METHOD FOR SEPARATING RARE EARTH ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a method for removing a rare earth element present in a trace amount in a solution containing nickel that efficiently removes the rare earth element down to a degree of an extremely low concentration by suppressing equipment investment and simplifying the operational method.SOLUTION: In a method for separating a rare earth element comprising separating, from any one solution of a solution containing a rare earth element and at least nickel, a solution containing a rare earth element and at least cobalt and a solution containing a rare earth element and at least nickel and cobalt, the rare earth element by solvent extraction, the method has an extraction step of mixing with a phosphoric acid extractant agent while maintaining a pH of the solution in the range of 1.5-2.0 to separate an extracted organic and raffinate and then a back extraction step of mixing the extracted organic separated in the extraction step with a sulfuric acid solution to produce a back extraction liquid and a back-extracted organic after back extraction.