Method for recycling battery material black powder

Abstract

The application provides a method for recycling battery material black powder, and relates to the field of solid waste recycling. The method comprises the following steps: mixing raw materials including battery material black powder and a reducing agent, roasting the mixed raw materials, then performing acid leaching on the roasting product, and performing solid-liquid separation to obtain a crude lithium sulfate solution and an acid leaching residue; performing heavy treatment on the crude lithium sulfate solution after impurity removal, and performing solid-liquid separation to obtain a heavy treatment residue and a heavy treatment liquid; performing concentration crystallization on the heavy treatment liquid, and performing solid-liquid separation to obtain sodium sulfate and a lithium precipitation mother liquor; performing lithium precipitation reaction on the lithium precipitation mother liquor by using sodium carbonate, performing solid-liquid separation to obtain crude lithium carbonate and a lithium precipitation liquid, and performing post-treatment on the crude lithium carbonate to obtain battery-grade lithium carbonate; performing lithium precipitation reaction on the lithium precipitation liquid by using sodium phosphate, performing solid-liquid separation to obtain lithium phosphate and a sodium sulfate waste liquid, performing post-treatment on the lithium phosphate to obtain battery-grade iron phosphate, and treating the sodium sulfate waste liquid to obtain sodium sulfate. The method provided by the application can realize effective recycling of battery material black powder.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid waste recycling, and in particular to a method for recycling and processing battery material black powder. BACKGROUND

[0002] With the rapid development of the new energy field, the peak of the scrap of lithium-ion power batteries is gradually coming, and the recycling of waste lithium-ion power batteries is increasingly prominent. Recycling battery material black powder can not only bring great environmental benefits, but also bring good economic and social benefits.

[0003] At present, the mainstream recycling process of waste ternary lithium-ion batteries is to recover nickel, cobalt and manganese first, and then recover lithium. This process has the disadvantages of high lithium recovery cost, low lithium product purity, high equipment requirement, wide occupation area, large amount of waste water salt discharge, waste residue as hazardous waste, and bloated public auxiliary configuration. In order to further reduce the production cost in the process of recovering nickel, cobalt and lithium metal and improve the operating efficiency, it is imperative to develop a process for high-value recycling of metals from battery material black powder. SUMMARY

[0004] The purpose of the present application is to provide a method for recycling and processing battery material black powder to solve the above problems.

[0005] To achieve the above purpose, the following technical scheme is adopted in the present application:

[0006] A method for recycling and processing battery material black powder, comprising:

[0007] Mixing raw materials including battery material black powder and a reducing agent, then roasting, and then acid leaching the roasting product to obtain a crude lithium sulfate solution and an acid leaching residue through solid-liquid separation; the acid leaching residue is used for metal recovery;

[0008] The crude lithium sulfate solution is purified and impurities are removed, then subjected to heavy treatment, and solid-liquid separation is performed to obtain a heavy post-liquid and a heavy residue, the heavy residue is used for metal recovery; the heavy post-liquid is concentrated and crystallized, and solid-liquid separation is performed to obtain sodium sulfate and a lithium precipitation mother liquor;

[0009] The lithium precipitation mother liquor is subjected to a first lithium precipitation reaction using sodium carbonate, and solid-liquid separation is performed to obtain crude lithium carbonate and a lithium precipitation post-liquid, and the crude lithium carbonate is subjected to a first post-treatment to obtain battery-grade lithium carbonate;

[0010] The lithium precipitation post-liquid is subjected to a second lithium precipitation reaction using sodium phosphate, and solid-liquid separation is performed to obtain lithium phosphate and a sodium sulfate waste liquid, and the lithium phosphate is subjected to a second post-treatment to obtain battery-grade iron phosphate, and the sodium sulfate waste liquid is treated to obtain sodium sulfate.

[0011] Preferably, the reducing agent includes waste residue with reducing property;

[0012] Preferably, the waste residue with reducing property comprises one or more of coconut shell activated carbon, carbon-containing leaching residue, and hazardous waste activated carbon.

[0013] Preferably, the carbon-containing leaching residue is used after being subjected to flotation and mechanical activation.

[0014] Preferably, the hazardous waste activated carbon is used after being subjected to gravity oil removal and acid washing regeneration.

[0015] Preferably, the amount of the reducing agent is 5% to 15% of the mass of the battery material black powder.

[0016] Preferably, the calcination is performed under inert gas protection, the heating rate of the calcination is 5 to 10℃ / min, the highest temperature is 600℃ to 900℃, and the time is 1h to 4h.

[0017] Preferably, the calcination product is crushed and passed through a 100 to 300 mesh screen before the acid leaching.

[0018] Preferably, the acid leaching is performed using a mixed solution of water and concentrated sulfuric acid.

[0019] Preferably, the liquid-solid ratio of the mixed solution to the calcination product is (4 to 8)mL:1g.

[0020] Preferably, the initial pH of the acid leaching system is 5 to 7, and concentrated sulfuric acid is added during the acid leaching process to maintain the pH of the system at 5 to 7.

[0021] Preferably, the temperature of the acid leaching is 50℃ to 80℃, and the time is 1h to 3h.

[0022] Preferably, the purification and impurity removal is performed using a purification and impurity removal agent.

[0023] Preferably, the purification and impurity removal agent comprises one or more of a phosphorus removal agent, a fluorine removal agent, a resin, and activated carbon.

[0024] Preferably, the amount of the purification and impurity removal agent used is 3% to 10% of the mass of the crude lithium sulfate solution.

[0025] Preferably, during the purification and impurity removal process, the pH of the system is 2 to 6.

[0026] Preferably, the heavy precipitation treatment is performed using a heavy precipitation agent.

[0027] Preferably, the heavy precipitation agent comprises sodium hydroxide and / or sodium carbonate; preferably a mixture of sodium hydroxide and sodium carbonate.

[0028] Preferably, the amount of the heavy precipitation agent used is 1 to 1.5 times the theoretical amount.

[0029] Preferably, the temperature of the heavy treatment is 40-80℃, and the pH of the system is 10-12.

[0030] Preferably, the pH of the heavy treatment liquid is adjusted to 6-8 before the concentration crystallization.

[0031] Preferably, the temperature of the concentration crystallization is 60-200℃.

[0032] Preferably, the amount of sodium carbonate used in the first lithium precipitation reaction is 1-1.5 times the theoretical amount.

[0033] Preferably, the temperature of the first lithium precipitation reaction is 60-90℃.

[0034] Preferably, the first post-treatment includes carbonization impurity removal, heating decomposition, and centrifugal drying of the crude lithium carbonate.

[0035] Preferably, the amount of sodium phosphate used in the second lithium precipitation reaction is 1.1-1.3 times the theoretical amount.

