A method for recycling battery-grade lithium carbonate and valuable metals from waste ternary lithium batteries by short-process black powder

Abstract

The present application belongs to the technical field of waste battery recycling, and particularly relates to a method for recycling battery-grade lithium carbonate and valuable metals from waste ternary lithium batteries by a short process of black powder. The present application constructs a lithium closed-loop technical system of "blank roasting-circulating leaching-synergistic impurity removal-lithium phosphate aluminum removal-directional extraction and split-flow lithium-nickel-magnesium extraction-crystal seed induction and lithium co-current precipitation", and the whole process does not need to add roasting aids, reducing agents and aluminum removal agents, and the redundant processes such as carbonization, resin purification, pyrolysis and the like in traditional lithium carbonate purification are omitted, the lithium liquid concentration cost is saved, green and clean production is realized without hazardous waste, and the synergistic impurity removal and directional extraction ensure the quality of the battery-grade product.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste battery recycling, and particularly relates to a method for recycling battery-grade lithium carbonate and valuable metals from waste ternary lithium battery black powder through a short process. BACKGROUND

[0002] Waste ternary lithium batteries are rich in valuable metals such as lithium, cobalt, nickel, copper and manganese, and efficient recovery of these metals and preparation of high-purity battery-grade products are of great significance to reduce industrial costs and reduce resource waste. However, the existing waste ternary lithium battery recycling process still has many deficiencies in process optimization, cost control, environmental protection benefits and product quality, and needs to be broken through.

[0003] The traditional roasting process of waste ternary lithium battery black powder mainly includes sulfuric acid roasting process and sodium carbonate roasting process. The sulfuric acid roasting process adds concentrated sulfuric acid for roasting, and the mixing process is easy to caking, and a large amount of sulfur dioxide is generated during the roasting process. The sodium carbonate roasting process needs to add additives such as sodium carbonate to promote the conversion of lithium, and the roasting temperature is high (800-1000℃), which not only has high cost, but also introduces sodium impurities, and a complex sodium removal process is needed subsequently.

[0004] The traditional crude lithium carbonate purification process needs to go through the links of "crude lithium carbonate → carbonization → resin removal of calcium and magnesium → pyrolysis", and the calcium and magnesium ions in the liquid after carbonization need to be removed by resin adsorption, and the resin needs to be regenerated frequently, which increases the cost and reduces the production efficiency. The process is complex, the lithium loss rate is high, the energy consumption is high (the pyrolysis temperature reaches 80-100℃), and the sodium and sulfate impurities are difficult to remove (such as the sodium content exceeding 0.05%), and the product quality fluctuates greatly.

[0005] The existing impurity removal process is mostly step-by-step impurity removal, which consumes a lot of reagents and has high metal loss. For example, aluminum sulfate is often used for fluorine ion removal, and sodium sulfide is used for heavy metal removal, and the use of multiple reagents greatly increases the cost; high-pH aluminum removal (such as using sodium carbonate to adjust the pH to 5-6 to remove aluminum) easily leads to the formation of hydroxide precipitates of valuable metals such as cobalt, nickel and manganese, resulting in loss, the aluminum removal residue has high water content and poor filtration, increasing the difficulty and cost of solid waste treatment, and also causing resource waste. At the same time, the traditional lithium extraction residue is subjected to sulfuric acid leaching, which often needs to add reducing agents such as sodium pyrosulfite to reduce high-valence metals, producing sulfur dioxide pollution, and the environmental protection treatment cost is high.

[0006] Lithium is dispersed in the leaching liquid, lithium precipitation mother liquor and raffinate in the recycling process, and the existing process lacks effective closed-loop enrichment means, resulting in a total lithium recovery rate of less than 90%; and the lithium concentration in the lithium extraction leaching liquid and raffinate is often lower than 5g / L, and the traditional evaporation and concentration treatment has high energy consumption, large equipment investment and high cost, which is difficult for enterprises to economically recover.

[0007] The recovery of metals such as cobalt, nickel, copper, manganese and magnesium is often not accurate and optimized, and additional purification is required to reach the battery grade standard. In the traditional extraction process, the selection of extractant and the setting of process parameters are unreasonable, which easily leads to the exceeding of impurity content in the product (such as the exceeding of nickel content in cobalt sulfate by 0.05%), limits the application of the product in high-end battery production, and reduces the added value of the recovered product.

[0008] In view of various problems existing in the recovery process of waste ternary lithium battery, it is urgent to develop a method for recovering battery-grade lithium carbonate and valuable metals from waste ternary lithium battery black powder by a short process. SUMMARY

[0009] The purpose of the present application is to provide a method for recovering battery-grade lithium carbonate and valuable metals from waste ternary lithium battery black powder by a short process, which has a short process and high production efficiency.

[0010] In order to achieve the above purpose, the present application provides the following technical scheme:

[0011] The present application provides a method for recovering battery-grade lithium carbonate and valuable metals from waste ternary lithium battery black powder by a short process, which comprises the following steps:

[0012] (1) blank roasting the waste ternary lithium battery black powder under a natural gas atmosphere to obtain a roasting residue;

[0013] (2) low-acid cyclic leaching and pressure filtration of the roasting residue with a dilute sulfuric acid solution to obtain a lithium-rich cyclic leaching solution and a low-acid leaching residue;

[0014] (3) when the lithium concentration in the lithium-rich cyclic leaching solution is ≥20g / L, mixing part of the lithium-rich cyclic leaching solution with calcium oxide, and sequentially performing defluorination and pressure filtration to obtain a defluorination and heavy metal removal solution;

[0015] (4) extracting calcium from the defluorination and heavy metal removal solution to obtain a calcium removal solution;

[0016] (5) adding zirconium hydroxide to the calcium removal solution to deeply remove silicon, phosphorus and fluorine to obtain a silicon, phosphorus and fluorine removal solution;

[0017] (6) using pure water as a bottom liquid, adding battery-grade lithium carbonate as a seed crystal, and adding the silicon, phosphorus and fluorine removal solution and a sodium carbonate solution into a synthesis kettle in a parallel flow form to induce lithium precipitation to obtain lithium carbonate and a lithium precipitation mother liquor;

[0018] (7) adding trisodium phosphate to the lithium precipitation mother liquor to synthesize a lithium phosphate crude product;

[0019] (8) sequentially performing high-acid leaching and pressure filtration on the low-acid leaching residue to obtain a high-acid leaching residue and a high-acid leaching solution;

[0020] (9) adding the high-acid leaching solution into manganese dioxide oxidation, and adding the obtained post-oxidation solution into the lithium phosphate crude product to remove iron and aluminum and to perform pressure filtration, to obtain a post-iron and aluminum removal solution and an iron and aluminum removal residue;

[0021] (10) performing copper extraction on the post-iron and aluminum removal solution to obtain a copper raffinate and a battery-grade copper sulfate;

[0022] (11) performing impurity extraction on the copper raffinate to obtain a post-impurity removal solution and a manganese solution; the obtained manganese solution is subjected to deep purification in sequence to obtain a battery-grade manganese sulfate; the deep purification is sulfurization, calcium removal and fluorine removal in sequence;

[0023] (12) performing cobalt extraction on the post-impurity removal solution to obtain a battery-grade cobalt sulfate and a cobalt raffinate containing low-concentration lithium, nickel and magnesium; the obtained cobalt raffinate containing low-concentration lithium, nickel and magnesium is subjected to lithium, nickel and magnesium extraction, and the obtained lithium, nickel and magnesium loaded organic phase is subjected to extraction separation again in the cobalt extraction section to obtain a raffinate containing high-concentration lithium, nickel and magnesium;

[0024] (13) performing magnesium extraction on the raffinate containing high-concentration lithium, nickel and magnesium to obtain a magnesium raffinate and a battery-grade magnesium sulfate;

[0025] (14) performing nickel extraction on the magnesium raffinate to obtain a lithium-rich solution and a battery-grade nickel sulfate; the lithium-rich solution is recycled to the step (3) for fluorine and heavy metal removal.

