Method for comprehensive recovery of carbon, lithium, aluminum and fluorine from aluminum electrolysis carbon residue

Abstract

The application provides a method for comprehensively recovering carbon, lithium, aluminum and fluorine from aluminum electrolysis carbon residue, and belongs to the technical field of comprehensive resource utilization. The method first recovers carbon through flotation, then mixes the carbon-removed tailings with a restructuring agent, mixes the obtained mineral phase restructuring slurry with sulfuric acid, stirs and leaches, and separates solid and liquid to obtain leaching liquor and filter cake; after mixing and separating the filter cake with water, washing liquor and leaching residue are obtained; potassium sulfate is added to the leaching liquor to obtain potassium aluminum sulfate crystals and aluminum-removed liquor; lime is added to the aluminum-removed liquor, and after separation, trisodium phosphate is added to the obtained purified solution to obtain crude lithium phosphate product, which is further washed to obtain lithium phosphate product. The method has low electrolyte loss rate, high-value utilization of valuable metals, good carbon and lithium recovery effect and high comprehensive resource utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource comprehensive utilization, and particularly relates to a method for comprehensively recovering carbon, lithium, aluminum and fluorine from aluminum electrolysis carbon residue. BACKGROUND

[0002] A large amount of waste residue is generated in the electrolytic aluminum industry every year, including waste cathode, electrolyte, electrolytic cell lining, refractory bricks and carbon residue. Since the raw material used for electrolytic aluminum, alumina, contains a small amount of lithium elements, and a certain amount of lithium electrolyte is added in the production process of electrolytic aluminum, the introduced lithium elements gradually accumulate, so that the aluminum electrolysis carbon residue contains a certain amount of lithium elements, generally about 0.2-2.5%, which has a high separation and recovery value. With the continuous rise of lithium salt prices for batteries in recent years, it is of great significance to separate and recover carbon and lithium from aluminum electrolysis carbon residue, and to comprehensively recover fluorine and aluminum.

[0003] The existing application CN 115893462 A discloses a method and device for recovering electrolytic aluminum waste residue, which solves the problem that the valuable element F in the lithium-containing electrolytic aluminum residue is not effectively recovered when the existing sulfuric acid leaching method and hydrochloric acid leaching method are used to treat the lithium-containing electrolytic aluminum residue. First, the electrolytic aluminum waste residue is mixed with concentrated sulfuric acid to form a slurry material, which is then sent to a sulfuric acid roasting furnace for roasting. The generated hydrogen fluoride gas is recovered to produce hydrofluoric acid, and the generated calcine is treated and hydrolyzed. The calcine solution after hydrolysis is filtered, sodium hydroxide is added to the filtrate, and aluminum hydroxide precipitate is produced after filtration. The filtrate after filtration is continuously added with sodium carbonate, and the produced filtrate is evaporated and treated to obtain sodium sulfate. The recovered hydrofluoric acid, aluminum hydroxide and sodium sulfate are used as raw materials to prepare cryolite.

[0004] The existing application CN 112718805 A discloses a comprehensive treatment device and method for electrolytic aluminum overhaul residue, which includes the steps of sorting and crushing, wet grinding and water leaching, filtering and diaphragm electrolysis. It realizes the separate recovery and utilization of aluminum residue, carbon blocks, refractory materials and sodium fluoride.

[0005] The existing application CN 109759423 B discloses a comprehensive utilization method of aluminum electrolysis carbon residue. After the aluminum electrolysis waste carbon residue is crushed, screened and ball milled, flotation is carried out, water glass is used as a depressant, and kerosene is used as a capturing agent to obtain carbon. The electrolyte discharged from the bottom of the flotation tank is filtered to obtain a filtrate. The filtrate is further treated to obtain AlF3. It realizes the separation of carbon powder and electrolyte in aluminum electrolysis waste carbon residue, and avoids the emission of fluorine.

