阅读说明：本技术 一种干法氟化铝的生产方法 (Dry-process aluminum fluoride production method ) 是由 肖建楠 张梦 夏娇彬 姚青松 *** 邢东伟 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种干法氟化铝生产方法,以由含铝原料制得的氢氧化铝,以磷化工企业副产氟硅酸制得氟化铵,再将所得氢氧化铝和氟化铵为原料,采用固-气相反应法生产干法氟化铝。该方法简化了工艺流程、减少设备投资,提升品质、降低成本、增加了经济效益。(The invention discloses a dry-method aluminum fluoride production method, which comprises the steps of preparing aluminum hydroxide from an aluminum-containing raw material, preparing ammonium fluoride from a byproduct fluosilicic acid of a phosphorus chemical industry enterprise, and producing the dry-method aluminum fluoride by using the obtained aluminum hydroxide and the ammonium fluoride as raw materials through a solid-gas phase reaction method. The method simplifies the process flow, reduces equipment investment, improves the quality, reduces the cost and increases the economic benefit.)

1. A dry-method aluminum fluoride production method is characterized in that: preparing ammonium fluoride from aluminum hydroxide prepared from an aluminum-containing raw material and fluosilicic acid serving as a byproduct of a phosphorus chemical industry enterprise, and producing dry-process aluminum fluoride by using the obtained aluminum hydroxide and ammonium fluoride as raw materials through a solid-phase mixed reaction method; specifically, the preparation of aluminum hydroxide and ammonium fluoride and the solid-gas phase reaction are operated according to the following steps:

(1) aluminum hydroxide preparation

Step 1: pretreatment of aluminium-containing materials

The method comprises the following steps of taking coal gangue, fly ash or any one of other aluminum-containing minerals, tailings and waste residues as a raw material, and crushing and grinding the aluminum-containing raw material to obtain aluminum-containing material powder with the fineness of 80 ~ 200 meshes;

and a step 2: leaching out

Mixing the powder obtained in the step 1 with liquid in an acid leaching reactor, wherein the liquid is water or a mixed solution of an eluate from an acid leaching residue washing step and a proper amount of inorganic acid, controlling process conditions to carry out leaching reaction after mixing, converting aluminum and iron in the material into sulfate or chloride to enter a liquid phase, and obtaining acid leaching liquid containing sulfate or chloride and acid leaching residue with a main component of silicon dioxide after the reaction is finished and filtering;

step 3: separating and extracting

Step 1: the acid leaching solution obtained in the step 2 is sent to an aluminum separation step and is mixed with a reducing agent in a reduction reactor, and Fe in the acid leaching solution is reacted³⁺Conversion to Fe²⁺After the reaction is finished, filtering to obtain reduced liquid and reduced residue; the liquid after reduction is sent to an aluminum precipitation process, and the reduction residue is returned to the reduction process for recycling;

step 2: sending the reduced liquid obtained in the step 1 to an aluminum precipitation process, and adjusting the pH value of a system by using alkali to convert aluminum in the acid leaching liquid into aluminum hydroxide;

after the reaction is finished, filtering and washing to obtain a crude aluminum hydroxide filter cake and a filter cake containing Fe²⁺Precipitating the aluminum solution; the obtained aluminum-precipitated liquid is sent to an iron precipitation process to further separate iron in the aluminum-precipitated liquid, and is sent to an iron oxide industrial pigment or a polymeric ferric sulfate production process to be used as a production raw material;

and step 3: sending the crude aluminum hydroxide filter cake obtained in the step 2 to an alkali dissolution process, mixing the crude aluminum hydroxide filter cake with water in an alkali dissolution reactor, and adding sodium hydroxide;