[0026] Preferably, the temperature of the blank roasting is 450-650℃, and the roasting time is 1-3h.

[0027] Preferably, in the low-acid cyclic leaching, the leaching solution obtained in each low-acid leaching is recycled to the low-acid cyclic leaching after being acid-adjusted, and the pH of the dilute sulfuric acid solution or the leaching solution after being acid-adjusted is 1-3; in each low-acid leaching, the liquid-solid ratio is 10-20 ml / g, and the time of each low-acid leaching is 1-4h.

[0028] Preferably, the time of the fluorine and heavy metal removal is 1-4h, and the temperature is 25-50℃; the ratio of the added amount of calcium oxide to the heavy metal ion molar amount of fluorine in the part of the lithium-rich cyclic leaching solution is 1.1-1.3:1; the heavy metal ion molar amount of fluorine is the sum of the molar amount of fluorine ions and the molar amount of heavy metal ions; the heavy metal includes one or more of Co, Ni, Mn and Cu.

[0029] Preferably, the extractant for the extraction calcium removal is di(2-ethylhexyl)phosphate; the added amount of the zirconium hydroxide is 20-60 times of the total mass of silicon, phosphorus and fluorine in the calcium removal solution; and the time of the deep removal of silicon, phosphorus and fluorine is 1-3h.

[0030] Preferably, in the step (6), the molar ratio of sodium carbonate in the sodium carbonate solution to Li element in the desiliconizing phosphorus fluorine solution is 1.1~1.2:2, the concentration of the sodium carbonate solution is 250~350g / L; the added amount of the battery-grade lithium carbonate is 5~15wt.% of the mass of the synthesized lithium carbonate, and the temperature for inducing lithium precipitation is 80~100℃.

[0031] Preferably, the ratio of the added molar amount of the trisodium phosphate to the molar amount of Li element in the lithium precipitation mother liquor is 1.1~1.2:3, the synthesis temperature of the lithium phosphate crude product is 80~100℃, and the synthesis time is 1~3h.

[0032] Preferably, the initial concentration of the high-acid leaching sulfuric acid solution is 4~7mol / L; the liquid-solid ratio of the high-acid leaching is 3~5mL / g; the temperature of the high-acid leaching is 60~90℃, and the time of the high-acid leaching is 3~6h.

[0033] Preferably, the ratio of the added molar amount of the manganese dioxide to the molar amount of Fe element in the high-acid leaching solution is 1.1~1.2:2, the oxidation time is 1~2h, and the ratio of the added molar amount of the lithium phosphate crude product to the total molar amount of iron ions and aluminum ions in the solution after oxidation is 1~1.2:1; when the iron and aluminum are removed, the pH value of the system is 3~4, and the reaction time for removing the iron and aluminum is 1~3h.

[0034] Preferably, the extractant for copper extraction is a mixture of 5-dodecyl salicylaldoxime and 2-hydroxy-5-nonyl phenylacetone oxime; the extractant for impurity extraction is di(2-ethylhexyl) phosphate; the extractant for cobalt extraction is 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester; the extractant for magnesium extraction is di(2,4,4-trimethylpentyl) phosphinic acid; and the extractant for nickel extraction is 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester.

[0035] Compared with the prior art, the technical scheme of the present application has at least the following beneficial effects:

[0036] (1) The blank roasting process of the waste ternary lithium battery black powder does not need roasting aids such as sodium carbonate or sulfuric acid, and utilizes the carbon dioxide generated by sufficient combustion of natural gas to efficiently convert lithium oxide in the black powder into lithium carbonate at high temperature, with a lithium carbonate yield of more than 90%, and sodium impurities are avoided, thereby saving the subsequent sodium removal process. The process is simplified, the cost is reduced, and the energy consumption is significantly reduced.

[0037] (2) This invention optimizes the lithium carbonate synthesis process by using a parallel-flow lithium precipitation + seed induction + hot water washing method. This avoids the formation of lithium sulfate sodium complex salt impurities during the lithium precipitation process and also avoids local supersaturation of lithium carbonate. This effectively reduces the sodium and sulfate content in the synthesized lithium carbonate, reduces washing difficulty, and improves filtration performance. The lithium carbonate after hot water washing meets the battery-grade product standards. The lithium precipitation process eliminates the redundant process of traditional "carbonation-resin calcium and magnesium removal-pyrolysis", and directly prepares battery-grade lithium carbonate in a short process, which greatly shortens the lithium carbonate preparation cycle, reduces costs and energy consumption, and improves production efficiency.

[0038] (3) Low-acid circulating leaching and diversion of blank roasted residue achieve lithium concentration enrichment, solving the problem of low lithium carbonate solubility. The lithium concentration in the leachate is enriched to over 20 g / L. Simultaneously, the cobalt extraction process adds a multi-stage synergistic lithium-nickel-magnesium extraction tank before the cobalt extraction section. This allows a portion of the raffinate containing low-concentration lithium-nickel-magnesium in the cobalt extraction section to be diverted into the lithium-nickel-magnesium extraction section for lithium-nickel-magnesium extraction. The lithium-nickel-magnesium-loaded organic phase is then returned to the cobalt extraction section for extraction and separation to obtain a raffinate containing high-concentration lithium-nickel-magnesium. The lithium concentration in the raffinate containing high-concentration lithium-nickel-magnesium can be enriched to over 10 g / L. The low-acid circulating leaching and cobalt extraction and diversion extraction lithium-nickel-magnesium lithium enrichment process of this invention solves the problem of high cost of low-concentration lithium concentration concentration, significantly improves lithium precipitation efficiency, reduces lithium recovery costs, and reduces energy consumption for subsequent evaporation and concentration.

[0039] (4) Calcium oxide is used to simultaneously remove fluoride and heavy metal impurities, achieving the removal of multiple impurities in one step; combined with the graded purification process of calcium extraction and zirconium hydroxide adsorption of silicon, phosphorus and fluorine, calcium, silicon, phosphorus and fluorine are efficiently removed, laying the foundation for the preparation of high-purity battery-grade lithium carbonate products. The acid leaching of low-acid leaching residue utilizes a high-temperature acidic environment to self-oxidize and dissolve metal oxides, eliminating the need for reducing agents and reducing sulfur dioxide pollution. After washing, the high-acid leaching residue meets the discharge standards; lithium phosphate prepared using lithium precipitation mother liquor is used in the iron and aluminum removal process of high-acid leaching solution. Iron and aluminum are removed under acidic conditions (pH 3~4), with good removal effect, eliminating the need for the addition of traditional aluminum removal agents such as sodium carbonate and calcium carbonate. After washing, the cobalt, nickel, manganese, copper and lithium metal entrainment in the iron and aluminum removal slag is less than 0.1%, realizing the resource utilization of mother liquor, greatly reducing the cost of aluminum removal, improving the filterability of aluminum removal slag, increasing aluminum removal capacity, and achieving the standard discharge of iron and aluminum removal slag.