[0006] It can be seen that although there are many researches on comprehensive recovery of electrolytic aluminum waste residue in the prior art, the prior art does not disclose a process for simultaneously recovering carbon, lithium, aluminum and fluorine, and the existing aluminum electrolysis carbon residue recovery technology mainly directly carries out carbon flotation, and the electrolyte is not comprehensively recovered, which has the characteristics of high electrolyte loss rate, low-value utilization of valuable metals, poor recovery effect of carbon and lithium, and low comprehensive utilization rate of resources. SUMMARY

[0007] The application provides a method for comprehensive recovery of carbon, lithium, aluminum and fluorine from aluminum electrolysis carbon residue.

[0008] To solve the above-mentioned application purposes, the technical scheme provided by the application is as follows:

[0009] A method for comprehensive recovery of carbon, lithium, aluminum and fluorine from aluminum electrolysis carbon residue, comprising the following steps:

[0010] S1, carbon roughing: adding aluminum electrolysis carbon residue and water into a flotation machine at a mass ratio of 1:(2-4), and stirring uniformly to obtain carbon residue slurry; adding a dispersing agent into the carbon residue slurry and stirring for 5-10 min; then adding a collecting agent and stirring for 1-2 min; further adding 2# oil and stirring for 1-2 min; and then floating to obtain carbon rough concentrate and roughing tailings;

[0011] S2, carbon cleaning: adding a dispersing agent into the carbon rough concentrate obtained in step S1 and stirring for 5-10 min; and floating for 2-3 times to obtain carbon concentrate and carbon middlings; and returning the carbon middlings to the previous operation;

[0012] S3, scavenging: adding a collecting agent into the roughing tailings obtained in step S1 and stirring for 1-2 min; adding 2# oil and stirring for 1-2 min; and floating for 2-4 times to obtain electrolyte slurry;

[0013] S4, mixing the electrolyte slurry obtained in step S3 with a reconfiguration agent and stirring and reacting to obtain a mineral phase reconfiguration slurry;

[0014] S5, mixing the mineral phase reconfiguration slurry obtained in step S4 with sulfuric acid, stirring and leaching, and solid-liquid separation to obtain leaching liquid and filter cake;

[0015] S6, uniformly mixing the filter cake obtained in step S5 with water at a mass ratio of 1:1, stirring at room temperature for 1-2 h, and then solid-liquid separation to obtain water washing liquid and leaching residue; the water washing liquid is returned to step S1 for reuse, and the leaching residue is sold to a cement plant for use;

[0016] S7, adding potassium sulfate into the leaching liquid obtained in step S5, stirring at 60-90 DEG C for 1-2 h, then cooling to 0-10 DEG C, crystallizing, and solid-liquid separation to obtain potassium aluminum sulfate crystals and aluminum-removed liquid;

[0017] S8, adding lime to the aluminum-removed solution obtained in step S7, adjusting the pH to 10-11, and separating the solid and the liquid to obtain a purified solution and a neutralization residue 1;

[0018] S9, adding trisodium phosphate to the purified solution obtained in step S8, stirring, precipitating, and separating the solid and the liquid to obtain a lithium phosphate crude product and waste water, wherein the molar ratio of lithium ions to phosphate radicals in the purified solution is 1:(0.3-1), the precipitation temperature is 80-98℃, and the stirring time is 1-4h;

[0019] S10, washing the lithium phosphate crude product obtained in step S9 with deionized water, separating the solid and the liquid, and drying in stages to obtain a lithium phosphate product;

[0020] S11, adding lime to the waste water obtained in step S7, stirring at room temperature for 1-2h, and separating the solid and the liquid to obtain purified waste water and a neutralization residue 2; the obtained purified waste water is returned to step S1 for use.

[0021] In step S1, the lithium grade of the aluminum electrolysis carbon residue is ≥0.2%, the carbon grade is ≥3%, and the particle size of -0.10mm is 100%.

[0022] The dispersant is a mixture of sodium carbonate, sodium hexametaphosphate, sodium methylene bis naphthalene sulfonate, and sodium dioctyl sulfosuccinate in a mass ratio of 1:2:2:1;

[0023] The dispersant dosage in step S1 is 300-1000g / t;

[0024] The dispersant dosage in step S2 is 30-200g / t.

[0025] The collector is a mixture of kerosene, diesel, light wax oil, and carbon twelve in a volume ratio of 2:2:3:1;

[0026] The collector dosage in step S1 is 100-400g / t, and the 2# oil dosage is 20-50g / t;

[0027] The collector dosage in step S3 is 30-100g / t, and the 2# oil dosage is 5-20g / t.