under the normal operation condition, the sodium aluminate solution is mixed with the sodium hydroxide solution recovered in the carbon content mother liquor treatment process, so that the aluminum in the crude aluminum hydroxide is converted into sodium aluminate to enter a liquid phase, and iron is remained in filter residue as an iron hydroxide phase or a sodium ferrite phase, thereby realizing the further separation of the aluminum and the iron; mixing the obtained iron-containing filter residue with the iron precipitate obtained by precipitating the aluminum-precipitated liquid in the step 2, and feeding the iron precipitate to an iron oxide industrial pigment or a polymeric ferric sulfate production process to be used as a production raw material; the obtained sodium aluminate solution is sequentially sent to the working procedures of desiliconization and deironing;

and 4, step 4: the sodium aluminate solution obtained in the step 3 is sent to a desiliconization and iron removal process, a desiliconization agent is added for desiliconization reaction, after the desiliconization reaction is finished, calcium silicate filter residues and desiliconized liquid are obtained through filtration, and the calcium silicate filter residues are collected and stored; then the desiliconized liquid is sent to a deironing process, and a deironing agent is added to remove iron; after the iron removal reaction is finished, obtaining pure sodium aluminate solution through pressure filtration and precise filtration in sequence;

and 5:

① carbon precipitation for producing industrial aluminium hydroxide

Sending the pure sodium aluminate solution obtained in the step 4 to a carbon precipitation reactor, carrying out carbon precipitation reaction with carbon dioxide, and converting aluminum in the sodium aluminate solution into aluminum hydroxide through the reaction; after the reaction is finished, filtering, washing, drying and packaging to obtain industrial aluminum hydroxide; separating aluminum hydroxide to obtain mother liquor containing sodium carbonate as main component, causticizing to react with calcium oxide or calcium hydroxide, and filtering to obtain sodium hydroxide solution and calcium carbonate; concentrating the obtained sodium hydroxide solution, then sending the concentrated sodium hydroxide solution to a storage tank, and sending the concentrated sodium hydroxide solution to a crude aluminum hydroxide alkali dissolution process from the storage tank to be used as an alkali solvent; the obtained calcium carbonate is dried and packaged to be sold as a commodity;

② carbonization and seed separation for producing sand-shaped aluminum hydroxide

When producing high-density or sandy aluminum hydroxide, sending the pure sodium aluminate solution obtained in the step 4 to a seed precipitation reactor, and carrying out seed precipitation reaction by using carbon-separated aluminum hydroxide obtained by carbon precipitation as seed crystals to gradually increase the grain size of the added seed crystals;

after the reaction is finished, the loose packed density of 0.9 ~ 1.5.5 g/cm is obtained by filtering, grading, washing, drying and packaging³Is in the form of sandAluminum melting; returning the aluminum hydroxide with smaller particle size obtained in the grading procedure to the seed precipitation reactor for continuous reaction;

sending the seed precipitation mother liquor obtained in the filtering procedure to the carbon precipitation reactor in the step (1), carrying out carbon precipitation reaction according to the process conditions in the step (1) to convert sodium aluminate in the mother liquor into aluminum hydroxide and sodium carbonate, and filtering to obtain carbon-separated aluminum hydroxide after the reaction is finished; the obtained carbon content aluminum hydroxide is sent to a seed separation process to be used as seed crystal, and the obtained carbon content mother liquor is treated according to the method in the step;

(2) preparation of ammonium fluoride

Step 1: ammoniation reaction

Step 1: sending fluosilicic acid byproduct from phosphorus chemical enterprises to an ammoniation reactor, and carrying out neutralization reaction with ammonia gas from an aluminum fluoride reactor to convert the fluosilicic acid into ammonium fluoride solution and precipitated white carbon black;

and a step 2: ammonium fluoride crystal

Sending the ammonium fluoride solution obtained in the step 1 to an evaporator, evaporating and concentrating the solution, and sending the solution to a cooling crystallizer to separate out ammonium fluoride crystals in the solution; when the crystallization end point is reached, centrifugal separation is carried out after proper curing, and ammonium fluoride finished products are obtained through separation, washing and drying; the obtained ammonium fluoride mother liquor returns to the evaporation process and is merged with the ammonium fluoride solution generated in the process 1 for cyclic evaporation;