[0040] (5) By optimizing the processes of copper extraction, impurity extraction, deep purification of manganese solution, cobalt extraction, magnesium extraction, and nickel extraction through targeted solvent extraction, battery-grade products such as copper sulfate, manganese sulfate, cobalt sulfate, magnesium sulfate, and nickel sulfate are prepared respectively, thereby improving product purity (≥99.9%), increasing the metal recovery rate of cobalt, nickel, manganese, copper, and magnesium, shortening the process flow, and improving production efficiency. The lithium-rich solution obtained from nickel extraction in P507 is returned to the defluorination and degravity removal process and enters the lithium precipitation system in a closed loop, thereby improving the lithium recovery rate and realizing the efficient recycling of lithium resources.

[0041] In summary: the process is short, the process is simple, the production efficiency is high, the energy consumption is low, the green clean production is realized, no dangerous waste is produced, the product quality is excellent, the recovery rate of valuable metals such as cobalt, nickel, copper, manganese, lithium and magnesium in the recovery process reaches more than 99%, the valuable metal products all reach the battery grade standard, and obvious economic benefits and environmental benefits are obtained. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0043] Figure 1 A flow chart of a short process for recycling battery-grade lithium carbonate and valuable metals from waste ternary lithium battery black powder is provided. DETAILED DESCRIPTION

[0044] The present application provides a method for recycling battery-grade lithium carbonate and valuable metals from waste ternary lithium battery black powder, comprising the following steps:

[0045] (1) blank roasting the waste ternary lithium battery black powder under a natural gas atmosphere to obtain a roasting residue;

[0046] (2) low-acid cyclic leaching and pressure filtration of the roasting residue with a dilute sulfuric acid solution to obtain a lithium-rich cyclic leaching solution and a low-acid leaching residue;

[0047] (3) when the lithium concentration in the lithium-rich cyclic leaching solution is ≥20 g / L, part of the lithium-rich cyclic leaching solution is mixed with calcium oxide, and defluorination and heavy metal removal are carried out in turn, and pressure filtration is carried out to obtain a defluorination and heavy metal removal solution;

[0048] (4) extraction calcium removal is carried out on the defluorination and heavy metal removal solution to obtain a calcium removal solution;

[0049] (5) zirconium hydroxide is added to the calcium removal solution to deeply remove silicon, phosphorus and fluorine to obtain a silicon, phosphorus and fluorine removal solution;

[0050] (6) pure water is used as a bottom liquid, battery-grade lithium carbonate is added as a seed crystal, the silicon, phosphorus and fluorine removal solution and a sodium carbonate solution are added in a parallel flow form into a synthesis kettle, and lithium precipitation is induced to obtain lithium carbonate and a lithium precipitation mother liquor;

[0051] (7) trisodium phosphate is added to the lithium precipitation mother liquor for synthesis to obtain a lithium phosphate crude product;

[0052] (8) high-acid leaching and pressure filtration are carried out in turn on the low-acid leaching residue to obtain a high-acid leaching residue and a high-acid leaching solution;

[0053] (9) the high-acid leaching solution is added to manganese dioxide oxidation, and the obtained post-oxidation solution is added to the lithium phosphate crude product to remove iron and aluminum and to perform pressure filtration, to obtain a post-iron and aluminum removal solution and an iron and aluminum removal residue;

[0054] (10) the post-iron and aluminum removal solution is subjected to copper extraction, to obtain a copper raffinate and a battery-grade copper sulfate;

[0055] (11) the copper raffinate is subjected to impurity extraction, to obtain a post-impurity removal solution and a manganese solution; the obtained manganese solution is subjected to deep purification in sequence, to obtain a battery-grade manganese sulfate; the deep purification is sulfurization, calcium removal and fluorine removal in sequence;

[0056] (12) the post-impurity removal solution is subjected to cobalt extraction, to obtain a battery-grade cobalt sulfate and a cobalt raffinate containing low-concentration lithium, nickel and magnesium; the obtained cobalt raffinate containing low-concentration lithium, nickel and magnesium is subjected to lithium, nickel and magnesium extraction, and the obtained lithium, nickel and magnesium loaded organic phase is subjected to extraction separation again in the cobalt extraction section, to obtain a raffinate containing high-concentration lithium, nickel and magnesium;

[0057] (13) the raffinate containing high-concentration lithium, nickel and magnesium is subjected to magnesium extraction, to obtain a magnesium raffinate and a battery-grade magnesium sulfate;

[0058] (14) the magnesium raffinate is subjected to nickel extraction, to obtain a lithium-rich solution and a battery-grade nickel sulfate; the lithium-rich solution is recycled to step (3) for fluorine and heavy metal removal.

[0059] The waste and old ternary lithium battery black powder is subjected to blank roasting under a natural gas atmosphere, to obtain a roasting residue.

[0060] As an embodiment of the present application, the temperature of the blank roasting can be 450-650 DEG C, and specifically can be 450 DEG C, 500 DEG C, 550 DEG C, 600 DEG C or 650 DEG C; the time of the blank roasting is 1-3 h, and specifically can be 1 h, 2 h or 3 h.

[0061] As an embodiment of the present application, the blank roasting can efficiently convert lithium into lithium carbonate.

[0062] The roasting residue is subjected to low-acid circulation leaching and pressure filtration with a dilute sulfuric acid solution, to obtain a lithium-rich circulation leaching solution and a low-acid leaching residue.

[0063] As an embodiment of the present application, the leaching solution obtained in each low-acid leaching needs to be adjusted in acid and returned to the circulation leaching of new roasting residue; the pH of the dilute sulfuric acid solution and the leaching solution after acid adjustment is 1-3, and specifically can be 2; the liquid-solid ratio is 10-20 mL / g in each low-acid leaching, and the leaching time can be 1-4 h, and specifically can be 1 h, 2 h, 3 h or 4 h.

[0064] When the lithium concentration in the lithium-rich circulating leaching solution is greater than or equal to 20 g / L, part of the lithium-rich circulating leaching solution is mixed with calcium oxide, and defluorination and heavy metal removal are sequentially performed, and a defluorinated and heavy metal removed solution is obtained.

[0065] As an embodiment of the present application, the reaction occurring in the defluorination and heavy metal removal process is:

[0066] MeSO4+CaO+H2O=Me(OH)2+CaSO4(Me: one or more of Co, Ni, Mn, and Cu elements);

[0067] 2HF+ CaO=CaF2↓+H2O.

[0068] As an embodiment of the present application, the ratio of the molar amount of calcium oxide added to the molar amount of fluorine and heavy metals in the part of the lithium-rich circulating leaching solution is 1.1-1.3:1; the molar amount of fluorine and heavy metals is 1 / 2 of the molar amount of fluorine ions plus the molar amount of heavy metal ions, and can be 1.1:1, 1.2:1, or 1.3:1; the defluorination and heavy metal removal time can be 1-4 h, and can be 1 h, 2 h, 3 h, or 4 h; the temperature can be 25-50°C, and can be 25°C, 35°C, 45°C, or 50°C.

