| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently producing a suitably recyclable high-purity rare earth oxide by simply and highly accurately removing the impurities from a rare earth oxysulfide phosphor containing at least iron, copper and chromium elements as impurities or from a rare earth oxide being as a starting material therefor. SOLUTION: The method for producing the rare earth oxide comprises the steps of: dissolving a rare earth oxysulfide phosphor containing at least iron, copper and chromium elements as impurities in a mineral acid to form a solution; adding an oxidizing agent to the solution to oxidize the ion impurities; removing the oxidized ion impurities by adsorption on an ion exchange resin; adding oxalic acid to the ion-impurity-free solution to form rare earth oxalates; and roasting the separated rare earth oxalates after the rare earth oxalates formed are separated to prepare a rare earth oxide. COPYRIGHT: (C)2003,JPO
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