(3) aluminum fluoride production

Step 1: further drying the prepared aluminum hydroxide under vacuum condition to completely remove free water contained in the aluminum hydroxide; sending the dried aluminum hydroxide into an aluminum hydroxide high-level bin;

and a step 2: further drying the prepared ammonium fluoride under the vacuum condition to completely remove free water contained in the ammonium fluoride, and conveying the dried ammonium fluoride into an ammonium fluoride overhead bin;

step 3: sending the aluminum hydroxide in an aluminum hydroxide high-level stock bin into an intensive fluorination reactor, wherein the intensive fluorination reactor consists of a first-stage fluorination reactor and a second-stage fluorination reactor, the aluminum hydroxide enters from a feed inlet of the first-stage fluorination reactor, the ammonium fluoride enters from a feed inlet of the second-stage fluorination reactor, and the aluminum hydroxide and the ammonium fluoride in the intensive fluorination reactor are in reverse contact

Carrying out reaction;

feeding aluminum hydroxide into the feed hopper of the first-stage fluorination reactor, feeding the aluminum hydroxide into the first-stage fluorination reactor through a quantitative feeding system for thermal decomposition and primary fluorination, wherein the fluorinating agent is ammonium fluoride in the second-stage fluorination reactor and is prepared from ammonium fluoride

The mixed gas composed of hydrogen fluoride and ammonia is generated by decomposing the materials entering the secondary fluorination reactor in the process of mixing and contacting, the used heat source is high-temperature tail gas discharged by a heater of the secondary fluorination reactor, and the reacted materials enter the secondary fluorination reactor;

the aluminum hydroxide entering the first-stage fluorination reactor is decomposed by heating, part of the aluminum hydroxide loses crystal water to form aluminum oxide, the aluminum hydroxide and the aluminum oxide are contacted with mixed gas of hydrogen fluoride and ammonia, fluorination reaction occurs and aluminum fluoride is converted, the reaction rate of the aluminum hydroxide/aluminum oxide is about 60%, the reacted materials enter a second-stage fluorination reactor and are further contacted with ammonium fluoride quantitatively added from a charging opening of the second-stage fluorination reactor and mixed gas containing hydrogen fluoride and ammonia generated by thermal decomposition in the adding process to complete the fluorination reaction, the generated aluminum fluoride is discharged from the second-stage fluorination reactor, and a dry-process aluminum fluoride product is prepared by cooling and packaging.

2. The dry aluminum fluoride production process of claim 1, wherein: in the step 3 and the step 1 of the preparation of the aluminum hydroxide, the reducing agent is one or a mixture of more than two of waste iron wires, scrap iron and reduced iron powder.

3. The dry aluminum fluoride production process of claim 1, wherein: in step 3 and step 2, the base used for adjusting the pH value is any one or a mixture of two or more of ammonia, ammonia water, sodium hydroxide, calcium oxide, calcium hydroxide and calcium carbonate.

4. The dry aluminum fluoride production process of claim 1, wherein: in the step 4 of the working procedure 3, when desiliconizing, the desiliconizing agent is any one of calcium oxide, calcium hydroxide and calcium aluminate, and the iron removing agent is any one of hydrogenated alumina and alumina.

5. The dry process aluminum fluoride production method of claim 1, wherein the carbon precipitation reaction is carried out by controlling the reaction time to 60 ~ 360min, the reaction temperature to 60 ~ 98 ℃, and the reaction end point pH to 7 ~ 11.

6. The dry process aluminum fluoride production method of claim 1, wherein the seed precipitation reaction is carried out by controlling the caustic ratio of the sodium aluminate solution to 1.1 ~ 2.5.5, the reaction temperature to 25 ~ 80 ℃, and the reaction time to 8 ~ 72 h.

7. The dry process aluminum fluoride production method as claimed in claim 1, wherein the amination is carried out under negative pressure, the reaction pressure is controlled to be-0.01 ~ -0.09MPa, and the reaction temperature is controlled to be 45 ~ 100 ℃.