[0069] After obtaining the defluorinated and heavy metal removed solution, the present application performs extraction calcium removal on the defluorinated and heavy metal removed solution to obtain a calcium removed solution.

[0070] As an embodiment of the present application, the extractant for the extraction calcium removal can be di(2-ethylhexyl) phosphate (P204).

[0071] As an embodiment of the present application, the phase ratio of the extraction calcium removal can be 4:1.

[0072] As an embodiment of the present application, the extraction calcium removal also obtains a calcium loaded organic phase, and the calcium loaded organic phase is stripped with a 1-3 mol / L hydrochloric acid solution.

[0073] After obtaining the calcium removed solution, the present application adds the calcium removed solution to zirconium hydroxide to deeply remove silicon, phosphorus, and fluorine to obtain a silicon, phosphorus, and fluorine removed solution.

[0074] As an embodiment of the present application, the addition amount of the zirconium hydroxide is 20-60 times the total mass of silicon, phosphorus, and fluorine in the calcium removed solution, and can be 30-40 times; the deep removal time of silicon, phosphorus, and fluorine can be 1-3 h, and can be 1 h; the deep removal mode is adsorption; as an embodiment of the present application, the zirconium hydroxide is regenerated by desorption with 5-10 wt.% liquid caustic after adsorption saturation.

[0075] After obtaining the silicon-phosphorus-fluorine-removing solution, the present application adds battery-grade lithium carbonate as a crystal seed into pure water as a base solution, and adds the silicon-phosphorus-fluorine-removing solution and a sodium carbonate solution into a synthesis kettle in a parallel flow mode to induce lithium precipitation (synthesis of lithium carbonate) to obtain battery-grade lithium carbonate and a lithium precipitation mother liquor.

[0076] As an embodiment of the present application, the reaction occurring in the process of inducing lithium precipitation is:

[0077] Li2SO4+Na2CO3=Li2CO3+Na2SO4.

[0078] As an embodiment of the present application, the molar ratio of sodium carbonate in the sodium carbonate solution to the Li element in the silicon-phosphorus-fluorine-removing solution is 1.1-1.2:2, the concentration of the sodium carbonate solution can be 250-350 g / L, and specifically can be 250 g / L, 300 g / L or 350 g / L; the added amount of the lithium carbonate crystal seed is 5-15 wt.% of the mass of the synthesized lithium carbonate, and the temperature of the induced lithium precipitation (synthesis of lithium carbonate) can be 80-100℃, and specifically can be 80℃, 90℃ or 100℃; as an embodiment of the present application, after obtaining the lithium carbonate by inducing lithium precipitation, the synthesized lithium carbonate is further subjected to 3 times of hot water washing, the washing temperature is 80-100℃, and the washing time is 1-2 h each time.

[0079] After obtaining the lithium precipitation mother liquor, the present application adds the lithium precipitation mother liquor into trisodium phosphate to synthesize a lithium phosphate crude product.

[0080] As an embodiment of the present application, the reaction occurring in the process of synthesizing the lithium phosphate crude product is:

[0081] 3Li2SO4+2Na3PO4=2Li3PO4+3Na2SO4.

[0082] As an embodiment of the present application, the ratio of the added molar amount of the trisodium phosphate to the molar amount of the Li element in the lithium precipitation mother liquor is 1.1-1.2:3, the synthesis temperature of the lithium phosphate crude product can be 80-100℃, and specifically can be 80℃, 90℃ or 100℃, the synthesis time can be 1-3 h, and specifically can be 1 h, 1.5 h, 2 h or 3 h.

[0083] The present application sequentially performs high-acid leaching and pressure filtration on the low-acid leaching residue to obtain a high-acid leaching residue and a high-acid leaching solution.

[0084] As an embodiment of the present application, the initial concentration of the high-acid leaching sulfuric acid solution is 4-7 mol / L, and can be specifically 4 mol / L, 5 mol / L, 6 mol / L or 7 mol / L; the liquid-solid ratio of the high-acid leaching can be 3-5 mL / g, and can be specifically 3 mL / g, 4 mL / g or 5 mL / g; the temperature of the high-acid leaching can be 60-90°C, and can be specifically 60°C, 70°C, 80°C or 90°C; and the time of the high-acid leaching can be 3-6 h, and can be specifically 3 h, 4 h, 5 h or 6 h.

[0085] After obtaining the high-acid leaching solution, the present application adds the high-acid leaching solution to manganese dioxide for oxidation, and adds the obtained oxidation solution to the lithium phosphate crude product for iron and aluminum removal and pressure filtration, to obtain an iron and aluminum removed solution.

[0086] As an embodiment of the present application, the reaction occurring in the oxidation process is:

[0087] 2Fe 2+ + MnO2+ 4H + = 2Fe 3+ + Mn 2+ + 2H2O.

[0088] As an embodiment of the present application, the reaction occurring in the iron and aluminum removal process is:

[0089] Fe2(SO4)3+ 2Li3PO4= 2FePO4↓+ 3Li2SO4;

[0090] Al2(SO4)3+ 2Li3PO4= 2AlPO4↓+ 3Li2SO4.

[0091] As an embodiment of the present application, the ratio of the molar amount of the manganese dioxide added to the molar amount of Fe in the high-acid leaching solution is 1.1-1.2:2, the time of the oxidation can be 1-2 h, and the ratio of the molar amount of the lithium phosphate crude product added to the total molar amount of iron ions and aluminum ions in the solution after the oxidation is 1-1.2:1; in the iron and aluminum removal, the pH value of the system can be 3-4, and the reaction time of the iron and aluminum removal can be 1-3 h, and can be specifically 1 h, 2 h or 3 h.

[0092] After obtaining the iron and aluminum removed solution, the present application sequentially performs copper extraction on the iron and aluminum removed solution, to obtain a copper raffinate and a battery-grade copper sulfate.

[0093] As an embodiment of the present application, the copper extraction extractant can be a mixture of 5-dodecyl salicylaldoxime and 2-hydroxy-5-nonyl acetophenone oxime (LIX 984N); as an embodiment of the present application, the copper extraction phase ratio can be 1-5:1, and the copper extraction obtained loaded copper organic phase is back-extracted with 2-4 mol / L sulfuric acid solution to obtain battery-grade copper sulfate.

[0094] After obtaining the copper raffinate, the present application carries out impurity extraction on the copper raffinate to obtain a decontaminated solution and a manganese solution; the obtained manganese solution is subjected to deep purification to obtain battery-grade manganese sulfate; the deep purification is sulfurization heavy metal removal, calcium removal and fluorine removal in sequence;

[0095] As an embodiment of the present application, the ratio of the molar amount of Na2S added to the molar amount of Me (Me is one or more of Fe, Al, Cu, Co elements) in the manganese solution during the sulfurization heavy metal removal is 1-1.5:1;

[0096] As an embodiment of the present application, the ratio of the molar amount of NaF added to the molar amount of Ca in the solution after sulfurization heavy metal removal during the calcium removal is 2-6:1; and the mass of zirconium hydroxide during the fluorine removal is 50-100 times the mass of fluorine ions in the solution after calcium removal.

