METHOD FOR RECOVERING RARE EARTH ELEMENT

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PROBLEM TO BE SOLVED : To provide a method which, when rare earth elements are recovered by a double sulfate precipitation method, does not require an operation of weighing a rare earth double sulfate precipitate to be seed crystals and feeding it to a reaction tank, and can therefore recover the rare earth elements by using it effectively and highly safely. SOLUTION : After the completion of a double sulfate formation reaction, an obtained solution is brought into an agitated state in which the double sulfate precipitate is kept unsettled, and the product except the solution component containing a predetermined amount of the double sulfate precipitate is passed through a solid/liquid separation apparatus to recover. Next, the solution containing the predetermined amount of the double sulfate precipitate is left standing in the reaction tank to settle the double sulfate precipitate, and thereafter, the supernatant liquid is withdrawn to leave the double sulfate precipitate in the reaction tank. Then, the rare earth element-containing solution in a state in which the left double sulfate precipitate as seed crystals is present in it, and an alkali metal sulfate is added to perform a double sulfate formation reaction. COPYRIGHT : (C)2014, JPO&INPIT