. the

Description of drawings

Preparation of aluminum ammonium sulfate, alumina and silica products from bauxite, high-iron bauxite, alunite, kaolin, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay and other aluminum-containing materials Flow chart

Fig. 1 is the process flow chart of adopting scheme one to deal with

Fig. 2 is the process flow diagram of adopting scheme two to deal with

Fig. 3 is the process flow diagram of adopting scheme three to deal with

Fig. 4 is the technological flow chart that adopts scheme four to deal with

Fig. 5 is the technological flow chart that adopts scheme five and scheme six to deal with

Detailed ways

Example 1

The main composition of the fly ash used is: Al ₂ O ₃ 41.2%, SiO ₂ 48.5%, Fe ₂ O ₃ 3.4%, CaO 3.3%, TiO ₂ 1.3%, MgO 0.2%.

After the fly ash that has been crushed and ground to less than 80 μm is removed by magnetic separation, it is mixed with ammonium sulfate and water in a mass ratio of 1:3.2:5 (the molar ratio of alumina and ammonium sulfate is 1:6), and the ℃ roasting reaction for 5h, and absorb the ammonia gas generated during the reaction with water. The roasted product is lowered in temperature, dissolved by adding water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Aluminum ammonium sulfate crystals are dehydrated at 200°C for 3 hours, decomposed at 550°C for 3 hours, and then heated to 1200°C for 5 hours to obtain alumina. the

Mix aluminum extraction slag with 50% sulfuric acid solution at a mass volume ratio (g:ml) of 1:4, stir and react for 2 hours at a temperature of 120°C, and filter to obtain a sulfuric acid solution containing metal ions such as iron And slag. The slag is washed, dried, and burned at 550°C to remove carbon and become silicon micropowder. the

Example 2

The composition of the bauxite used is: Al ₂ O ₃ 65.3%, SiO ₂ 23.1%, Fe ₂ O ₃ 4.8%, CaO 1.6%, TiO ₂ 3.5%, K ₂ O 0.5%.

After the bauxite that has been crushed and ground to less than 80 μm is removed by magnetic separation, it is mixed with ammonium sulfate and water in a mass ratio of 1:5:7.2 (the molar ratio of alumina and ammonium sulfate is 1:6), and the ℃ roasting reaction for 6h, the gas released during the reaction is absorbed by water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. The pure aluminum ammonium sulfate crystals were dissolved with water, ammonia water was added to control the initial concentration of [Al ³⁺ ] in the solution at 50°C to 0.15mol·L ^-1 , and the pH value was 4.0 to prepare aluminum hydroxide precipitates. The solution after the aluminum hydroxide is prepared is an ammonium sulfate solution, which is evaporated and concentrated and returned to the batching process. Aluminum hydroxide is heated to 1300°C and calcined for 4 hours to produce α-Al ₂ O ₃ .

Mix the aluminum extraction slag with 85% sulfuric acid at a mass volume ratio (g:ml) of 1:5, react for 1 hour at 180°C with stirring, then stop heating, cool down to 80°C, and add 5 times the volume of Dilute with water, continue leaching at 85°C for 30 minutes, and then filter and separate to obtain a sulfuric acid solution containing iron and other metal ions and a slag mainly containing SiO ₂ . The slag is SiO ₂ after washing, drying, and dehydration by burning at 1050°C.

Example 3

The main composition of the high-iron low-grade bauxite used is: Al ₂ O ₃ 29.4%, SiO ₂ 8.9%, Fe ₂ O ₃ 43.5%, TiO ₂ 1.6%, MnO 1.1%, K ₂ O 0.78%.

