The rare earth elements from abrasive material used for recovery of the rare earth element

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PROBLEM TO BE SOLVED : To recover a rare earth element from a used rare earth element type abrasive material as hydroxide or oxide in high purity at a relatively low cost. SOLUTION : A used rare earth element type abrasive material is treated with an aq. mineral acid soln. to dissolve the rare earth element and the resultant soln. is separated from the undissolved material and recovered. Oxalic acid and an aq. alkali oxalate soln. are added to the recovered soln. so that the soln. is adjusted to <=pH 5 and the rare earth element is deposited as oxalate. This oxalate is recovered by solid-liquid separation and converted into hydroxide by treatment with an aq. alkali hydroxide soln. The hydroxide of the rare earth element and an aq. alkali oxalate soln. formed by the treatment are recovered by solid-liquid separation. The recovered aq. alkali oxalate soln. is reutilized in the oxalate depositing step.