[0097] As an embodiment of the present application, the impurity extraction extractant can be di(2-ethylhexyl) phosphate (P204); as an embodiment of the present application, the impurity extraction phase ratio can be 1-5:1, and the impurity extraction obtained loaded metal impurity organic phase is back-extracted with 2-4 mol / L sulfuric acid solution.

[0098] After obtaining the decontaminated solution, the present application carries out cobalt extraction on the decontaminated solution to obtain battery-grade cobalt sulfate and cobalt raffinate containing low-concentration lithium nickel magnesium; the obtained cobalt raffinate containing low-concentration lithium nickel magnesium is divided into two streams and enters a lithium nickel magnesium extraction section to extract lithium nickel magnesium, and the obtained loaded lithium nickel magnesium organic phase enters a cobalt extraction section again for extraction and separation to obtain raffinate containing high-concentration lithium nickel magnesium.

[0099] As an embodiment of the present application, the cobalt extraction extractant can be 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507); as an embodiment of the present application, the cobalt extraction phase ratio can be 1-5:1, and the cobalt extraction obtained loaded cobalt organic phase is back-extracted with 1-3 mol / L sulfuric acid solution to obtain battery-grade cobalt sulfate.

[0100] As an embodiment of the present application, the cobalt extraction and the lithium-nickel-magnesium extraction are carried out in the cobalt extraction section and the lithium-nickel-magnesium extraction section, respectively; as an embodiment of the present application, a plurality of lithium-nickel-magnesium extraction sections can be added in front of the cobalt extraction section, and the extractant of the lithium-nickel-magnesium extraction section is P507; the number of stages of the lithium-nickel-magnesium extraction section is 2-6. As an embodiment of the present application, the raffinate containing low-concentration lithium-nickel-magnesium in the cobalt extraction section is introduced into the lithium-nickel-magnesium extraction section to extract lithium-nickel-magnesium, and the obtained lithium-nickel-magnesium loaded organic phase is returned to the cobalt extraction section to extract and separate, thereby obtaining raffinate containing high-concentration lithium-nickel-magnesium.

[0101] After obtaining the raffinate containing high-concentration lithium-nickel-magnesium, the present application extracts magnesium from the raffinate containing high-concentration lithium-nickel-magnesium to obtain magnesium raffinate and battery-grade magnesium sulfate.

[0102] As an embodiment of the present application, the extractant for the magnesium extraction can be di(2,4,4-trimethylpentyl) phosphinic acid (C272); the extraction phase ratio for the magnesium extraction can be 1-5:1, and the magnesium loaded organic phase obtained by the magnesium extraction is stripped with 2-4 mol / L sulfuric acid solution to obtain battery-grade magnesium sulfate.

[0103] After obtaining the magnesium raffinate, the present application extracts nickel from the magnesium raffinate to obtain lithium-rich solution and battery-grade nickel sulfate; the lithium-rich solution is returned to step (3) for fluorine and heavy metal removal.

[0104] As an embodiment of the present application, the extractant for the nickel extraction can be P507; when the nickel extraction is carried out, the extraction phase ratio can be 1-5:1, specifically 1:1, 2:1, 3:1, 4:1 or 5:1, and the nickel loaded organic phase obtained by the nickel extraction is stripped with 2-4 mol / L sulfuric acid solution to obtain battery-grade nickel sulfate.

[0105] The present application constructs a lithium closed-loop technology system of "blank roasting-circulating leaching-synergistic impurity removal-lithium phosphate aluminum removal-directional extraction and lithium-nickel-magnesium extraction by diversion", which does not need to add roasting aids, reducing agents and aluminum removal agents in the whole process, eliminates the redundant processes such as carbonization, resin purification, pyrolysis and the like in the traditional lithium carbonate purification, saves the lithium solution concentration cost, realizes green and clean production without hazardous waste, and ensures high product quality through synergistic impurity removal and directional extraction. The recovery rates of cobalt, nickel, copper, manganese, magnesium and lithium in the whole process are all over 99%, and the products of cobalt, nickel, copper, manganese, magnesium and lithium all reach the battery grade standard. The battery-grade lithium carbonate preparation process is shortened by more than 50% compared with the traditional process, and the processing cost per ton of lithium is reduced by more than 40%. The process is short, the technology is simple, the efficiency is high, the energy consumption is low, and the product quality is excellent, which provides an efficient solution for green and high-value recycling of waste lithium batteries.

[0106] In order to further illustrate the present application, the schemes of the present application are described in detail below in conjunction with the accompanying drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0107] Example 1

[0108] The waste ternary lithium battery was crushed and sieved to obtain waste ternary lithium battery black powder, and the main element content of the waste ternary lithium battery black powder is shown in Table 1.

[0109] Table 1 Main element content of waste ternary lithium battery black powder (unit: %)

[0110]

[0111] Reaction scheme:

[0112] (1) The waste ternary lithium battery black powder was blank roasted by passing natural gas, the roasting temperature was 550℃, and the roasting time was 2h, to obtain a roasting residue.

[0113] (2) The roasting residue was subjected to cyclic leaching and lithium enrichment with a dilute sulfuric acid solution with a pH of 2, and when the lithium concentration of the lithium-rich cyclic leaching solution was ≥20g / L, part of the leaching solution was diverted to the defluorination and heavy metal removal process, and the lithium-rich cyclic leaching solution that was not diverted was adjusted to a pH of 2 and returned to the cyclic leaching of new roasting residues. The liquid-solid ratio of each low-acid leaching was 10 mL / g, the leaching time of each low-acid leaching was 1h, and the leaching solution obtained by each low-acid leaching was adjusted to a pH of 2 and returned to the cyclic leaching of new roasting residues. The low-acid cyclic leaching process obtained the diverted lithium-rich leaching solution and the low-acid leaching residue. The concentration of part of the elements in the diverted lithium-rich leaching solution and the content of part of the elements in the low-acid leaching residue are shown in Table 2 and Table 3.

[0114] Table 2 Concentration of part of the elements in the diverted lithium-rich leaching solution (g / L)

[0115]

[0116] Table 3 Content of part of the elements in the low-acid leaching residue (%)

[0117]

[0118] (3) According to n(CaO):[n(Me)+n(F - ) / 2]=1.2:1 (Me: Co, Ni, Mn, Cu elements), calcium oxide was added to the diverted lithium-rich leaching solution to remove fluorine and heavy metals, the reaction time was 2h, and the reaction temperature was 30℃, to obtain a defluorination and heavy metal removal solution, and Table 4 shows the concentration of part of the elements in the defluorination and heavy metal removal solution.

[0119] Table 4 Concentration of part of the elements in the defluorination and heavy metal removal solution (g / L)

[0120]

[0121] (4) The defluorination and heavy liquid were subjected to P204 calcium extraction treatment, and the extraction phase ratio was 3:1, to obtain a calcium-removed liquid. Table 5 shows the concentration of some elements in the calcium-removed liquid.

