Method for recovering lithium in waste lithium iron phosphate battery by synergistic extraction with polar diluent

Abstract

The application relates to the technical field of battery recycling treatment, and discloses a method for recycling lithium in waste lithium iron phosphate batteries by utilizing polar diluent synergistic extraction, which comprises the following steps: waste battery powder is mixed with a hydrochloric acid solution to obtain a lithium-containing solution; hydrogen peroxide aqueous solution is added to the lithium-containing solution to oxidize the divalent iron ions into ferric chloride to play a synergistic extraction agent role, and aluminum chloride solid is added to adjust the pH value; an organic phase solution obtained by mixing tributyl phosphate and a polar diluent is used for extraction reaction; the extraction liquid is back-extracted with a hydrochloric acid solution, and a lower lithium ion solution is obtained through separation. Compared with a traditional non-polar system, the electrostatic attraction provided by the polar diluent molecules is utilized to improve the micro-polarity environment of the system, the upper limit of the solubility of the ligand complex is improved, the precipitation of the third phase substance is inhibited, the liquid-liquid separation speed is accelerated, and the overall lithium extraction efficiency is improved.

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