Method for removing and recovering silicon from aluminum electrolysis waste residue

Abstract

The application discloses a method for removing and recycling silicon in aluminum electrolysis waste residue, which comprises the following steps: mixing aluminum electrolysis waste residue powder with an aqueous solution to prepare a leaching solution, and then performing a leaching reaction to obtain first filter residue and first filtrate; washing the first filter residue, and then filtering to obtain second filter residue and second filtrate, wherein the second filtrate is returned to the previous leaching solution for recycling; mixing the first filtrate with a desiliconizing agent to remove silicon in the first filtrate, and then filtering to obtain third filter residue and third filtrate; heating the third filtrate to remove excess desiliconizing agent, and then returning the heated decomposition solution to the leaching solution for recycling; washing the third filter residue, and then filtering to obtain fourth filter residue and fourth filtrate, wherein the fourth filtrate is returned to the previous step of washing the third filter residue; and calcining the fourth filter residue to obtain a silicon oxide product, so that silicon is recycled. The method has the advantages of simple operation, single chemical reagent added in the treatment process, no introduction of impurities, no special requirement for the silicon content of the original filtrate, wide application range, short overall disposal process, high desiliconizing efficiency, and formation of silicon oxide as a high value-added product in the desiliconizing process.

Description

Technical Field

[0001] This application relates to the field of aluminum electrolysis waste residue resource utilization technology, and in particular to a method for removing and recovering silicon from aluminum electrolysis waste residue. Background Technology

[0002] Common aluminum electrolysis waste residue is a type of aluminum-silica overhaul slag, containing valuable components such as silicon dioxide, alumina, iron oxide, and fluoride salts. The annual output of this waste reaches hundreds of thousands of tons. In recent years, more and more technologies have emerged for the extraction of valuable elements from aluminum electrolysis waste residue, mainly focusing on the efficient extraction of fluorine and lithium. However, there are few reports on the treatment of silicon content in aluminum electrolysis waste residue. This is partly because existing technologies for silicon treatment lack a technology fully suitable for large-scale industrial application, and partly because most current silicon removal processes in the aluminum industry focus on pre-desiliconization, neglecting the treatment and recovery of silicon in aluminum electrolysis waste residue. It is well known that excessively high silicon content in the waste liquid generated during aluminum electrolysis waste residue treatment can lead to equipment scaling and product quality contamination, especially in the electrolytic aluminum industry where silicon impurities have a significant impact on the quality of aluminum products.

[0003] The main methods for desilication of industrial wastewater currently include coagulation sedimentation, ion exchange, membrane separation, and electrocoagulation. Coagulation sedimentation is a non-deep desilication method that mainly utilizes the adsorption of silicon by metal oxides or hydroxides. Adding magnesium, iron salts, aluminum salts, lime, or other metal oxides or hydroxides to industrial wastewater achieves silicon removal. After subsequent filtration and clarification, 60%-90% of the silicon can generally be removed. However, this method introduces impurities and is mostly used for the treatment of upstream solutions. Ion exchange is a deep desilication technology. After ion exchange treatment, the silicon content can reach below 1 mg / L, but it cannot remove colloidal silicon in the water. Furthermore, the resin materials used are expensive, resulting in high operating costs. Membrane separation uses ultrafiltration or reverse osmosis membranes to remove silicon from wastewater. Ultrafiltration membranes are only effective at removing colloidal silicon and cannot remove dissolved silicon, while reverse osmosis membranes are not suitable for desilication of large volumes of wastewater. Electrocoagulation not only introduces impurities but also significantly increases the consumption of aluminum and electricity. Summary of the Invention

[0004] This application provides a method for removing and recovering silicon from aluminum electrolysis waste residue, in order to solve the technical problems of introducing impurities and high costs in existing silicon removal technologies for aluminum electrolysis waste residue.

[0005] This application provides a method for removing and recovering silicon from aluminum electrolysis waste residue, comprising the following steps:

[0006] Aluminum electrolysis waste residue powder and water are mixed to prepare an aluminum electrolysis waste residue aqueous dissolution solution and carry out a dissolution reaction. The solution is then filtered to obtain the first filter residue and the first filtrate.

[0007] A desilication agent is added to the first filtrate to carry out a desilication reaction, and after filtration, a third filtrate and a third filter residue are obtained.

[0008] The third filtrate is heated to obtain a decomposed liquid, which is then combined with the dissolution solution for recycling.

