EXTRACTION AGENT FOR RARE EARTH METAL AND METHOD FOR SEPARATING AND REFINING RARE EARTH METAL

Japanese Patent JP3310728

B2

PURPOSE: To provide a method for separating and refining rare earth metals, in which the separation factor of every adjacent rare earth elements from each other is large and the rare earth metals can be back-extracted with a dilute mineral acid and no gelation occurs even when the amount to be extracted is large, by specifying an acid phosphate compound used for extracting rare earth metals with the solvent exraction from an aqueous solution contg. them.
CONSTITUTION: An extractant contg. an acid phosphoric ester represented by the general formula as the extraction agent is brought into liquid-liquid contact with an aqueous solution contg. rare earth metals and the pH of the aqueous solution is appropriately adjusted to separate desired one or several of the rare earth metals from the other rare earth metals. Then the extracted rare earth metals in the extractant are back-extracted by allowing the extractant contg. the extracted rare earth metals to contact with another aqueous solution having a lower pH than that of the aqueous solution used at the time of extracting the rare earth metals. The above acid phosphoric ester is generally used as a 5 to 70vol.% solution obtained by diluting it with an organic diluent. As the effective diluent, an aliphatic or aromatic hydrocarbon having a high flash point, etc., can be used.

Victory Inoue
Kazuharu Yoshizuka
Keisuke Owatari
Hiroshi Kosaka
Norio Nakatsukasa
Takashi Hashida
Kouki Domoto

JP20028693A

August 05, 2002

July 20, 1993

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Mitsui Mining & Smelting Co., Ltd.

C07F9/09; C22B59/00; (IPC1-7): C22B59/00; C07F9/09

Eiji Tomomatsu

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