Importance

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Abstract

A highly efficient method for recovering Y.sub.2 O.sub.3 from casting slurries and cores containing Y.sub.2 O.sub.3 in combination with a binder is disclosed. The slurry is first treated with a gelling agent which causes the slurry to gel. The gelled slurry is then ignited in order to remove residual organic compounds. After ignition, the product is crushed and pulverized to form a powder. Thereafter, the powder is calcined at a temperature sufficient to crystallize the silica binder in the powder. The calcined product is subsequently dissolved in a heated acid solution for a selected time period. The resulting solution contains dissolved Y.sub.2 O.sub.3 and undissolved binder residue, which is filtered and removed. The Y.sub.2 O.sub.3 in the solution is then diluted with deionized water, and precipitated, preferably using oxalic acid to produce yttrium oxalate. The yttrium oxalate is ultimately removed from the solution and calcined to produce high purity Y.sub.2 O.sub.3. Cores are processed in a similar manner.

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First Claim