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

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% Eu(2)O(3). 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. Similar grades (95.0 +/- 0.5% Eu(2)O(3)) were obtained with both Zn amalgam and pure Zn powders. The precipitation with sulfuric acid was more selective as compared to that with ammonium sulfate (95% and 80% Eu(2)O(3), respectively, for 95%, recovery). The continuous addition of the precipitating agent was the main factor responsible for improving europium grades, which increased from 93% to 97% in the first stage, with less acid requirements (SO(4)(2-): Eu molar ratio decreased From 16 to 5.3). After two stages of reduction-precipitation, grades were higher than 99.99% Eu(2)O(3) and recovery was 94%. The levels of individual rare earth impurities in the final Eu(2)O(3) product were below 0.001%. (C) 2001 published by Elsevier Science B.V.