Method for separating and purifying cryolite from electrolytic aluminum carbon residues

Abstract

The invention provides a method for separating and purifying cryolite from electrolytic aluminum carbon residues, which comprises the following steps: sequentially performing impurity removal and crushing on the electrolytic aluminum carbon residues to obtain crushed materials of the electrolytic aluminum carbon residues, and removing carbon components in the crushed materials of the electrolytic aluminum carbon residues to obtain carbon-free waste materials of the electrolytic aluminum; the method comprises the following steps: carrying out secondary crushing on the electrolytic aluminum carbon-free waste residues to obtain crushed electrolytic aluminum carbon-free waste residues, preparing the crushed electrolytic aluminum carbon-free waste residues into slurry fluid, and diluting and blending the slurry fluid into a leaching solution; carrying out acidification treatment and solid-liquid separation treatment on the leaching solution, and extracting solid substances precipitated in the leaching solution; carrying out primary cleaning and extraction on the solid substance to obtain a cryolite extract; the cryolite extract is deeply cleaned and dried to obtain a cryolite product, and then the cryolite product is melted and solidified to obtain a cryolite refined product, so that the cryolite in the electrolytic aluminum carbon residues can be efficiently extracted and recycled with high purity, the reusability of the cryolite is improved, and the pollution of the electrolytic aluminum carbon residues to the environment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum electrolysis, and in particular to a method for separating and purifying cryolite from aluminum electrolysis carbon slag. Background Art

[0002] Cryolite (Na3AlF6) can dissolve alumina in a molten state and is mainly used as a solvent for aluminum electrolysis. Carbon anodes are required in the production process of aluminum electrolysis, and the anodes in contact with the electrolyte are the first to oxidize. As the electrolyte is washed away, some carbon particles that do not participate in the electrolysis reaction fall off from the anode and fall into the electrolytic cell. The detached carbon particles are soaked and penetrated by the electrolyte for a long time, forming a mixed floating material floating on the surface of the electrolyte, namely, electrolytic aluminum carbon slag. The main components of electrolytic aluminum carbon slag are fluorides such as cryolite and sodium fluoride, of which the weight of cryolite can reach 40%-60%. The cost of using cryolite in the aluminum electrolysis process is relatively high. If the electrolytic aluminum carbon slag is directly discarded, it will not only cause environmental pollution, but also cause serious waste of cryolite. Therefore, the recovery and purification of cryolite from electrolytic aluminum carbon slag can not only reduce pollution to the environment, but also reduce the cost of electrolytic aluminum production to a certain extent. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides a method for separating and purifying cryolite from electrolytic aluminum carbon slag, wherein the electrolytic aluminum carbon slag is sequentially decontaminated and crushed to obtain electrolytic aluminum carbon slag crushed materials, and the carbon components inside the electrolytic aluminum carbon slag crushed materials are removed to obtain electrolytic aluminum carbon-free waste slag materials; the electrolytic aluminum carbon-free waste slag materials are secondary crushed into electrolytic aluminum carbon-free waste slag crushed materials, and the electrolytic aluminum carbon-free waste slag crushed materials are prepared into a slurry fluid, and the slurry fluid is diluted and prepared into a leaching solution; the leaching solution is acidified and solid-liquid separated to extract the solid matter precipitated therein; the solid matter is preliminarily cleaned and extracted to obtain a cryolite extract; the cryolite extract is deeply cleaned and dried to obtain a cryolite product, and then the cryolite product is melted and solidified to obtain a cryolite refined product, which can extract and recover cryolite in the electrolytic aluminum carbon slag with high efficiency and high purity, improve the reusability of cryolite, and reduce the pollution of the electrolytic aluminum carbon slag to the environment.

[0004] The present invention provides a method for separating and purifying cryolite from electrolytic aluminum carbon slag, comprising the following steps:

[0005] Step S1, sequentially performing impurity removal and crushing treatments on electrolytic aluminum carbon slag to obtain electrolytic aluminum carbon slag scraps; performing carbon removal treatment on the electrolytic aluminum carbon slag scraps to obtain electrolytic aluminum carbon-free waste slag material;

[0006] Step S2, performing secondary crushing on the electrolytic aluminum carbon-free waste slag material to obtain electrolytic aluminum carbon-free waste slag fragments; preparing the electrolytic aluminum carbon-free waste slag fragments into a slurry fluid, and then diluting the slurry fluid to prepare a leaching solution;

[0007] Step S3, subjecting the leaching solution to an acidification treatment and a solid-liquid separation treatment, and then extracting the solid matter precipitated inside the leaching solution; subjecting the solid matter to a preliminary cleaning treatment and an extraction treatment to obtain a cryolite extract;

[0008] Step S4, performing deep cleaning and drying treatments on the cryolite extract to obtain a cryolite product; performing melting and solidification treatments on the cryolite product to obtain a cryolite refined product.

