A process for the recovery of the europium proportion of any mixture of soluble salts of trivalent metals of the rare earths, by reduction of the europium

摘要

1,132,804. Extracting europium. PRODUITS CHIMIQUES PECHINEY-SAINT-GOBAIN. 30 Jan., 1967 [31 Jan., 1966], No. 4475/67. Heading C1A. A mixture of trivalent soluble salts of rare earth metals including europium is treated with bivalent samarium, sulphuric acid and an alkaline-earth metal salt, such as barium sulphate intimately mixed with the bivalent samarium salt, the pH preferably being kept at about 4 with ammonium acetate. The precipitated bivalent europium sulphate and alkalineearth metal salt may be separated by fractional crystallization, or by treating the precipitate with nitric acid to redissolve the europium in its trivalent state. The bivalent samarium may be produced by reducing the trivalent samarium chloride in a chloride mixture of trivalent rare earth salts with sodium vapour or with calcium, at 750‹ C.