CN116605898A - Method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste - Google Patents

Abstract

The present application relates to a method for preparing anhydrous aluminum fluoride from aluminum electrolytic carbon slag waste, comprising the following steps: providing aluminum electrolytic carbon slag waste with a particle size not higher than a predetermined size; soaking the aluminum electrolytic carbon slag in an acid solution After the solid-liquid separation of waste, the separation liquid obtained by the solid-liquid separation is collected; after adding a reaction accelerator to the separation liquid, the molar ratio of fluorine and aluminum elements in the separation liquid is adjusted to be 3-5:1 to obtain Prefabricated solution; treating the prefabricated solution at a first temperature to obtain anhydrous aluminum hydroxyfluoride; using the anhydrous aluminum hydroxyfluoride as a raw material to prepare anhydrous aluminum fluoride, wherein the reaction accelerator includes styrene-acryl At least one of amino acid, valine, leucine, kerosene, ethyl acetate, ammonium bifluoride, and sodium fluoride. In this application, through the addition of a reaction accelerator, aluminum fluoride hydroxy, which is closer to the structure of AlF ₃ , is easier to generate, and a hydrophobic protective layer can be formed on the surface of aluminum fluoride hydroxy, so as not to carry crystal water.

Description

A method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon slag waste materials

technical field

This application relates to the field of aluminum electrolysis, in particular to aluminum electrolysis carbon slag.

Background technique

In the production process of electrolytic aluminum, due to various reasons such as the anode carbon body not fully participating in the reaction, long-term corrosion and erosion by the electrolyte, and unqualified quality, some carbon particles in the anode fall off and enter the electrolytic cell to form carbon slag. Carbon slag has a great impact on electrolytic production. Once carbon slag exists in the electrolytic cell, it will seriously endanger the electrolytic production, such as causing the voltage of the cell to increase, resulting in the generation of heat in the cell, etc. In order to reduce this hazard, it is necessary to salvage the electrolytic cell in time. of charcoal. Carbon slag was included in the "National List of Hazardous Wastes" (code: 321-025-48, hazardous characteristic T) in 2016 because it contains fluorine and other toxic substances that will harm the environment.

Since the carbon slag contains elements such as aluminum and fluorine, the carbon slag is treated in this field, usually after the aluminum and fluorine are dissolved in the form of ions in the solution, and then precipitated into aluminum hydroxyfluoride. Aluminum hydroxyfluoride is a class of ionic compounds composed of aluminum ions, hydroxide ions and fluoride ions. It has a series of chemical formulas with different ratios of hydroxide ions and fluoride ions, such as AlF _1.5 (OH) _1.5 ( H ₂ O) _0.375 , Al ₂ F _3.24 (OH) _2.76 ·H ₂ O, the above two aluminum hydroxyfluorides are also commonly obtained products in the existing carbon slag treatment process. The aluminum hydroxyfluoride obtained by the existing carbon slag treatment scheme, including the aluminum hydroxyfluoride of the above structure, has a small molar ratio of fluorine and aluminum, and often contains crystal water, which leads to strong side reactions in the dehydration and dehydroxylation process , the generated aluminum fluoride is decomposed into alumina in a large amount, and the purity is low.

Contents of the invention

The embodiment of the present application provides a method for preparing anhydrous aluminum fluoride from carbon slag wastes of aluminum electrolysis, in order to solve the technical problem that the aluminum hydroxyfluoride obtained by the treatment of the existing carbon slag has a low fluorine-to-aluminum ratio and contains crystal water.

The embodiment of the present application provides a method for preparing anhydrous aluminum fluoride from aluminum electrolytic carbon slag waste. The method for preparing anhydrous aluminum fluoride from aluminum electrolytic carbon slag includes the following steps:

Provide aluminum electrolytic carbon slag waste with a particle size not higher than the predetermined size;

Soaking the aluminum electrolytic carbon slag waste in an acid solution, separating the solid from the liquid, and collecting the separation liquid obtained from the solid-liquid separation;

After adding a reaction accelerator to the separation liquid, adjust the molar ratio of fluorine and aluminum elements in the separation liquid to 3-5:1 to obtain a prefabricated solution;

Treating the prefabricated solution at a first temperature to obtain anhydrous aluminum hydroxyfluoride;

Using the anhydrous aluminum hydroxyfluoride as raw material to prepare anhydrous aluminum fluoride,

Wherein, the reaction accelerator includes at least one of phenylalanine, valine, leucine, kerosene, ethyl acetate, ammonium bifluoride, and sodium fluoride.