Mix the crushed and ground high-iron bauxite with ammonium sulfate and water at a mass ratio of 1:3:4.3 (the molar ratio of alumina and ammonium sulfate is 1:8), and roast at 500°C for 4 hours. The gas released during the reaction was absorbed with water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

Feed ferrous oxide ions in the air into the ammonium aluminum sulfate solution, and use the yellow ammonium ironite method to remove iron. Add ammonia to the ammonium aluminum sulfate solution after iron removal to adjust the pH value to 4.5, and precipitate aluminum hydroxide. Aluminum hydroxide is heated to 1200°C and calcined for 3 hours to produce alumina. The filtrate is ammonium sulfate solution, which is used for roasting reaction after concentration. the

The aluminum extraction slag is mainly iron oxide, and its grade can reach more than 60%, which can be directly used as raw material for ironmaking. the

Example 4

The composition of kaolin used is: Al ₂ O ₃ 46.6%, SiO ₂ 50.9%, Fe ₂ O ₃ 0.41%, CaO 0.08%, TiO ₂ 0.35%, K ₂ O 0.36%.

Mix the crushed and ground kaolin with ammonium sulfate and water at a mass ratio of 1:4.2:6 (the molar ratio of alumina and ammonium sulfate is 1:7), and roast at 450°C for 4 hours. During the reaction The released gas is absorbed with water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Dissolve the aluminum ammonium sulfate crystals with water, then add urea to the aluminum ammonium sulfate solution, and control the concentration of [Al ³⁺ ] in the solution at 0.15mol·L ^-1 at 80°C, [Al ³⁺ ]/[CO(NH ₂ ) ₂ ] The molar ratio is 0.05, prepares aluminum hydroxide. The solution after the aluminum hydroxide is prepared is an ammonium sulfate solution, which is evaporated and concentrated and then returned to the batching process; the carbon dioxide released by the urea during the preparation of the aluminum hydroxide and the ammonia gas released by the roasting of the ammonium sulfate are recovered to prepare urea.

Mix the aluminum extraction slag with a sulfuric acid solution with a concentration of 40% in a mass-volume ratio (g:ml) of 1:6, stir and react for 2.5 hours at a temperature of 100°C, and filter to obtain sulfuric acid containing metal ions such as iron solution and slag. The slag is washed, dried, and dehydroxylated by burning at 1000°C to become silica. the

Example 5

The composition of the bauxite used is: Al ₂ O ₃ 69.8%, SiO ₂ 25.7%, Fe ₂ O ₃ 1.71%, MgO 0.17%, TiO ₂ 2.44%, K ₂ O 0.12%, Na ₂ O 0.06%.

The bauxite that has been crushed and ground to less than 80 μm is magnetically separated to remove iron, mixed with ammonium sulfate and water at a mass ratio of 1:4.5:6.5 (ammonium oxide and ammonium sulfate molar ratio is 1:5), and kept at 450°C 3h, carry out roasting reaction, and the gas released during the reaction process is absorbed by water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Dissolve aluminum ammonium sulfate crystals with water, then add ammonia to the aluminum ammonium sulfate solution, control the initial concentration of [Al ³⁺ ] in the solution at 50°C to 0.2mol·L ^-1 , and pH 4.5 to prepare aluminum hydroxide. The solution after the aluminum hydroxide is prepared is an ammonium sulfate solution, which is evaporated and concentrated and returned to the batching process. Aluminum hydroxide was calcined at 1000°C for 5 hours to produce alumina.

Mix the aluminum extraction slag with a sulfuric acid solution with a concentration of 30% in a mass-volume ratio (g:ml) of 1:5, stir and react for 2.5 hours at a temperature of 100°C, and filter to obtain sulfuric acid containing metal ions such as iron solution and slag. The slag is washed, dried, and dehydroxylated by burning at 1000°C to become silica. the

Example 6

The composition of aluminum ash used is: Al 14%, Al ₂ O ₃ 70.5%, SiO ₂ 8.6%, Fe ₂ O ₃ 3.7%.

