Method for preparing battery-grade lithium carbonate by recycling high-aluminum battery black powder

Abstract

The invention discloses a method for preparing battery-grade lithium carbonate by recycling high-aluminum battery black powder, and belongs to the technical field of resource recycling, the high-aluminum battery black powder is roasted, lithium in the battery black powder is converted into lithium elementary substance / soluble lithium salt, heavy metal is converted into insoluble oxide form, and subsequent treatment is facilitated; the roasted product is leached with water, a sulfuric acid solution is added at a constant speed in the leaching process, and a large amount of aluminum hydroxide flocculent precipitate is prevented from being formed, so that the aluminum hydroxide precipitate is prevented from entraining lithium, product loss is caused, and the lithium yield is reduced; extraction is carried out under a specific pH value and an extraction agent, so that the content of impurity cations is effectively reduced; and then fluorine removal, evaporation and concentration, lithium precipitation in the sodium carbonate solution and carbonization are carried out, so that the aluminum element, the fluorine element and other impurity elements in the high-aluminum battery black powder are effectively removed, the lithium yield is greatly improved, battery-grade lithium carbonate is obtained, and the method has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of resource recycling and reuse, and in particular to a method for preparing battery-grade lithium carbonate by recycling high-aluminum battery black powder. Background Art

[0003] Retired lithium batteries are "high-grade ores" rich in precious metals. After being discharged, disassembled, crushed and treated by a series of physical and chemical methods, lithium salts and valuable metals can be extracted. China already has a relatively mature technology for disassembling and powdering waste lithium batteries. The content of copper and aluminum in the black powder obtained after disassembling, shredding, roasting and crushing a complete battery pack is less than 1%. Based on this raw material condition, a complete set of smelting and recycling lithium processes has been derived.

[0004] At present, battery-grade lithium carbonate is usually obtained by reduction roasting, water leaching, impurity removal, lithium precipitation, carbonization, and pyrolysis. However, when the aluminum content is too high, excessive aluminum slag will carry out a large amount of lithium during the impurity removal process, greatly reducing the lithium yield. In particular, the black powder on the overseas market has a copper and aluminum content of up to 4%. When the existing technology processes such high-aluminum materials, the lithium yield usually does not exceed 85%.

[0005] In view of this, this application is filed. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate, which effectively removes aluminum, fluorine and other impurity elements in high-aluminum battery black powder, greatly improves the yield of lithium, and obtains battery-grade lithium carbonate, which has broad application prospects.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0009] (1) calcining high-aluminum battery black powder to obtain a calcined product;

[0010] (2) leaching the roasted product with water, and adding sulfuric acid solution at a uniform rate during the leaching process to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0011] (3) uniformly mixing the extractant and sulfonated kerosene to obtain an extracted organic phase, adding sodium hydroxide to the extracted organic phase for saponification to obtain a saponified organic phase;

[0012] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 2-3 to obtain an aqueous phase;

[0013] The aqueous phase is extracted with the saponified organic phase to obtain a purified solution;

[0014] (4) adding a defluorinating agent to the purified liquid, reacting, filtering, and obtaining a defluorinating liquid;

[0015] (5) evaporating and concentrating the defluorination liquid to obtain a concentrated liquid;

[0016] (6) adding sodium carbonate solution to the concentrated solution, reacting, washing, and centrifuging to obtain crude lithium carbonate;

[0017] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 7.5-9.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze, and centrifuge to obtain battery-grade lithium carbonate.

[0018] The present invention creatively roasts high-aluminum battery black powder, converts lithium in the battery black powder into lithium element / soluble lithium salt, and converts heavy metals into insoluble oxide forms, which is convenient for subsequent treatment; the roasted product is leached with water, and sulfuric acid solution is added at a uniform speed during the leaching process to avoid the formation of a large amount of aluminum hydroxide flocculation precipitation, thereby avoiding the aluminum hydroxide precipitation from entraining lithium, causing product loss, and resulting in a decrease in lithium yield; extraction is performed under specific pH and extraction agent to effectively reduce the content of impure cations (such as iron, aluminum, calcium, nickel, cobalt, manganese, and copper); then defluorination, evaporation concentration, sodium carbonate solution lithium precipitation, and carbonization are performed to effectively remove aluminum, fluorine and other impurity elements in the high-aluminum battery black powder, greatly improve the lithium yield, and obtain battery-grade lithium carbonate, which has broad application prospects.