[0009] Wash the third filter residue, and filter to obtain a fourth filter residue and a fourth filtrate;

[0010] The fourth filtrate is returned to the previous stage for washing the third filter residue;

[0011] The fourth filter residue was calcined to obtain silicon dioxide.

[0012] Optionally, the method further includes washing the first filter residue, filtering to obtain a second filter residue and a second filtrate, wherein the second filtrate is returned to the previous dissolution solution for recycling.

[0013] Optionally, the liquid-to-solid ratio in the aqueous solution of the aluminum electrolysis waste residue is 1:1 to 5:1.

[0014] Optionally, the dissolution reaction is carried out at room temperature.

[0015] Optionally, the dissolution reaction time is 0.5 h to 1 h.

[0016] Optionally, the desilication agent is hydrogen peroxide.

[0017] Optionally, the desilication reaction is a room temperature reaction for 20 to 40 minutes.

[0018] Optionally, during the desilication reaction, the amount of desilication agent added should be such that the pH of the mixture after the desilication reaction is 9.0-11.5.

[0019] Optionally, the liquid-to-solid ratio of the third filter residue washing solution is 0.5:1 to 2:1.

[0020] Optionally, the washing time for the third filter residue is 20 min to 40 min.

[0021] Optionally, the heating temperature of the third filtrate is 30℃~70℃.

[0022] Optionally, the heating time for the third filtrate is 10 min to 20 min.

[0023] Optionally, the roasting temperature of the fourth filter residue is 300℃~600℃.

[0024] Optionally, the aluminum electrolysis waste residue includes at least one of overhaul slag, waste refractory materials, and seepage-proof materials.

[0025] Optionally, the aluminum electrolysis waste powder is 50 mesh to 200 mesh.

[0026] Optionally, the aluminum electrolysis waste residue powder is prepared by crushing it with a crusher and then finely grinding it with a ball mill, and the electrolysis waste residue powder is passed through a 50-200 mesh sieve.

[0027] The technical solution provided by this invention has the following advantages compared with the prior art:

[0028] This invention provides a method for removing and recovering silicon from aluminum electrolysis waste residue. The method is simple to operate, requires only a single chemical agent during treatment without introducing impurities, and has no special requirements on the silicon content of the original filtrate, making it widely applicable. The overall treatment process is short, with high desiliconization efficiency, and the desiliconization process can form silicon oxide, a high-value-added product of silicon. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart illustrating a method for removing and recovering silicon from aluminum electrolysis waste residue, provided in an embodiment of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges 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 range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0034] In this application, unless otherwise stated, terms including "comprising" and the like mean "including but not limited to". Relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" 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 singular or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0036] This application provides a method for removing and recovering silicon from aluminum electrolysis waste residue, comprising the following steps:

[0037] Aluminum electrolysis waste residue powder and water are mixed to prepare an aluminum electrolysis waste residue aqueous dissolution solution and carry out a dissolution reaction. The solution is then filtered to obtain the first filter residue and the first filtrate.

[0038] A desilication agent is added to the first filtrate to carry out a desilication reaction, and after filtration, a third filtrate and a third filter residue are obtained.

[0039] The third filtrate is heated to obtain a decomposed liquid, which is then combined with the dissolution solution for recycling.

[0040] Wash the third filter residue, and filter to obtain a fourth filter residue and a fourth filtrate;

[0041] The fourth filtrate is returned to the previous stage for washing the third filter residue;

[0042] The fourth filter residue was calcined to obtain silicon dioxide.

[0043] In the above embodiments, this method has no special requirements for the silicon content of the filtrate in the original leaching solution. The silicon removal process in the treatment of aluminum electrolysis waste residue is simple to operate, the chemical agent added during the treatment is single and does not introduce impurities, the process flow is short, the added agent is single and does not introduce impurities, it is suitable for the removal and recovery of silicon in the treatment of large-scale aluminum electrolysis waste residue, the silicon efficiency is high and the silicon removal process can form high-value-added silicon products.

[0044] In an optional embodiment, the method further includes washing the first filter residue, filtering to obtain a second filter residue and a second filtrate, wherein the second filtrate is returned to the previous dissolution solution for recycling.

[0045] In the above embodiment, the second filtrate obtained after cleaning the first filter residue is returned to the dissolution solution for recycling, which saves water consumption and avoids the direct discarding of the "silicon" attached to the first filter residue, thus reducing silicon recovery.

