A method for preparing battery-grade lithium carbonate using lithium-containing organic waste liquid

Abstract

This invention relates to the field of lithium extraction technology from lithium-containing organic wastewater, specifically to a method for preparing battery-grade lithium carbonate from lithium-containing organic wastewater. The method provided by this invention first recovers organic acids from the wastewater through esterification and hydrolysis reactions. Then, under pH 11-12 conditions, lithium is precipitated with trisodium phosphate to obtain crude lithium phosphate solid. The lithium is then enriched, dissolved in acid, and extracted to remove phosphoric acid. The raffinate is adjusted to pH 9-11 to remove impurities, yielding a lithium sulfate solution. After concentration using MVR (Medium-Volume Reduction), impurities are further removed under pH 10.5-11.5 and activated carbon adsorption conditions to obtain a pure lithium sulfate solution. The obtained pure lithium sulfate solution is mixed with a carbonate solution to obtain crude lithium carbonate. Finally, after washing, drying, crushing, and iron removal, battery-grade lithium carbonate is obtained.

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