[0019] The present invention adopts extraction to remove impurities, and no waste residue is generated during the impurity removal process, and lithium loss due to waste residue entrainment will not be caused, thereby effectively improving the lithium yield. In addition, metal ions such as nickel, cobalt, manganese, copper, zinc, iron, and calcium are removed together on the basis of aluminum removal, thereby saving the process of chemical impurity removal.

[0020] The high-aluminum battery black powder has a lithium content of 3-6%, an aluminum content of 2-5%, and a fluorine content of 0.5-1.5%.

[0021] In one embodiment, the calcination temperature is 500-700° C., and the calcination time is 0.5-2 h;

[0022] The calcination is carried out in the presence of a reducing agent; the reducing agent comprises at least one of reducing carbon powder, hydrogen, carbon monoxide, sodium sulfate, ammonium sulfate, and sulfuric acid solution.

[0023] In one embodiment, 1 g of the calcined product, water, and sulfuric acid solution: (3-5) mL: (0.5-1) mL;

[0024] The molar concentration of the sulfuric acid solution is 1-3 mol / L.

[0025] In one embodiment, the leaching temperature with water is 50-80° C., and the leaching time is 0.5-3 hours.

[0026] In one embodiment, the volume concentration of the extractant in the extracted organic phase is 10-25%;

[0027] The saponification rate of the organic phase in the saponification process is 30-50%.

[0028] In one embodiment, the extractant includes at least one of di(2-ethylhexyl)phosphate and 2-ethylhexyl mono-2-ethylhexyl phosphate.

[0029] The volume ratio of the water phase to the saponified organic phase is 1:(1.8-3.6).

[0030] In one embodiment, the ratio of the mass concentration of fluorine in the purification liquid to the defluorination agent is 1:(3-10).

[0031] In one embodiment, the reaction temperature in step (4) is 60-80° C., and the reaction time is 2-4 h;

[0032] In step (6), the reaction temperature is 85-95° C. and the reaction time is 1.5-3 h.

[0033] In one embodiment, the defluorination liquid is evaporated and concentrated until the lithium concentration in the defluorination liquid is 20-30 g / L.

[0034] In one embodiment, the ratio of the amount of lithium in the concentrate to the amount of sodium in the sodium carbonate solution is 1:(1.1-1.2);

[0035] The mass concentration of the sodium carbonate solution is 200-500 g / L.

[0036] In one embodiment, carbon dioxide is introduced into the lithium adjustment solution according to a molar ratio of Li to C of 3:(1.5-2.5);

[0037] The carbonization temperature is 90-100° C., and the carbonization time is 0.5-2 hours.

[0038] The beneficial effects of the present invention are as follows: the present invention creatively roasts high-aluminum battery black powder, converts lithium in the battery black powder into lithium element / soluble lithium salt, and converts heavy metals into insoluble oxide forms, which is convenient for subsequent treatment; the roasted product is leached with water, and sulfuric acid solution is added at a uniform speed during the leaching process to avoid the formation of a large amount of aluminum hydroxide flocculation precipitation, thereby avoiding the aluminum hydroxide precipitation from entraining lithium, causing product loss, and resulting in a decrease in lithium yield; extraction is performed under specific pH and extraction agent to effectively reduce the content of impure cations (such as iron, aluminum, calcium, nickel, cobalt, manganese, and copper); then defluorination, evaporation concentration, sodium carbonate solution lithium precipitation, and carbonization are performed to effectively remove aluminum, fluorine and other impurity elements in the high-aluminum battery black powder, greatly improve the lithium yield, and obtain battery-grade lithium carbonate, which has broad application prospects. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0040] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0041] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0042] In the present application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0043] Unless otherwise specified, the components, raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the components and raw materials used in each parallel experiment are all of the same kind.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] Example 1

[0046] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0047] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0048] (2) grinding the roasted product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.5 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0049] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0050] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 2.5 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0051] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0052] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0053] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0054] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0055] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0056] The mass concentration of the sodium carbonate solution is 400 g / L.

[0057] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0058] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0059] Example 2

[0060] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0061] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0062] (2) grinding the roasted product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.5 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0063] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0064] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 2 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0065] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0066] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0067] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0068] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0069] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0070] The mass concentration of the sodium carbonate solution is 400 g / L.