After crushing and grinding the aluminum ash to be less than 80 μm and removing iron by magnetic separation, mix it with ammonium sulfate and water in a mass ratio of 1:5:7.2 (the molar ratio of alumina and ammonium sulfate is 1:4), and roast at 450°C React for 5h, and absorb the gas released during the reaction with water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Dehydrate aluminum ammonium sulfate crystals at 300°C, heat to 700°C and decompose for 5 hours to obtain aluminum sulfate, and then heat up to 1200°C for calcination to prepare alumina products, and absorb sulfur trioxide and ammonia as by-products with water to prepare ammonium sulfate. the

Mix the aluminum extraction slag with 80% sulfuric acid at a mass volume ratio (g:ml) of 1:5, react for 1 hour at 180°C with stirring, then cool down to 80°C, add 5 times the volume of water to dilute, After leaching at 85°C for 30 minutes, filter and separate to obtain a sulfuric acid solution containing iron and other metal ions and a slag mainly containing SiO ₂ . The slag is washed, dried, and dehydroxylated by burning at 1000°C to become SiO ₂ .

Example 7

The main composition of nepheline used is: Al ₂ O ₃ 23.21%, SiO ₂ 54.32%, Fe ₂ O ₃ 3.41%, FeO 1.91%, Na ₂ O 10.42%, K ₂ O 3.14%.

Mix nepheline that has been crushed and ground to less than 80 μm with ammonium sulfate and water in a mass ratio of 1:1.5:2.2 (the molar ratio of alumina and ammonium sulfate is 1:5), and roast at 500°C for 2 hours. The reaction process Absorb the gas released in water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Pure aluminum ammonium sulfate crystals were dehydrated at 350°C for 3 hours, decomposed at 550°C for 3 hours, and then heated to 1200°C for 5 hours to prepare alumina. the

Mix the aluminum extraction slag with the sulfuric acid solution with a concentration of 98% according to the mass volume ratio (g:ml) of 1:4, stir and react for 2 hours at a temperature of 270°C, and filter to obtain a sulfuric acid solution containing metal ions such as iron And slag. The slag is washed, dried, and dehydroxylated by burning at 1000°C to become silica. the

Example 8

The main composition of the clay used is: Al ₂ O ₃ 18.26%, SiO ₂ 61.99%, Fe ₂ O ₃ 4.5%, MgO 2.98%, CaO 0.18%, Na ₂ O 3.24%, K ₂ O 3.46%, TiO ₂ 0.21%, MnO 0.04%, other impurities 5.14%.

After the clay that has been crushed and ground to less than 80 μm is removed by magnetic separation, it is mixed with ammonium sulfate and water in a mass ratio of 1:1.4:2 (the molar ratio of alumina and ammonium sulfate is 1:6), and it is kept at 400 ° C. 5h, carry out the roasting reaction, and the gas released during the reaction process is absorbed by water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is aluminum ammonium sulfate solution, and the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Dissolve the ammonium aluminum sulfate crystals in water, then add ammonium bicarbonate solution to the ammonium aluminum sulfate solution, and control the initial concentration of [Al ³⁺ ] in the solution at 0.4mol·L ^-1 and the initial concentration of NH ₄ HCO ₃ at 1.5 at 50°C mol·L ^-1W , the pH value is 9.0, and ammonium aluminum carbonate precipitation is prepared. The solution after the ammonium aluminum carbonate is prepared is an ammonium sulfate solution, which returns to the batching process after evaporation and concentration. The aluminum ammonium carbonate precipitate is calcined and decomposed at 1200°C to prepare alumina, and the mixed gas of ammonia and carbon dioxide obtained by calcining is absorbed with the ammonia gas released by roasting ammonium sulfate with water to prepare ammonium bicarbonate solution; the filtrate after filtering ammonium aluminum carbonate is ammonium sulfate The solution is evaporated and concentrated and then returned to the mixing process.