In some embodiments of the present application, the predetermined size is 75 μm.

In some embodiments of the present application, the method of adjusting the molar ratio of fluorine and aluminum elements in the separation liquid is to add a fluorine-containing reagent, and the fluorine-containing reagent includes at least one of soluble fluorine salt and hydrogen fluoride.

In some embodiments of the present application, the first temperature is 75-85°C.

In some embodiments of the present application, the preparation of anhydrous aluminum fluoride using the anhydrous aluminum hydroxyfluoride as a raw material includes the following steps:

After adding a dehydroxylation aid to the anhydrous aluminum hydroxyfluoride, treating the anhydrous aluminum hydroxyfluoride at a second temperature to obtain the anhydrous aluminum fluoride.

In some embodiments of the present application, the dehydroxylation aid is at least one of vanadium pentoxide, manganese dioxide, titanium dioxide, and ferric oxide.

In some embodiments of the present application, the added amount of the dehydroxylation aid is 0.01‰-2.00‰ of the total mass of anhydrous aluminum hydroxyfluoride.

In some embodiments of the present application, the second temperature is 350-400°C.

In some embodiments of the present application, the anhydrous aluminum hydroxyfluoride is treated at the second temperature for 80-160 minutes.

In some embodiments of the present application, the aluminum electrolytic carbon slag waste includes at least one of the following materials:

Aluminum electrolytic carbon slag collected from aluminum electrolytic cells;

The fluorine-containing material after the aluminum electrolytic carbon slag has been wet-processed;

The fluorine-containing material after the aluminum electrolytic carbon slag is dry-processed.

Compared with the prior art, the above-mentioned technical solutions provided by the embodiments of the present application have the following advantages:

A method for preparing anhydrous aluminum fluoride from aluminum electrolytic carbon slag waste provided in the embodiment of the present application, through the addition of a reaction accelerator, makes it easier to generate aluminum hydroxyfluoride that is closer to the structure of AlF ₃ , and can A hydrophobic protective layer is formed on the aluminum surface so that no water of crystallization is carried.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description serve to explain the principles of the application.

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, In other words, other drawings can also be obtained from these drawings without paying creative labor.

FIG. 1 is a schematic flow chart of a method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon slag waste provided in an embodiment of the present application.

Figure 2 is the XRD pattern of the aluminum hydroxyfluoride obtained in Example 1 of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of this application, but not all of them. Based on the embodiments in the present application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present application.

Unless otherwise specified, terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, this specification shall take precedence.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

The aluminum hydroxyfluoride obtained by the existing carbon residue treatment has the technical problems of low fluorine-aluminum ratio and containing crystal water.

The technical solutions provided by the embodiments of the present application are to solve the above technical problems, and the general idea is as follows:

The embodiment of the present application provides a method for preparing anhydrous aluminum fluoride from aluminum electrolytic carbon slag waste. The method for preparing anhydrous aluminum fluoride from aluminum electrolytic carbon slag includes the following steps:

S1: Provide aluminum electrolytic carbon slag waste with a particle size not higher than the predetermined size;

S2: soaking the aluminum electrolytic carbon slag waste in an acid solution, and then separating the solid and liquid, and collecting the separation liquid obtained by the solid-liquid separation;

S3: After adding a reaction accelerator to the separation liquid, adjust the molar ratio of fluorine and aluminum elements in the separation liquid to 3-5:1 to obtain a prefabricated solution;

S4: Treating the prefabricated solution at a first temperature to obtain anhydrous aluminum hydroxyfluoride;

S5: using the anhydrous aluminum hydroxyfluoride as a raw material to prepare anhydrous aluminum fluoride,

Wherein, the reaction accelerator includes at least one of phenylalanine, valine, leucine, kerosene, ethyl acetate, ammonium bifluoride, and sodium fluoride.

Those skilled in the art can obtain aluminum electrolytic carbon slag wastes with a particle size not higher than a predetermined size through conventional technical means, for example, through technical means such as grinding and sieving.

Those skilled in the art can understand that immersing the aluminum electrolytic carbon slag waste in an acid solution is a conventional technical means to dissolve elements such as aluminum and fluorine in the aluminum electrolytic carbon slag waste. As an example, the acid solution may be at least one of sulfuric acid and hydrochloric acid.

