80 results about "Lithium carbonate preparation" patented technology

The invention relates to a method for producing high-purity lithium carbonate by using lithium concentrate. The method is characterized by comprising the following steps of: preparing an acid clinker, preparing a mixing size, preparing a lithium sulfate leaching solution, preparing a lithium sulfate purification liquid, preparing a lithium sulfate finishing solution, preparing a sodium carbonate solution, performing primary lithium deposition reaction, preparing a sodium separating mother liquor, preparing excellent lithium carbonate in a sweating manner, and preparing 99.99% of high-purity lithium carbonate. By adopting the method, the principle of removing calcium and magnesium ions is ingeniously utilized in preparation of common lithium carbonate; a fussy procedure of removing calcium and magnesium by ion exchange resin is avoided when the common lithium carbonate is purified to prepare the high-purity lithium carbonate; a method of recycling after separating out sodium sulfate in a freezing manner is adopted to process the primary lithium settling mother liquor; the high-purity lithium carbonate mother liquor in precipitation of the high-purity lithium carbonate is used as an optimal lithium carbonate washing liquor for primary lithium sedimentation after being recycled for a plurality of times. Thus, the method has the characteristics of simple process, high production efficiency, high recovery rate and low production cost.

The invention relates to a method for purifying lithium carbonate, belonging to the technical field of the preparation of high-purity lithium carbonate. The method is characterized by safe production process and high lithium yield. The method comprises the following specific steps: (1) washing lithium carbonate to be purified to remove impurities, and adding water to prepare lithium carbonate slurry; (2) introducing CO2 into the lithium carbonate slurry prepared in the step (1) to carry out hydrogenation reaction, stopping introducing CO2 when the concentration of lithium oxide concentration in a solution is 10-30g/L, and filtering the solution to obtain a hydrogenated solution, wherein the hydrogenation reaction is carried out at the pressure of 0.2-0.6Mpa and the temperature of 20-30 DEG C; (3) subjecting the hydrogenated solution obtained in the step (2) to an ion exchange resin to remove impurity ions in the hydrogenated solution; and (4) heating the hydrogenated solution in which the impurity ions are removed in the step (3) to 70-90 DEG C to carry out decomposition reaction, separating solid from liquid to obtain the wet lithium carbonate, and drying the wet lithium carbonate. The produced battery-level lithium carbonate has high main content, excellent quality and stable performance.

The invention discloses a method for preparing nano lithium carbonate in the technical field of nano lithium carbonate preparation. The method comprises the following steps: preparing water-soluble lithium salt or lithium hydroxide, water and a water-soluble dispersing agent into a mixed solution; then spraying and dispersing the mixed solution to porous aggregate in the annular filling area of arotary filling bed, simultaneously introducing CO2 or a water-soluble carbonate solution, and rapidly and completely mixing under the action of centrifugal force; discharging nano lithium carbonate particles generated by reaction crystallization out of the discharge hole of the rotary filling bed along with the mixed solution; and filtering, washing and drying so as to obtain nano lithium carbonate powder. In the method, a rotary filling bed reactor is used and has the advantages of simple equipment, small volume and small energy consumption, and reaction is carried out at normal pressure, thus the preparation cost is low. The method has the characteristics that the process is simple, the operation is convenient, the production efficiency is high, side reactions and toxic and harmful substances are not generated in the reaction process, and the method is environmental-friendly. The prepared nano lithium carbonate has the advantages of stable components, uniform particle size and narrow particle size distribution range.

The invention discloses a method for preparing high-purity lithium carbonate with co-production of lithium fluoride by employing crude lithium carbonate. The method includes following steps: (1) preparing the crude lithium carbonate into lithium carbonate concentrate; (2) preparing the lithium carbonate concentrate into a slurry material with addition of lime and performing filtration to obtain a crude lithium hydroxide solution; (3) concentrating and filtering the crude lithium hydroxide solution, adding a complexing agent to remove impurity metal ions to obtain a refined lithium hydroxide solution; (4) feeding CO2 into the refined lithium hydroxide solution for carbonization and performing filtration to obtain a lithium bicarbonate solution; and (5) heating the lithium bicarbonate solution, performing a filtering and washing process, drying a filter cake to obtain the high-purity lithium carbonate, mixing the filtrate and a washing liquid with addition of hydrofluoric acid, performing a filtering and washing process, and then drying the filter cake to obtain the lithium fluoride. By means of the method, impurity ions in the high-purity lithium carbonate is in the trace-amount grade. The quality of the high-purity lithium carbonate is better in an industrial requirement in YS/T546-2008. Problems of poor quality, low lithium yield and high production cost in preparation of the high-purity lithium carbonate from salt lake lithium are solved.