[0046] In one optional embodiment, the liquid-to-solid ratio in the leaching solution prepared from the aluminum electrolysis waste water is 1:1 to 5:1.

[0047] In the above embodiments, the ratio of water to aluminum electrolysis waste powder ranges from 1:1 to 5:1, without specific limitation. For example, the liquid-solid ratio can be set to 1:1, 2:1, 3:1, 4:1, or 5:1. Here, "water" includes not only the newly added water but also the second filtrate obtained after washing the first filter residue.

[0048] In one alternative embodiment, the dissolution reaction is carried out at room temperature.

[0049] In one optional embodiment, the dissolution reaction time is 0.5 h to 1 h.

[0050] In one optional embodiment, the desilication agent is hydrogen peroxide.

[0051] In one optional embodiment, the desilication reaction is a room temperature reaction for 20 to 40 minutes.

[0052] In an optional embodiment, during the desilication reaction, the amount of desilication agent added should be such that the pH of the mixture after the desilication reaction is 9.0-11.5.

[0053] In the above embodiments, in order to ensure that the silicon in the first filtrate is completely removed, the amount of hydrogen peroxide added must be sufficient. When the pH of the mixture after the reaction is 9.0-11.5, it indicates that the "silicon" in the mixture has been completely reacted. The specific pH is not limited. For example, the pH of the mixture after the reaction can be 9, 9.5, 10, 10.5, 11 or 11.5.

[0054] In one optional embodiment, the liquid-to-solid ratio during the third filter residue washing is 0.5:1 to 2:1.

[0055] In the above embodiments, the determination of the liquid-solid ratio during the washing of the third filter residue takes into account not only the added water, but also the fourth filtrate. That is, the ratio of the mass of the fourth filtrate + water to the third filter residue is 0.5:1 to 2:1. The specific value is not limited. For example, the liquid-solid ratio can be controlled to be 0.5:1, 1:1, 1.5:1 or 2:1.

[0056] In one optional embodiment, the washing time of the third filter residue is 20 min to 40 min.

[0057] In one optional embodiment, the heating temperature of the third filtrate is 30°C to 70°C.

[0058] In the above embodiments, the heating temperature of the third filtrate is 30℃~70℃, mainly to decompose excess hydrogen peroxide so that it does not affect the subsequent circulation of the third filtrate.

[0059] In one optional embodiment, the heating time of the third filtrate is 10 min to 20 min.

[0060] In the above embodiments, the heating time is mainly determined by whether the hydrogen peroxide has reacted completely. This can be achieved using an indicator, such as adding a small amount of the test solution to an acidic ferrous chloride solution. If the solution does not change from green to yellow, it indicates that the hydrogen peroxide has reacted completely, and the heating reaction can be stopped. Therefore, the specific time is not limited. For example, the heating time can be set to 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, or 20 min.

[0061] In one optional embodiment, the roasting temperature of the fourth filter residue is 300℃ to 600℃.

[0062] In the above embodiments, when the calcination temperature is 300℃ to 600℃, the silicon-containing compound can be calcined to decompose it into silicon oxide, thereby achieving silicon recovery. The specific calcination temperature is not limited; for example, the calcination temperature can be set to 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, or 600℃.

[0063] In one optional embodiment, the aluminum electrolysis waste residue includes at least one of overhaul slag, waste refractory materials, and anti-seepage materials.

[0064] In one optional embodiment, the aluminum electrolysis waste powder is 50 mesh to 200 mesh.

[0065] In one optional embodiment, the aluminum electrolysis waste residue powder is prepared by crushing it with a crusher and then finely grinding it with a ball mill, and the electrolysis waste residue powder is passed through a 50-200 mesh sieve.

[0066] In the above embodiments, ball milling the aluminum electrolysis waste residue to 50-200 mesh increases the contact area between the powder and water when mixing with water to prepare the dissolution solution, thereby accelerating the dissolution rate. The specific size of the aluminum electrolysis waste residue powder is not limited; for example, it can be set to 50 mesh, 100 mesh, 150 mesh, or 200 mesh.

[0067] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0068] Example 1

[0069] This embodiment provides a method for removing and recovering silicon from aluminum electrolysis waste residue. The process flow is as follows: Figure 1 As shown, the specific steps include:

[0070] Step 1: Silicon removal in aluminum electrolysis waste treatment

[0071] (1) The aluminum electrolysis overhaul slag is crushed and ball-milled. The main components of the aluminum electrolysis overhaul slag are carbonaceous, aluminum silicon, sodium fluoride, calcium fluoride, lithium fluoride, cryolite, iron, etc., and it is passed through a 50-200 mesh sieve.