[0028] In step S4, the reconstituting agent is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide, and the dosage is 2000-10000g / t (relative to the dosage of the aluminum electrolysis carbon residue); the reaction temperature is 80-98℃, and the reaction time is 3-6h.

[0029] In step S5, the mass concentration of sulfuric acid is 50-98%, the mass ratio of the mineral phase reconstituted ore slurry to sulfuric acid is 1:(1-4); the leaching reaction temperature is 80-98℃, and the stirring time is 1-4h.

[0030] The amount of potassium sulfate in the step S7 ensures that the molar ratio of potassium ions to aluminum ions is 1:(0.5-1).

[0031] The step S7 is replaced by: adding lime to the leaching solution obtained in step S5, stirring at room temperature, adjusting the pH to 5-5.5, and solid-liquid separation to obtain aluminum hydroxide and an aluminum-removed liquid.

[0032] The mass ratio of the lithium phosphate crude product to deionized water in the step S10 is 1:1, the washing temperature is 80-98°C, and the drying is performed in three stages at 60°C, 85°C and 110°C, respectively, and each drying time is 1h.

[0033] The molar ratio of phosphate in the wastewater to calcium ions in the lime in the step S11 is 1:(0.5-1.5).

[0034] The neutralized slag 1 and the neutralized slag 2 obtained above are transported to a cement plant for use.

[0035] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0036] The above scheme has the characteristics of low electrolyte loss rate, high-value utilization of valuable metals, good carbon and lithium recovery effect, and high resource comprehensive utilization rate.

[0037] (1) The present application can realize efficient dispersion of electrolyte (cryolite) by adding a combination of dispersants such as sodium carbonate, sodium hexametaphosphate, sodium methylene bis naphthalene sulfonate, and sodium dioctyl sulfosuccinate; and can realize selective collection of carbon by adding a combination of collectors such as kerosene, diesel oil, light wax oil, and carbon twelve, thereby reducing the entrainment loss of cryolite, improving the quality of carbon concentrate, and further improving the economic benefits of enterprises, with the characteristics of high-quality carbon concentrate, good recovery effect, and low electrolyte loss rate.

[0038] (2) The present application can realize efficient recovery of lithium by adding a restructuring agent to the electrolyte (cryolite) obtained after flotation of carbon, converting lithium that is difficult to dissolve directly by acid into lithium that is easily soluble in acid under strong alkaline conditions, and further through sulfuric acid leaching, neutralization and impurity removal, and sodium phosphate precipitation.

[0039] (3) In the present application, the addition of a restructuring agent to the overhaul slag can destroy the structure of lithium under the strong alkaline conditions of calcium hydroxide, converting lithium that is difficult to dissolve in acid into lithium that is easily soluble in acid, and the excess calcium ions can react with fluoride ions to form calcium fluoride precipitate, and the components of the leaching residue are mainly calcium fluoride and calcium sulfate, which can be sold as cement raw material; the leaching solution can be used to recover aluminum by low-temperature crystallization or hydrolysis, and the aluminum is recovered in the form of potassium aluminum sulfate or aluminum hydroxide, with the characteristics of high-value utilization of valuable metals and high resource comprehensive utilization rate.

[0040] (4) The present application can realize efficient recovery of carbon and lithium and comprehensive utilization of fluorine, aluminum and other resources through selective carbon removal, mineral phase reconstruction, sulfuric acid leaching, comprehensive aluminum recovery, neutralization and impurity removal, chemical precipitation and other processes. Carbon is recovered in the form of carbon concentrate, with a carbon grade of more than 20% and a carbon recovery rate of more than 90%, and an ice crystal loss rate of less than 1%; lithium is recovered in the form of lithium phosphate, with a lithium phosphate product purity of more than 98% and a lithium recovery rate of more than 90%. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described below in conjunction with embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0042] The present application provides a method for comprehensive recovery of carbon, lithium, aluminum and fluorine from aluminum electrolysis carbon residue.

