Method for recovering lithium bis (fluorosulfonyl) imide

The invention provides a method for recovering lithium bis (fluorosulfonyl) imide. The method comprises the following steps: mixing waste residues from a lithium bis (fluorosulfonyl) imide manufacturing process with a carbonic ester solvent to obtain a mixture; carrying out solid-liquid separation on the mixture to obtain discharged liquid and solid residues; monitoring the chromatic value of the discharged liquid, and comparing the chromatic value of the discharged liquid with a reference chromatic value; when the chromatic value of the discharged liquid is greater than the reference chromatic value, circulating the discharged liquid into the mixture; and when the chromatic value of the discharged liquid is less than or equal to the reference chromatic value, circulating the discharged liquid to a lithium bis (fluorosulfonyl) imide manufacturing process.