[0009] In one embodiment disclosed in the present application, in step S1, the electrolytic aluminum carbon slag is subjected to impurity removal treatment and crushing treatment in sequence to obtain electrolytic aluminum carbon slag crushed materials, including:

[0010] Placing the electrolytic aluminum carbon slag in a strong magnetic field environment for iron impurity adsorption and removal treatment, and stirring the electrolytic aluminum carbon slag at a uniform speed during the iron impurity adsorption and removal treatment; wherein the magnetic field strength of the strong magnetic field environment is greater than or equal to 3000 Gauss, and the duration of the iron impurity adsorption and removal treatment is not less than 30 minutes;

[0011] The electrolytic aluminum carbon slag that has completed the iron impurity adsorption and removal treatment is crushed and ground to break it into electrolytic aluminum carbon slag fragments with an average particle size of 100-200 meshes.

[0012] In one embodiment disclosed in the present application, in the step S1, the electrolytic aluminum carbon slag scraps are subjected to a carbon removal treatment to obtain electrolytic aluminum carbon-free waste slag material, including:

[0013] The electrolytic aluminum carbon slag fragments are placed in a combustion furnace, oxygen is supplied to the interior of the combustion furnace, and the carbon substances inside the electrolytic aluminum carbon slag fragments are burned and removed, thereby obtaining electrolytic aluminum carbon-free waste slag materials; according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace, the flow rate of oxygen supplied to the interior of the combustion furnace is adjusted.

[0014] In one embodiment disclosed in the present application, in the step S1, adjusting the flow rate of oxygen delivered to the interior of the combustion furnace according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace includes:

[0015] According to the combustion temperature change data inside the combustion furnace and the carbon dioxide flow rate change data discharged from the combustion furnace, it is judged whether the carbon material inside the electrolytic aluminum carbon slag fragments is fully burned inside the combustion furnace; if so, the current flow rate of oxygen delivered to the combustion furnace is maintained unchanged; if not, the flow rate of oxygen delivered to the combustion furnace is increased.

[0016] In one embodiment disclosed in the present application, in the step S2, the electrolytic aluminum carbon-free waste slag material is subjected to secondary crushing treatment to obtain electrolytic aluminum carbon-free waste slag crushed material, including:

[0017] The electrolytic aluminum carbon-free waste slag material is subjected to secondary rolling and grinding treatment, so as to break the electrolytic aluminum carbon-free waste slag material into electrolytic aluminum carbon-free waste slag fragments with an average particle size of 250-350 meshes.

[0018] In one embodiment disclosed in the present application, in the step S2, the electrolytic aluminum carbon-free waste slag is prepared into a slurry fluid, and then the slurry fluid is diluted and mixed into a leaching solution, including:

[0019] The electrolytic aluminum carbon-free waste slag fragments, water, a collector, and a foaming agent are uniformly mixed in a weight ratio of 10000-20000:4000-6000:8-10:3-5 to prepare a slurry fluid; wherein the collector is kerosene or diesel, and the foaming agent is methanol or camphor oil;

[0020] The slurry fluid, water and hexanol are uniformly mixed in a weight ratio of 1000-2000:20000-30000:10-12 to prepare a leaching solution.

[0021] In one embodiment disclosed in the present application, in the step S3, the leaching solution is subjected to acidification treatment and solid-liquid separation treatment, and then the solid matter precipitated in the leaching solution is extracted, including:

[0022] Add corresponding amounts of hydrochloric acid to the leaching solution in succession, so that the pH value of the leaching solution becomes 5-6; heat and stir the leaching solution, and then allow the leaching solution to stand to allow solid-liquid separation to occur inside the leaching solution; then filter the leaching solution to extract solid matter precipitated inside the leaching solution.

[0023] In one embodiment disclosed in the present application, in step S3, the solid material is subjected to preliminary cleaning and extraction treatment to obtain a cryolite extract, comprising:

[0024] The solid matter is repeatedly subjected to water washing treatment and extraction treatment to obtain a cryolite extract.

