Rhone-poulenc Specialites Chimiques

Rhone-poulenc Chimie De Base

Jean-Paul Tognet

Frederic Fabre

Andre Lambert

Claude Magnier

Jean Fava

Rare earth hydroxides are recovered from the rare earth ores, e.g., monazite, xenotime and/or bastnasite, by treating the ore with an aqueous solution of an alkali metal hydroxide, under agitation and essentially constant pressure, at a temperature of from about 100.degree. to 220.degree. C., and wherein the ratio by weight of alkali metal hydroxide/ore ranges from about 1.4 to 0.5, e.g., a weight ratio of sodium hydroxide/ore of from about 1 to 0.5, or a weight ratio of potassium hydroxide/ore of from about 1.4 to 0.7.

Processing of rare earth ores

The rare earth hydroxides are improvedly prepared by (i) treating a rare earth phosphate mineral, e.g., monazite or xenotime, with an aqueous solution of an alkali metal hydroxide, (ii) separating therefrom rare earth hydroxide solids and a liquid phase essentially consisting of alkali metal phosphate and alkali metal hydroxide, (iii) crystallizing alkali metal phosphate from said liquid phase, (iv) separating the mother liquor of crystallization therefrom which contains said alkali metal hydroxide, (v) adding calcium oxide or hydroxide to the mother liquor thus separated to form a precipitate therein, (vi) separating said formed precipitate, and (vii) recycling the mother liquor of separation to said treatment step (i).

Production of rare earth hydroxides from phosphate ores

The uranium, yttrium, thorium and rare earth values contained in a phosphate rock are essentially totally recovered therefrom by, during the wet-process preparation of phosphoric acid from said phosphate rock, acidulating same in the presence of aluminum and/or iron, and optionally silica, and thence recovering said values from the phosphoric acid thus produced.

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La Rochelle, France

Jean-Paul Tognet