[0122] Table 5 Concentration of some elements in the calcium-removed liquid (g / L)

[0123]

[0124] (5) Zirconium hydroxide was added into the calcium-removed liquid, and the total mass of silicon, phosphorus and fluorine in the solution was 30 times that of the zirconium hydroxide, to remove silicon, phosphorus and fluorine in depth. The treatment time was 1 h, to obtain a silicon-phosphorus-fluorine-removed liquid. Table 6 shows the concentration of some elements in the silicon-phosphorus-fluorine-removed liquid.

[0125] Table 6 Concentration of some elements in the silicon-phosphorus-fluorine-removed liquid (g / L)

[0126]

[0127] (6) The silicon-phosphorus-fluorine-removed liquid and a sodium carbonate solution were added into a synthesis reactor in parallel flow. During the synthesis, battery-grade lithium carbonate was added as a seed crystal to induce lithium precipitation. The sodium carbonate was added in a molar ratio of n(Na2CO3):n(Li)=1.2:2, the concentration of the sodium carbonate solution was 300 g / L, the amount of the seed crystal added was 10 wt.% of the mass of the synthesized lithium carbonate, and the synthesis temperature was 100°C. After the synthesis, lithium carbonate and a lithium precipitation mother liquor were obtained by centrifugation. The battery-grade lithium carbonate was obtained after being washed with hot water for 3 times. The hot water washing temperature was 80°C, and the washing time was 1 h. The concentration of some elements in the lithium precipitation mother liquor and the purity of the battery-grade lithium carbonate were analyzed, and the results are shown in Tables 7 and 8.

[0128] Table 7 Concentration of some elements in the lithium precipitation mother liquor (g / L)

[0129]

[0130] Table 8 Content of the battery-grade lithium carbonate (%)

[0131]

[0132] (7) The lithium precipitation mother liquor was added into trisodium phosphate to synthesize lithium phosphate crude product. The trisodium phosphate was added in a molar ratio of n(Na3PO4):n(Li)=1.1:3, the synthesis temperature was 80°C, and the synthesis time was 1.5 h. Table 9 shows the content of some elements in the lithium phosphate crude product.

[0133] Table 9 Content of some elements in the lithium phosphate crude product (%)

[0134]

[0135] (8) The low-acid leaching residue is added into 6 mol / L sulfuric acid solution for high-acid leaching, the high-acid leaching liquid-solid ratio is 5 mL / g, the leaching temperature is 80°C, and the leaching time is 5 h, to obtain high-acid leaching residue and high-acid leaching liquid, and the high-acid leaching residue is subjected to 4 times of countercurrent washing to obtain washed high-acid leaching residue. The concentration of partial elements in the high-acid leaching liquid and the content of partial elements in the washed high-acid leaching residue are analyzed, and the results are shown in Tables 10 and 11.

[0136] Table 10 Concentration of partial elements in high-acid leaching liquid (g / L)

[0137]

[0138] Table 11 Content of partial elements in washed high-acid leaching residue (%)

[0139]

[0140] (9) Manganese dioxide is added into the high-acid leaching liquid for oxidation according to n(MnO2):n(Fe) = 1.1:2, and the oxidation time is 1 h. Lithium phosphate crude product is added into the oxidized liquid for iron and aluminum removal according to n(Li3PO4):[n(Fe 3+ )+n(Al 3+ )]=1.05:1, the pH for iron and aluminum removal is controlled at 3.5, the reaction time is 2 h, to obtain iron and aluminum removal liquid and iron and aluminum removal residue, and the iron and aluminum removal residue is subjected to 4 times of countercurrent washing to obtain washed iron and aluminum removal residue. The concentration of partial elements in the iron and aluminum removal liquid and the content of partial elements in the washed iron and aluminum removal residue are analyzed, and the results are shown in Tables 12 and 13.

[0141] Table 12 Concentration of partial elements in iron and aluminum removal liquid (g / L)

[0142]

[0143] Table 13 Content of partial elements in washed iron and aluminum removal residue (%)

[0144]

[0145] (10) After iron and aluminum are removed, the solution is sequentially subjected to LIX984N copper extraction, P204 miscellaneous extraction, manganese solution deep purification, P507 cobalt extraction, and split-flow lithium, nickel and magnesium extraction, C272 magnesium extraction, and P507 nickel extraction, with an extraction phase ratio of 3:1. The P507 cobalt extraction process has 4 stages in the lithium, nickel and magnesium extraction section. The stripping acids for LIX984N copper extraction, P204 miscellaneous extraction, P507 cobalt extraction, C272 magnesium extraction, and P507 nickel extraction are 3 mol / L sulfuric acid, 3 mol / L sulfuric acid, 2 mol / L sulfuric acid, 2 mol / L sulfuric acid, and 3 mol / L sulfuric acid, respectively, to obtain battery-grade copper sulfate, manganese solution, battery-grade cobalt sulfate, battery-grade magnesium sulfate, and battery-grade nickel sulfate. The manganese solution is subjected to heavy metal removal (the molar ratio of Na2S added to Me in the manganese solution is 1.5:1, and Me is Fe, Al, Cu, and Co), calcium removal (the molar ratio of NaF added to Ca in the solution after heavy metal removal is 4:1), and fluorine removal (the mass of zirconium hydroxide is 50 times the mass of fluorine in the solution after calcium removal) to obtain battery-grade manganese sulfate. The raffinate containing high concentrations of lithium, nickel and magnesium obtained in the split-flow lithium, nickel and magnesium extraction section of the P507 cobalt extraction process is subjected to C272 magnesium extraction and P507 nickel extraction to obtain a lithium-rich solution, which is returned to the heavy metal and fluorine removal process to realize lithium closed-loop recovery. The purity of battery-grade products such as copper sulfate, manganese sulfate, cobalt sulfate, magnesium sulfate, and nickel sulfate, and the content of some elements in the lithium-rich solution are analyzed, and the results are shown in Tables 14-15.

[0146] Table 14 Purity of battery-grade products such as copper sulfate, manganese sulfate, cobalt sulfate, magnesium sulfate, and nickel sulfate (g / L)

[0147]

[0148] Table 15 Concentration of some elements in the lithium-rich solution (g / L)

[0149]

[0150] The recovery rates of cobalt, nickel, copper, manganese, magnesium, and lithium in Example 1 are shown in Table 16.

[0151] Table 16 Recovery rates of cobalt, nickel, copper, manganese, magnesium, and lithium (%)

[0152]

[0153] Example 2

[0154] The waste ternary lithium battery is crushed and sieved to obtain a waste ternary lithium battery black powder, and the content of main elements is shown in Table 17.

[0155] Table 17 Content of main elements in waste ternary lithium battery black powder (%)

[0156]

[0157] (1) The waste ternary lithium battery black powder is blank roasted by natural gas, the roasting temperature is 600 DEG C, and the roasting time is 1.5 h, and the roasting slag is obtained.

[0158] (2) The roasting slag is subjected to cyclic leaching and lithium enrichment by using a dilute sulfuric acid solution with a pH of 2.5, and when the lithium concentration of the lithium-rich cyclic leaching solution is greater than or equal to 20 g / L, part of the solution is diverted to a defluorination and heavy metal removal process, and the lithium-rich leaching solution that is not diverted is adjusted to a pH of 2.5 and returned to the new roasting slag for cyclic leaching. The liquid-solid ratio of each low-acid leaching is controlled to be 15 mL / g, the time of each low-acid leaching is 1 h, and the leaching solution obtained by each low-acid leaching is adjusted to a pH of 2.5 and returned to the new roasting slag for cyclic leaching. The diverted lithium-rich leaching solution and the low-acid leaching slag are obtained by the low-acid cyclic leaching process. The concentrations of part of the elements in the diverted lithium-rich leaching solution and the contents of part of the elements in the low-acid leaching slag are analyzed, and the results are shown in Tables 18 and 19.