Those skilled in the art will understand that for step S4, the solution containing fluoride ions and aluminum ions in a specific molar ratio is

The molar ratio of fluorine to aluminum is 3-5:1, which can reduce the aluminum content in the product aluminum hydroxyfluoride, thereby promoting the formation of aluminum hydroxyfluoride with a higher ratio of fluorine to aluminum.

It is a conventional technical means in this field to obtain anhydrous aluminum hydroxyfluoride by certain temperature treatment.

Those skilled in the art can understand that for step S5, the preparation of anhydrous aluminum fluoride by anhydrous aluminum hydroxyfluoride is a conventional technical means in this field. The existing technical solutions generally include wet treatment and dry treatment. Wet treatment generally involves the use of aluminum hydroxyfluoride and fluorine-containing reactants, such as hydrofluoric acid, a mixture of hydrofluoric acid and ethanol, ammonium fluoride solution, hydrogen fluoride Ammonium and other mixed heat treatment, dry treatment is usually the co-heating of aluminum hydroxyfluoride and HF gas.

The reaction accelerator includes at least one of phenylalanine, valine, leucine, kerosene, ethyl acetate, ammonium bifluoride, and sodium fluoride. The action principle of the above-mentioned reaction accelerator is to utilize phenylalanine , valine, leucine, kerosene, ethyl acetate and other substances, reduce the combination of fluorine and aluminum ions with water, thereby avoiding the formation of hydroxyaluminum fluoride containing crystal water; ammonium bifluoride, sodium fluoride, etc. The fluorine-containing reagent can ensure that sufficient fluorine is preferentially combined with aluminum to ensure that the ratio of fluorine to aluminum in the generated aluminum hydroxyfluoride is 3:1.

The preferred combination of the reaction accelerator can be a mixture of phenylalanine, kerosene and sodium fluoride with a mass ratio of 1:1:1; a mixture of valine and ammonium bifluoride with a mass ratio of 1:0.5; the mass ratio is 1:0.25 mixture of valine and ethyl acetate; mass ratio of 1:0.5 mixture of phenylalanine and ethyl acetate; mass ratio of 1:0.45 mixture of valine and leucine.

In this application, through the addition of a reaction accelerator, aluminum fluoride hydroxy, which is closer to the structure of AlF ₃ , is easier to generate, and a hydrophobic protective layer can be formed on the surface of aluminum fluoride hydroxy, so as not to carry crystal water.

In some embodiments of the present application, the predetermined size is 75 μm.

Those skilled in the art can understand that limiting aluminum electrolysis carbon slag waste to no more than 75 μm is conducive to the dissolution of aluminum and fluorine elements during acid solution immersion.

The mesh size corresponding to 75 μm is 200 mesh, and aluminum electrolysis carbon slag wastes with a particle size below 75 μm can be screened through a 200-mesh sieve in actual production.

In some embodiments of the present application, the method of adjusting the molar ratio of fluorine and aluminum elements in the separation liquid is to add a fluorine-containing reagent, and the fluorine-containing reagent includes at least one of soluble fluorine salt and hydrogen fluoride.

In some embodiments of the present application, the first temperature is 75-85°C.

In some embodiments of the present application, the preparation of anhydrous aluminum fluoride using the anhydrous aluminum hydroxyfluoride as a raw material includes the following steps:

After adding a dehydroxylation aid to the anhydrous aluminum hydroxyfluoride, treating the anhydrous aluminum hydroxyfluoride at a second temperature to obtain the anhydrous aluminum fluoride.

In some embodiments of the present application, the dehydroxylation aid is at least one of vanadium pentoxide, manganese dioxide, titanium dioxide, and ferric oxide.

The principle of action of vanadium pentoxide, manganese dioxide, titanium dioxide, and ferric oxide is that the dehydroxylation additive metal oxide can significantly increase the oxygen vacancies in the metal oxide/anhydrous aluminum fluoride fluoride under the action of the temperature field, It is beneficial to the separation and transfer of effective charges between hydroxyl, fluorine, and aluminum, thereby promoting the breaking of the bond between hydroxyl, fluorine, and aluminum and the effective combination between fluorine and aluminum.

The preferred dehydroxylation aids can be 0.01‰ vanadium pentoxide, 0.08‰ manganese dioxide, 0.15‰ titanium dioxide, 0.10‰ mixture of ferric oxide and manganese dioxide and 0.20‰ ferric oxide.