The invention relates to a preparation method of high-purity lithium carbonate, which belongs to the technical field of preparation of high-purity lithium carbonate. The invention aims at providing the method for directly preparing 99.99% lithium hydroxide by adopting lithium hydroxide, which is simple in production process. The technical scheme of the invention is as follows: preparing battery level lithium hydroxide monohydrate into solution of Li2O with concentration of 50-90g/L; introducing CO2 gas at the flow rate of 3-5L/s into the lithium hydroxide solution, wherein the flow rate of CO2 is decreased to 2-3L/s when the concentration of Li2O in the solution is decreased to 40g/L; decreasing the flow rate of CO2 to 0.8-1.2L/s when the concentration of Li2O in the solution is decreased to 20g/L; stop introducing the gas when a large number of liquids appear in the solution, and preparing lithium carbonate slurry; and separating the lithium carbonate slurry, washing the solids, drying until moisture is less than 0.1%, finally preparing the lithium carbonate. The battery level lithium hydroxide monohydrate is adopted as raw material, the high-purity lithium carbonate with the purity of 99.99% can be simply and conveniently prepared by adopting the method, and further purification is not required.

The invention relates to the field of salt lake resource comprehensive utilization, in particular to a method for preparing lithium carbonate through salt lake brine with the high ratio of magnesium to lithium. The salt lake brine with the high ratio of magnesium to lithium serves as a raw material, a certain amount of soluble trivalent metal salt is added, the ratio of magnesium to lithium in the salt lake brine is reduced by synthesizing magnesium-based stratified functional materials, magnesium and lithium in the salt lake brine with the high ratio of magnesium to lithium are separated, and then lithium carbonate is prepared through hydrotalcite mother liquor with the low ratio of magnesium to lithium. The technical problems that an existing method is complex in process, cost is high, and the magnesium and lithium separation effect is not ideal can be effectively solved through magnesium and lithium separation and lithium carbonate preparation methods, the lithium carbonate preparation process is simplified, cost is reduced, waste magnesium resources are fully utilized, and meanwhile the cost of the magnesium-based functional materials is reduced; high-valued and comprehensive utilization of salt lake magnesium, lithium and boron resources is achieved, and good industrialization prospects are achieved.

The invention provides a process for recovering lithium phosphorous from a lithium phosphate crude product to prepare battery-level lithium carbonate and iron phosphate, and belongs to the technical field of resource recycling. The process comprises: lithium phosphate slurrying: adding pure water or washing water to the lithium phosphate crude product to prepare slurry, and performing high-speed dispersion and grinding dispersion to obtain uniform lithium phosphate slurry; iron solution preparation: filtering an iron solution to obtain a refined iron solution; iron orthophosphate preparation:adding inorganic acid into a pure water base solution to regulate pH to 2-3, adding the lithium phosphate slurry and the refined iron solution after temperature rise, performing solid-liquid separation after reaction is completed, initially washing a solid by the pure water, re-washing the solid by slurry mixing, and drying and crushing the solid, so as to obtain iron orthophosphate; battery-levellithium carbonate preparation: purifying a lithium-containing mother solution obtained by preparing the iron orthophosphate, and inputting into a mixed solution of sodium carbonate and EDTA to perform lithium deposition reaction, and performing separation, washing, drying and crushing to obtain lithium carbonate. The lithium phosphate crude product is treated by means of the process of the invention, so that iron orthophosphate and lithium carbonate products meeting quality requirements of a lithium battery can be obtained.

The invention belongs to the technical field of lithium carbonate preparation, and discloses a method for preparing low-magnetism high-purity lithium carbonate by using saline lithium salt. The method using the saline lithium salt as a raw material mainly comprises the following steps: pulping the saline lithium salt, carrying out countercurrent washing, hydrogenating carbonic acid, removing magnetic substances, carrying out resin purification to remove impurities, carrying out evaporative crystallization, refining, calcining, and crushing to prepare the low-magnetism high-purity lithium carbonate product. The purity of the lithium carbonate product prepared through the method is 99.95-99.98%, and the contents of magnetic Fe, magnetic Cr and magnetic Zn in the product are not greater than 0.081g/t, not greater than 0.002g/t and not greater than 0.002g/t respectively. The method has the advantages of simplicity, stable operation process, short production period and small device investment, the prepared lithium carbonate is highly pure, contains a small amount of magnetic substances, has a comprehensive recovery rate of lithium of 98.65%, has a low production cost, and is suitable for industrial production.