[0036] Preferably, the temperature of the second lithium precipitation reaction is 40-70℃.

[0037] Preferably, the second post-treatment includes:

[0038] The lithium phosphate and water are mixed and slurried, then mixed with iron sulfate, and after reaction, solid-liquid separation is performed, the obtained solid is reacted with sodium phosphate, and calcination treatment obtains battery-grade iron phosphate, and the liquid is a lithium sulfate solution, which is returned to the heavy treatment liquid for recycling;

[0039] Preferably, the liquid-solid ratio of the water and the lithium phosphate is (7-14) mL:1 g.

[0040] Preferably, the amount of iron sulfate used is 1.2-1.6 times the theoretical amount.

[0041] Preferably, the reaction time with iron sulfate is 2-4 h.

[0042] Preferably, the temperature of the reaction of the solid with the sodium phosphate is 60-150℃, and the time is 2-6 h.

[0043] Compared with the prior art, the application has the following beneficial effects:

[0044] The method for recycling and treating battery material black powder provided by the application realizes the separation of lithium sulfate and acid leaching residue through roasting in the presence of a reducing agent and acid leaching, and lithium and other valuable metals can be recycled respectively, wherein the application can effectively treat solid waste residue by regenerating the waste reducing agent, and the economy and environmental protection of the overall process are improved; the separation of valuable metals, sodium sulfate and lithium precipitation mother liquor is realized through heavy treatment and concentration crystallization, wherein the application can effectively improve the lithium recovery rate by using a mixture of sodium carbonate and sodium hydroxide as a heavy agent, and the waste of sodium can be reduced and the quality of lithium products can be improved by separating sodium sulfate; lithium precipitation reaction and post-treatment are carried out in turn by using sodium carbonate and sodium phosphate, battery-grade lithium carbonate and battery-grade iron phosphate are obtained at the same time, and sodium sulfate is obtained from waste liquid; the method combines pyrometallurgical process and hydrometallurgical process, improves the lithium recovery rate, can obtain various by-products, reasonably utilizes the reducing waste residue, has less waste, and is low in cost and more green and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope of the application.

[0046] Figure 1 The process flow diagram of the method for recycling and treating battery material black powder provided by the embodiments. DETAILED DESCRIPTION

[0047] As used herein the term "about" when used before a numerical designation, including a range of values, includes the numerical indication and approximations thereof as would be understood by persons of ordinary skill in the art to which the application pertains. If the numerical value is preceded by the term "about" it represents an approximation to the numerical value stated. If the numerical value is preceded by only the term "about" it represents a measurement that varies by less than 10% from the numerical value stated.

[0048] "Made from" is synonymous with "comprising". The terms "comprising", "including", "having" and "including" or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0049] The conjunction "consisting of" excludes any unrecited elements, steps, or components. If used in the claims, this phrase will close the claims to the inclusion of materials not specifically recited. When the phrase "consisting of" appears in the body of a claim, it defines the subject matter of the claim, but does not exclude additional unrecited materials that are inherent in the claim subject matter. When the phrase "consisting of" follows the introductory language "a composition comprising," it defines the scope of the claim based on the recited elements, but does not exclude additional unrecited materials that are inherent in the claim subject matter.

[0050] When expressing amounts, concentrations, or other values or parameters of a substance in a range, preferably a range, or a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pair of an upper limit or preferred value and a lower limit or preferred value, whether or not the range is expressly disclosed, are specifically disclosed. For example, when a range "1-5" is disclosed, the described range should be interpreted to include the range "1-4," "1-3," "1-2," "1-2 and 4-5," "1-3 and 5," etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include the end values and all integers and fractions within that range.

[0051] In these embodiments, the parts and percentages described are by mass, unless otherwise indicated.

[0052] "Mass parts" refers to a basic unit of measurement that represents the mass ratio relationship of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass parts of component A is a parts, and the mass parts of component B is b parts, it means that the mass ratio of component A to component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0053] "And / or" is used to indicate that one or both of the described conditions can occur, for example, A and / or B includes (A and B) and (A or B).

[0054] A method for recycling battery material black powder, comprising:

[0055] After mixing raw materials including battery material black powder and a reducing agent, roasting is performed, and then the roasting product is subjected to acid leaching, and solid-liquid separation to obtain a crude lithium sulfate solution and an acid leaching residue; the acid leaching residue is used for recycling metals;

[0056] After purification and impurity removal of the crude lithium sulfate solution, heavy treatment is performed, and solid-liquid separation is performed to obtain a heavy treatment residue and a heavy treatment liquid, the heavy treatment residue is used for recycling metals; the heavy treatment liquid is subjected to concentration and crystallization, and solid-liquid separation to obtain sodium sulfate and a lithium precipitation mother liquor;

[0057] The lithium precipitation mother liquor is subjected to a first lithium precipitation reaction using sodium carbonate, and solid-liquid separation to obtain crude lithium carbonate and a lithium precipitation liquid, and the crude lithium carbonate is subjected to a first post-treatment to obtain battery-grade lithium carbonate;

[0058] The lithium precipitation liquid is subjected to a second lithium precipitation reaction using sodium phosphate, and solid-liquid separation to obtain lithium phosphate and a sodium sulfate waste liquid, and the lithium phosphate is subjected to a second post-treatment to obtain battery-grade lithium phosphate, and the sodium sulfate waste liquid is treated to obtain sodium sulfate.

[0059] In an optional embodiment, the reducing agent comprises waste residue with reducing property;

[0060] In an optional embodiment, the waste residue with reducing property comprises one or more of coconut shell activated carbon, carbon-containing leaching residue, and hazardous waste activated carbon;

[0061] The use of waste residue with reducing property can effectively treat solid waste residue and hazardous waste residue, turning waste into treasure, and reducing the cost of reducing agent by more than 60%.

[0062] In an optional embodiment, the carbon-containing leaching residue is used after being floated and mechanically activated;

[0063] In an optional embodiment, the hazardous waste activated carbon is used after being regenerated by gravity oil removal and acid pickling;

[0064] In an optional embodiment, the amount of the reducing agent is 5%-15% of the mass of the battery material black powder.

[0065] Optionally, the amount of the reducing agent can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any value between 5% and 15% of the mass of the battery material black powder.

[0066] In an optional embodiment, the calcination is performed under inert gas protection, the heating rate of the calcination is 5-10°C / min, the highest temperature is 600-900°C, and the time is 1-4h.

[0067] Optionally, the heating rate of the calcination can be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, or any value between 5°C / min and 10°C / min, the highest temperature can be 600°C, 700°C, 800°C, 900°C, or any value between 600°C and 900°C, and the time can be 1h, 2h, 3h, 4h, or any value between 1h and 4h.