Mix the aluminum extraction slag with the sulfuric acid solution with a concentration of 50% according to the mass volume ratio (g:ml) of 1:4, stir and react for 2 hours at a temperature of 120°C, and filter to obtain the sulfuric acid solution and slag containing iron plasma . The slag is washed, dried, and dehydroxylated by burning at 1000°C to become silica. the

Example 9

The main composition of the alunite used is: Al ₂ O ₃ 54.78%, SiO ₂ 17.63%, Fe ₂ O ₃ 5.04%, SO ₃ 11.34%, CaO 0.26%, Na ₂ O 0.19%, K ₂ O 3.26%, TiO ₂ 0.53%.

After the crushed and ground alunite is magnetically separated to remove iron, it is calcined and dehydrated at 650°C for 4 hours, and then mixed with ammonium sulfate and water in a mass ratio of 1:5:7.2 (the molar ratio of alumina and ammonium sulfate is 1:7), keep the temperature at 450°C for 5 hours, carry out the roasting reaction, and absorb the gas released during the reaction with water. The roasted product is cooled, dissolved in water, and then separated into solid and liquid. The filtrate is a sulfate mixed solution, and the main ions in the solution are aluminum ions, ammonium ions, potassium ions, and sulfate ions; the filter residue is aluminum extraction slag. the

After the ammonium aluminum sulfate solution is purified by recrystallization to remove impurities such as iron, pure ammonium aluminum sulfate crystals are prepared. Dissolve aluminum ammonium sulfate crystals with water, then add ammonia to the aluminum ammonium sulfate solution, control the initial concentration of [Al ³⁺ ] in the solution at 40°C to 0.18mol·L ^-1 , and pH 4.5 to prepare aluminum hydroxide. Aluminum hydroxide was calcined at 1000°C for 3 hours to produce alumina. After the aluminum hydroxide is precipitated, the solution is mainly ammonium sulfate and potassium sulfate. After evaporation, concentration, cooling and crystallization, a nitrogen and potassium mixed fertilizer is obtained.

Mix the aluminum extraction slag with the sulfuric acid solution with a concentration of 50% according to the mass volume ratio (g:ml) of 1:4, stir and react for 2 hours at a temperature of 120°C, and filter to obtain the sulfuric acid solution and slag containing iron plasma . The slag is washed, dried, and dehydroxylated by burning at 1000°C to become silica. the

Claims (8)