The invention provides a preparation method for lithium carbonate. The method comprises the following steps of: (1) mixing lithium hydroxide serving as a raw material and water for dissolving, adding a precipitating agent, and collecting filtrate of the lithium hydroxide, wherein the lithium hydroxide serving as the raw material is in an industrial grade; (2) introducing carbon dioxide into water, adding lithium carbonate serving as a raw material, adding a precipitating agent, introducing carbon dioxide until the pH is between 8 and 9, and collecting filtrate of solution of lithium hydrogen carbonate, wherein the lithium carbonate serving as the raw material is in an industrial grade; (3) mixing the solution of the lithium hydrogen carbonate obtained in the step (2) and the solution of the lithium hydroxide obtained in the step (1), heating the solution, and preserving the heat; (4) separating solid from liquid of a product in the step (3), and collecting the separated lithium carbonate wet material; and (5) drying a product in the step (4) in vacuum to obtain a product. By the process, the defects of the conventional process are better overcome, the product prepared from two industrial-grade raw materials can meet the requirement on 99.9 percent or higher-grade index, and the total yield of the product is over 95 percent.

The invention discloses a method for removing calcium magnesium slag and recycling lithium and preparing a ternary precursor material, and belongs to the field of waste lithium ion battery wet recycling. The method comprises the following steps of (1) magnesium salt transformation, (2) cobalt, nickel and manganese precipitation, (3) alkalization and magnesium removal, (4) lithium carbonate preparation, (5) nickel, cobalt and manganese slag acid leaching, (6) calcium magnesium removal, (7) extraction, (8) precursor synthesis, and (9) ternary precursor material preparation by drying. The technology is simple, is low in energy cost and is safe and stable. Efficiency of separating the cobalt, the nickel and the manganese from lithium is high, and the comprehensive recycling rate of each valuable metal is high. The main content of prepared lithium carbonate is up to 99.61%, the battery level requirements can be met, the overall recycling rate of the nickel, the cobalt, the manganese and thelithium in the calcium magnesium slag is up to 98.5%, and the lithium recycling rate is up to 98.8%. The method is suitable for industrial production, and can achieve high economic benefits.

The invention relates to the field of lithium carbonate preparation, in particular to a method for extracting lithium from brine to prepare battery-grade lithium carbonate by an ion exchange method. The method includes the steps of 1), removing magnesium by a coprecipitation method; 2), adsorbing to extract the lithium by a manganese adsorbent; 3), preparing the battery-grade lithium carbonate, namely adding alkaline liquor into a desorption solution in the step 2), regulating a pH value to 7-12, producing manganese hydroxide precipitate, filtering the manganese hydroxide precipitate, concentrating filtrate until the lithium content reaches 20-30 g/L, filtering to remove sodium chloride, adding a saturated sodium carbonate solution to react, filtering, and subjecting filter cakes to water scrubbing so as to obtain the battery-grade lithium carbonate. The method has the advantages that hydrotalcite is obtained after magnesium removal, so that the problem of recycling the magnesium in the brine is solved; the content of various impurity ions in the desorption solution can be controlled effectively by removing the magnesium and extracting the lithium by adsorption sequentially, and then the battery-grade lithium carbonate is prepared.

The invention provides a method of producing battery-grade lithium carbonate through a sulfuric acid process and belongs to the technical field of battery-grade lithium carbonate preparation. The method includes: transform-roasting, acidify-roasting, leaching, purifying, lithium-setting, washing, drying, and smashing. A circulatory leaching mode is adopted, so that lithium concentration in leachate can be increased effectively, and high-concentration lithium-containing leachate can be produced directly; evaporation and concentration are not needed, and lithium setting can be directly performedafter purifying to produce lithium carbonate. The high-concentration lithium-containing leachate can be obtained through circulatory leaching, so that requirements of lithium setting on high-concentration lithium can be met without increasing calcium ion concentration in purified liquid, and product quality is improved effectively. By adopting the method, using of triple-effect high-temperature evaporation equipment can be avoided, so that energy conservation and consumption reduction are realized, equipment investment cost is lowered, technological processes are simplified, and battery-gradelithium carbonate produced by the method is stable and high in quality and environment-friendly.