[0159] Table 18 Concentrations of part of the elements in the diverted lithium-rich leaching solution (g / L)

[0160]

[0161] Table 19 Contents of part of the elements in the low-acid leaching slag (%)

[0162]

[0163] (3) The diverted lithium-rich leaching solution is added with calcium oxide according to n(CaO):[n(Me)+n(F - ) / 2]=1.15:1 (Me: Co, Ni, Mn, Cu elements) for defluorination and heavy metal removal. The reaction time is 1.5 h, and the defluorination and heavy metal removal solution is obtained. The concentrations of part of the elements in the defluorination and heavy metal removal solution are analyzed, and the results are shown in Table 20.

[0164] Table 20 Concentrations of part of the elements in the defluorination and heavy metal removal solution (g / L)

[0165]

[0166] (4) The defluorination and heavy metal removal solution is subjected to P204 calcium extraction treatment, and the extraction phase ratio is 4:1, and the calcium removal solution is obtained. The concentrations of part of the elements in the calcium removal solution are analyzed, and the results are shown in Table 21.

[0167] Table 21 Concentrations of part of the elements in the calcium removal solution (g / L)

[0168]

[0169] (5) Zirconium hydroxide is added to the calcium removal solution, and the total mass of silicon, phosphorus and fluorine in the solution is 40 times that of the zirconium hydroxide for deep silicon, phosphorus and fluorine removal. The treatment time is 1 h, and the silicon, phosphorus and fluorine removal solution is obtained. The concentrations of part of the elements in the silicon, phosphorus and fluorine removal solution are analyzed, and the results are shown in Table 22.

[0170] Table 22 Partial element concentration (g / L) of desiliconized phosphorus-fluorine solution

[0171]

[0172] (6) The desiliconized phosphorus-fluorine solution and the sodium carbonate solution were added into a synthesis reactor in parallel flow, and battery-grade lithium carbonate was added as a seed crystal for inducing lithium precipitation during the synthesis. The sodium carbonate was added in a molar ratio of n(Na2CO3):n(Li) = 1.15:2, the concentration of the sodium carbonate solution was 330 g / L, and the amount of the seed crystal added was 15% of the mass of the synthesized lithium carbonate. The synthesis temperature was 100°C. After the synthesis, lithium carbonate and a lithium precipitation mother liquor were obtained by centrifugation. The battery-grade lithium carbonate was obtained after three hot water washes, the hot water washing temperature was 80°C, and the washing time was 1 h. The partial element concentration of the lithium precipitation mother liquor and the purity of the battery-grade lithium carbonate were analyzed, and the results are shown in Tables 23 and 24.

[0173] Table 23 Partial element concentration (g / L) of lithium precipitation mother liquor

[0174]

[0175] Table 24 Content of battery-grade lithium carbonate (%)

[0176]

[0177] (7) The lithium precipitation mother liquor was added to trisodium phosphate to synthesize lithium phosphate crude product. The trisodium phosphate was added in a molar ratio of n(Na3PO4):n(Li) = 1.15:3, the synthesis temperature was 80°C, and the synthesis time was 2 h. The partial element content of the lithium phosphate crude product was analyzed, and the results are shown in Table 25.

[0178] Table 25 Partial element content (%) of lithium phosphate crude product

[0179]

[0180] (8) The low-acid leaching residue was added to a 7 mol / L sulfuric acid solution for high-acid leaching. The solid-to-liquid ratio of the leaching solution was 5:1, the leaching temperature was 80°C, and the leaching time was 6 h. A high-acid leaching residue and a high-acid leaching solution were obtained. The high-acid leaching residue was washed four times in countercurrent to obtain a washed high-acid leaching residue. The partial element concentration of the high-acid leaching solution and the partial element content of the washed high-acid leaching residue were analyzed, and the results are shown in Tables 26 and 27.

[0181] Table 26 Partial element concentration (g / L) of high-acid leaching solution

[0182]

[0183] Table 27 Partial element content (%) of washed high-acid leaching residue

[0184]

[0185] (9) The high acid leaching solution is added with manganese dioxide for oxidation in the ratio of n(Mn02):n(Fe) = 1.1:2, and the oxidation time is 1 h. The lithium phosphate is added to the oxidized solution for iron and aluminum removal in the ratio of n(Li3PO4):[n(Fe)+n(Al)] = 1.05:1, the pH for iron and aluminum removal is controlled at 3.7, and the reaction time is 2 h, to obtain the solution after iron and aluminum removal and the iron and aluminum removal residue, and the iron and aluminum removal residue is washed for 4 times to obtain the washed iron and aluminum removal residue. The concentrations of some elements in the solution after iron and aluminum removal and the contents of some elements in the washed iron and aluminum removal residue are analyzed, and the results are shown in Tables 28 and 29.

[0186] Table 28 Concentrations of some elements in the solution after iron and aluminum removal (g / L)

[0187]

[0188] Table 29 Contents of some elements in the washed iron and aluminum removal residue (%)

[0189]

[0190] (10) The solution after iron and aluminum removal is sequentially subjected to LIX984N copper extraction, P204 miscellaneous extraction, manganese solution deep purification, P507 cobalt extraction, and split-flow lithium, nickel and magnesium extraction, C272 magnesium extraction, and P507 nickel extraction, and the extraction phase ratio is 4:1, the split-flow enrichment lithium section in the P507 cobalt extraction process has 5 stages, the stripping acids for LIX984N copper extraction, P204 miscellaneous extraction, P507 cobalt extraction, C272 magnesium extraction, and P507 nickel extraction are 3 mol / L sulfuric acid, 3 mol / L sulfuric acid, 2 mol / L sulfuric acid, 2 mol / L sulfuric acid, and 3 mol / L sulfuric acid respectively, to obtain battery-grade copper sulfate, manganese solution, battery-grade cobalt sulfate, battery-grade magnesium sulfate, and battery-grade nickel sulfate. The manganese solution is subjected to heavy metal removal (the ratio of the added amount of Na2S to the amount of Me in the manganese solution is 1.5:1, Me is Fe, Al, Cu, and Co), calcium removal (the ratio of the added amount of NaF to the amount of Ca in the solution after heavy metal removal by sulfuration is 4:1), and fluorine removal (the mass of zirconium hydroxide is 50 times the mass of fluorine in the solution after calcium removal) for deep purification, to obtain battery-grade manganese sulfate. The raffinate containing high concentrations of lithium, nickel and magnesium obtained in the split-flow lithium, nickel and magnesium extraction section in the P507 cobalt extraction process is subjected to C272 magnesium extraction and P507 nickel extraction in sequence to obtain a lithium-rich solution, and the lithium-rich solution is returned to the heavy metal removal and fluorine removal process to realize lithium closed-loop recovery. The purity of battery-grade products such as copper sulfate, manganese sulfate, cobalt sulfate, magnesium sulfate, and nickel sulfate, and the content of some elements in the lithium-rich solution are analyzed, and the results are shown in Tables 30 and 31.

