Yttrium-group earths, separation

Sm, Eu and Gd can be concentrated by crystallization through double magnesium nitrates, followed by crystallization of bismuth magnesium nitrates [30]. Sm and Eu are then removed by a proceedure based on valence change, and Gd is recovered by bromate crystallizations. Yttrium group earths may be conveniently separated by bromate crystallization. 

Cement, laboratory, 1 189 Cerite, extraction of, 2 44 Cerium, phosphor containing strontium sulfide and, 3 23 separation of, from rare earth mixtures, 2 43, 47, 48 test for, 2 50 Cerium amalgam, 1 15 Cerium-group earths, separation of, from yttrium earths by doublesulfate method, 2 44, 46 Cerium (III) magnesium nitrate, 2Ce(N03)s-3Mg(N03)2-24H,0, separation of praseodymium from lanthanum by, 2 57 Cerium(III) nitrate, 2 51 Cerium (IV) nitrate, basic, 2 49 Cesium, cesium azide for preparation of, 1 79... 

Yttrium-group earths, containing samarium, separation from mona-zite by magnesium nitrate, 2 56 separation by fractional crystallization of bromates, 2 56, 62 separation from cerium earths by double-sulfate method, 2 44, 46... 

Double sulphate precipitation is one of the most common methods used in industry for the separation of cerium group from yttrium group rare earths. Various other precipitants such as chromates, double chromates, ferrocyanides, phosphates etc. have been tried. 

Ketelle, B.H. and Boyd, GE. (1947) The exchange adsorption of ions from aqueous solutions by organic zeolites. IV. The separation of tiie yttrium group rare earths. Journal of the American Chemical Society, 69 (11), 2800-2812. 

If the material is to be separated into the cerium and yttrium groups of rare earths by precipitation of the double sulfates of the former, removal of the last trace of cerium is unnecessary since it does not seriously interfere in the fractionation of the cerium group double magnesium nitrates. It is important, however, that there be no ceriuni in a bromate series,... 

Liquid-liquid extraction has proved a practical technique for the isolation of rare earths and yttrium as a group and for the isolation of individual members of this group, the separation being accomplished especially easily in instances in which a valence other than +3 might be employed. It has proved useful in the determination of stability constants of lanthanide and actinide chloride and nitrate complexes. And it has demonstrated the existence of mixed extracted entities such as Th(N03)(HY2)3. 

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