Rhone-poulenc Chimie

Michel Ries

Jean-Luc Le Loarer

Francoise Seon

Bernard Pacaud

Bernard-Antoine Dissaux

Very finely divided ammonium rare earth double oxalates, readily converted into corresponding rare earth oxides by calcination, such oxides being well adopted, e.g., for the production of luminescent compounds therefrom, are prepared by (a) admixing a second solution of a rare earth compound, e.g., a salt, with a first solution containing oxalate and ammonium ions, (b) then separating the precipitate thus obtained from such mixed solution of reaction, and (c) optionally, drying the separated precipitate.

Production of finely divided rare earth ammonium oxalates/finely divided

Vanadium values useful for catalyst regeneration are recovered from compositions/materials comprised thereof, typically spent V.sub.2 O.sub.5 catalysts, by intimately contacting an aqueous suspension of such a material with a gaseous admixture of sulfur dioxide and oxygen, whereby a phase separation thus results, and recovering an aqueous phase constituting a solution of vanadium values.

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Vitry/sur/Seine, France

Michel Ries