1. A method for preparing ammonium aluminum sulfate, aluminum oxide and silicon dioxide products from bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay, is characterized in that comprising the following step: (1) Bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, and clay are crushed and ground to below 80 μm as raw materials, and kaolin, alunite, and clay need to be dehydrated and roasted; (2) Mix the finely ground aluminum-containing material with ammonium sulfate and water, dry and remove moisture below 200°C, then heat the dried dry material to 200-700°C for roasting, keep it warm for 1-8h, and the reaction produces Absorb ammonia gas with water to obtain ammonia water, or pressurize to make liquid ammonia; (3) Dissolve the solid roasted product obtained by (2) in water, filter to obtain aluminum ammonium sulfate solution and aluminum extraction slag, absorb the gas produced by roasting with water, and make ammonia water, if the raw material is high-iron bauxite, directly to Add an oxidizing agent to the solution to oxidize ferrous ions, then use ammonia to adjust the pH value, first precipitate ferric hydroxide, then precipitate aluminum hydroxide, the solution after precipitation is ammonium sulfate solution, return to the ingredients after evaporation; if the raw material is not high-iron bauxite , then use the recrystallization method to purify the aluminum ammonium sulfate solution to remove iron impurities, and prepare pure aluminum ammonium sulfate crystals; (4) four schemes are adopted to process the pure aluminum ammonium sulfate crystal obtained: Option 1: Dry and calcinate ammonium aluminum sulfate crystals to obtain alumina, and absorb the mixed gas of ammonia gas and sulfur trioxide obtained from the calcining process with the ammonia gas generated in the roasting process to obtain ammonium sulfate solution, which is evaporated to obtain concentrated ammonium sulfate The solution returns to the ingredients; Solution 2: Dissolve aluminum ammonium sulfate crystals in water, use ammonia to adjust the pH value of the solution to precipitate to prepare aluminum hydroxide, filter the filter residue to obtain aluminum hydroxide, calcined and decompose to prepare alumina, the filtrate is ammonium sulfate solution, return to the mixture after evaporation material process; Solution 3: Dissolve aluminum ammonium sulfate crystals in water, adjust the pH value of the solution with urea to precipitate to prepare aluminum hydroxide, filter the filter residue to obtain aluminum hydroxide, and decompose it to prepare alumina by calcining, the filtrate is ammonium sulfate solution, return to the mixture after evaporation The raw material process, the carbon dioxide released in the process of preparing aluminum hydroxide from urea and the ammonia produced in the roasting process are used to prepare urea; Scheme 4: Dissolve the ammonium aluminum sulfate crystal in water, add ammonium bicarbonate solution to it, and obtain ammonium aluminum carbonate precipitation; filter the filter residue to obtain ammonium aluminum carbonate precipitation, and the filtrate is ammonium sulfate solution, and the ammonium aluminum carbonate is calcined and decomposed to prepare alumina and ammonia gas The mixed gas with carbon dioxide and the ammonia gas produced in the roasting process are absorbed with water, and after mixing, they are ammonium carbonate or ammonium bicarbonate solution, which is returned to the batching; the ammonium sulfate solution is returned to the mixing process after being evaporated and concentrated; (5) If the aluminum extraction slag obtained by (3) contains less iron, then use acid leaching or acid roasting, washing treatment to remove Fe, Ca, Al metal impurities in the slag, and filter to obtain pickling solution and silica , the pickling solution is returned to the acid treatment and impurity removal process; (6) If the aluminum extraction slag obtained according to (3) contains more iron, it is treated with alkali leaching or alkali roasting to generate sodium silicate and then carbonizes to prepare silica products. The silicon extraction slag after silica extraction is mainly Contains iron, used as a raw material for ironmaking. 2. a kind of according to claim 1 prepares aluminum ammonium sulfate, aluminum oxide and dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for silicon product is characterized in that in step (2) in the mixing process, aluminum oxide and ammonium sulfate The molar ratio of ammonium sulfate to water is 1:4-1:10, and the mass ratio of ammonium sulfate to water is 5:10-7:10. 3. a kind of according to claim 1 prepares aluminum ammonium sulfate, aluminum oxide and dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for silicon products is characterized in that the scheme one in step (4) adopts the dehydration of pure aluminum ammonium sulfate crystals at 200-400°C, and is heated to 500-700°C for 2-6h to decompose to obtain aluminum sulfate, and then heats up to 800- Calcined at 1300°C to prepare alumina products, and the by-products sulfur trioxide and ammonia gas are absorbed with water as raw materials for the preparation of ammonium sulfate solution. 