[0191] Table 30 Purity of battery-grade products such as copper sulfate, manganese sulfate, cobalt sulfate, magnesium sulfate, and nickel sulfate (g / L)

[0192]

[0193] Table 31 Concentration of partial elements of lithium-rich solution (g / L)

[0194]

[0195] The recovery rates of cobalt, nickel, copper, manganese, magnesium and lithium in Example 2 are shown in Table 32.

[0196] Table 32 Recovery rates of cobalt, nickel, copper, manganese, magnesium and lithium (%)

[0197]

[0198] Although the above embodiment has made a detailed description of the present application, it is only a part of the embodiments of the present application, but not all the embodiments, and other embodiments can be obtained according to the present embodiment without creativity, which all belong to the protection scope of the present application.

Claims

1. A method for recycling battery-grade lithium carbonate and valuable metals from spent ternary lithium batteries by a short process of black powder, characterized in that, The method comprises the following steps: (1) blank roasting waste ternary lithium battery black powder under natural gas atmosphere to obtain roasting slag; (2) low-acid cyclic leaching and pressure filtration of the roasting slag with dilute sulfuric acid solution to obtain lithium-rich cyclic leaching solution and low-acid leaching residue; (3) when the lithium concentration in the lithium-rich cyclic leaching solution is greater than or equal to 20 g / L, part of the lithium-rich cyclic leaching solution is mixed with calcium oxide, and defluorination and heavy metal removal are carried out in turn, and pressure filtration is carried out to obtain defluorination and heavy metal removal solution; (4) the defluorination and heavy metal removal solution is subjected to calcium removal by extraction to obtain calcium removal solution; (5) zirconium hydroxide is added to the calcium removal solution to deeply remove silicon, phosphorus and fluorine to obtain silicon, phosphorus and fluorine removal solution; (6) pure water is used as a bottom liquid, and battery-grade lithium carbonate is added as a seed crystal, and the silicon, phosphorus and fluorine removal solution and sodium carbonate solution are added to a synthesis kettle in a parallel flow mode to induce lithium precipitation to obtain lithium carbonate and lithium precipitation mother liquor; (7) trisodium phosphate is added to the lithium precipitation mother liquor to synthesize lithium phosphate crude product; (8) the low-acid leaching residue is subjected to high-acid leaching and pressure filtration in turn to obtain high-acid leaching residue and high-acid leaching solution; (9) manganese dioxide is added to the high-acid leaching solution for oxidation, and the obtained oxidized solution is added to the lithium phosphate crude product for iron and aluminum removal and pressure filtration to obtain iron and aluminum removal solution and iron and aluminum removal residue; (10) the iron and aluminum removal solution is subjected to copper extraction to obtain copper raffinate and battery-grade copper sulfate; (11) the copper raffinate is subjected to impurity extraction to obtain impurity removal solution and manganese solution; The manganese solution is subjected to deep purification in turn to obtain battery-grade manganese sulfate; the deep purification is sulfidation, calcium removal and fluorine removal in turn; (12) the impurity removal solution is subjected to cobalt extraction to obtain battery-grade cobalt sulfate and cobalt raffinate containing low-concentration lithium, nickel and magnesium; the cobalt raffinate containing low-concentration lithium, nickel and magnesium is subjected to lithium, nickel and magnesium extraction, and the obtained lithium, nickel and magnesium loaded organic phase is subjected to extraction separation in the cobalt extraction section again to obtain raffinate containing high-concentration lithium, nickel and magnesium; (13) the raffinate containing high-concentration lithium, nickel and magnesium is subjected to magnesium extraction to obtain magnesium raffinate and battery-grade magnesium sulfate; (14) the magnesium raffinate is subjected to nickel extraction to obtain lithium-rich solution and battery-grade nickel sulfate; the lithium-rich solution is recycled to step (3) for defluorination and heavy metal removal.

2. The method of claim 1, wherein, The temperature of the blank roasting is 450-650 DEG C, and the roasting time is 1-3 h.

3. The method of claim 1, wherein, In the low-acid cyclic leaching, the leaching solution obtained by each low-acid leaching is recycled for low-acid cyclic leaching after acid adjustment, and the pH of the dilute sulfuric acid solution or the leaching solution after acid adjustment is 1-3; in each low-acid leaching, the liquid-solid ratio is 10-20 ml / g, and the time of each low-acid leaching is 1-4 h.

4. The method of claim 1 wherein, The time of the defluorination and heavy metal removal is 1-4 h, and the temperature is 25-50 DEG C; the molar ratio of the added calcium oxide to the molar amount of fluorine and heavy metals in the part of the lithium-rich cyclic leaching solution is 1.1-1.3:1; the molar amount of fluorine and heavy metals is the sum of the molar amount of fluorine ions and the molar amount of heavy metal ions; the heavy metals include one or more of Co, Ni, Mn and Cu.

5. The method of claim 1 wherein, The extractant for the calcium removal by extraction is di(2-ethylhexyl) phosphate; the added amount of zirconium hydroxide is 20-60 times the total mass of silicon, phosphorus and fluorine in the calcium removal solution; the time of the deep removal of silicon, phosphorus and fluorine is 1-3 h.

6. The method of claim 1 wherein, In the step (6), the molar ratio of sodium carbonate in the sodium carbonate solution to Li element in the desiliconized phosphorus fluorine solution is 1.1-1.2:2, the concentration of the sodium carbonate solution is 250-350 g / L; the added amount of the battery-grade lithium carbonate is 5-15 wt.% of the mass of the synthesized lithium carbonate, and the temperature for inducing lithium precipitation is 80-100 ℃.

7. The method of claim 1 wherein, The ratio of the added molar amount of the trisodium phosphate to the molar amount of Li element in the lithium precipitation mother liquor is 1.1-1.2:3, the synthesis temperature of the lithium phosphate crude product is 80-100 ℃, and the synthesis time is 1-3 h.

8. The method of claim 1 wherein, The initial concentration of the sulfuric acid solution subjected to high-acid leaching is 4-7 mol / L; the liquid-solid ratio of the high-acid leaching is 3-5 mL / g; the temperature of the high-acid leaching is 60-90 ℃, and the time of the high-acid leaching is 3-6 h.

9. The method of claim 1 wherein, The ratio of the added molar amount of the manganese dioxide to the molar amount of Fe element in the high-acid leaching solution is 1.1-1.2:2, the oxidation time is 1-2 h, and the ratio of the added molar amount of the lithium phosphate crude product to the total molar amount of iron ions and aluminum ions in the solution after oxidation is 1-1.2:1; when the iron and aluminum are removed, the pH value of the system is 3-4, and the reaction time for removing the iron and aluminum is 1-3 h.

10. The method of claim 1 wherein, The extractant for extracting copper is a mixture of 5-dodecyl salicylaldoxime and 2-hydroxy-5-nonyl acetophenone oxime; the extractant for extracting impurities is di(2-ethylhexyl) phosphate; the extractant for extracting cobalt is 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester; the extractant for extracting magnesium is di(2,4,4-trimethylpentyl) phosphinic acid; and the extractant for extracting nickel is 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester.

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