8. The dry aluminum fluoride production process of claim 1, wherein: the ammonification reaction system is configured in a double-set mode so as to be switched at any time, and the accumulation of ammonia gas generated by the aluminum fluoride reactor due to temporary stop in the material flow process of the ammonification reactor can be avoided.

9. The dry process aluminum fluoride production method of claim 1, wherein the first-stage fluorination reactor is controlled to have a material reaction time of 20 ~ 180min, a reaction temperature of 200 ~ 500 ℃ and a reaction pressure of-0.02 ~ -0.09MPa, and the second-stage fluorination reactor is controlled to have a reaction temperature of 400 ~ 700 ℃ and a reaction pressure of-0.02 ~ -0.09MPa, and the reaction time of 30 ~ 180 min.

10. The dry aluminum fluoride production process of claim 1, wherein: and 3, the nitrogen seal or mechanical seal devices are respectively arranged at each feed inlet, each discharge outlet and equipment connecting parts of the intensive fluorination reactor, so that air is prevented from entering and mixing with ammonia gas in the reactor, and ammonia explosion accidents are avoided.

Technical Field

The invention belongs to the technical field of chemical industry, and particularly relates to a production method of dry-process aluminum fluoride.

Background

The aluminum fluoride is an important inorganic chemical raw material, and is mainly used as an electrolytic aluminum auxiliary agent, a ceramic cosolvent, an alcohol fermentation inhibitor, a nonmetal smelting solvent and the like, the anhydrous aluminum fluoride is sand-shaped powder, and the wet-process aluminum fluoride is white powder and is needle-shaped crystal.

Disclosure of Invention

Aiming at the defects of the process, the application provides a novel dry-method aluminum fluoride production method in order to overcome the defects of the prior art. The method simplifies the process flow, reduces equipment investment, improves the quality, reduces the cost and increases the economic benefit.

In order to achieve the purpose, the invention adopts the technical scheme that: the dry-method aluminum fluoride production method is characterized by comprising the following steps: preparing ammonium fluoride from aluminum hydroxide prepared from an aluminum-containing raw material and fluosilicic acid serving as a byproduct of a phosphorus chemical industry enterprise, and producing dry-process aluminum fluoride by using the obtained aluminum hydroxide and ammonium fluoride as raw materials through a solid-phase mixed reaction method; specifically, the preparation of aluminum hydroxide and ammonium fluoride and the solid-gas phase reaction are operated according to the following steps:

1. preparation of aluminium hydroxide

Step 1: pretreatment of aluminium-containing materials

The method comprises the following steps of taking coal gangue, fly ash or any one of other aluminum-containing minerals, tailings and waste residues as a raw material, and crushing and grinding the aluminum-containing raw material to obtain aluminum-containing material powder with the fineness of 80 ~ 200 meshes;

and a step 2: leaching out

Mixing the powder obtained in the step 1 with liquid in an acid leaching reactor, wherein the liquid is water or a mixed solution of an eluate from an acid leaching residue washing step and a proper amount of inorganic acid, controlling process conditions to carry out leaching reaction after mixing, converting aluminum and iron in the material into sulfate or chloride to enter a liquid phase, and obtaining acid leaching liquid containing sulfate or chloride and acid leaching residue with a main component of silicon dioxide after the reaction is finished and filtering;

step 3: separating and extracting

Step 1: the acid leaching solution obtained in the step 2 is sent to an aluminum separation step and is mixed with a reducing agent in a reduction reactor, and Fe in the acid leaching solution is reacted³⁺Conversion to Fe²⁺After the reaction is finished, filtering to obtain reduced liquid and reduced residue; the liquid after reduction is sent to an aluminum precipitation process, and the reduction residue is returned to the reduction process for recycling;