[0025] In one embodiment disclosed in the present application, in step S4, the cryolite extract is subjected to deep cleaning and drying treatment to obtain a cryolite product, comprising:

[0026] The cryolite extract is repeatedly subjected to ultrasonic water vibration cleaning treatment and hot air drying treatment to obtain a cryolite product.

[0027] In one embodiment disclosed in the present application, in the step S4, the cryolite product is subjected to a melting and solidification treatment to obtain a cryolite refined product, comprising:

[0028] The cryolite product is subjected to high-temperature calcination treatment so that the cryolite product is melted and solidified, thereby obtaining a cryolite refined product.

[0029] Compared with the prior art, the method for separating and purifying cryolite from electrolytic aluminum carbon slag sequentially removes impurities and crushes the electrolytic aluminum carbon slag to obtain electrolytic aluminum carbon slag fragments, and removes the carbon components inside the electrolytic aluminum carbon slag fragments to obtain electrolytic aluminum carbon-free waste slag material; the electrolytic aluminum carbon-free waste slag material is secondary crushed into electrolytic aluminum carbon-free waste slag fragments, and the electrolytic aluminum carbon-free waste slag fragments are prepared into a slurry fluid, and the slurry fluid is diluted and prepared into a leaching solution; the leaching solution is acidified and solid-liquid separated to extract the solid matter precipitated therein; the solid matter is preliminarily cleaned and extracted to obtain a cryolite extract; the cryolite extract is deeply cleaned and dried to obtain a cryolite product, and then the cryolite product is melted and solidified to obtain a cryolite refined product, which can extract and recover cryolite in the electrolytic aluminum carbon slag with high efficiency and high purity, improve the reusability of cryolite, and reduce the pollution of the electrolytic aluminum carbon slag to the environment.

[0030] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0031] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1A schematic flow chart of a method for separating and purifying cryolite from electrolytic aluminum carbon slag provided by the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figure 1 , is a schematic flow chart of a method for separating and purifying cryolite from electrolytic aluminum carbon slag provided by an embodiment of the present invention. The method for separating and purifying cryolite from electrolytic aluminum carbon slag comprises:

[0036] Step S1, performing impurity removal and crushing treatment on the electrolytic aluminum carbon slag in sequence to obtain electrolytic aluminum carbon slag scraps; performing carbon removal treatment on the electrolytic aluminum carbon slag scraps to obtain electrolytic aluminum carbon-free waste slag material;

[0037] Step S2, performing secondary crushing treatment on the electrolytic aluminum carbon-free waste slag material to obtain electrolytic aluminum carbon-free waste slag fragments; preparing the electrolytic aluminum carbon-free waste slag fragments into a slurry fluid, and then diluting the slurry fluid to prepare a leaching solution;

[0038] Step S3, acidifying and solid-liquid separation the leaching solution, and then extracting the solid matter precipitated in the leaching solution; performing preliminary cleaning and extraction on the solid matter to obtain a cryolite extract;

[0039] Step S4, deep cleaning and drying the cryolite extract to obtain a cryolite product; and melting and solidifying the cryolite product to obtain a cryolite refined product.

[0040] The beneficial effects of the above technical scheme are as follows: the method for separating and purifying cryolite from electrolytic aluminum carbon slag sequentially removes impurities and crushes the electrolytic aluminum carbon slag to obtain electrolytic aluminum carbon slag fragments, and removes the carbon components inside the electrolytic aluminum carbon slag fragments to obtain electrolytic aluminum carbon-free waste slag material; the electrolytic aluminum carbon-free waste slag material is secondary crushed into electrolytic aluminum carbon-free waste slag fragments, and the electrolytic aluminum carbon-free waste slag fragments are prepared into a slurry fluid, and the slurry fluid is diluted and prepared into a leaching solution; the leaching solution is acidified and solid-liquid separated to extract the solid matter precipitated therein; the solid matter is preliminarily cleaned and extracted to obtain a cryolite extract; the cryolite extract is deeply cleaned and dried to obtain a cryolite product, and then it is melted and solidified to obtain a cryolite refined product, which can extract and recover cryolite in the electrolytic aluminum carbon slag with high efficiency and high purity, improve the reusability of cryolite, and reduce the pollution of the electrolytic aluminum carbon slag to the environment.