The invention provides a method for preparing battery-grade lithium carbonate from lepidolite, and belongs to the field of battery-grade lithium carbonate preparation. The method specifically comprises the following steps: roasting and leaching lepidolite, adding a fluorine removal agent to remove fluorine, carrying out concentrating, removing calcium and magnesium by chelating ion exchange resinto obtain a refined lithium solution, adding the refined lithium solution into a refined sodium carbonate solution of which calcium and magnesium are removed by chelating ion exchange resin, carryingout reacting, and settling to obtain crude lithium carbonate and lithium settling mother liquor; concentrating and evaporating the lithium precipitation mother liquor, freezing and salting out, addingthe product into a refined lithium solution for recycling, washing crude lithium carbonate, precipitating, centrifugally separating, drying, carrying out jet milling, mixing and packaging to obtain the battery-grade lithium carbonate. According to the method, the leachate is subjected to fluorine removal treatment, calcium and magnesium removal and then added into the refined sodium carbonate solution for reaction, the lithium precipitation mother liquor is recycled for production after being treated, and the method disclosed by the invention is simple in process step and relatively low in cost, ensures the quality of the battery-grade lithium carbonate and can be used for continuous production.

The invention relates to a battery-grade lithium carbonate preparation method based on phase transformation, belonging to the technical field of the preparation of inorganic chemical materials. The preparation method comprises the following steps: by taking lithium concentrate as a raw material, first mixing the lithium concentrate and water to prepare 10 to 50% serous fluid, then adding a phase transformation agent, and reacting for 0.5 to 5 hours at 10 to 100 DEG C to obtain a high-concentration lithium salt solution; then mixing the lithium salt solution and inorganic alkali, and reacting to obtain a high-concentration causticization solution; introducing the causticization solution into a cation exchange column to obtain a refined causticization solution, and then introducing carbon dioxide into the refined causticization solution to obtain crude lithium carbonate; and finally mixing the crude lithium carbonate and an appropriate amount of composite refined impurity removal agent in water, and reacting to obtain a battery-grade lithium carbonate product with a main content more than or equal to 99.5 percent by weight. By adopting the phase transformation method, the concentration of the lithium salt solution is remarkably increased, the high-concentration causticization and carbonization can be realized, the preparation efficiency of the battery-grade lithium carbonate is increased, and a novel way is provided for the industrialized preparation of the battery-grade lithium carbonate.

The invention relates to a method of extracting lithium carbonate from lepidolite ore, and belongs to the field of preparation of lithium batteries. For overcoming the technical defect of low purity of lithium carbonate extracted from lepidolite in the prior art, the invention provides the method of extracting lithium carbonate from lepidolite ore, which includes the steps of sulfuric acid reaction, low-temperature vanadium deposition, impurity removal with Ca(OH)2 and Na2CO3, etc., so that metal ions in a leaching liquid of lepidolite are removed almost, and finally, saturated Na2CO3 is added to carry out a heating reaction to produce a high-purity lithium carbonate product. The method is low in energy consumption and demand on equipment, has significant impurity removal effects, and is suitable for promotion and application of preparation technologies of lithium carbonate with the lepidolite as raw material.

The invention discloses a system and method for preparing battery-grade lithium carbonate, belongs to the field of resource recycling and aims to solve the problem that waste resources generated in the conventional battery-grade lithium carbonate preparation process cannot be recycled or reused. According to the system and the method, filtrate generated from solid-liquid separation and separationmother liquor generated from filtration are subjected to acidification, concentration, decontamination and lithium settlement in acidification equipment, concentration equipment, decontamination equipment and lithium settlement equipment, the water outlet of the concentration equipment is connected with the raw material inlet of pulping equipment, the carbon dioxide outlet of pyrolysis equipment is connected with the carbon dioxide inlet of carbonization equipment and the carbon dioxide inlet of the lithium settlement equipment, and the sulfuric acid outlet of electrolysis equipment is connected with the sulfuric inlet of the acidification equipment. By adopting the system and the method, waste resources generated in the battery-grade lithium carbonate preparation process can be recycled and reused.