The treatment process of aluminum hydroxyfluoride that has been obtained generally includes wet treatment and dry treatment, and wet treatment is often the combination of aluminum hydroxyfluoride and fluorine-containing reactants, such as hydrofluoric acid, hydrofluoric acid and Mixed solution of ethanol, ammonium fluoride solution, ammonium bifluoride and other mixed heat treatment, although aluminum fluoride with high purity can be obtained, but because the reactant contains a large amount of fluorine, there are very high requirements for the corrosion resistance of the reaction equipment and the treatment of industrial tail gas. High, and these fluorine-containing reactants are very harmful to the human body, and the safety cost is high, which leads to high processing costs for wet treatment; while dry treatment usually heats aluminum hydroxyfluoride and HF gas together, and the hydroxyfluoride Aluminum reacts directly with HF gas, which also has the problems of high equipment requirements and complicated operation.

In this application, by co-heating anhydrous aluminum hydroxyfluoride and dehydroxylation auxiliary agent, since step S3 has adjusted the fluorine-aluminum ratio of the separation liquid, the process of converting anhydrous aluminum hydroxyfluoride into anhydrous aluminum fluoride During the process, no HF atmosphere is required, the requirements for equipment are reduced, and the operation is simplified.

It should be noted that the oxygen element in the hydroxyl group itself cannot be completely removed, unless hydrogen ions or ammonium ions and other ions that can form water with the hydroxyl group and be removed are introduced into the system. Therefore, the anhydrous aluminum fluoride obtained in the present application may have a certain amount of impurities. The purity of the anhydrous aluminum fluoride obtained in the present application can be adjusted by the type of fluorine-containing reagent added when adjusting the molar ratio of fluorine-aluminum elements in the separation liquid. If it is adjusted by fluorine-containing reagents such as HF, ammonium fluoride, and ammonium bifluoride, no new impurity ions will be introduced, and hydrogen ions that can form water molecules together with the hydroxyl group will be introduced. In this case, it is easier to completely remove the hydroxyl group. Except, this situation is generally applicable to the situation where the fluorine-aluminum ratio of the original separation liquid is relatively low and a large amount of fluorine-containing reagent needs to be introduced; if the original separation liquid has a relatively high fluorine-aluminum ratio, just add a small amount of fluorine-containing reagent, and the introduction of impurity ions is less In this case, the fluorine-containing reagent can also use fluorine salts such as sodium fluoride.

In some embodiments of the present application, the added amount of the dehydroxylation aid is 0.01‰-2.00‰ of the total mass of anhydrous aluminum hydroxyfluoride.

If the addition amount of the dehydroxylation aid is too small, the dehydroxylation reaction speed will be too slow. Too much addition of the dehydroxylation aid will lead to an increase in the impurity content of the product and affect the quality of the product.

In some embodiments of the present application, the second temperature is 350-400°C.

Because the aluminum hydroxyfluoride obtained by the existing carbon slag treatment process often contains crystal water, there is incomplete dehydration at lower temperatures (350°C-450°C), and aluminum fluoride trihydrate phase remains in the aluminum fluoride; The aluminum fluoride generated at low temperature (450-650°C) will react with hydroxyl or water to generate aluminum oxide and hydrogen fluoride, resulting in a large amount of aluminum oxide in the product, and the purity is not high.

The aluminum hydroxyfluoride in this application is anhydrous aluminum hydroxyfluoride, and by adding a dehydroxylation aid, the hydroxyl group can be removed at a relatively low temperature to obtain anhydrous aluminum fluoride. It should be noted that aluminum hydroxyfluoride containing crystal water is not suitable for this solution, and crystal water will affect the effect of the dehydroxylation aid.

In some embodiments of the present application, the anhydrous aluminum hydroxyfluoride is treated at the second temperature for 80-160 minutes.

In some embodiments of the present application, the aluminum electrolytic carbon slag waste includes at least one of the following materials:

Aluminum electrolytic carbon slag collected from aluminum electrolytic cells;

The fluorine-containing material after the aluminum electrolytic carbon slag has been wet-processed;

The fluorine-containing material after the aluminum electrolytic carbon slag is dry-processed.

Those skilled in the art can understand that in actual production, the fluorine-containing material after the aluminum electrolytic carbon slag is wet-processed, and the fluorine-containing material after the aluminum electrolytic carbon slag is dry-processed can also be subjected to secondary extraction.

The present application will be further elaborated below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods not indicating specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, proceed according to general international standards, conventional conditions, or the conditions suggested by the manufacturer.