[0041] Preferably, in step S1, the electrolytic aluminum carbon slag is subjected to a removal treatment and a crushing treatment in sequence to obtain electrolytic aluminum carbon slag crushed materials, including:

[0042] Placing the electrolytic aluminum carbon slag in a strong magnetic field environment for iron impurity adsorption and removal treatment, and stirring the electrolytic aluminum carbon slag at a uniform speed during the iron impurity adsorption and removal treatment; wherein the magnetic field intensity of the strong magnetic field environment is greater than or equal to 3000 Gauss, and the duration of the iron impurity adsorption and removal treatment is not less than 30 minutes;

[0043] The electrolytic aluminum carbon slag that has completed the iron impurity adsorption and removal treatment is crushed and ground to break the electrolytic aluminum carbon slag into electrolytic aluminum carbon slag fragments with an average particle size of 100-200 meshes.

[0044] The beneficial effects of the above technical solution are as follows: electrolytic aluminum carbon slag is formed by long-term immersion and penetration of carbon particles in the carbon anode that do not participate in the electrolytic reaction in the electrolyte environment, so that the electrolytic aluminum carbon slag will be doped with iron impurities on the surface, and these iron impurities will affect the subsequent extraction purity of cryolite. In order to avoid the influence of iron impurities on the recovery and purification of cryolite and to utilize the magnetic characteristics of iron impurities, the electrolytic aluminum carbon slag is first placed in a strong magnetic field environment and stirred at a uniform speed, so that the tiny iron impurities widely distributed inside the electrolytic aluminum carbon slag can be fully exposed to the strong magnetic field environment, thereby adsorbing and removing all iron impurities from the electrolytic aluminum carbon slag; wherein the magnetic field strength of the strong magnetic field environment is greater than or equal to 3000 Gauss, and the duration of the iron impurity adsorption and removal treatment is not less than 30 minutes, so that the iron impurities can be completely adsorbed and iron impurities can be avoided from remaining in the electrolytic aluminum carbon slag. There is also a rolling and grinding treatment for the electrolytic aluminum carbon slag that has completed the iron impurity adsorption and removal treatment. For example, the electrolytic aluminum carbon slag is repeatedly ground with a grinding roller to break the electrolytic aluminum carbon slag into electrolytic aluminum carbon slag fragments with an average particle size of 100-200 mesh. This can increase the surface area of ​​the electrolytic aluminum carbon slag, making it easier to subsequently carry out sufficient high-temperature decarbonization treatment of the electrolytic aluminum carbon slag.

[0045] Preferably, in step S1, the electrolytic aluminum carbon slag fragments are subjected to a carbon removal treatment to obtain electrolytic aluminum carbon-free waste slag material, comprising:

[0046] The electrolytic aluminum carbon slag fragments are placed in a combustion furnace, oxygen is supplied to the interior of the combustion furnace, and the carbon substances inside the electrolytic aluminum carbon slag fragments are burned and removed, thereby obtaining electrolytic aluminum carbon-free waste slag materials; the flow rate of oxygen supplied to the interior of the combustion furnace is adjusted according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace.

[0047] The beneficial effects of the above technical solution are as follows: electrolytic aluminum carbon slag is formed by long-term immersion and penetration of carbon particles in the carbon anode that do not participate in the electrolytic reaction in the electrolyte environment. Therefore, there will be a large number of tiny carbon particles in the electrolytic aluminum carbon slag fragments, which will affect the subsequent purification purity of cryolite. To this end, the electrolytic aluminum carbon slag fragments are placed in a combustion furnace, oxygen is transported into the combustion furnace, and then ignited in the combustion furnace so that the carbon substances inside the electrolytic aluminum carbon slag fragments can be burned to generate carbon dioxide and discharged from the combustion furnace, thereby achieving carbon removal of the electrolytic aluminum carbon slag fragments. The combustion efficiency inside the combustion furnace directly affects the thoroughness of the decarbonization of the electrolytic aluminum carbon slag fragments. In order to remove carbon with maximum efficiency, the flow rate of oxygen supplied to the combustion furnace is adjusted according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace. When the combustion temperature inside the combustion furnace is low or the amount of carbon dioxide discharged from the combustion furnace is small, it indicates that the carbon substances inside the electrolytic aluminum carbon slag fragments are not fully burned. At this time, the flow rate of oxygen supplied to the combustion furnace is increased to provide favorable conditions for the full combustion of the carbon substances.

