Rhone-poulenc Chimie

Francoise Picard

Jean-Luc Le Loarer

Claire David

Ceric oxide particulates having a specific surface of at least 190 m.sup.2 /g, measured after calcination at a temperature of from 350.degree. to 450.degree. C., and a specific surface of at least 15 m.sup.2 /g after calcination at 800.degree. C., are prepared by (a) suspending, in an aqueous solution of a decomposable base, a ceric hydroxide of the formula (I):

Ceric oxide particulates having improved morphology

Essentially anhydrous (i.e., containing no more than 2.5% by weight of water of hydration) admixtures of (i) dehydrated rare earth halides, (ii) at least 10% by weight of alkali and/or alkaline earth metal halides, and (iii) up to 4.5% by weight of rare earth oxyhalides, these halides being other than fluorides, are produced by mixing hydrated rare earth halides with alkali and/or alkaline earth metal halides and then raising the temperature of such admixtures, advantageously in the presence of a gaseous flux containing a dehydrating halocompound, to a value ranging from 150.degree. to 350.degree. C. as to essentially dehydrate the hydrated rare earth halides, the final admixtures are well adapted for the production of rare earth metals therefrom.

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Fontenay/Sous/Bois, France

Francoise Picard