[0068] In an optional embodiment, the calcination product is crushed and passed through a 100-300 mesh screen before the acid leaching;

[0069] Optionally, the mesh number of the screen can be 100 mesh, 200 mesh, 300 mesh, or any value between 100 mesh and 300 mesh.

[0070] In an optional embodiment, the acid leaching is performed using a mixed solution of water and concentrated sulfuric acid;

[0071] In an alternative embodiment, the liquid-solid ratio of the mixed solution to the calcination product is (4-8) mL:1 g;

[0072] Alternatively, the liquid-solid ratio of the mixed solution to the calcination product can be 4 mL:1 g, 5 mL:1 g, 6 mL:1 g, 7 mL:1 g, 8 mL:1 g, or any value between 4-8 mL:1 g.

[0073] In an alternative embodiment, the initial pH of the acid leaching system is 5-7, and concentrated sulfuric acid is added during the acid leaching process to maintain the pH of the system at 5-7.

[0074] Alternatively, the initial pH of the acid leaching system and the pH during the acid leaching process are both maintained at 5, 6, 7, or any value between 5-7.

[0075] The higher the pH of the acid leaching, the closer to neutral, which will not dissolve other metals such as nickel, cobalt, and manganese, so that the resulting acid leaching solution is mainly lithium sulfate, reducing the difficulty of subsequent lithium recovery and improving the lithium recovery rate.

[0076] In an alternative embodiment, the acid leaching temperature is 50-80°C, and the time is 1-3 h.

[0077] Alternatively, the acid leaching temperature can be 50°C, 60°C, 70°C, 80°C, or any value between 50-80°C, and the time can be 1 h, 2 h, 3 h, or any value between 1-3 h.

[0078] In an alternative embodiment, the purification and impurity removal are performed using a purification and impurity removal agent.

[0079] In an alternative embodiment, the purification and impurity removal agent includes one or more of a phosphorus removal agent, a fluorine removal agent, a resin, and activated carbon, wherein the phosphorus removal agent and the fluorine removal agent are polymeric ferric sulfate and polymeric aluminum sulfate, respectively, and other calcium, magnesium, aluminum, and iron inorganic mixed salts can also be used as mixed purification agents for phosphorus and fluorine removal.

[0080] In an alternative embodiment, the amount of the purification and impurity removal agent used is 3-10% of the mass of the crude lithium sulfate solution.

[0081] Alternatively, the amount of the purification and impurity removal agent used can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between 3-10% of the mass of the crude lithium sulfate solution.

[0082] In an alternative embodiment, during the purification and impurity removal process, the pH of the system is 2-6.

[0083] Optionally, the pH of the system during the purification and impurity removal process can be 2, 3, 4, 5, 6, or any value between 2 and 6.

[0084] In an optional embodiment, the heavy treatment uses a heavy agent.

[0085] In an optional embodiment, the heavy agent comprises sodium hydroxide and / or sodium carbonate; preferably a mixture of sodium hydroxide and sodium carbonate.

[0086] Using a combination of sodium hydroxide and sodium carbonate for the purification of lithium liquid can maximize the utilization rate of the heavy agent and maximize the reduction of Li loss in the heavy process.

[0087] Using the strong alkalinity of sodium hydroxide, the solution can be pre-adjusted to a pH of about 10 with a small amount of sodium hydroxide, and then the calcium and magnesium impurity ions can be removed by a small amount of sodium carbonate. The amount of precipitation in the entire process is small, which can significantly reduce the loss of Li caused by entrainment of precipitation. If only sodium hydroxide is used to adjust the pH value, the strong alkalinity of sodium hydroxide will cause local excessive alkalinity and generate lithium hydroxide precipitate. If only sodium carbonate is used to adjust the pH value, the alkalinity of sodium carbonate is not enough, a large amount of sodium carbonate needs to be added, which will introduce too much carbonate and form a lot of lithium carbonate precipitate, resulting in more lithium loss in the heavy process. Using a combination of sodium hydroxide and sodium carbonate as a heavy agent will not introduce new impurities, and sodium ions can be effectively recovered in the form of sodium sulfate by-product in the subsequent process, greatly improving the economic efficiency of the entire process.

[0088] In an optional embodiment, the amount of the heavy agent used is 1-1.5 times the theoretical amount.

[0089] In an optional embodiment, the temperature of the heavy treatment is 40-80°C, and the pH of the system is 10-12.

[0090] Optionally, the amount of the heavy agent used can be 1 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, or any value between 1 and 1.5 times the theoretical amount; the temperature of the heavy treatment can be 40°C, 50°C, 60°C, 70°C, 80°C, or any value between 40°C and 80°C, and the pH of the system can be 10, 11, 12, or any value between 10 and 12.

[0091] In an optional embodiment, the pH of the heavy liquid is adjusted to 6-8 before the concentration and crystallization.

[0092] In an optional embodiment, the temperature of the concentration and crystallization is 60-200°C.

[0093] Optionally, the heavy post-lithium precipitation solution is pre-adjusted to a pH of 6, 7, 8, or any value between 6 and 8 before the concentration crystallization; the concentration crystallization temperature can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, or any value between 60℃ and 200℃.

[0094] After concentration crystallization and solid-liquid separation, the lithium concentration in the lithium precipitation mother liquor is controlled at 6g / L-15g / L.

[0095] In an optional embodiment, the amount of sodium carbonate used in the first lithium precipitation reaction is 1-1.5 times the theoretical amount.

[0096] In an optional embodiment, the temperature of the first lithium precipitation reaction is 60℃-90℃.

[0097] In an optional embodiment, the first post-treatment includes: carbonizing and removing impurities, heating and decomposing, and centrifugal drying of the crude lithium carbonate to obtain battery-grade lithium carbonate, which meets the GB / T 11075-2013 standard.

[0098] Optionally, the amount of sodium carbonate used in the first lithium precipitation reaction can be 1 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, or any value between 1 and 1.5 times the theoretical amount; the temperature of the first lithium precipitation reaction can be 60℃, 70℃, 80℃, 90℃, or any value between 60℃ and 90℃.

[0099] After the first lithium precipitation reaction, the lithium concentration in the post-lithium precipitation solution is less than 3g / L.

[0100] In an optional embodiment, the amount of sodium phosphate used in the second lithium precipitation reaction is 1.1-1.3 times the theoretical amount.

[0101] In an optional embodiment, the temperature of the second lithium precipitation reaction is 40℃-70℃.

[0102] Optionally, the amount of sodium phosphate used can be 1.1 times, 1.2 times, 1.3 times, or any value between 1.1 and 1.3 times the theoretical amount; the temperature of the second lithium precipitation reaction can be 40℃, 50℃, 60℃, 70℃, or any value between 40℃ and 70℃.

[0103] After the second lithium precipitation reaction, the lithium concentration in the sodium sulfate waste solution is less than 0.3g / L.