[0043] The method comprises the following steps:

[0044] S1, carbon roughing: aluminum electrolysis carbon residue and water are added to a flotation machine in a mass ratio of 1:(2-4), and stirred uniformly to obtain carbon residue slurry; a dispersing agent is added to the carbon residue slurry and stirred for 5-10 min; then a collector is added and stirred for 1-2 min; 2# oil is added and stirred for 1-2 min; and flotation is performed to obtain carbon rough concentrate and roughing tailings;

[0045] S2, carbon cleaning: a dispersing agent is added to the carbon rough concentrate obtained in step S1 and stirred for 5-10 min, and flotation is performed 2-3 times to obtain carbon concentrate and carbon middlings; the carbon middlings are returned to the previous operation;

[0046] S3, scavenging: a collector is added to the roughing tailings obtained in step S1 and stirred for 1-2 min; 2# oil is added and stirred for 1-2 min; and flotation is performed 2-4 times to obtain electrolyte slurry;

[0047] S4, the electrolyte slurry obtained in step S3 is mixed with a reconstruction agent and stirred to react to obtain a mineral phase reconstruction slurry;

[0048] S5, the mineral phase reconstruction slurry obtained in step S4 is mixed with sulfuric acid, stirred for leaching, and solid-liquid separation is performed to obtain a leaching solution and a filter cake;

[0049] S6, the filter cake obtained in step S5 is mixed with water in a mass ratio of 1:1, stirred at room temperature for 1-2 h, and solid-liquid separation is performed to obtain a water washing solution and a leaching residue; the water washing solution is returned to step S1 for reuse, and the leaching residue is sold to a cement plant for use;

[0050] S7, potassium sulfate is added to the leaching solution obtained in step S5, stirred at 60-90°C for 1-2 h, then cooled to 0-10°C, crystallized, and solid-liquid separation is performed to obtain potassium aluminum sulfate crystals and an aluminum-removed solution;

[0051] S8, lime is added to the aluminum-removed solution obtained in step S7, and the pH is adjusted to 10-11, and solid-liquid separation is performed to obtain a purified solution and a neutralization residue 1;

[0052] S9, trisodium phosphate is added to the purified solution obtained in step S8, stirred, precipitated, and solid-liquid separation is performed to obtain a lithium phosphate crude product and wastewater, wherein the molar ratio of lithium ions to phosphate in the purified solution and trisodium phosphate is 1:(0.3-1), the precipitation temperature is 80-98°C, and the stirring time is 1-4 h;

[0053] S10, the lithium phosphate crude product obtained in step S9 is washed with deionized water, solid-liquid separation is performed, and gradient drying is performed to obtain a lithium phosphate product;

[0054] S11, lime is added to the wastewater obtained in step S7, stirred at room temperature for 1-2 h, and solid-liquid separation is performed to obtain a purified wastewater and a neutralization residue 2; the purified wastewater obtained is returned to step S1 for use.

[0055] The following will be described in conjunction with specific examples.

[0056] Example 1

[0057] For a certain electrolytic aluminum carbon residue, the lithium grade is 0.22%, the carbon grade is 3.5%, and the fineness is 100% to -0.10 mm, and the carbon, lithium, aluminum, and fluorine are comprehensively recovered by the following process.

[0058] S1, carbon roughing: aluminum electrolytic carbon residue and water are added to a flotation machine in a mass ratio of 1:2, stirred uniformly, and a carbon residue slurry is obtained; a dispersant obtained by mixing sodium carbonate, sodium hexametaphosphate, sodium methylene bisnaphthalene sulfonate, and sodium dioctyl sulfosuccinate in a mass ratio of 1:2:2:1 is added to the carbon residue slurry, and stirred for 6 min; then a collector obtained by mixing kerosene, diesel oil, light wax oil, and carbon twelve in a volume ratio of 2:2:3:1 is added, stirred for 2 min; then 2# oil is added, stirred for 2 min; and flotation is performed to obtain a carbon rough concentrate and a roughing tailing; wherein the dispersant dosage is 500 g / t, the collector dosage is 200 g / t, and the 2# oil dosage is 30 g / t;

