To efficiently recover Ta, Nb and Sc from a composite raw material contg. metals and having significant-level radioactivity by conducting a succession of acid cooking and alkali reaction after sulfation-roasting and applying wet refining. i.e., dissolution and/or precipitation, to a desired compd. in a different stage.
The following treatments are practically applied. Namely, a composite raw material is allowed to react with sulfuric acid to form a metal sulfate. The composite raw material is washed with water to recover a part of the sulfate which is leached out in the washing water. A part of the sulfate remaining in the raw material is dissolved in hydrochloric acid, etc., and recovered. The bisulfate in the sulfate is allowed to react with a sodium hydroxide soln. to form a metal hydroxide. The metal hydroxide is let react with hydrochloric acid or nitric acid to form the metal chloride or nitrate. The tantalum oxide, niobium oxide, etc., remaining in the raw material are concentrated by recovering the chloride and nitrate.
TIERNEY DAVID R
NOTZ-LOISELLE HENRIETTA
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