[0104] In an optional embodiment, the second post-treatment includes:

[0105] The lithium phosphate and water are mixed and slurried, then mixed with iron sulfate, after reaction, solid-liquid separation, the solid is reacted with sodium phosphate, calcination treatment to obtain battery-grade iron phosphate, the liquid is lithium sulfate solution, which is returned to the heavy liquid after precipitation for recycling; the battery-grade iron phosphate meets the standard of HG / T 4701-2021.

[0106] In an alternative embodiment, the liquid-solid ratio of the water and the lithium phosphate is (7-14) mL: 1 g;

[0107] In an alternative embodiment, the amount of the iron sulfate is 1.2-1.6 times the theoretical value;

[0108] In an alternative embodiment, the reaction time with the iron sulfate is 2h-4h;

[0109] Preferably, the reaction temperature of the solid with the sodium phosphate is 60-150℃, and the reaction time is 2-6h.

[0110] Alternatively, the liquid-solid ratio of the water and the lithium phosphate can be 7mL: 1g, 8mL: 1g, 9mL: 1g, 10mL: 1g, 11mL: 1g, 12mL: 1g, 13mL: 1g, 14mL: 1g, or any value between (7-14) mL: 1g; the amount of the iron sulfate can be 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times the theoretical value, or any value between 1.2-1.6 times; the reaction time with the iron sulfate can be 2h, 3h, 4h, or any value between 2h-4h; the reaction temperature of the solid with the sodium phosphate can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, or any value between 60-150℃, and the reaction time can be 2h, 3h, 4h, 5h, 6h, or any value between 2-6h.

[0111] It should be noted that the theoretical amount or theoretical value described herein refers to the corresponding amount of the substance in the corresponding chemical reaction formula of the reaction.

[0112] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of the reagent or instrument is specified, it is a conventional product that can be purchased on the market.

[0113] First, the ingredients of the raw material battery black powder used in the examples and the carbon-containing leaching residue produced by the company are described, as shown in Table 1:

[0114] Table 1 Battery material black powder composition

[0115]

[0116] Table 2 Self-produced carbonaceous leaching residue

[0117]

[0118] Example 1

[0119] like Figure 1 As shown, this embodiment provides a method for recycling and processing battery material black powder, which specifically includes the following steps:

[0120] 1) Take 50g of battery material black powder and 2.5g of commonly used industrial-grade coconut shell powdered activated carbon on the market, mix them evenly, put them into a crucible, place them in a box-type atmosphere furnace under inert gas (nitrogen) protection at 600℃ for 1h to obtain a calcined product, with a heating rate of 5℃ / min. The calcined product is ground and passed through a 200-mesh sieve.

[0121] 2) 50 g of the calcined product was added to 200 mL of pure water. Concentrated sulfuric acid was added to adjust the initial solution pH to 5. The mixture was stirred at 50°C for 1 hour. During the reaction, the pH was monitored in real time and acid was added to maintain the system pH at 5 ± 0.1. After leaching, the filtrate and leaching residue were filtered. The leaching efficiency of the liquid was 93.25%, the leaching efficiency of nickel was 3.36%, the leaching efficiency of cobalt was 0.96%, and the leaching efficiency of manganese was 0.68%.

[0122] 3) The crude lithium sulfate solution obtained in 2) was added with a purifier, which was a resin, to purify and remove impurities. The amount of the purifier added was 3 wt % of the solution. After purification and impurity removal, F: 8 ppm, P: 15 ppm, Si: 8 ppm.

[0123] 4) The purified and impurity-removed liquid is weighed with sodium hydroxide solution, the weighing agent is 1.2 times the theoretical amount, the weighing temperature is 50°C, the weighing pH is 11, and the weighing reaction is filtered. The filter residue can be returned to the wet process system for precious metal recovery. The filtrate contains Ni: 8ppm, Co: 9ppm, and Mn: 3ppm.

[0124] 5) Adjust the pH of the heavy liquid to 6, evaporate and concentrate at 150°C, and filter. The filter residue is the sodium sulfate product, and the filtrate is the lithium precipitation mother liquor with a Li content of 10 g / L.

[0125] 6) The lithium precipitation mother liquor in 5) is subjected to lithium precipitation with Na2CO3, the amount of Na2CO3 added is 1.1 times the theoretical amount, and after 2 h of reaction at 60°C, filtration is performed, the filtrate is the first lithium precipitation liquid, which is sent to the next process for secondary lithium precipitation, and the filter residue is crude lithium carbonate, which is subjected to carbonization and impurity removal, heating and decomposition, and centrifugal drying to obtain battery-grade lithium carbonate.

[0126] 7) The first lithium precipitation liquid is subjected to secondary lithium precipitation by adding sodium phosphate, the amount of sodium phosphate added is 1.2 times the theoretical amount, the reaction temperature is 60°C, and after 2 h of reaction, filtration separation is performed, the filtrate is sodium sulfate wastewater with a Li content of 0.2 g / L, and the filter residue is lithium phosphate. The sodium sulfate wastewater is treated to obtain industrial-grade sodium sulfate.

[0127] 8) The lithium phosphate residue is slurried in pure water, the liquid-solid ratio is 10 mL:1 g, after a period of slurry, ferric sulfate is added, the amount of ferric sulfate added is 1.5 times the theoretical amount, and after 3 h of reaction, pressure filtration is performed, the filter residue is converted (at 60-150°C, by adding sodium phosphate for low-temperature reaction for 2-6 h to form ferric phosphate from the involved Fe ions), and calcination treatment can prepare battery-grade ferric phosphate, and the filtrate is a lithium sulfate solution which is recycled into the heavy precipitation liquid.

[0128] 9) The comprehensive recovery rate of Li is 91.69%, and the prepared lithium carbonate is a national standard battery-grade lithium carbonate.

[0129] Example 2

[0130] The present embodiment provides a method for recycling and treating battery material black powder, which specifically comprises the following steps:

[0131] 1) 50 g of battery material black powder and 3.2 g of coconut shell powder activated carbon are uniformly mixed and then loaded into a crucible, which is placed in a box-type atmosphere furnace and calcined at 900°C for 1 h under the protection of inert gas (nitrogen), and the heating rate is 5°C / min. The calcined product is ground through a 200-mesh sieve.

[0132] 2) 50 g of the calcined product is added to 250 mL of pure water, concentrated sulfuric acid is added to adjust the initial solution pH to 7, and stirring reaction is carried out at 80°C for 3 h, during which the pH is monitored in real time and the acid is supplemented in time to ensure that the system pH is maintained at 7±0.1. After leaching, the filtrate and leaching residue are obtained. The liquid lithium leaching rate is 90.69%, the nickel leaching rate is 1.67%, the cobalt leaching rate is 0.23%, and the manganese leaching rate is 0.26%.