[0059] S2, carbon concentrate: add the same component dispersant to the carbon rough concentrate obtained in step S1, stir for 6 min, float for 2 times, obtain carbon concentrate and carbon middlings; carbon middlings return to the previous operation; wherein, the amount of dispersant is 100 g / t;

[0060] S3, cleaning: add the same component collector to the roughing tailings obtained in step S1, stir for 2 min; add 2# oil, stir for 2 min; float for 2 times, obtain carbon removal tailings, i.e. electrolyte slurry; wherein, the amount of collector is 50 g / t, and the amount of 2# oil is 10 g / t;

[0061] S4, mix the carbon removal tailings obtained in step S3 with the restructuring agent sodium hydroxide, stir uniformly, and react at 85℃ for 4h to obtain a mineral phase restructuring slurry; wherein, the amount of restructuring agent is 2000 g / t;

[0062] S5, mix the mineral phase restructuring slurry obtained in step S4 with 60% mass concentration sulfuric acid in a mass ratio of 1:2, stir and leach, solid-liquid separation, obtain leaching liquid and filter cake; wherein, the leaching reaction temperature is 85℃, and the stirring time is 2h;

[0063] S6, mix the filter cake obtained in step S5 with water in a mass ratio of 1:1, stir at room temperature for 1h, solid-liquid separation, obtain water washing liquid and leaching residue; the water washing liquid is returned to step S1 for reuse, and the leaching residue is sold to a cement plant for use;

[0064] S7, add potassium sulfate to the leaching liquid obtained in step S5, ensure the molar ratio of potassium ion to aluminum ion is 1:0.5, stir at 80℃ for 1h, then cool to 4℃, crystallize, solid-liquid separation, obtain potassium aluminum sulfate crystals and aluminum-removed liquid;

[0065] S8, add lime to the aluminum-removed liquid obtained in step S7, adjust the pH to 10, solid-liquid separation, obtain purified solution and neutralization residue 1;

[0066] S9, add trisodium phosphate to the purified solution obtained in step S8, stir, precipitate, solid-liquid separation, obtain lithium phosphate crude product and wastewater, wherein, the molar ratio of lithium ion to phosphate in the purified solution and trisodium phosphate is 1:0.5, the precipitation temperature is 85℃, and the stirring time is 2h;

[0067] S10, wash the lithium phosphate crude product obtained in step S9 with deionized water, the mass ratio of lithium phosphate crude product to deionized water is 1:1, the washing temperature is 85℃, solid-liquid separation, and the product is obtained by gradient drying at 60℃, 85℃ and 110℃ for 1h each time;

[0068] S11, lime is added to the wastewater obtained in step S7, to ensure that the molar ratio of phosphate in the wastewater to calcium ions in the lime is 1:0.8, and stirring is performed at room temperature for 2 h, followed by solid-liquid separation, to obtain purified wastewater and neutralization residue 2.

[0069] After the above steps, the product obtained is recovered in the form of carbon concentrate, with a carbon grade of 22% and a carbon recovery rate of 93%, and a cryolite loss rate of less than 1%; lithium is recovered in the form of lithium phosphate, with a lithium phosphate product purity of 98.5% and a lithium recovery rate of 93%.

[0070] Example 2

[0071] For a certain electrolytic aluminum carbon residue, the lithium grade is 0.25%, and the carbon grade is 4.8%, which is ground to 100% passing -0.10 mm, and the carbon, lithium, aluminum, and fluorine are comprehensively recovered by the following process.

[0072] S1, carbon roughing: the aluminum electrolysis carbon residue and water are added to a flotation machine at a mass ratio of 1:3, and stirred uniformly to obtain a carbon residue slurry; a dispersing agent obtained by mixing sodium carbonate, sodium hexametaphosphate, sodium methylene bisnaphthalene sulfonate, and sodium dioctyl sulfosuccinate at a mass ratio of 1:2:2:1 is added to the carbon residue slurry, and stirred for 8 min; then a collector obtained by mixing kerosene, diesel oil, light wax oil, and carbon twelve at a volume ratio of 2:2:3:1 is added, and stirred for 2 min; then 2# oil is added, and stirred for 2 min; flotation is performed to obtain a carbon rough concentrate and a roughing tailing; wherein the dispersing agent dosage is 800 g / t, the collector dosage is 200 g / t, and the 2# oil dosage is 30 g / t;