[0072] (2) Weigh 300g of aluminum electrolysis overhaul slag, measure water with a liquid-to-solid ratio of 1:1, mix aluminum electrolysis anti-seepage material with water to prepare a dissolution solution, and stir at room temperature for 1 hour to carry out the dissolution reaction.

[0073] (3) After the reaction is completed, the mixture is filtered to obtain the first filter residue and the first filtrate. The first filter residue is washed and filtered to obtain the second filter residue and the second filtrate. The second filtrate is returned to the previous dissolution solution for recycling.

[0074] (4) The silicon content in the first filtrate is 0.42 g / L. Take 200 mL of the solution and measure 1 mL of hydrogen peroxide to adjust the pH of the mixed solution to 11.5. Carry out the desilication reaction at room temperature for 20 min. Filter to obtain the third filter residue and the third filtrate.

[0075] (5) The third filtrate is heated at 30°C for 20 minutes to remove excess hydrogen peroxide. The decomposed solution after heating is returned to the previous dissolution solution for recycling.

[0076] Step 2: Recycling the extracted silicon

[0077] (1) The silicon-containing filter residue obtained in step 4 above is washed with a liquid-to-solid ratio of 2:1 for 20 minutes and filtered to obtain the fourth filter residue and the fourth filtrate. The fourth filter residue is calcined to obtain silicon oxide product at a calcination temperature of 500℃. The fourth filtrate is returned to the previous third filter residue for recycling.

[0078] Example 2

[0079] This embodiment provides a method for removing and recovering silicon from aluminum electrolysis waste residue. The process flow is as follows: Figure 1 As shown, the specific steps include:

[0080] Step 1: Silicon removal in aluminum electrolysis waste treatment

[0081] (1) The aluminum electrolysis overhaul slag is crushed and ball-milled. The main components of the aluminum electrolysis overhaul slag are carbonaceous, aluminum silicon, sodium fluoride, calcium fluoride, lithium fluoride, cryolite, iron, etc., and it is passed through a 50-200 mesh sieve.

[0082] (2) Weigh 250g of aluminum electrolysis overhaul slag, measure water with a liquid-to-solid ratio of 2:1, mix aluminum electrolysis anti-seepage material with water to prepare a dissolution solution, and stir at room temperature for 1 hour to carry out the dissolution reaction.

[0083] (3) After the reaction is completed, the mixture is filtered to obtain the first filter residue and the first filtrate. The first filter residue is washed and filtered to obtain the second filter residue and the second filtrate. The second filtrate is returned to the previous dissolution solution for recycling.

[0084] (4) The silicon content in the first filtrate is 0.53 g / L. Take 300 mL and measure 2 mL of hydrogen peroxide to adjust the pH of the mixed solution to 10.15. Carry out the desilication reaction at room temperature for 30 min. Filter to obtain the third filter residue and the third filtrate.

[0085] (5) The third filtrate is heated at 40°C for 15 minutes to remove excess hydrogen peroxide. The decomposed solution after heating is returned to the previous dissolution solution for recycling.

[0086] Step 2: Recycling the extracted silicon

[0087] (1) The silicon-containing filter residue obtained in step 4 above is washed with a liquid-to-solid ratio of 1.5:1 for 25 minutes and filtered to obtain the fourth filter residue and the fourth filtrate. The fourth filter residue is calcined to obtain silicon oxide product at a calcination temperature of 600℃. The fourth filtrate is returned to the previous third filter residue for recycling.

[0088] Example 3

[0089] This embodiment provides a method for removing and recovering silicon from aluminum electrolysis waste residue. The process flow is as follows: Figure 1 As shown, the specific steps include:

[0090] Step 1: Silicon removal in aluminum electrolysis waste treatment

[0091] (1) The aluminum electrolysis overhaul slag is crushed and ball-milled. The main components of the aluminum electrolysis overhaul slag are carbonaceous, aluminum silicon, sodium fluoride, calcium fluoride, lithium fluoride, cryolite, iron, etc., and it is passed through a 50-200 mesh sieve.

[0092] (2) Weigh 200g of aluminum electrolysis overhaul slag, measure water with a liquid-to-solid ratio of 3:1, mix aluminum electrolysis anti-seepage material with water to prepare a dissolution solution, and stir at room temperature for 0.5h to carry out the dissolution reaction.