[0133] 3) The crude lithium sulfate solution obtained in 2) is subjected to purification and impurity removal by adding a purifying agent, the purifying agent is a mixture of conventional phosphorus removal agent and fluorine removal agent, i.e. polymeric ferric sulfate and polymeric aluminum sulfate at a ratio of 1:1, the amount of purifying agent added is 10 wt% of the solution amount, and after purification and impurity removal, F: 2 ppm, P: 5 ppm, and Si: 1 ppm.

[0134] 4) The purified impurity-removed solution is subjected to heavy precipitation with sodium hydroxide solid, the amount of the precipitant is 1.2 times of the theoretical amount, the precipitation temperature is 50°C, the precipitation pH is 10.5, and after the precipitation reaction, filtration is performed, the filter residue can be returned to the wet process system for recovery of noble metals, the filter liquor contains Ni: 5 ppm, Co: 4 ppm, and Mn: 8 ppm.

[0135] 5) The solution after precipitation is adjusted to pH 6.8, concentrated by evaporation at 150°C, and filtered. The filter residue is sodium sulfate product, and the filter liquor is lithium precipitation mother liquor containing 11 g / L of Li.

[0136] 6) The lithium precipitation mother liquor in 5) is subjected to lithium precipitation with Na2CO3, the amount of Na2CO3 added is 1.1 times of the theoretical amount, and after 2 h of reaction at 70°C, filtration is performed, the filter liquor is the solution after first lithium precipitation, which is sent to the next process for second lithium precipitation, and the filter residue is crude lithium carbonate, which is subjected to carbonization and impurity removal, heating and decomposition, and centrifugal drying to obtain battery-grade lithium carbonate.

[0137] 7) The solution after first lithium precipitation is added with sodium phosphate for second lithium precipitation, the amount of sodium phosphate added is 1.2 times of the theoretical amount, the reaction temperature is 60°C, and after 2 h of reaction, filtration separation is performed, the filter liquor is sodium sulfate wastewater containing 0.2 g / L of Li, and the filter residue is lithium phosphate. The sodium sulfate wastewater is treated to obtain industrial-grade sodium sulfate.

[0138] 8) The lithium phosphate residue is slurried with pure water, the liquid-solid ratio is 10:1, after a period of slurry, ferric sulfate is added, the amount of ferric sulfate added is 1.5 times of the theoretical amount, after 3 h of reaction, pressure filtration is performed, the filter residue is treated by conversion and calcination to prepare battery-grade ferric phosphate, and the filter liquor is lithium sulfate solution which is recycled into the solution after heavy precipitation.

[0139] 9) The comprehensive recovery rate of Li is 92.23%, and the prepared lithium carbonate is battery-grade lithium carbonate according to the national standard.

[0140] Example 3

[0141] The embodiment provides a method for recycling and treating battery material black powder, and specifically comprises the following steps:

[0142] 1) 50 g of battery material black powder and 3 g of coconut shell powder activated carbon are uniformly mixed and then loaded into a crucible, which is placed in a box-type atmosphere furnace and calcined at 900°C for 3 h under the protection of inert gas (nitrogen), to obtain a calcined product, and the calcined product is ground to pass through a 200-mesh sieve.

[0143] 2) 50 g of the calcined product was added to 300 mL of pure water, concentrated sulfuric acid was added to adjust the initial solution pH to 6.5, and the reaction was stirred at 65°C for 3 h, during which the pH was monitored in real time and the acid was added in time to ensure that the system pH was maintained at 6.5 ± 0.1. After the leaching was completed, filtration was performed to obtain a filtrate and a leaching residue. The liquid-phase lithium leaching rate was 94.26%, the nickel leaching rate was 2.98%, the cobalt leaching rate was 0.22%, and the manganese leaching rate was 0.35%.

[0144] 3) The crude lithium sulfate solution obtained in 2) was added to a purification agent to remove impurities, the purification agent was prepared by mixing a conventional phosphorus removal agent and a fluorine removal agent, i.e., polymeric ferric sulfate and polymeric aluminum sulfate at a ratio of 1:1, the amount of the purification agent added was 6 wt% of the solution, and after the purification and removal of impurities, F: 3 ppm, P: 2 ppm, and Si: 3 ppm.

[0145] 4) The solution after the purification and removal of impurities was subjected to heavy precipitation with solid sodium hydroxide and solid sodium carbonate, the amount of the precipitation agent was 1.2 times the theoretical amount, the precipitation temperature was 60°C, and the precipitation pH was 11. After the precipitation reaction, filtration was performed, the filter residue could be returned to the wet system for recovery of noble metals, the filter solution contained Ni: 2 ppm, Co: 3 ppm, and Mn: 2 ppm.

[0146] 5) The solution after the precipitation was adjusted to a pH of 7, and was subjected to evaporation and concentration at a temperature of 150°C, and then was filtered. The filter residue was a sodium sulfate product, and the filter solution was a lithium precipitation mother liquor with a Li content of 10.6 g / L.

[0147] 6) The lithium precipitation mother liquor in 5) was subjected to lithium precipitation with Na2CO3, the amount of Na2CO3 added was 1.1 times the theoretical amount, and after the reaction was performed at 90°C for 2 h, filtration was performed. The filter solution was a first lithium precipitation solution, which was sent to the next process for secondary lithium precipitation, and the filter residue was a crude lithium carbonate, which was subjected to carbonization and impurity removal, heating and decomposition, and centrifugal drying to obtain a battery-grade lithium carbonate.

[0148] 7) Secondary lithium precipitation was performed on the first lithium precipitation solution by adding sodium phosphate, the amount of sodium phosphate added was 1.2 times the theoretical amount, the reaction temperature was 60°C, and after the reaction was performed for 2 h, filtration was performed to separate the filter solution and the filter residue. The filter solution was a sodium sulfate wastewater with a Li content of 0.2 g / L, and the filter residue was lithium phosphate. The sodium sulfate wastewater was treated to obtain an industrial-grade sodium sulfate.

[0149] 8) The lithium phosphate residue was slurried in pure water, the liquid-solid ratio was 10:1, ferric sulfate was added after the slurry was stirred for a period of time, the amount of ferric sulfate added was 1.5 times the theoretical amount, and after the reaction was performed for 3 h, pressure filtration was performed. The filter residue was subjected to conversion and calcination to prepare a battery-grade ferric phosphate, and the filter solution was a lithium sulfate solution which was recycled into the precipitation solution.

[0150] 9) The comprehensive recovery rate of Li was 91.02%, and the lithium carbonate prepared was a battery-grade lithium carbonate according to the national standard.