Example 1

Grind aluminum electrolytic carbon slag, pass through a 200-mesh sieve, take the sieved powder, leaching the powder with sulfuric acid at a liquid-solid ratio of 5:1, separate the solid and liquid, add the total mass of the solution to the filtrate, and the mass ratio is 1 : 1:1 mixture of phenylalanine, kerosene and sodium fluoride as a reaction accelerator, adjust the fluorine-aluminum ratio of the filtrate to 3.0 by adding hydrofluoric acid, adjust the pH to 5.0-6.0, react at 75°C for 3h, filter, 105°C Dry to obtain aluminum hydroxyfluoride; add 0.01‰ vanadium pentoxide to aluminum hydroxyfluoride as a dehydroxylation aid, react at 360°C for 160 minutes, and obtain anhydrous aluminum fluoride whose fluorine and aluminum composition index meets AF-2 after cooling .

In this example, XRD characterization was also performed on the obtained aluminum hydroxyfluoride, please refer to FIG. 2 for the characterization results. All peaks in Fig. 2 are Al(OH·F) ₃ characteristic peaks, as can be seen from Fig. 2, the peak type of each characteristic peak is obvious and sharp, and there are no other miscellaneous peaks, this shows that the obtained aluminum hydroxyfluoride The structural formula is Al(OH·F) ₃ , and it does not contain crystal water and other impurities.

Example 2

Grind aluminum electrolytic carbon slag, pass through a 200-mesh sieve, take the sieved powder, leaching the powder with hydrochloric acid at a liquid-solid ratio of 6:1, separate the solid and liquid, add the total mass of the solution to the filtrate, and the mass ratio is 1 : The mixture of valine and ammonium bifluoride of 0.5 is the reaction accelerator, the fluorine-aluminum ratio of the filtrate is adjusted to 3.5 by adding hydrofluoric acid, the pH is adjusted to 5.0-6.0, the reaction is at 80°C for 3h, filtered, and dried at 105°C to obtain hydroxyl Aluminum fluoride: add 0.08‰ manganese dioxide to aluminum hydroxyfluoride as a dehydroxylation aid, react at 370°C for 130 minutes, and obtain anhydrous aluminum fluoride whose fluorine and aluminum composition index meets AF-2 after cooling.

Example 3

Grind aluminum electrolytic carbon slag, pass through a 200-mesh sieve, take the sieved powder, leaching the powder with sulfuric acid at a liquid-solid ratio of 4:1, separate the solid from the liquid, and add the total mass of the solution to the filtrate at a mass ratio of 1.5‰ to 1 : The mixture of valine and ethyl acetate at 0.25 is the reaction accelerator. By adding hydrofluoric acid, adjust the fluorine-aluminum ratio of the filtrate to 4.5, adjust the pH to 5.0-6.0, react at 85°C for 1.5h, filter, and dry at 105°C. Obtain aluminum hydroxyfluoride; add 0.15‰ titanium dioxide to the aluminum hydroxyfluoride as a dehydroxylation aid, react at 380°C for 100 minutes, and obtain anhydrous aluminum fluoride whose fluoroaluminum composition index meets AF-2 after cooling.

Example 4

Grind aluminum electrolytic carbon slag finely, pass through a 200-mesh sieve, take the sieved powder, leaching the powder with hydrochloric acid at a liquid-solid ratio of 4:1, separate the solid and liquid, add the total mass of the solution to the filtrate with a mass ratio of 1.3‰ to 1 : 0.5 mixture of phenylalanine and ethyl acetate as a reaction accelerator, adjust the filtrate fluoroaluminum ratio to 4.0 by adding hydrofluoric acid, adjust the pH to 5.0-6.0, react at 83°C for 2h, filter, and dry at 105°C. Obtain aluminum hydroxyfluoride; add 0.10‰ of a mixture of ferric oxide and manganese dioxide to aluminum hydroxyfluoride as a dehydroxylation aid, react at 400°C for 80 minutes, and obtain anhydrous aluminum fluoride whose composition index meets AF-2 after cooling aluminum fluoride.

Example 5

Grind the aluminum electrolytic carbon slag finely, pass through a 200-mesh sieve, take the sieved powder, leaching the powder with hydrochloric acid at a liquid-solid ratio of 6:1, and separate the solid and liquid. Add the total mass of the solution to the filtrate at a mass ratio of 1.6‰: The mixture of valine and leucine at 0.45 is used as a reaction accelerator. By adding hydrofluoric acid, adjust the fluorine-aluminum ratio of the filtrate to 5.1, adjust the pH to 5.0-6.0, react at 81°C for 2h, filter, and dry at 105°C to obtain hydroxyl Aluminum fluoride: add 0.20‰ ferric oxide to aluminum hydroxyfluoride as a dehydroxylation aid, react at 390°C for 110 minutes, and obtain anhydrous aluminum fluoride whose fluorine and aluminum composition index meets AF-2 after cooling.