The invention discloses a lithium carbonate preparation method, which comprises: enriching natural spodumene into a concentrate, feeding into a rotary kiln, roasting to convert alpha-spodumene in theore into beta-spodumene, stopping the heating, and naturally cooling; crushing when the temperature of spodumene is reduced to 80-120 DEG C, screening, adding excess concentrated sulfuric acid, feeding into a converter, sintering, and leaching the sulfuric acid sintering block by using water to prepare water-soluble lithium sulfate; neutralizing the excess sulfuric acid to achieve the pH value of5.5-6.5, filtering, removing calcium, magnesium, iron and aluminum from the filtrate, carrying out decolorization, and concentrating the material liquid to prepare a saturated lithium sulfate solution; and adding a saturated sodium carbonate solution to the saturated lithium sulfate solution to generate lithium carbonate precipitate, separating the precipitate to obtain lithium carbonate with a product purity of more than 70%, repeatedly washing with hot water to obtain lithium carbonate with a purity of 96-97%, and drying to obtain the product. According to the present invention, the preparation method is simple, the energy consumption is greatly reduced, and the economic benefits of the enterprise are improved.

The invention relates to a method for preparing lithium hydroxide monohydrate by using lithium carbonate. The method comprises the steps: adopting industrial grade lithium carbonate as a raw material,performing a reaction on suspension of the lithium carbonate, calcium oxide and water under the conditions of heating, pressurizing and stirring for 90-110 min, and performing filtration, purification, elution crystallization, drying and the like so as to obtain lithium hydroxide monohydrate. The method has the advantages that industrialization can be realized easily through adoption of industrial grade lithium carbonate to prepare the lithium hydroxide monohydrate, and improvement of the reaction speed and shortening of the reaction time are achieved by adopting a pressurized mode to increase the reaction temperature, so that the conversion rate of lithium carbonate is achieved; by adopting the elution crystallization method, the problems that a previously adopted evaporative crystallization method has large energy consumption and a high temperature, and lithium hydroxide is easily converted into lithium carbonate during evaporation are solved, and conversion, caused by water loss, of lithium hydroxide monohydrate into anhydrous lithium hydroxide can be prevented during evaporation; the product has stable quality and high purity, and organic solvents used during the elution crystallization can be recycled, so that discharge without solid and liquid waste is achieved.

The invention discloses a comprehensive utilization method of lithium-containing waste fluids. Lithium carbonate washing water in lithium carbonate preparation technology, pyrolysis mother-liquor generated during high-purity lithium carbonate preparation by a carbonization-decomposition method, or a liquid with similar composition of the lithium carbonate washing water or the pyrolysis mother-liquor is used as a raw material. The raw material undergoes primary or secondary electrodialysis treatment, and a cation exchange membrane and an anion exchange membrane are utilized. On one hand, Li<+> is concentrated and enriched so as to obtain a lithium-rich concentrate with Li<+> content being 10g/L-20g/L; and on the other hand, water produced by primary desalination can be purified so as to obtain deionized water with TDS value being lower than 20mg/L for reuse. By combination of electrodialysis and reverse osmosis, a closed-cycle technology is formed. Then, comprehensive yield of Li<+> is close to 100%, and water loss is zero. Thus, Li<+> and water in the lithium carbonate washing water and the solution with the similar composition are synchronously and completely recovered.

The invention provides a preparation method of an antibacterial coating for household appliances .According to the preparation method, the antibacterial effect and the continuous antibacterial capacity of the coating are improved through the antibacterial efficacy of silver, and the adhesive force of the coating is improved by taking white carbon black as a carrier and taking silicone rubber as a substrate, wherein nano-white carbon black antibacterial powder is prepared from silver nitrate, nickel carbonate, zinc oxide and lithium carbonate to generate the synergistic effect, and therefore the antibacterial property of the coating is better; antibacterial liquid is prepared by taking carbon black and titanium dioxide as raw materials, active substances such as .OH and O2 are generated on the surface of titanium dioxide and have the high oxidation effect to enable bacteria to be decomposed, and then the sterilizing effect is achieved; the substrate of the coating can generate the bacterial adhesion resisting effect through ultraviolet irradiation .Therefore, the prepared antibacterial coating for the household appliances has the advantages of being high in antibacterial efficiency, low in toxicity and good in heat resistance.