[0151] Example 4

[0152] The present embodiment provides a method for recycling battery material black powder, which specifically comprises the following steps:

[0153] 1) Take 50 g of battery material black powder and 3.5 g of coconut shell powdered activated carbon, mix them uniformly, and then load them into a crucible, which is placed in a box-type atmosphere furnace to be calcined at 850°C for 2.5 h under the protection of inert gas (nitrogen), with a heating rate of 10°C / min. The calcined product is ground through a 200-mesh sieve.

[0154] 2) Add 50 g of the calcined product to 200 mL of pure water, add concentrated sulfuric acid to adjust the initial solution pH to 5.5, and stir and react at 65°C for 2.5 h. Monitor the pH in real time during the process and promptly supplement the acid to ensure that the system pH is maintained at 5.5±0.1. After leaching, filter to obtain the filtrate and leaching residue. The liquid lithium leaching rate is 94.14%, the nickel leaching rate is 3.21%, the cobalt leaching rate is 0.68%, and the manganese leaching rate is 0.79%.

[0155] 3) Add the crude lithium sulfate solution obtained in 2) to a purification agent to remove impurities. The purification agent is a mixture of conventional phosphorus removal agent and fluorine removal agent, i.e., polymeric ferric sulfate and polymeric aluminum sulfate at a ratio of 1:1. The amount of purification agent added is 4 wt% of the solution. After purification and impurity removal, F: 4 ppm, P: 7 ppm, and Si: 6 ppm.

[0156] 4) After purification and impurity removal, the solution is subjected to heavy precipitation with sodium hydroxide solution and sodium carbonate solid. The amount of precipitation agent is 1.3 times the theoretical amount. The precipitation temperature is 50°C, and the precipitation pH is 10.5. After the precipitation reaction, filtration is performed. The filter residue can be returned to the wet system for recovery of precious metals. In the filtrate, Ni: 2 ppm, Co: 4 ppm, and Mn: 2 ppm.

[0157] 5) The pH of the solution after precipitation is adjusted to 7.5, and evaporation and concentration are performed at a temperature of 150°C, followed by filtration. The filter residue is sodium sulfate product, and the filtrate is lithium precipitation mother liquor with a Li content of 11 g / L.

[0158] 6) The lithium precipitation mother liquor in 5) is subjected to lithium precipitation with Na2CO3. The amount of Na2CO3 added is 1.1 times the theoretical amount. After reaction at 75°C for 1.5 h, filtration is performed. The filtrate is the first lithium precipitation solution, which is sent to the next process for secondary lithium precipitation. The filter residue is crude lithium carbonate, which is subjected to carbonization and impurity removal, heating and decomposition, and centrifugal drying to obtain battery-grade lithium carbonate.

[0159] 7) After the first lithium precipitation, sodium phosphate is added to the solution for the second lithium precipitation. The amount of sodium phosphate added is 1.2 times the theoretical amount, and the reaction temperature is 60°C. After 2 hours of reaction, filtration is performed to separate the solution and the residue. The solution is sodium sulfate wastewater, and the lithium content is 0.2 g / L. The residue is lithium phosphate. The sodium sulfate wastewater is treated to obtain industrial-grade sodium sulfate.

[0160] 8) The lithium phosphate residue is added to pure water for slurry. The liquid-solid ratio is 10:1. After a period of slurry, ferric sulfate is added. The amount of ferric sulfate added is 1.5 times the theoretical amount. After 3 hours of reaction, pressure filtration is performed. The residue is treated by conversion and calcination to prepare battery-grade ferric phosphate. The filtrate is a lithium sulfate solution and is recycled into the heavy solution.

[0161] 9) The comprehensive recovery rate of Li is 91.23%, and the lithium carbonate prepared is the national standard battery-grade lithium carbonate.

[0162] Example 5

[0163] The present embodiment provides a method for recycling and treating battery black powder, which specifically comprises the following steps:

[0164] 1) 50g of battery black powder and 4.5g of coconut shell powder activated carbon are mixed uniformly and then loaded into a crucible, which is placed in a box-type atmosphere furnace for calcination under the protection of inert gas (nitrogen) at 750°C for 3h to obtain a calcined product. The heating rate is 6°C / min. The calcined product is ground through a 200 mesh sieve.

[0165] 2) 50g of the calcined product is added to 400mL of pure water. Concentrated sulfuric acid is added to adjust the initial solution pH to 5.8. The solution is stirred at 65°C for 2.5h. The pH is monitored in real time during the process and the acid is added in time to ensure that the system pH is maintained at 5.8±0.1. After the leaching is completed, the filtrate and the leaching residue are obtained by filtration. The leaching rate of lithium is 94.69%, the leaching rate of nickel is 3.81%, the leaching rate of cobalt is 0.56%, and the leaching rate of manganese is 0.38%.

[0166] 3) The crude lithium sulfate solution obtained in 2) is added to a purification agent to remove impurities. The purification agent is a mixture of conventional phosphorus removal agent and fluorine removal agent, i.e. polymeric ferric sulfate and polymeric aluminum sulfate at a ratio of 1:1. The amount of purification agent added is 4wt% of the solution. After purification and impurity removal, F: 4ppm, P: 7ppm, Si: 6ppm.

[0167] 4) The purified and impurity-removed solution is precipitated with sodium hydroxide solution and sodium carbonate solid. The amount of precipitant is 1.1 times the theoretical amount. The precipitation temperature is 50°C, and the precipitation pH is 10.2. After the precipitation reaction, filtration is performed. The residue can be returned to the wet system for recovery of precious metals. In the filtrate, Ni: 3ppm, Co: 8ppm, Mn: 2ppm.

[0168] 5) The heavy post-liquid is adjusted to pH 8 and evaporated at 150°C to concentrate and filter. The filter residue is sodium sulfate product, and the filtrate is lithium sink mother liquor with Li content of 11.2 g / L.

[0169] 6) The lithium sink mother liquor in 5) is subjected to lithium sinking with Na2CO3, and the amount of Na2CO3 added is 1.1 times the theoretical amount. After reacting at 60°C for 0.5 h, filtration is performed, and the filtrate is the first lithium sinking post-liquid, which is sent to the next process for secondary lithium sinking. The filter residue is crude lithium carbonate, which is subjected to carbonization and impurity removal, heating and decomposition, and centrifugal drying to obtain battery-grade lithium carbonate.

[0170] 7) Sodium phosphate is added to the first lithium sinking post-liquid for secondary lithium sinking, and the amount of sodium phosphate added is 1.2 times the theoretical amount. After reacting at 60°C for 2 h, filtration separation is performed, and the filtrate is sodium sulfate wastewater with Li content of 0.2 g / L, and the filter residue is lithium phosphate. The sodium sulfate wastewater is treated to obtain industrial-grade sodium sulfate.