[0073] S2, carbon cleaning: the same component dispersing agent is added to the carbon rough concentrate obtained in step S1, and stirred for 8 min; flotation is performed twice to obtain a carbon concentrate and a carbon middling; the carbon middling is returned to the previous operation; wherein the dispersing agent dosage is 80 g / t;

[0074] S3, scavenging: the same component collector is added to the roughing tailing obtained in step S1, and stirred for 2 min; 2# oil is added, and stirred for 2 min; flotation is performed twice to obtain a carbon-removed tailing, i.e., an electrolyte slurry; wherein the collector dosage is 60 g / t, and the 2# oil dosage is 8 g / t;

[0075] S4, the carbon-removed tailing obtained in step S3 is mixed with a restructuring agent sodium hydroxide, and stirred uniformly, and a mineral phase restructuring slurry is obtained by reacting at 90°C for 4 h; wherein the restructuring agent dosage is 8000 g / t;

[0076] S5, the mineral phase restructuring slurry obtained in step S4 is mixed with 80% sulfuric acid at a mass ratio of 1:3, and stirred for leaching, and solid-liquid separation is performed to obtain a leaching solution and a filter cake; wherein the leaching reaction temperature is 90°C, and the stirring time is 2 h;

[0077] S6, the filter cake obtained in step S5 is mixed with water at a mass ratio of 1:1, stirred at room temperature for 1 h, and solid-liquid separation is performed to obtain a water washing solution and a leaching residue; the water washing solution is returned to step S1 for reuse, and the leaching residue is sold to a cement plant for use;

[0078] S7, potassium sulfate is added to the leaching solution obtained in step S5 to ensure that the molar ratio of potassium ions to aluminum ions is 1:1, stirring is performed at 60°C for 1 h, and then the temperature is lowered to 2°C, crystallization is performed, and solid-liquid separation is performed to obtain potassium aluminum sulfate crystals and an aluminum-removed solution;

[0079] S8, lime is added to the aluminum-removed solution obtained in step S7, and the pH is adjusted to 11, and solid-liquid separation is performed to obtain a purified solution and a neutralization residue 1;

[0080] S9, trisodium phosphate is added to the purified solution obtained in step S8, stirring is performed, precipitation is performed, and solid-liquid separation is performed to obtain a lithium phosphate crude product and wastewater, wherein the molar ratio of lithium ions to phosphate radicals in the purified solution and trisodium phosphate is 1:0.5, the precipitation temperature is 90°C, and the stirring time is 1.5 h;

[0081] S10, the lithium phosphate crude product obtained in step S9 is washed with deionized water, the mass ratio of the lithium phosphate crude product to deionized water is 1:1, the washing temperature is 90°C, solid-liquid separation is performed, and gradient drying is performed at 60°C, 85°C and 110°C, each time for 1 h, to obtain a lithium phosphate product;

[0082] S11, lime is added to the wastewater obtained in step S7 to ensure that the molar ratio of phosphate radicals in the wastewater to calcium ions in the lime milk is 1:0.8, stirring is performed at room temperature for 2 h, and solid-liquid separation is performed to obtain a purified wastewater and a neutralization residue 2.

[0083] After the above steps, in the obtained product, carbon is recovered in the form of carbon concentrate, the carbon grade reaches 25%, the carbon recovery rate reaches 92.4%, and the loss rate of cryolite is less than 1%; lithium is recovered in the form of lithium phosphate, the purity of the lithium phosphate product reaches 98.6%, and the lithium recovery rate reaches 94%.

