AUTOCLAVE TUNGSTATE UPGRADING OF SCHEELITE CONCENTRATES

摘要

AUTOCLAVE TUNGSTATE UPGRADING OF SCHEELITE CONCENTRATES A calcium tungstate concentrate is produced by slurrying an aqueous sodium tungstate liquor with calcium carbonate at about 130.degree.C to about 200.degree.C while providing sufficient carbon dioxide overpressure to convert sodium carbonate in the slurry to sodium bicarbonate, wherein the conversion of sodium tungstate to solid calcium tungstate in the slurry is promoted. The carbon dioxide is then stripped from the slurry, causing the sodium bicarbonate to convert to sodium carbonate, and a calcium tungstate concentrate is filtered from the slurry. The invention is useful in upgrading impure calcium tungstate concentrates.