[0171] 8) The lithium phosphate residue is slurried with pure water at a liquid-to-solid ratio of 10:1. After a period of slurry, ferric sulfate is added in an amount of 1.5 times the theoretical amount. After reacting for 3 h, pressure filtration is performed, and the filter residue is treated by conversion and calcination to prepare battery-grade ferric phosphate. The filtrate is lithium sulfate solution and is recycled into the heavy post-liquid for treatment.

[0172] 9) The comprehensive recovery rate of Li is 90.36%, and the prepared lithium carbonate is battery-grade lithium carbonate according to the national standard.

[0173] Example 6

[0174] The present embodiment provides a method for recycling and treating battery material black powder, which specifically comprises the following steps:

[0175] 1) 50 g of battery material black powder and 3 g of carbon-containing leaching residue (see Table 2) are mixed uniformly and then loaded into a crucible. The specific components of the carbon-containing leaching residue are shown in Table 2. The carbon-containing leaching residue is dried at 200°C to a moisture content of less than 0.5%, and 50% of the upper floating material is obtained by gravity flotation. The planetary ball mill is ground at 300 r / min for 6 h to obtain the product. The crucible is placed in a box-type atmosphere furnace and calcined at 700°C for 2 h under the protection of inert gas (nitrogen) at a heating rate of 6°C / min. The calcined product is ground through a 200-mesh sieve.

[0176] 2) 50 g of the calcined product was added to 400 mL of pure water, concentrated sulfuric acid was added to adjust the initial solution pH to 6.1, and the reaction was stirred at 65°C for 2 h, during which the pH was monitored in real time and the acid was added in time to ensure that the pH of the system was maintained at 6 ± 0.1. After the leaching was completed, the filtrate and the leaching residue were obtained by filtration. The liquid-phase lithium leaching rate was 85.19%, the nickel leaching rate was 2.61%, the cobalt leaching rate was 0.22%, and the manganese leaching rate was 0.16%.

[0177] 3) The crude lithium sulfate solution obtained in 2) was added to a purification agent to remove impurities, the purification agent was activated carbon, and the amount of the purification agent added was 3.5 wt% of the solution. After the impurities were removed by purification, F: 12 ppm, P: 8 ppm, and Si: 9 ppm.

[0178] 4) The solution after the impurities were removed by purification was subjected to heavy precipitation with a sodium hydroxide solution and a sodium carbonate solution, the amount of the precipitation agent was 1.1 times the theoretical amount, the precipitation temperature was 50°C, and the precipitation pH was 10. After the precipitation reaction, filtration was performed, the filter residue could be returned to the wet system for recovery of noble metals, the filter liquid contained Ni: 4 ppm, Co: 9 ppm, and Mn: 6 ppm.

[0179] 5) The solution after the precipitation was adjusted to a pH of 7, and was subjected to evaporation and concentration at a temperature of 150°C, and then was filtered. The filter residue was a sodium sulfate product, and the filter liquid was a lithium precipitation mother liquor, and the Li content was 11.2 g / L.

[0180] 6) The lithium precipitation mother liquor in 5) was subjected to lithium precipitation with Na2CO3, the amount of Na2CO3 added was 1.1 times the theoretical amount, and the reaction was performed at 70°C for 4 h, and then was filtered. The filter liquid was a first lithium precipitation solution, and was sent to the next process for secondary lithium precipitation. The filter residue was crude lithium carbonate, and the crude lithium carbonate was subjected to carbon removal, heating decomposition, and centrifugal drying to obtain battery-grade lithium carbonate.

[0181] 7) Sodium phosphate was added to the first lithium precipitation solution for secondary lithium precipitation, the amount of sodium phosphate added was 1.2 times the theoretical amount, the reaction temperature was 60°C, and after the reaction was performed for 2 h, filtration was performed to separate the filter liquid and the filter residue. The filter liquid was sodium sulfate wastewater, and the Li content was 0.2 g / L. The filter residue was lithium phosphate. The sodium sulfate wastewater was treated to obtain industrial-grade sodium sulfate.

[0182] 8) The lithium phosphate residue was slurried with pure water, the liquid-solid ratio was 10:1, iron sulfate was added after the slurry was stirred for a period of time, the amount of iron sulfate added was 1.5 times the theoretical amount, the reaction was performed for 3 h, and then pressure filtration was performed. The filter residue was treated by conversion and calcination to prepare battery-grade iron phosphate. The filter liquid was a lithium sulfate solution and was recycled into the precipitation solution.

[0183] 9) The comprehensive recovery rate of Li was 86.23%, and the lithium carbonate prepared was battery-grade lithium carbonate according to the national standard.

[0184] Example 7

[0185] On the basis of Example 6, only step 1) is modified to use regenerated oil-removed hazardous waste activated carbon (coconut shell activated carbon after adsorbing oil, which is commercially available), and the oil-removed hazardous waste activated carbon is from the company, which is coconut shell activated carbon after adsorbing oil, that is, 50 g of battery material black powder and 3 g of hazardous waste activated carbon are uniformly mixed and then loaded into a crucible, wherein the oil-removed hazardous waste activated carbon is regenerated by gravity oil removal and acid pickling, that is, after being blown and dispersed by air, most of the oil is removed by taking advantage of the difference in gravity between oil and activated carbon, then the activated carbon is soaked in a dilute sulfuric acid solution with a pH of 2 for 12 h, and then washed with water until the washing water has a pH of 6.5, and then baked in an oven at 200°C for 2 h to obtain the regenerated oil-removed hazardous waste activated carbon. In this way, the comprehensive recovery rate of Li is 87.56%.

[0186] Comparative Example 1

[0187] On the basis of Example 4, only the addition of the heavy agent in 4) is changed, and only sodium hydroxide solution is added as the heavy agent, and the lithium content of the lithium precipitation mother liquor in 5) is 10.6 g / L, and the comprehensive recovery rate of Li is 89.28%.

[0188] Comparative Example 2

[0189] On the basis of Example 4, only the addition of the heavy agent in 4) is changed, and only sodium carbonate solution is added as the heavy agent, and the lithium content of the lithium precipitation mother liquor in 5) is 10.72 g / L, and the comprehensive recovery rate of Li is 90.25%.

[0190] Comparative Example 3

[0191] On the basis of Example 5, only the step of secondary lithium precipitation in 7) is cancelled, and only one-time lithium precipitation is performed, that is, the lithium precipitation mother liquor is precipitated with Na2CO3, the amount of Na2CO3 added is 1.1 times the theoretical amount, and after reaction at 60°C for 0.5 h, filtration is performed, the filtrate is the one-time lithium precipitation liquid, which is sent to the next process for secondary lithium precipitation, and the filter residue is crude lithium carbonate. After carbonization and impurity removal, heating and decomposition, and centrifugal drying, battery-grade lithium carbonate is obtained. Since the Li content in the one-time lithium precipitation liquid is 3.0 g / L, Li in the one-time lithium precipitation liquid cannot be effectively recovered without secondary lithium precipitation, and the comprehensive recovery rate of Li is only 87.29%, and the byproduct iron phosphate cannot be produced without secondary lithium precipitation.

