Method of de-calcifying rare-earth metals formed by a reduction-diffusion process

摘要

Mixtures of a rare-earth element and an intermetallic compound comprising the rare-earth and a ferromagnetic metal which is either iron or cobalt, which are formed by a calcium reduction-diffusion process are de-calcified by washing with an aqueous ammoniacal solution comprising a reagent capable of reacting with the calcium hydroxide formed during the process to form a calcium salt soluble in alkaline solution, whilst maintaining the pH value of the aqueous ammoniacal solution above 9.0.