The invention belongs to the technical field of waste battery
recovery, particularly relates to a method for efficiently extracting regenerated
lithium carbonate from low-concentration
lithium leaching liquid through an extraction-reverse extraction
coupling process, and is particularly suitable for
recovery treatment of waste
lithium ion battery black
powder and lithium
precipitation mother liquor with low lithium content, such as
lithium iron phosphate and lithium
manganate. Aiming at the problems that the lithium
recovery efficiency in the low-concentration lithium liquid (less than or equal to 5g / L) is low, the
impurity interference is serious, the traditional process depends on an exogenous precipitator and the like, the method realizes high-efficiency lithium extraction by designing a novel composite extraction agent and a gas-liquid reverse extraction mechanism, the enrichment efficiency of the low-concentration lithium is remarkably improved, a CO2 gas-liquid reverse extraction technology is innovatively introduced, and by regulating and controlling the pressure and temperature conditions, the concentration of the low-concentration lithium is greatly improved. The
lithium bicarbonate solution is generated in the strip liquor, additional
impurity removal is not needed, Li2CO3 can be promoted to be converted into Li2CO3 through
pyrolysis in one step, the step of adding Na2CO3 after traditional acid strip extraction is omitted,
sodium salt
pollution is avoided, and the process is simplified. According to the process, through the extraction-reverse extraction
coupling design, high-selectivity
precipitation of
lithium carbonate is achieved under the condition of low lithium concentration, the purity of the obtained product reaches the battery grade standard (larger than 99.5%), meanwhile, the overall
energy consumption is reduced by 40% or above, and a green and efficient solution is provided for recycling of waste lithium
ion batteries.