[0192] The method provided by the embodiments of the present application has the following advantages:

[0193] 1) The pyrometallurgical method is used to precipitate lithium, and the lithium recovery rate can reach 93%, the nickel recovery rate can reach 96%, and the cobalt recovery rate can reach 95%.

[0194] 2) The waste slag can be recycled, and metal recovery can be greatly achieved.

[0195] 3) Synchronous processable solid waste / hazardous waste residue (waste residue has certain reducibility). The filter residue after lithium extraction can reduce the comprehensive cost of nickel-cobalt metal recovery due to low Li content, combined with pyrometallurgical process.

[0196] 4) Less waste, the generated slag and liquid can be effectively opened, and more by-products can be obtained. The flexibility and adaptability of the production line are high.

[0197] 5) Effective series connection of wet process and pyrometallurgical process, efficient and high-quality, low-cost recovery of ternary black powder, Li recovery rate can reach 93%, and the wet process Li recovery rate is less than 85%.

[0198] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0199] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in the background section is only intended to deepen the understanding of the overall background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for recycling battery material black powder, characterized in that: include: The raw materials including battery material black powder and reducing agent are mixed and roasted, and the roasted product is then subjected to acid leaching, and solid-liquid separation is performed to obtain a crude lithium sulfate solution and an acid leaching residue; the acid leaching residue is used to recover metals; the initial pH of the acid leaching system is 5-7 and concentrated sulfuric acid is added during the acid leaching process to maintain the system pH at 5-7; The crude lithium sulfate solution is purified and impurities removed, and then subjected to a heavy treatment, solid-liquid separation to obtain a heavy liquid and heavy residue, and the heavy residue is used to recover metals; the heavy liquid is concentrated and crystallized, and solid-liquid separation is performed to obtain sodium sulfate and lithium precipitation mother liquor; the heavy treatment is performed using a heavy agent, which is a mixture of sodium hydroxide and sodium carbonate; The lithium precipitation mother liquor is subjected to a first lithium precipitation reaction using sodium carbonate, solid-liquid separation is performed to obtain crude lithium carbonate and a lithium precipitation liquid, and the crude lithium carbonate is subjected to a first post-treatment to obtain battery-grade lithium carbonate; The post-lithium precipitation liquid uses sodium phosphate to undergo a second lithium precipitation reaction, and solid-liquid separation is performed to obtain lithium phosphate and sodium sulfate waste liquid. The lithium phosphate is subjected to a second post-treatment to obtain battery-grade iron phosphate, and the sodium sulfate waste liquid is treated to obtain sodium sulfate.

2. The method according to claim 1, characterized in that The reducing agent includes waste residue having reducing properties.

3. The method according to claim 2, characterized in that The waste residue with reducing properties includes one or more of coconut shell activated carbon, carbon-containing leaching residue, and hazardous waste activated carbon.

4. The method according to claim 3, characterized in that The carbonaceous leaching residue is used after being subjected to flotation and mechanical activation.

5. The method according to claim 3, characterized in that The hazardous waste activated carbon is regenerated and used after being deoiled by gravity and washed with acid.

6. The method according to claim 1, characterized in that The amount of the reducing agent used is 5%-15% of the mass of the battery material black powder.

7. The method according to claim 1, characterized in that The calcination is carried out under the protection of an inert gas, the heating rate of the calcination is 5-10° C. / min, the maximum temperature is 600° C.-900° C., and the calcination time is 1 hour-4 hours.

8. The method according to claim 1, characterized in that Before the acid leaching, the roasted product is crushed and passed through a 100-300 mesh sieve.

9. The method according to claim 1, characterized in that The acid leaching is performed using a mixed solution of water and concentrated sulfuric acid.

10. The method according to claim 9, characterized in that The liquid-to-solid ratio of the mixed solution to the calcined product is (4-8) mL:1 g.

11. The method according to claim 1, wherein The acid leaching temperature is 50° C.-80° C., and the time is 1 h-3 h.

12. The method according to claim 1, characterized in that The purification and impurity removal is carried out using a purification and impurity removal agent.

13. The method according to claim 12, characterized in that The purification and impurity removal agent includes one or more of a dephosphorizing agent, a defluorinating agent, a resin and activated carbon.

14. The method according to claim 12, characterized in that The usage amount of the purification and impurity removal agent is 3%-10% of the mass of the crude lithium sulfate solution.

15. The method according to claim 1, wherein During the purification and impurity removal process, the pH of the system is 2-6.

16. The method according to claim 1, characterized in that The dosage of the heavy agent is 1-1.5 times of the theoretical dosage.

17. The method according to claim 1, wherein The temperature of the heavy treatment is 40° C.-80° C., and the pH of the system is 10-12.

18. The method according to claim 1, wherein The pH of the heavy after-liquid is pre-adjusted to 6-8 before the concentrated crystallization.

19. The method according to claim 1, wherein The temperature of the concentrated crystallization is 60°C-200°C.

20. The method according to claim 1, wherein In the first lithium precipitation reaction, the amount of sodium carbonate used is 1-1.5 times the theoretical amount.

21. The method according to claim 1, wherein The temperature of the first lithium precipitation reaction is 60°C-90°C.

22. The method according to claim 1, wherein The first post-treatment includes: carbonizing and removing impurities, heating and decomposing, and centrifuging and drying the crude lithium carbonate.

23. The method according to claim 1, wherein In the second lithium precipitation reaction, the amount of sodium phosphate used is 1.1-1.3 times the theoretical amount.

24. The method according to claim 1, wherein The temperature of the second lithium precipitation reaction is 40°C-70°C.

25. The method according to any one of claims 1 to 24, characterized in that The second post-processing comprises: The lithium phosphate and water are mixed into a slurry, and then mixed with ferric sulfate. After the reaction, the solid and liquid are separated. The obtained solid reacts with sodium phosphate and is calcined to obtain battery-grade ferric phosphate. The liquid is a lithium sulfate solution, which is returned to the heavy liquid for recycling.

26. The method according to claim 25, characterized in that The liquid-to-solid ratio of the water to the lithium phosphate is (7-14) mL:1 g.

27. The method according to claim 25, characterized in that The amount of ferric sulfate used is 1.2-1.6 times the theoretical amount.

28. The method according to claim 25, characterized in that The reaction time with ferric sulfate is 2h-4h.

29. The method according to claim 25, characterized in that The temperature for reacting the solid matter with the sodium phosphate is 60-150° C., and the time is 2-6 hours.

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