The invention belongs to the field of chemical industry, and provides a lithium carbonate preparation method, which comprises: mixing an extraction organic phase and a lithium-containing solution according to a volume ratio of 1:1-10 to form an alkaline extraction system, and extracting 1-3 times to obtain a lithium-containing organic phase, wherein the single extraction time is 1-15 min; mixing the lithium-containing organic phase and a back extraction solution according to a volume ratio of 1:1-10, carrying out back extraction 1-3 times, and collecting a lithium ion-containing lithium hydrogen carbonate aqueous solution, wherein the single back extraction time is 1-15 min, and the back extraction solution is an aqueous solution prepared by introducing carbon dioxide into a combination comprising one or any materials selected from pure water, an alkali metal salt and an ammonium salt aqueous solution; and heating the lithium ion-containing lithium hydrogen carbonate aqueous solution to crystallize and precipitate the lithium hydrogen carbonate in the aqueous solution, and thermally decomposing to obtain lithium carbonate. According to the present invention, the method has high extraction efficiency, can directly extract lithium ions from alkaline brine or aqueous solutions to prepare lithium carbonate, and further has advantages of low corrosion on production equipment, low production cost and environmental protection.

The invention discloses a method for extracting lithium from old brine in a salt field. The method comprises: (1) magnesium adsorption removal, (2) stepwise speed-variable elution of lithium, (3) deepmagnesium adsorption removal based on an ion exchange resin, (4) reverse osmosis and (5) lithium carbonate preparation. The method comprehensively utilizes various processes such as magnesium adsorption removal, stepwise speed-variable elution of lithium, deep magnesium adsorption removal based on an ion exchange resin and reverse osmosis, completely solves the problems of too high magnesium-lithium ratio of the old brine in a salt field, realizes a low production cost and a low building cost and has strong adaptability. The product has lithium carbonate purity reaching to the purity of electronic grade lithium carbonate.

The invention relates to the technical field of salt chemical industry, and particularly relates to and discloses a salt lake lithium extraction system based on membrane separation. The system comprises a magnesium removal system, a boron removal system, a lithium carbonate preparation system and a lithium precipitation mother liquor recycling system which are connected in sequence; themagnesium removal system comprises a nano-filtrationmagnesium removal unit; the boron removal system comprises a reverse osmosis boron removal unit and an electrodialysis boron removal concentration unit, which are connected in sequence; the lithium carbonate preparation system comprises an MVR concentration unit and a lithium precipitation unit, which are connected in sequence; and the lithium precipitation mother liquor recycling system comprises lithium absorption resin and a bipolar membrane electrodialysis unit, which are connected in sequence. The invention also discloses a salt lake lithium extraction method based on membrane separation. The method comprises the following steps: 1) deeply removing magnesium; 2) deeply removing boron; 3) preparing lithium carbonate; and 4) recycling the lithium precipitation mother liquor. The salt lake lithium extraction system and method based on membrane separation have the advantages that no extra pollution is generated, the cost is saved, the energy consumption is reduced, the product purity is high, the production cost is low, and the pollution degree is low.

The invention provides a method for preparing battery-grade lithium carbonate by freezing and recycling lithium precipitation concentrated mother liquor, and belongs to the field of lithium carbonatepreparation. The method comprises the following steps: (1) roasting and leaching lepidolite to obtain leachate, and purifying, concentrating, evaporating, lithium precipitating and filtering the leachate to obtain lithium carbonate and lithium precipitation mother liquor; (2) concentrating and evaporating the lithium precipitation mother liquor to obtain lithium precipitation concentrated mother liquor; and (3) adding the lithium precipitation concentrated mother liquor in the step (2) into the leachate to obtain a mixed solution, purifying, concentrating, evaporating and freezing the mixed solution to remove potassium and sodium salts, filtering, introducing ion exchange resin to remove calcium and magnesium, precipitating to obtain battery-grade lithium carbonate and lithium precipitation mother liquor, treating the lithium precipitation mother liquor, and recycling the lithium precipitation mother liquor in the process. According to the method, the lithium precipitation mother liquor is treated and then mixed with the leachate according to a certain volume ratio, lithium precipitation is carried out after potassium and sodium are removed through freezing, and the obtained lithium precipitation mother liquor can be recycled in the production process, so that the cost is reduced, and the production efficiency can be improved.