step 2: and (3) sending the reduced liquid obtained in the step (1) to an aluminum precipitation process, and adjusting the pH value of the system by using alkali to convert aluminum in the acid leaching liquid into aluminum hydroxide. After the reaction is finished, filtering and washing to obtain a crude aluminum hydroxide filter cake and a filter cake containing Fe²⁺Precipitating the aluminum solution; the obtained aluminum-precipitated liquid is sent to an iron precipitation process to further separate iron in the aluminum-precipitated liquid, and is sent to an iron oxide industrial pigment or a polymeric ferric sulfate production process to be used as a production raw material;

and step 3: and (3) sending the crude aluminum hydroxide filter cake obtained in the step (2) to an alkali dissolution process, mixing the crude aluminum hydroxide filter cake with water in an alkali dissolution reactor, and adding sodium hydroxide. Under the normal operation condition, the sodium aluminate solution is mixed with the sodium hydroxide solution recovered in the carbon content mother liquor treatment process, so that the aluminum in the crude aluminum hydroxide is converted into sodium aluminate to enter a liquid phase, and iron is remained in filter residue as an iron hydroxide phase or a sodium ferrite phase, thereby realizing the further separation of the aluminum and the iron; mixing the obtained iron-containing filter residue with the iron precipitate obtained by precipitating the aluminum-precipitated liquid in the step 2, and feeding the iron precipitate to an iron oxide industrial pigment or a polymeric ferric sulfate production process to be used as a production raw material; the obtained sodium aluminate solution is sequentially sent to the working procedures of desiliconization and deironing;

and 4, step 4: the sodium aluminate solution obtained in the step 3 is sent to a desiliconization and iron removal process, a desiliconization agent is added for desiliconization reaction, after the desiliconization reaction is finished, calcium silicate filter residues and desiliconized liquid are obtained through filtration, and the calcium silicate filter residues are collected and stored; then the desiliconized liquid is sent to a deironing process, and a deironing agent is added to remove iron; after the iron removal reaction is finished, obtaining pure sodium aluminate solution through pressure filtration and precise filtration in sequence;

and 5:

(1) carbon precipitation for producing industrial aluminium hydroxide

Sending the pure sodium aluminate solution obtained in the step 4 to a carbon precipitation reactor, carrying out carbon precipitation reaction with carbon dioxide, and converting aluminum in the sodium aluminate solution into aluminum hydroxide through the reaction; after the reaction is finished, filtering, washing, drying and packaging to obtain industrial aluminum hydroxide; separating aluminum hydroxide to obtain mother liquor containing sodium carbonate as main component, causticizing to react with calcium oxide or calcium hydroxide, and filtering to obtain sodium hydroxide solution and calcium carbonate; concentrating the obtained sodium hydroxide solution, then sending the concentrated sodium hydroxide solution to a storage tank, and sending the concentrated sodium hydroxide solution to a crude aluminum hydroxide alkali dissolution process from the storage tank to be used as an alkali solvent; the obtained calcium carbonate is dried and packaged to be sold as a commodity;

(2) production of sand-like aluminium hydroxide by carbon separation and seed separation

When producing high-density or sand-like aluminum hydroxide, the pure sodium aluminate solution obtained in the step 4 is sent to a seed precipitation reactor, the carbon-separated aluminum hydroxide obtained by carbon precipitation is used as seed crystal for seed precipitation reaction, the grain size of the added seed crystal is gradually increased, after the reaction is finished, the loose packing density of 0.9 ~ 1.5.5 g/cm is obtained by filtering, grading, washing, drying and packaging³The sand-like aluminum hydroxide of (a); returning the aluminum hydroxide with smaller particle size obtained in the grading procedure to the seed precipitation reactor for continuous reaction;

sending the seed precipitation mother liquor obtained in the filtering procedure to the carbon precipitation reactor in the step (1), carrying out carbon precipitation reaction according to the process conditions in the step (1) to convert sodium aluminate in the mother liquor into aluminum hydroxide and sodium carbonate, and filtering to obtain carbon-separated aluminum hydroxide after the reaction is finished; the obtained carbon content aluminum hydroxide is sent to a seed separation process to be used as seed crystal, and the obtained carbon content mother liquor is treated according to the method in the step;

