PROCESS FOR RECOVERING RARE EARTH OXIDE FROM WASTE LIQUID CONTAINING RARE EARTH ELEMENT, AND PROCESS FOR PRODUCING RARE EARTH OXIDE USING SAME

摘要

ABSTRACT Rare earth oxides capable of being re-used as an abrasive are recovered from an abrasive waste liquid by a process comprising the steps of (1) mixing and heating a rare earth element-containing waste liquid with an acid, to dissolve rare earth elements contained in the liquid; (2) removing insoluble matter from the rare earth element solution; (3) incorporating a soluble carbonate salt or a soluble hydrogencarbonate salt, or an oxalic acid in the rare earth element solution, to convert the rare earth elements to rare earth carbonates or rare earth oxalates; (4) separating the rare earth carbonates or rare earth oxalates from a slurry of the rare earth carbonates or rare earth oxalates; (5) baking the separated rare earth carbonate or rare earth oxalate to produce rare earth oxides; and (6) recovering the rare earth oxides.