PURPOSE: To recover the title compound useful as an eluent efficiently and in high purity, by mutually separating rare earth elements with ethylenediaminetetraacetic acid (herein after abbreviated as EDTA) and a cation exchange resin to give an eluate, precipitating and separating EDTA and the rare earth elements to give separated mother liquor and treating the mother liquor by a specific method.
CONSTITUTION: Rare earth elements are mutually separated with EDTA and a cation exchange resin to give an eluate consisting of the rare earth elements and EDTA. Then EDTA and the rare earth elements are precipitated and separated from the eluate to give separated mother liquor containing EDTA, which is treated. In the operation, the separated mother liquor is passed through a column packed with a strongly acidic cation exchange resin, EDTA is absorbed, water is passed through, EDTA is desorbed and recovered. In passing through water, water or water containing an alkali, preferably NH3 is used and preferably the effluent is repeatedly circulated to efficiently desorb and concentrate an aqueous solution of EDTA.
MURAKAMI TSUGIO
ETO NOBUO
TAKADA YUTAKA
| JPS5835151A | 1983-03-01 |