2. preparation of ammonium fluoride

Step 1: ammoniation reaction

Step 1: sending fluosilicic acid byproduct from phosphorus chemical enterprises to an ammoniation reactor, and carrying out neutralization reaction with ammonia gas from an aluminum fluoride reactor to convert the fluosilicic acid into ammonium fluoride solution and precipitated white carbon black;

and a step 2: ammonium fluoride crystal

Sending the ammonium fluoride solution obtained in the step 1 to an evaporator, evaporating and concentrating the solution, and sending the solution to a cooling crystallizer to separate out ammonium fluoride crystals in the solution; when the crystallization end point is reached, centrifugal separation is carried out after proper curing, and ammonium fluoride finished products are obtained through separation, washing and drying; the obtained ammonium fluoride mother liquor returns to the evaporation process and is merged with the ammonium fluoride solution generated in the process 1 for cyclic evaporation;

3. aluminum fluoride production

Step 1: further drying the prepared aluminum hydroxide under vacuum condition to completely remove free water contained in the aluminum hydroxide; sending the dried aluminum hydroxide into an aluminum hydroxide high-level bin;

and a step 2: further drying the prepared ammonium fluoride under the vacuum condition to completely remove free water contained in the ammonium fluoride, and conveying the dried ammonium fluoride into an ammonium fluoride overhead bin;

step 3: sending the aluminum hydroxide in an aluminum hydroxide high-level stock bin into an intensive fluorination reactor, wherein the intensive fluorination reactor consists of a first-stage fluorination reactor and a second-stage fluorination reactor, the aluminum hydroxide enters from a feed inlet of the first-stage fluorination reactor, the ammonium fluoride enters from a feed inlet of the second-stage fluorination reactor, and the aluminum hydroxide and the ammonium fluoride in the intensive fluorination reactor are in reverse contact

Carrying out reaction;

feeding aluminum hydroxide into the feed hopper of the first-stage fluorination reactor, feeding the aluminum hydroxide into the first-stage fluorination reactor through a quantitative feeding system for thermal decomposition and primary fluorination, wherein the fluorinating agent is ammonium fluoride in the second-stage fluorination reactor and is prepared from ammonium fluoride

The mixed gas composed of hydrogen fluoride and ammonia is generated by decomposing the materials entering the secondary fluorination reactor in the process of mixing and contacting, the used heat source is high-temperature tail gas discharged by a heater of the secondary fluorination reactor, and the reacted materials enter the secondary fluorination reactor;

the aluminum hydroxide entering the first-stage fluorination reactor is subjected to thermal decomposition, part of the aluminum hydroxide loses crystal water to form aluminum oxide, the aluminum hydroxide contacts with mixed gas of hydrogen fluoride and ammonia, fluorination reaction occurs and aluminum fluoride is converted into aluminum fluoride, the reaction rate of the aluminum hydroxide/aluminum oxide is about 60%, the reacted materials enter a second-stage fluorination reactor and further contact with ammonium fluoride quantitatively added from a charging opening of the second-stage fluorination reactor and mixed gas containing hydrogen fluoride and ammonia generated by thermal decomposition in the adding process to complete the fluorination reaction, the generated aluminum fluoride is discharged from the second-stage fluorination reactor, and a dry-process aluminum fluoride product is prepared by cooling and packaging.

Preferably, step 3 of aluminum hydroxide production: in the step 1, the reducing agent is one or a mixture of more than two of waste iron wires, scrap iron and reduced iron powder.

Preferably, in step 3 and step 2, the base used for adjusting the pH is any one or a mixture of two or more of ammonia, aqueous ammonia, sodium hydroxide, calcium oxide, calcium hydroxide, and calcium carbonate.

Preferably, in the desiliconization in step 3, step 4, the desiliconization agent is any one of calcium oxide, calcium hydroxide and calcium aluminate. The iron removing agent is any one of aluminum hydroxide or aluminum oxide.

