Method for recovering casting refractory compositions from investment casting slurries and from cores

摘要

A slurry containing Y₂O₃ and a binder is gelled and is then ignited to remove residual organic compounds. The resulting product is powdered and then calcined to crystallize the silica binder. The calcined mixture is treated with a heated acid to dissolve Y₂O₃ and undissolved binder residue is then removed by filtration. The solution is diluted and treated with oxalic acid to precipitate yttrium oxalate which is then separated and calcined. Cores are processed in a similar manner, except that gelling and ignition are unnecessary.