PURPOSE: To separate Sm, Eu, Gd in a high purity condition with good efficiency by treating an aq. soln. contg. Sm, Eu, Gd by utilizing zinc amalgum, an ion exchange fiber and an aq. soln. of a chelating agent, etc.
CONSTITUTION: An aq. soln. contg. Sm, Eu, Gd and other hevy rate earth metals is passed reiteratively a plural number of times through a zinc amalgum packed layer. Concd. sulfuric acid is added to the liquid treated with the amalgum in such a way to settle Eu. Nitric acid and hydrogen peroxide are added to the precipitate obtd. by filtering said precipitate and the precipitate is dissolved. Oxalic acid is added to such liquid to make oxalate, which is then calcined and Eu2O3 is obtd. Sulfuric acid is removed by adding barium chloride to the filtrate, then the filtrate is treated with an ion exchange fiber having a strong cation exchange group and a weak cation exchange group, so that Sm and Gd are adsorbed. The same is treated with an aq. soln. of a chelating agent as an aq. soln. of ammonium salt of ethylenediaminetetraacetic acid or nitrilotriacetic acid to elute Sm and Gd and to convert them to oxalate. The oxalate is then calcined and Sm2O3 and Gd2O3 are separated and recovered.
OGAWA SHIGEO
TAMURA TERU
UZUMAKI MITSUTAKA
DAIICHI ENG CO LTD
NICHIBI KK