4. a kind of according to claim 1 prepares aluminum ammonium sulfate, aluminum oxide and dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for silicon products is characterized in that scheme two in step (4) adopts water-soluble pure aluminum ammonium sulfate crystals, then adds ammonia to the pure aluminum ammonium sulfate solution, and controls the solution under the temperature range of 20°C-80°C [ Al ³⁺ ] with an initial concentration of 0.05-0.2mol·L ^-1 and a pH value of 3.4-4.5 to prepare aluminum hydroxide, and the solution after preparing aluminum hydroxide is ammonium sulfate solution, which is evaporated and concentrated and returned to the batching process. 5. a kind of according to claim 1 prepares aluminum ammonium sulfate, aluminum oxide and dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for silicon products is characterized in that the scheme three in step (4) adopts the water-dissolving of pure ammonium aluminum sulfate crystals, then adds urea to the pure ammonium aluminum sulfate solution, and controls [Al ³⁺ in the solution at 50°C-100°C ] at a concentration of 0.05-0.2mol·L ^-1 , the molar ratio of [Al ³⁺ ]/[CO(NH ₂ ) ₂ ] is 0.04-0.06, to prepare aluminum hydroxide, and the solution after the preparation of aluminum hydroxide is ammonium sulfate The solution is evaporated and concentrated and returned to the batching process; the carbon dioxide released during the process of preparing aluminum hydroxide from urea and the ammonia released by roasting ammonium sulfate are used to prepare urea. 6. a kind of according to claim 1 prepares aluminum ammonium sulfate, aluminum oxide and dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for silicon products is characterized in that the fourth solution in step (4) is to dissolve the pure aluminum ammonium sulfate crystals with water, add them to the ammonium bicarbonate solution, and control the initial [Al ³⁺ ] in the solution at 20°C-60°C The concentration is above 0.4mol L ^-1 , the initial concentration of NH ₄ HCO ₃ is above 1.5mol L ^-1 , the pH value is 8.0-10.0, and the precipitation of ammonium aluminum carbonate is prepared; the solution after the preparation of ammonium aluminum carbonate is ammonium sulfate solution After evaporation and concentration, return to the batching process, ammonium aluminum carbonate precipitate is calcined and decomposed at 800°C-1200°C to prepare alumina, and the mixed gas of ammonia and carbon dioxide obtained by calcining and the ammonia gas released from the roasting process are absorbed with water to prepare ammonium bicarbonate. 7. a kind of according to claim 1 prepares ammonium sulfate, aluminum oxide, silicon dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for the product is characterized in that the aluminum slag acid leaching, washing and impurity removal of the step (5) is that the aluminum slag and the sulfuric acid with a concentration of 20%-90% are 1: 3-1 in mass volume ratio g:ml: 6. Mix and react for 0.5-3h at a temperature of 60°C-200°C and stirring. When the temperature of the system drops below 100°C, add 2-5 times the volume of water to dilute, and continue leaching at 80-90°C for 20-40min. , the obtained slag is washed, dried, and burned to be silica; or the aluminum-extracting slag is acid-roasted, washed, and impurity-removed. Mix 1:0.5-1:2, react at a temperature of 200°C-300°C for 0.5-3h, then add 2-5 times the volume of water, stir and dissolve at 80-90°C for 20-40min, the obtained slag is washed, After drying and burning, it becomes silica. 8. a kind of according to claim 1 prepares ammonium sulfate, aluminum oxide, silicon dioxide by bauxite, alunite, bauxite, fly ash, coal gangue, aluminum ash, nepheline, clay aluminum-containing material The method for the product is characterized in that the aluminum extraction slag alkali leaching or alkali roasting of step (6) adopts three processes of sodium hydroxide leaching, sodium hydroxide roasting, and sodium carbonate roasting respectively; sodium hydroxide leaching is to extract aluminum The slag is mixed with sodium hydroxide with a concentration of 20%-90% according to the mass volume ratio g:ml of 1:2-1:6, and reacted for 0.5-3h at a temperature of 60°C-280°C and stirring. Lower the temperature below 100°C, add 2-5 times the volume of water to dilute, continue to dissolve at 80-90°C for 20-40 minutes, obtain sodium silicate solution and slag after filtration and separation, and prepare silica by carbon of sodium silicate solution; The obtained slag mainly contains iron and is used as a raw material for ironmaking; the roasting of the aluminum extraction slag with sodium hydroxide is to mix the aluminum extraction slag and sodium hydroxide at a mass ratio of 1:0.5-1:8 at a temperature of 350°C-600°C Under the condition of reaction for 0.5-3h; the roasting of aluminum slag and sodium carbonate is to mix the aluminum slag and sodium carbonate in a mass ratio of 1:0.5-1:8, and react at a temperature of 800°C-1200°C for 0.5-3h; Aluminum slag roasted with sodium hydroxide or sodium carbonate, add 2-5 times the volume of water, stir and dissolve at 80-90°C for 20-40min, filter and separate to obtain sodium silicate solution and slag, carbon content of sodium silicate solution Silica is prepared, and the obtained slag mainly contains iron, which is used as a raw material for ironmaking.

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