Rhone-poulenc Chimie

William Fogel

Laurent Frouin

Eric Garcin

Yves Mottot

The invention relates to a process of treatment for the recovery of the precious metals, such as platinum, rhodium and palladium, contained in various compositions including a layer of oxide(s) which is deposited on a metal support, in particular worn or spent motor vehicle postcombustion catalysts, in which the layer of oxide(s) containing the precious metals is separated from the metal support by an electrochemical route, the composition to be treated forming one of the electrodes employed or being in direct contact with one of the electrodes employed.

Process for the treatment, by an electrochemical route, of compositions

Novel aluminum phosphates, in particular amorphous aluminum phosphate powders having a BET specific surface no greater than 25 m.sup.2 /g, well suited as binders/hardeners or for the production of ceramic shaped articles, are prepared by reacting at least one aluminum compound, e.g., an aluminum oxide, hydroxide or oxyhydroxide, with phosphoric acid or an aluminum phosphate, e.g., an acid aluminum orthophosphate, in a liquid reaction medium devoid of inorganic acid anions other than of phosphoric acid, and then spray- or freeze-drying the suspension thus obtained.

Aluminum phosphates and binder compositions/ceramic materials comprised

Phosphomagnesia compositions settable into improvedly water-insensitive cements that retain their mechanical properties comprise an intimate admixture of (i) a binder phase including (a) at least one phosphorous compound (P.sub.2 O.sub.5 or derivative/precursor thereof) and (b) at least one magnesium compound reactive therewith in the presence of water, (ii) an effective amount of cementitious aggregate, and (iii) a water sensitivity-reducing amount of at least one silicone homogeneously distributed therethrough.

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Ales, France

William Fogel