Patent ID: 7959881

Claim:
A method for scrubbing an amine extractant after stripping, said method being a scrubbing method of an amine extractant (A) containing a ferric chloro complex ion and a zinc chloro complex ion obtained by back extracting cobalt with hydrochloric acid aqueous solution from an amine extractant after extracting cobalt, in a solvent extraction to extract cobalt from the hydrochloric acid aqueous solution containing nickel and cobalt and separating cobalt from nickel, comprising the procedures of the following steps (1) to (3): (1) an amine extractant (B) containing sulfite ion is obtained by adding an aqueous solution containing a sulfite ion to the amine extractant (A) and stirring the mixture so that oxidation-reduction potential (based on silver/silver chloride electrode) of the aqueous solution after scrubbing becomes 80 to 550 mV, reducing the ferric chloro complex ion in said amine extractant (A) to divalent, then after leaving at rest, separating the aqueous solution containing the ferrous chloro complex ion and zinc sulfite formed; (2) an amine extractant (C) containing a sulfate ion is obtained by adding an aqueous solution containing an oxidizing agent or an oxidizing agent and water to the amine extractant (B) and stirring the mixture so that oxidation-reduction potential (based on silver/silver chloride electrode) of the aqueous solution after scrubbing becomes 80 to 550 mV, oxidizing a sulfite ion in said amine extractant (B) to sulfate ion, then after leaving at rest, separating the sulfate aqueous solution formed; and (3) an amine extractant (D) is obtained by adding an aqueous solution containing a chloride ion to the amine extractant (C) and stirring the mixture, replacing a sulfate ion in said amine extractant (C) with chloride ion, then after leaving at rest, separating an aqueous solution containing a sulfate ion formed.