Recovery of europium by chemical reduction of a commercial solution of europium and gadolinium chlorides

Abstract

A chemical reduction-precipitation process was applied to the separation and recovery of high-grade europium oxide from a europium/gadolinium mixture containing 1.90 percent Eu2 O3.The effects on europium recovery of the presence of mercury in the reducing agent, temperature, aging time, the nature of the sulfate carrier, and the method of addition of the precipitation agent were studied in detail.The precipitation with sulfuric acid was more selective as compared to that with ammonium sulfate. The contiuous addition of the precipitating agent was the main factor responsible for improving europium grades, which increased from 93 percent to 97 percent in the first stage, with less acid requriments. The levels of individual rare earths impurities in the final Eu2 O3 product were below 0.001 percent.