Manganese-lithium separation process and pre-extraction solution preparation process in comprehensive recovery of ternary battery wastes, and method for comprehensive recovery of cobalt, nickel, manganese and lithium elements from ternary battery wastes

A method for comprehensive recovery of cobalt, nickel, manganese and lithium elements from ternary battery wastes, comprising the following steps:

• a, disassembling waste ternary batteries to obtain waste ternary battery powder, and leaching the waste ternary battery powder with an acid for removing copper, iron and aluminum to obtain an impurity-removed solution;
• b, adjusting a pH of the impurity-removed solution to 5.5-6.5 with sodium hydroxide, precipitating a mixture of cobalt hydroxide and nickel hydroxide, filtering and washing to obtain a filter cake and a filtrate, and treating the filter cake and the filtrate respectively;
• c, dissolving the filter cake, which is a mixture of cobalt hydroxide and nickel hydroxide, with sulfuric acid, then, adjusting the pH to 5.0-6.0, adding fluoride into the dissolving solution to remove calcium and magnesium ions, filtering and washing to obtain a filtrate, allowing the filtrate to enter into a first impurity extraction procedure, removing impurities deeply, allowing raffinate to enter into a second extraction procedure, performing the second extraction procedure cobalt ion full extraction and full back-extraction to obtain a high-concentration pure solution of cobalt sulfate, evaporating and crystallizing the solution to obtain a battery-grade cobalt sulfate product, and allowing a nickel sulfate solution as the raffinate to enter into a third impurity extraction procedure;
• d, obtaining pure nickel sulfate liquid as the raffinate after the third impurity extraction procedure, adjusting the pH to 6-10 with sodium hydroxide, precipitating nickel hydroxide, reversely washing the precipitates with pure water for 2-4 times to obtain a filter cake which is battery-grade nickel hydroxide, and treating the filtrate and the washing solution by a wastewater station for recycling;
• e, adding sodium sulfide into the filtrate and the washing solution obtained in step b to remove the residual cobalt and nickel ions, filtering and washing to obtain a filter cake which is a mixture of cobalt sulfide and nickel sulfide, returning to the acid dissolution procedure, and allowing the filtrate and the washing solution to enter into the manganese precipitation procedure;
• and
• in step e of adding sodium sulfide, solid sodium sulfide is added by 2.0-5.0 times of the total amount of cobalt and nickel in the filtrate and the washing solution obtained in step b;
• and the reaction lasts for 30-60 minutes to recover the residual cobalt and nickel ions;
• f, adjusting the pH of the filtrate and the washing solution obtained in step e to 8-11 with sodium hydroxide, to precipitate manganese ions, filtering and washing to obtain a manganese hydroxide filter cake and a lithium-containing filtrate and washing solution;
• g, evaporating and crystallizing sodium sulfate from the lithium-containing filtrate and washing solution to obtain a concentrated lithium solution, precipitating lithium carbonate with sodium carbonate, filtering and washing to obtain a lithium carbonate filter cake and a lithium precipitation mother liquor.