[0084] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for the comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag, characterized in that, The steps include the following: S1. Coal roughing: Add aluminum electrolysis carbon slag and water to a flotation machine at a mass ratio of 1:(2~4), stir evenly to obtain carbon slag slurry; add dispersant to the carbon slag slurry and stir for 5~10 min; then add collector and stir for 1~2 min; then add No. 2 oil and stir for 1~2 min; float to obtain carbon rough concentrate and roughing tailings; S2, Carbon Refinement: Add dispersant to the carbon rough concentrate obtained in step S1, stir for 5-10 minutes, and float 2-3 times to obtain carbon concentrate and carbon middlings; return the carbon middlings to the previous operation; S3, Scavenging: Add collector to the roughing tailings obtained in step S1 and stir for 1-2 minutes; add No. 2 oil and stir for 1-2 minutes; float 2-4 times to obtain electrolyte slurry; S4. Mix the electrolyte slurry obtained in step S3 with the reconstructing agent, stir and react to obtain the mineral phase reconstructing slurry; S5. Mix the mineral phase reconstruction slurry obtained in step S4 with sulfuric acid, stir and leach, and separate the solid and liquid to obtain leachate and filter cake. S6. Mix the filter cake obtained in step S5 with water at a mass ratio of 1:1, stir at room temperature for 1-2 hours, and separate the solid and liquid to obtain a washing liquid and a leaching residue. The washing liquid is returned to step S1 for reuse, and the leaching residue is sold to a cement plant for use. S7. Add potassium sulfate to the leachate obtained in step S5, stir at 60~90℃ for 1~2h, then cool to 0~10℃, crystallize, separate solid and liquid to obtain potassium aluminum sulfate crystals and aluminum-removed liquid. S8. Add lime to the aluminum-removed liquid obtained in step S7, adjust the pH to 10-11, separate the solid and liquid, and obtain the purified solution and neutralized residue 1. S9. Add trisodium phosphate to the purified solution obtained in step S8, stir, precipitate, and separate solid and liquid to obtain crude lithium phosphate product and wastewater. The molar ratio of lithium ions to trisodium phosphate ions in the purified solution is 1:(0.3~1), the precipitation temperature is 80~98℃, and the stirring time is 1~4h. S10. Wash the crude lithium phosphate product obtained in step S9 with deionized water, separate the solid and liquid, and dry it in stages to obtain the lithium phosphate product. S11. Add lime to the wastewater obtained in step S9 and stir at room temperature for 1-2 hours to separate the solid and liquid, obtaining purified wastewater and neutralization residue 2; the obtained purified wastewater is returned to step S1 for use. The dispersant is a mixture of sodium carbonate, sodium hexametaphosphate, sodium methylene bis(naphthalene) sulfonate, and sodium dioctyl sulfosuccinate in a mass ratio of 1:2:2:

1. The collector is a mixture of kerosene, diesel oil, light wax oil, and C12 in a volume ratio of 2:2:3:

1.

2. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S1, the lithium grade in the aluminum electrolysis carbon slag is ≥0.2%, the carbon grade is ≥3%, and the particle size of -0.10mm accounts for 100%.

3. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, The amount of dispersant used in step S1 is 300~1000g / t; The amount of dispersant used in step S2 is 30~200g / t.

4. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S1, the amount of collector used is 100~400g / t, and the amount of No. 2 oil used is 20~50g / t; In step S3, the amount of collector used is 30~100g / t, and the amount of No. 2 oil used is 5~20g / t.

5. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S4, the reconstitution agent is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide, and its dosage is 2000~10000 g / t; the reaction temperature is 80~98℃, and the reaction time is 3~6 h.

6. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S5, the mass concentration of sulfuric acid is 50-98%, the mass ratio of mineral phase reconstruction slurry to sulfuric acid is 1:(1-4), the leaching reaction temperature is 80-98℃, and the stirring time is 1-4h.

7. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S7, the amount of potassium sulfate used is such that the molar ratio of potassium ions to aluminum ions is 1:(0.5~1).

8. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S7, lime is added to the leachate obtained in step S5, stirred at room temperature, and the pH is adjusted to 5-5.

5. Solid-liquid separation is performed to obtain aluminum hydroxide and aluminum-removed liquid.

9. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S10, the mass ratio of crude lithium phosphate to deionized water is 1:1, the washing temperature is 80~98℃, and the drying is carried out in three stages at temperatures of 60℃, 85℃ and 110℃, with each drying time being 1 hour.

10. The method for comprehensive recovery of carbon, lithium, aluminum, and fluorine from aluminum electrolysis slag according to claim 1, characterized in that, In step S11, the molar ratio of phosphate ions to calcium ions in the wastewater is 1:(0.5~1.5).