[0048] Preferably, in step S1, adjusting the flow rate of oxygen delivered to the interior of the combustion furnace according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace includes:

[0049] According to the combustion temperature change data inside the combustion furnace and the carbon dioxide flow rate change data discharged from the combustion furnace, it is judged whether the carbon material inside the electrolytic aluminum carbon slag fragments is fully burned inside the combustion furnace; if so, the current flow rate of oxygen delivered to the combustion furnace is maintained unchanged; if not, the flow rate of oxygen delivered to the combustion furnace is increased.

[0050] The beneficial effect of the above technical scheme is: according to the combustion temperature change data inside the combustion furnace and the carbon dioxide flow rate change data discharged from the combustion furnace, if the combustion temperature inside the combustion furnace continues to decrease or the carbon dioxide flow rate discharged from the combustion furnace decreases, it indicates that the carbon material inside the electrolytic aluminum carbon slag fragments is not fully burned inside the combustion furnace. At this time, the flow rate of oxygen supplied to the combustion furnace is increased; otherwise, it indicates that the carbon material inside the electrolytic aluminum carbon slag fragments is fully burned inside the combustion furnace. At this time, the current flow rate of oxygen supplied to the combustion furnace is kept unchanged, which can ensure that the carbon content inside the electrolytic aluminum carbon slag fragments is fully reduced.

[0051] Preferably, in step S2, the electrolytic aluminum carbon-free waste slag is subjected to secondary crushing to obtain electrolytic aluminum carbon-free waste slag fragments, including:

[0052] The electrolytic aluminum carbon-free waste slag is subjected to secondary rolling and grinding treatment, so as to break the electrolytic aluminum carbon-free waste slag into electrolytic aluminum carbon-free waste slag fragments with an average particle size of 250-350 meshes.

[0053] The beneficial effect of the above technical scheme is: in order to fully extract the cryolite component inside the electrolytic aluminum carbon-free waste slag, the electrolytic aluminum carbon-free waste slag is subjected to secondary rolling and grinding treatment using grinding rollers, thereby breaking the electrolytic aluminum carbon-free waste slag into electrolytic aluminum carbon-free waste slag fragments with an average particle size of 250-350 mesh, which can improve the subsequent reaction efficiency.

[0054] Preferably, in step S2, the electrolytic aluminum carbon-free waste slag fragments are prepared into a slurry fluid, and then the slurry fluid is diluted and mixed into a leaching solution, including:

[0055] The electrolytic aluminum carbon-free waste slag fragments, water, a collector, and a foaming agent are uniformly mixed in a weight ratio of 10000-20000:4000-6000:8-10:3-5 to prepare a slurry fluid; wherein the collector is kerosene or diesel, and the foaming agent is methanol or camphor oil;

[0056] The slurry fluid, water and hexanol are uniformly mixed in a weight ratio of 1000-2000:20000-30000:10-12 to prepare a leaching solution.

[0057] The beneficial effects of the above technical solution are: electrolytic aluminum carbon-free waste slag fragments, water, collector, and foaming agent are uniformly mixed in a weight ratio of 10000-20000: 4000-6000: 8-10: 3-5 to prepare a slurry fluid, so that the slurry fluid can fully capture the cryolite component inside itself. In addition, the slurry fluid, water, and hexanol are uniformly mixed in a weight ratio of 1000-2000: 20000-30000: 10-12 to prepare a leaching solution, and hexanol is used as an extractant to effectively extract the cryolite component therein.

[0058] Preferably, in step S3, the leaching solution is subjected to acidification treatment and solid-liquid separation treatment, and then the solid matter precipitated in the leaching solution is extracted, comprising:

[0059] Add corresponding amounts of hydrochloric acid to the leaching solution gradually, so that the pH value of the leaching solution becomes 5-6; heat and stir the leaching solution, and then let the leaching solution stand to separate the solid and liquid inside the leaching solution; then filter the leaching solution to extract the solid matter precipitated inside the leaching solution.

[0060] The beneficial effects of the above technical solution are as follows: a corresponding amount of hydrochloric acid is added to the leaching solution in succession, so that the pH value of the leaching solution becomes 5-6, so that the inside of the leaching solution gradually becomes an acidic environment, and the leaching solution is also heated and stirred, and then the leaching solution is allowed to stand, at which time solid-liquid separation gradually occurs inside the leaching solution, and the cryolite component therein gradually settles at the bottom of the leaching solution. The leaching solution is then filtered to extract the solid matter precipitated inside the leaching solution, so that the solid matter is mainly cryolite, and the preliminary extraction of cryolite is achieved.

