| 摘要 |
PURPOSE:To efficiently separate and recover rare earth elements and complexing agent by adding an oxalic acid in a high temp. state to a rear earth ion complex soln. to prepare the precipitate of the oxalic acid rare earth and complexing agent soln. thereby separating both. CONSTITUTION:A mineral acid is passed into a column in which a strongly acidic cation exchange resin is packed and set at about 90 deg.C to convert the resin in the column to a hydrogen type. A rare earth ion liquid mixture contg. an EDTA is supplied to the ion exchange column to form a rare earth adsorption zone. The soln. contg. the EDTA is then adjusted in pH with dilute aq. ammonia and is supplied into the exchange column where the development and elution of the rare earth ions are executed. The oxalic acid is added to the high-temp. eluate of >=90 deg.C removed from the column to mature the eluate and thereafter the precipitate of the oxalic acid rare earth is filtered and separated. An adequate amt. of hydrogen peroxide is added as necessary to the filtrate contg. the dissolved EDTA to decompose the excess EDTA and thereafter the filtrate is subjected to the concn. adjustment of the EDTA and pH adjustment. Such liquid is cyclically used as a raw material supply liquid or developing liquid. |