[0093] (3) After the reaction is completed, the mixture is filtered to obtain the first filter residue and the first filtrate. The first filter residue is washed and filtered to obtain the second filter residue and the second filtrate. The second filtrate is returned to the previous dissolution solution for recycling.

[0094] (4) The silicon content in the first filtrate is 1.02 g / L. Take 400 mL and measure 1.5 mL of hydrogen peroxide to adjust the pH of the mixed solution to 9.0. Carry out the desilication reaction at room temperature for 20 min. Filter to obtain the third filter residue and the third filtrate.

[0095] (5) The third filtrate is heated at 55°C for 10 minutes to remove excess hydrogen peroxide. The decomposed solution after heating is returned to the previous dissolution solution for recycling.

[0096] Step 2: Recycling the extracted silicon

[0097] (1) The silicon-containing filter residue obtained in step 4 above is washed with a liquid-solid ratio of 1:1 for 30 minutes and filtered to obtain the fourth filter residue and the fourth filtrate. The fourth filter residue is calcined to obtain silicon oxide product at a calcination temperature of 400℃. The fourth filtrate is returned to the previous third filter residue for recycling.

[0098] Example 4

[0099] This embodiment provides a method for removing and recovering silicon from aluminum electrolysis waste residue. The process flow is as follows: Figure 1 As shown, the specific steps include:

[0100] Step 1: Silicon removal in aluminum electrolysis waste treatment

[0101] (1) The aluminum electrolysis waste refractory material is crushed and ball-milled. The main components of the aluminum electrolysis waste refractory material are nepheline, cryolite, sodium fluoride, calcium fluoride, etc., and it is passed through a 50-200 mesh sieve.

[0102] (2) Weigh 250g of aluminum electrolysis waste refractory material, measure water with a liquid-to-solid ratio of 4:1, mix aluminum electrolysis anti-seepage material with water to prepare a leaching solution, and stir for 40 minutes at room temperature to carry out the leaching reaction.

[0103] (3) After the reaction is completed, the mixture is filtered to obtain the first filter residue and the first filtrate. The first filter residue is washed and filtered to obtain the second filter residue and the second filtrate. The second filtrate is returned to the previous dissolution solution for recycling.

[0104] (4) The silicon content in the first filtrate is 0.38 g / L. Take 600 mL and measure 1.5 mL of hydrogen peroxide to adjust the pH of the mixed solution to 10.75. Carry out the desilication reaction at room temperature for 25 min. Filter to obtain the third filter residue and the third filtrate.

[0105] (5) The third filtrate is heated at 60°C for 10 minutes to remove excess hydrogen peroxide. The decomposed solution after heating is returned to the previous dissolution solution for recycling.

[0106] Step 2: Recycling the extracted silicon

[0107] (1) The silicon-containing filter residue obtained in step 4 above is washed with a liquid-to-solid ratio of 0.5:1 for 30 minutes and filtered to obtain the fourth filter residue and the fourth filtrate. The fourth filter residue is calcined to obtain silicon oxide product at a calcination temperature of 350°C. The fourth filtrate is returned to the previous third filter residue for recycling.

[0108] Example 5

[0109] This embodiment provides a method for removing and recovering silicon from aluminum electrolysis waste residue. The process flow is as follows: Figure 1 As shown, the specific steps include:

[0110] Step 1: Silicon removal in aluminum electrolysis waste treatment

[0111] (1) The aluminum electrolytic anti-seepage material is crushed and ball-milled. The main components of the aluminum electrolytic anti-seepage material are fluorine, aluminum, sodium, silicon, etc., and it passes through a 50-200 mesh sieve.

[0112] (2) Weigh 300g of aluminum electrolytic anti-seepage material, measure water with a liquid-solid ratio of 5:1, mix the aluminum electrolytic anti-seepage material and water to prepare a dissolution solution, and stir at room temperature for 1 hour to carry out the dissolution reaction.

[0113] (3) After the reaction is completed, the mixture is filtered to obtain the first filter residue and the first filtrate. The first filter residue is washed and filtered to obtain the second filter residue and the second filtrate. The second filtrate is returned to the previous dissolution solution for recycling.