[0071] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0072] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0073] Example 3

[0074] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0075] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0076] (2) grinding the roasted product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.5 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0077] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0078] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 3 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0079] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0080] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0081] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0082] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0083] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0084] The mass concentration of the sodium carbonate solution is 400 g / L.

[0085] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0086] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0087] Example 4

[0088] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0089] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0090] (2) grinding the calcined product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 5 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 1 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0091] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0092] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 2.5 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0093] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0094] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0095] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0096] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0097] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0098] The mass concentration of the sodium carbonate solution is 400 g / L.

[0099] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0100] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0101] Comparative Example 1

[0102] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0103] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0104] (2) grinding the roasted product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.5 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0105] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0106] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 4 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0107] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0108] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0109] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0110] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0111] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0112] The mass concentration of the sodium carbonate solution is 400 g / L.

[0113] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0114] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0115] Comparative Example 2

[0116] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0117] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0118] (2) grinding the roasted product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.5 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0119] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0120] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 1 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0121] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0122] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0123] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0124] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0125] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0126] The mass concentration of the sodium carbonate solution is 400 g / L.

[0127] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0128] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0129] Comparative Example 3

[0130] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0131] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0132] (2) grinding the calcined product to 100 mesh, leaching with water at 70°C at a solid-liquid ratio of 1 g:3 mL, leaching for 2 h, and filtering to obtain a leachate;

[0133] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0134] The leachate was adjusted to pH 2.5 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0135] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0136] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0137] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0138] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0139] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0140] The mass concentration of the sodium carbonate solution is 400 g / L.

[0141] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0142] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0143] Comparative Example 4

[0144] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0145] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0146] (2) grinding the calcined product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.2 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0147] (3) P204 extractant and sulfonated kerosene are uniformly mixed to prepare an extraction organic phase with an extractant volume concentration of 18%, and sodium hydroxide is added to the extraction organic phase for saponification, and the saponification rate is controlled to be 50%, thereby obtaining a saponified organic phase;

[0148] The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 4 with 3 mol / L sulfuric acid solution to obtain an aqueous phase;

[0149] The aqueous phase was extracted with the saponified organic phase in a volume ratio of 1:3 for 10 steps to obtain a purified solution;

[0150] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0151] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0152] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0153] The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:1.1;

[0154] The mass concentration of the sodium carbonate solution is 400 g / L.

[0155] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0156] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0157] Comparative Example 5

[0158] This comparative example adopts precipitation to remove aluminum.

[0159] A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate comprises the following steps:

[0160] (1) calcining high-aluminum battery black powder in a hydrogen atmosphere to obtain a calcined product, the calcination temperature is 600° C., and the calcination time is 1 h;

[0161] (2) grinding the roasted product to 100 mesh, leaching water at 70° C. at a solid-liquid ratio of 1 g: 3 mL, and adding 2 mol / L sulfuric acid solution at a constant rate at a solid-liquid ratio of 1 g: 0.5 mL during the leaching process to control the leaching pH, leaching for 2 h, and filtering to obtain a mixed solution of lithium hydroxide and lithium sulfate;

[0162] (3) adjusting the pH of the mixed solution of lithium hydroxide and lithium sulfate to 4.5 using a 5 mol / L lithium hydroxide solution, reacting at 70° C. for 2 h, then separating the slurry solid-liquid to obtain a mixed solution of lithium hydroxide and lithium sulfate after aluminum removal, and stirring and washing the filter residue at a liquid-solid ratio of 3:1 and a temperature of 70° C., and filtering it twice;

[0163] (4) adding a defluorinating agent, polyaluminium sulfate, to the purified liquid, reacting at 80° C. for 3 hours, filtering, and obtaining a defluorinating liquid; the ratio of the mass concentration of fluorine in the purified liquid to the added defluorinating agent is 1:5;

[0164] (5) evaporating and concentrating the defluorination liquid to a lithium concentration of 25 g / L to obtain a concentrated liquid;

[0165] (6) adding sodium carbonate solution to the concentrated solution, reacting at 90° C. for 2 h, washing, and centrifuging to obtain crude lithium carbonate;

[0166] The molar ratio of the lithium in the concentrated solution to the sodium in the sodium carbonate solution is 1:1.1;

[0167] The mass concentration of the sodium carbonate solution is 400 g / L.

