Recovery of europium by electrochemical reduction from sulfate solutions

Polarization behaviour of Eu, Sm, and Gd was investigated in acidic sulfate solutions using Cu and Cu–Hg cathodes and electrolytic reduction–precipitation of europium from sulfate solutions was studied using a mercury-coated copper electrode. The effect of magnetic stirring, N2 gas sparging, and use of a cation permeable membrane on electrolytic reduction was determined. Europium recovery of 71.9% for magnetic stirring increases to 74.4% for N2 gas sparging and to 79.5% for N2 gas sparging+membrane system. The purity of the precipitated EuSO4 is 98.5%, 96.0%, and 94.4%, respectively.