[0114] (4) The silicon content in the first filtrate is 0.31 g / L. Take 800 mL and measure 3 mL of hydrogen peroxide to adjust the pH of the mixed solution to 10.92. Carry out the desilication reaction at room temperature for 30 min. Filter to obtain the third filter residue and the third filtrate.

[0115] (5) The third filtrate is heated at 70°C for 15 minutes to remove excess hydrogen peroxide. The decomposed solution after heating is returned to the previous dissolution solution for recycling.

[0116] Step 2: Recycling the extracted silicon

[0117] (1) The silicon-containing filter residue obtained in step 4 above is washed with a liquid-to-solid ratio of 2:1 for 20 minutes and filtered to obtain the fourth filter residue and the fourth filtrate. The fourth filter residue is calcined to obtain silicon oxide product at a calcination temperature of 300℃. The fourth filtrate is returned to the previous third filter residue for recycling.

[0118] The silicon content of the solutions (third filtrate) after silicon removal in Examples 1-5 was determined, and the experimental results are shown in Table 1:

[0119] Table 1

[0120] Example Silicon content in the solution after desilication (g / L) Solution desilication recovery rate (%) 1 0.045 89.3 2 0.055 89.6 3 0.1 90.2 4 0.042 88.9 5 0.04 88.7

[0121] As can be seen from the data in the table above, the method for removing and recovering silicon from aluminum electrolysis waste provided in this invention can reduce the silicon content in the third filtrate of aluminum electrolysis waste to 0.04-0.1 g / L, with a desiliconization rate as high as 90.2%. Furthermore, after silicon recovery, the recovery rate can reach over 90%, greatly increasing silicon recovery efficiency.

[0122] In summary, compared with the prior art, the method for removing and recovering silicon from aluminum electrolysis waste provided by the present invention has no special requirements on the silicon content in the prepared original leaching solution. After the silicon removal process, the silicon removal rate is as high as 90% or more. Moreover, the silicon removal process of the present invention is simple to operate, the chemical agent added during the process is singular and does not introduce impurities, the process flow is short, the added agent is singular and does not introduce impurities, it is suitable for the removal and recovery of silicon in large-scale aluminum electrolysis waste treatment, the silicon efficiency is high, and the silicon removal process can form high-value-added silicon products.

[0123] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this 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 this application. Therefore, this application is not to 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

1. A method for removing and recovering silicon from aluminum electrolysis waste residue, characterized in that, Includes the following steps: Aluminum electrolysis waste residue powder and water are mixed to prepare an aluminum electrolysis waste residue aqueous dissolution solution and carry out a dissolution reaction. The solution is then filtered to obtain the first filter residue and the first filtrate. A desilication agent is added to the first filtrate to carry out a desilication reaction, and after filtration, a third filtrate and a third filter residue are obtained. The third filtrate is heated to obtain a decomposed liquid, which is then combined with the dissolution solution for recycling. Wash the third filter residue, and filter to obtain a fourth filter residue and a fourth filtrate; The fourth filtrate is returned to the previous stage for washing the third filter residue; Calcination of the fourth filter residue yields silicon dioxide; The desilication agent is hydrogen peroxide; During the desilication reaction, the amount of desilication agent added should be such that the pH of the mixture after the desilication reaction is 9.0-11.5; The aluminum electrolysis waste residue includes at least one of the following: overhaul slag, waste refractory materials, and seepage-proof materials.

2. The method for removing and recovering silicon from aluminum electrolysis waste slag according to claim 1, characterized in that, It also includes washing the first filter residue, filtering to obtain a second filter residue and a second filtrate, wherein the second filtrate is returned to the previous dissolution solution for recycling.

3. The method for removing and recovering silicon from aluminum electrolysis waste slag according to claim 1, characterized in that, The liquid-to-solid ratio in the aqueous solution of aluminum electrolysis waste residue is 1:1 to 5:

1.

4. The method for removing and recovering silicon from aluminum electrolysis waste slag according to claim 1, characterized in that, The dissolution reaction time is 0.5h to 1h.

5. The method for removing and recovering silicon from aluminum electrolysis waste slag according to claim 1, characterized in that, The heating temperature of the third filtrate is 30℃~70℃.

6. The method for removing and recovering silicon from aluminum electrolysis waste slag according to claim 1, characterized in that, The roasting temperature of the fourth filter residue is 300℃~600℃.

7. The method for removing and recovering silicon from aluminum electrolysis waste slag according to claim 1, characterized in that, The aluminum electrolysis waste residue powder is 50 mesh to 200 mesh.

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