Preferably, the carbon precipitation reaction is carried out by controlling the reaction time to be 60 ~ 360min, the reaction temperature to be 60 ~ 98 ℃ and the pH value of the reaction end point to be 7 ~ 11.

Preferably, the seed precipitation reaction is carried out by controlling the caustic ratio of the sodium aluminate solution to be 1.1 ~ 2.5.5, the reaction temperature to be 25 ~ 80 ℃ and the reaction time to be 8 ~ 72 h.

Preferably, the amination reaction is operated under the condition of negative pressure, the reaction pressure is controlled to be-0.01 ~ -0.09MPa, and the reaction temperature is controlled to be 45 ~ 100 ℃ to 100 ℃.

Preferably, in order to avoid accumulation of ammonia gas generated by the aluminum fluoride reactor due to temporary shutdown in the material flow process of the ammoniation reactor, the ammoniation reaction system should be in a double-set configuration so as to be switched at any time.

Preferably, the first-stage fluorination reactor controls the material reaction time to be 20 ~ 180min, the reaction temperature to be 200 ~ 500 ℃, the reaction pressure to be-0.02 ~ -0.09MPa, the second-stage fluorination reactor controls the reaction time to be 30 ~ 180min at 400 ~ 700 ℃, and the reaction pressure to be-0.02 ~ -0.09 MPa.

Preferably, in the aluminum fluoride production process 3, nitrogen seals or mechanical sealing devices are respectively installed at each feeding hole, each discharging hole and each equipment connecting part of the intensive fluorination reactor, so that air is prevented from entering and mixing with ammonia gas in the reactor, and ammonia explosion accidents are avoided.

In the preparation of aluminum hydroxide, industrial-grade aluminum hydroxide and sandy aluminum hydroxide are prepared from a sodium aluminate solution obtained by separating and extracting the aluminum-containing material, calcium oxide or calcium hydroxide is used as a causticizer to treat a carbonation mother liquor obtained in a carbonation process, and a sodium hydroxide solution and calcium carbonate are obtained. Therefore, the system internal recycle of the alkali solvent-sodium hydroxide is realized, the production cost is reduced, the wastewater discharge is avoided, and the harmlessness of the aluminum hydroxide production is realized.

Compared with the prior art, the advantage of this patent:

1. the aluminum hydroxide is produced by aluminum-containing solid waste and minerals, and the ammonium fluoride and the white carbon black are produced by the byproduct fluosilicic acid of phosphorus chemical enterprises, so that the raw material cost is low, and the economic benefit is remarkable.

2. The method realizes the recycling of the alkali solvent-sodium hydroxide in the system, not only reduces the production cost, but also avoids the discharge of waste water and realizes the harmlessness of the production of aluminum hydroxide.

3. Aluminum fluoride is directly produced from aluminum hydroxide and ammonium fluoride, solid-phase mixing between the aluminum hydroxide and the ammonium fluoride is carried out, reaction is carried out, the gasification process of the ammonium fluoride is reduced, and other methods are not needed to prepare hydrogen fluoride gas. The energy consumption in the production process is obviously reduced, the working procedures are reduced, the production cost is favorably reduced, and the equipment investment is saved.

4. The solid ammonium fluoride and the aluminum hydroxide are directly reacted by adopting a secondary aluminum fluoride reactor, and the fluorination reaction is completed in the same equipment, so that the intensification of the aluminum fluoride production process and the simplification of the process flow are realized, and the equipment investment is reduced.

5. The direct recycling of the fluosilicic acid neutralizer is realized, the technical problems of ammonia explosion prevention and control and the like are solved, and the potential safety hazard is eliminated.

Drawings

FIG. 1 is a process flow diagram for the preparation of aluminum hydroxide;

FIG. 2 is a process flow diagram of the preparation process of ammonium fluoride and aluminum fluoride.

Detailed Description