[0061] Preferably, in step S3, the solid material is subjected to preliminary cleaning and extraction treatment to obtain a cryolite extract, comprising:

[0062] The solid matter is repeatedly subjected to water washing treatment and extraction treatment to obtain a cryolite extract.

[0063] The beneficial effect of the above technical solution is: using pure water to repeatedly perform alternating water washing and extraction treatments on the solid matter, which can remove larger impurities inside the solid matter and ensure the purity of the obtained cryolite extract.

[0064] Preferably, in step S4, the cryolite extract is subjected to deep cleaning and drying to obtain a cryolite product, comprising:

[0065] The cryolite extract is repeatedly subjected to ultrasonic water vibration cleaning treatment and hot air drying treatment to obtain a cryolite product.

[0066] The beneficial effect of the above technical scheme is: the cryoalite extract is repeatedly subjected to alternating ultrasonic water vibration cleaning treatment and hot air drying treatment to obtain a cryoalite product, which can remove smaller-sized impurity components inside the cryoalite extract and achieve dehydration of the cryoalite extract, thereby further improving the purity of the cryoalite product.

[0067] Preferably, in step S4, the cryolite product is subjected to a melting and solidification treatment to obtain a cryolite refined product, comprising:

[0068] The cryolite product is subjected to high-temperature calcination treatment to cause the cryolite product to melt and solidify, thereby obtaining a cryolite refined product.

[0069] The beneficial effect of the above technical solution is: the cryolite product is subjected to high-temperature calcination treatment, so that the cryolite product is melted and solidified, thereby obtaining a cryolite refined product, so that all cryolite products can be polymerized and formed, and the cryolite refined product that is easy to extract can be reused in the next electrolytic aluminum production process.

[0070] It can be seen from the contents of the above embodiments that the method for separating and purifying cryolite from electrolytic aluminum carbon slag sequentially removes impurities and crushes the electrolytic aluminum carbon slag to obtain electrolytic aluminum carbon slag fragments, and removes the carbon components inside the electrolytic aluminum carbon slag fragments to obtain electrolytic aluminum carbon-free waste slag material; the electrolytic aluminum carbon-free waste slag material is secondary crushed into electrolytic aluminum carbon-free waste slag fragments, and the electrolytic aluminum carbon-free waste slag fragments are prepared into a slurry fluid, and the slurry fluid is diluted and prepared into a leaching solution; the leaching solution is acidified and solid-liquid separated to extract the solid matter precipitated therein; the solid matter is preliminarily cleaned and extracted to obtain a cryolite extract; the cryolite extract is deeply cleaned and dried to obtain a cryolite product, and then the cryolite product is melted and solidified to obtain a cryolite refined product, which can extract and recover cryolite in the electrolytic aluminum carbon slag with high efficiency and high purity, improve the reusability of cryolite, and reduce the pollution of the electrolytic aluminum carbon slag to the environment.

[0071] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for separating and purifying cryolite from electrolytic aluminum carbon slag, characterized in that: It includes the following steps: Step S1, sequentially performing impurity removal and crushing treatments on electrolytic aluminum carbon slag to obtain electrolytic aluminum carbon slag scraps; performing carbon removal treatment on the electrolytic aluminum carbon slag scraps to obtain electrolytic aluminum carbon-free waste slag material; Step S2, performing secondary crushing treatment on the electrolytic aluminum carbon-free waste slag material to obtain electrolytic aluminum carbon-free waste slag crushed material; The electrolytic aluminum carbon-free waste slag fragments are prepared into a slurry fluid, and then the slurry fluid is diluted and prepared into a leaching solution; Step S3, subjecting the leaching solution to an acidification treatment and solid-liquid separation treatment, and then extracting the solid matter precipitated in the leaching solution; performing preliminary cleaning and extraction treatments on the solid matter to obtain a cryolite extract; Step S4, performing deep cleaning and drying treatment on the cryolite extract to obtain a cryolite product; The cryolite product is subjected to a melting and solidification treatment to obtain a cryolite refined product.

2. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 1, characterized in that: In the step S1, the electrolytic aluminum carbon slag is subjected to impurity removal treatment and crushing treatment in sequence to obtain electrolytic aluminum carbon slag crushed materials, including: Placing the electrolytic aluminum carbon slag in a strong magnetic field environment for iron impurity adsorption and removal treatment, and stirring the electrolytic aluminum carbon slag at a uniform speed during the iron impurity adsorption and removal treatment; wherein the magnetic field strength of the strong magnetic field environment is greater than or equal to 3000 Gauss, and the duration of the iron impurity adsorption and removal treatment is not less than 30 minutes; The electrolytic aluminum carbon slag that has completed the iron impurity adsorption and removal treatment is crushed and ground to break it into electrolytic aluminum carbon slag fragments with an average particle size of 100-200 meshes.

3. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 2, characterized in that: In the step S1, the electrolytic aluminum carbon slag scraps are subjected to a decarbonization treatment to obtain electrolytic aluminum carbon-free waste slag material, including: The electrolytic aluminum carbon slag fragments are placed in a combustion furnace, oxygen is supplied to the interior of the combustion furnace, and the carbon substances inside the electrolytic aluminum carbon slag fragments are burned and removed, thereby obtaining electrolytic aluminum carbon-free waste slag materials; according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace, the flow rate of oxygen supplied to the interior of the combustion furnace is adjusted.

4. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 3, characterized in that: In the step S1, the flow rate of oxygen delivered to the interior of the combustion furnace is adjusted according to the combustion temperature inside the combustion furnace and the amount of carbon dioxide discharged from the combustion furnace, including: According to the combustion temperature change data inside the combustion furnace and the carbon dioxide flow rate change data discharged from the combustion furnace, it is judged whether the carbon material inside the electrolytic aluminum carbon slag fragments is fully burned inside the combustion furnace; if so, the current flow rate of oxygen delivered to the combustion furnace is maintained unchanged; if not, the flow rate of oxygen delivered to the combustion furnace is increased.

5. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 1, characterized in that: In the step S2, the electrolytic aluminum carbon-free waste slag is subjected to secondary crushing to obtain electrolytic aluminum carbon-free waste slag fragments, including: The electrolytic aluminum carbon-free waste slag material is subjected to secondary rolling and grinding treatment, so as to break the electrolytic aluminum carbon-free waste slag material into electrolytic aluminum carbon-free waste slag fragments with an average particle size of 250-350 meshes.

6. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 5, characterized in that: In the step S2, the electrolytic aluminum carbon-free waste slag is prepared into a slurry fluid, and then the slurry fluid is diluted and mixed into a leaching solution, including: The electrolytic aluminum carbon-free waste slag fragments, water, a collector, and a foaming agent are uniformly mixed in a weight ratio of 10000-20000:4000-6000:8-10:3-5 to prepare a slurry fluid; wherein the collector is kerosene or diesel, and the foaming agent is methanol or camphor oil; The slurry fluid, water and hexanol are uniformly mixed in a weight ratio of 1000-2000:20000-30000:10-12 to prepare a leaching solution.

7. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 1, characterized in that: In the step S3, the leaching solution is subjected to an acidification treatment and a solid-liquid separation treatment, and then the solid matter precipitated in the leaching solution is extracted, comprising: Add corresponding amounts of hydrochloric acid to the leaching solution in succession, so that the pH value of the leaching solution becomes 5-6; heat and stir the leaching solution, and then allow the leaching solution to stand to allow solid-liquid separation to occur inside the leaching solution; then filter the leaching solution to extract solid matter precipitated inside the leaching solution.

8. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 7, characterized in that: In the step S3, the solid material is subjected to preliminary cleaning and extraction treatment to obtain a cryolite extract, including: The solid matter is repeatedly subjected to water washing treatment and extraction treatment to obtain a cryolite extract.

9. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 1, characterized in that: In the step S4, the cryolite extract is subjected to deep cleaning and drying to obtain a cryolite product, comprising: The cryolite extract is repeatedly subjected to ultrasonic water vibration cleaning treatment and hot air drying treatment to obtain a cryolite product.

10. The method for separating and purifying cryolite from electrolytic aluminum carbon slag according to claim 9, characterized in that: In the step S4, the cryolite product is subjected to a melting and solidification treatment to obtain a cryolite refined product, comprising: The cryolite product is subjected to high-temperature calcination treatment so that the cryolite product is melted and solidified, thereby obtaining a cryolite refined product.

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