Preparation of ammonium rare earth double oxalates and rare earth oxides produced therefrom
AssigneeRhone-Poulenc Chimie
InventorClaire David
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Abstract
Particulate and coarse ammonium rare earth double oxalate crystals, readily converted into rare earth oxide particles by simple calcination, e.g., yttrium oxide particles, are prepared by (a) intimately admixing, in an aqueous medium, (i) at least one rare earth neutral oxalate with (ii) at least one precursor compound adapted to liberate ammonium ions in water and (iii) at least one precursor compound adapted to liberate oxalate ions in water, (b) separating the double oxalate precipitate thus formed, and (c), optionally, washing and drying such double oxalate precipitate.
Claims19
A process for the preparation of an ammonium rare earth double oxalate, comprising (a) forming a suspension by intimately admixing, in an aqueous medium, (i) at least one rare earth neutral oxalate with (ii) at least one precursor compound liberating ammonium ions in water and (iii) at least one precursor compound liberating oxalate ions in water, and converting the rare earth neutral oxalate by precipitation into a precipitate of an ammonium rare earth double oxalate, (b) separating the double oxalate precipitate formed in step (a).
A process for the preparation of an ammonium rare earth double oxalate, comprising (a) forming a suspension by intimately admixing, in an aqueous medium, (i) at least one rare earth neutral oxalate with (ii) at least one precursor compound liberating ammonium ions in water and (iii) at least one precursor compound liberating oxalate ions in water, and converting the rare earth neutral oxalate by precipitation into a precipitate of an ammonium rare earth double oxalate and (b) separating the double oxalate precipitate formed in step (a) wherein said process provides particulate and coarse ammonium rare earth double oxalate crystals having a mean particle size of at least 5 .mu.m and cubic shape.
A process for preparing ammonium rare earth double oxalate crystals comprising (a) intimately admixing, in an aqueous medium, (i) at least one rare earth neutral oxalate with (ii) at least one precursor compound liberating ammonium ions in water and (iii) at least one precursor compound liberating oxalate ions in water, and converting the rare earth neutral oxalate by precipitation into crystals of an ammonium rare earth double oxalate having a mean particle size of 5-10 .mu.m, (b) separating the double oxalate crystals thus formed, and (c) optionally, washing and drying said double oxalate crystals.
Dependencies are inferred from the claim text.