Various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the application; therefore, the described range should be regarded as The description has specifically disclosed all possible subranges as well as individual values within that range. For example, a description of a range from 1 to 6 should be considered to have specifically disclosed subranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and Single numbers within the stated ranges, eg 1, 2, 3, 4, 5 and 6, apply regardless of the range. Additionally, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.

In the present application, unless otherwise stated, the used orientation words such as "upper" and "lower" specifically refer to the direction of the drawings in the drawings. In addition, in the description of the specification of the present application, the terms "including" and "comprising" mean "including but not limited to". Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the statement "comprising..." does not exclude the presence of additional same elements in the process, method, article or device comprising said element. In this document, relational terms such as "first" and "second", etc., are only used to distinguish one entity or operation from another, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or sequence. In this article, "and/or" describes the association relationship of associated objects, indicating that there may be three kinds of relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone . For the association relationship of more than three associated objects described with "and/or", it means that any of the three associated objects can exist independently, or any at least two of them can exist at the same time, for example, for A, and/or B , and/or C, may mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or three of them exist simultaneously. Herein, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, "at least one item (unit) of a, b, or c", or "at least one item (unit) of a, b, and c" can mean: a, b, c, a-b( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

The above descriptions are only specific implementation manners of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims (10)

1. The method for preparing the anhydrous aluminum fluoride from the aluminum electrolysis carbon residue waste is characterized by comprising the following steps of:

providing aluminum electrolysis carbon residue waste with the grain diameter not higher than a preset size;

soaking the aluminum electrolysis carbon residue waste material with acid liquor, then carrying out solid-liquid separation, and collecting a separation liquid obtained by the solid-liquid separation;

after adding a reaction promoter into the separation liquid, adjusting the mole ratio of fluorine and aluminum elements in the separation liquid to be 3-5:1, obtaining a prefabricated solution;

treating the prefabricated solution at a first temperature to obtain anhydrous aluminum hydroxyfluoride;

preparing anhydrous aluminum fluoride by taking the anhydrous aluminum fluoride hydroxide as a raw material,

wherein the reaction promoter comprises at least one of phenylalanine, valine, leucine, kerosene, ethyl acetate, ammonium bifluoride and sodium fluoride.

2. The method for producing anhydrous aluminum fluoride from aluminum electrolysis carbon slag waste of claim 1, wherein the predetermined size is 75 μm.

3. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste according to claim 1, wherein the molar ratio of fluorine aluminum element in the separated liquid is adjusted by adding a fluorine-containing reagent, and the fluorine-containing reagent comprises at least one of soluble fluorine salt and hydrogen fluoride.

4. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste according to claim 1, wherein the first temperature is 75-85 ℃.

5. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste according to claim 1, wherein the method for preparing anhydrous aluminum fluoride from the anhydrous aluminum hydroxyfluoride comprises the following steps:

and after adding a dehydroxylation auxiliary agent into the anhydrous aluminum hydroxyfluoride, treating the anhydrous aluminum hydroxyfluoride at a second temperature to obtain the anhydrous aluminum fluoride.

6. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste according to claim 5, wherein the dehydroxylation auxiliary agent is at least one of vanadium pentoxide, manganese dioxide, titanium dioxide, and ferric oxide.

7. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste material according to claim 6, wherein the addition amount of the dehydroxylation auxiliary agent is 0.01 per mill-2.00 per mill of the total mass of the anhydrous aluminum fluoride.

8. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste of claim 5, wherein the second temperature is 350-400 ℃.

9. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste material according to claim 5, wherein the anhydrous aluminum hydroxyfluoride is treated at the second temperature for 80-160min.

10. The method for preparing anhydrous aluminum fluoride from aluminum electrolysis carbon residue waste according to any one of claims 1 to 9, wherein the aluminum electrolysis carbon residue waste comprises at least one of the following materials:

collecting the obtained aluminum electrolysis carbon slag by an aluminum electrolysis cell;

fluorine-containing materials obtained after the aluminum electrolysis carbon slag is subjected to wet treatment;

and (3) carrying out dry treatment on the fluorine-containing material of the aluminum electrolysis carbon slag.