[0168] (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 8.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze at 95° C. for 1 h, and obtain battery-grade lithium carbonate through centrifugation, drying, crushing, screening, demagnetization, and packaging.

[0169] (8) Collect the centrifuged mother liquors in steps (6) and (7), adjust the pH to 4, and pump them into an evaporation system to evaporate the concentrated liquid, centrifuge, and separate the sodium sulfate crystals. The centrifuged mother liquor after evaporation and concentration in this step is returned to the evaporation system for further evaporation. When the Li concentration of the centrifuged mother liquor is enriched to 8 g / L, it is reused in step (5).

[0170] Test Case

[0171] The same batch of ternary battery black powder (lithium content is 4.5%, aluminum content is 3.9%, fluorine content is 1.2) was treated according to the methods of Examples 1 to 4 and Comparative Examples 1 to 4, and the indicators of the obtained lithium carbonate are shown in Table 1.

[0172] Table 1

[0173]

[0174]

[0175] As can be seen from Table 1, the method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate of the present invention greatly improves the yield of lithium and obtains battery-grade lithium carbonate.

[0176] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate, characterized in that: The following steps are involved: (1) calcining high-aluminum battery black powder to obtain a calcined product; (2) leaching the roasted product with water, and adding sulfuric acid solution at a uniform rate during the leaching process to obtain a mixed solution of lithium hydroxide and lithium sulfate; (3) uniformly mixing the extractant and sulfonated kerosene to obtain an extracted organic phase, adding sodium hydroxide to the extracted organic phase for saponification to obtain a saponified organic phase; The mixed solution of lithium hydroxide and lithium sulfate is adjusted to pH 2-3 to obtain an aqueous phase; The aqueous phase is extracted with the saponified organic phase to obtain a purified solution; (4) adding a defluorinating agent to the purified liquid, reacting, filtering, and obtaining a defluorinating liquid; (5) evaporating and concentrating the defluorination liquid to obtain a concentrated liquid; (6) adding sodium carbonate solution to the concentrated solution, reacting, washing, and centrifuging to obtain crude lithium carbonate; (7) Add water to the crude lithium carbonate to adjust the lithium concentration to 7.5-9.5 g / L to obtain a lithium solution, introduce carbon dioxide to obtain a lithium bicarbonate solution, filter, pyrolyze, and centrifuge to obtain battery-grade lithium carbonate.

2. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The calcination temperature is 500-700°C and the calcination time is 0.5-2h; The calcination is carried out in the presence of a reducing agent; the reducing agent comprises at least one of reducing carbon powder, hydrogen, carbon monoxide, sodium sulfate, ammonium sulfate, and sulfuric acid solution.

3. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: 1g of the calcined product, water, and sulfuric acid solution: (3-5)mL: (0.5-1)mL; The molar concentration of the sulfuric acid solution is 1-3 mol / L.

4. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The volume concentration of the extractant in the extracted organic phase is 10-25%.

5. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The extractant comprises at least one of di(2-ethylhexyl)phosphate and 2-ethylhexyl phosphate mono-2-ethylhexyl ester; The volume ratio of the water phase to the saponified organic phase is 1:(1.8-3.6).

6. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The ratio of the fluorine mass concentration in the purification liquid to the defluorination agent is 1:(3-10).

7. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The reaction temperature in step (4) is 60-80°C and the reaction time is 2-4h; In step (6), the reaction temperature is 85-95° C. and the reaction time is 1.5-3 h.

8. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The defluorination liquid is evaporated and concentrated until the lithium concentration in the defluorination liquid is 20-30 g / L.

9. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The ratio of the amount of lithium in the concentrated solution to the amount of sodium in the sodium carbonate solution is 1:(1.1-1.2); The mass concentration of the sodium carbonate solution is 200-500 g / L.

10. The method for recovering high-aluminum battery black powder to prepare battery-grade lithium carbonate according to claim 1, characterized in that: According to the molar ratio of Li to C being 3:(1.5-2.5), carbon dioxide is introduced into the lithium adjustment solution; The carbonization temperature is 90-100° C., and the carbonization time is 0.5-2 hours.

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