Battery-level Ni—Co—Mn mixed solution and preparation method for battery-level Mn solution

A method of preparing a battery-grade Ni—Co—Mn mixed solution and a battery-grade Mn solution, comprising an acid dissolution step, an alkalization step to remove impurities, a synchronous precipitation of calcium, magnesium and lithium step, a deep ageing step to remove impurities, a synergistic extraction step, and a refining extraction step;

• the alkalization step to remove impurities comprises:
• adding an oxidizing agent and an alkali solution to a solution gained after the acid dissolution step, and after adjusting a pH value of a solution gained after alkalization and oxidation to 2.5-5.5, filtering a solution gained after pH adjusting to remove iron and aluminum, so as to obtain an alkalization mixed solution;
• the synchronous precipitation of calcium, magnesium and lithium step comprises:
• adding a soluble fluoride salt to the alkalization mixed solution, and after a stirring reaction, filtering the mixture to remove lithium, calcium and magnesium, so as to obtain a synchronous precipitation filtrate;
• the soluble fluoride salt is one or a mixture of two of sodium fluoride and ammonium fluoride, and an addition amount of the soluble fluoride salt is 1-2 times a molar amount of lithium, calcium and magnesium in the solution;
• a temperature of the stirring reaction is 60° C., and a reaction time is 2 hours;
• the deep ageing step to remove impurities comprises:
• subjecting a filtrate obtained after the synchronous precipitation of calcium, magnesium and lithium step to deep ageing, and filtering the filtrate to remove impurities to obtain a deep ageing filtrate, wherein a deep ageing time is more than 4 hours, and a deep ageing temperature is 25° C.;
• the synergistic extraction step comprises:
• subjecting the deep ageing filtrate to synergistic extraction by using P204 extractant, so as to obtain a loaded organic phase and a raffinate;
• the loaded organic phase is subjected to acid washing and then multistage back-extraction, so as to obtain a battery-grade Ni—Co—Mn mixed solution and a manganese-containing solution, separately;
• the refining extraction step comprises:
• subjecting the Mn-containing solution to extraction for impurity removal by using P204 extractant, wherein a raffinate obtained is a battery-grade Mn solution.