关键词: iron chromite ore;lead sulfide ore;gold associated with sulfides;leaching;pretreatment; fused sodium;hydroxide leaching;carbonate conversion of lead sulfide, carbonate conversion of lead sulfide

Abstract: The newly developed green leaching processes for chromium, lead and gold
extraction from ores or concentrates are described. The chromium is extracted from the iron
chromite ore with fused sodium hydroxide at 500－550°C as sodium chromate. The galena in
lead sulfide concentrate is converted into lead carbonate in ammonium or sodium carbonate
solution at 50－80°C followed by the separation of lead carbonate formed from the
unconverted sulfide ores by flotation. Gold associated with sulfide ore (such as pyrite and
chalcopyrite) can be extracted into sodium thiosulfate solution without any pretreatment
such as roasting, high pressure aqueous oxidation or bacteria pre-leaching.

Key words: iron chromite ore, lead sulfide ore, gold associated with sulfides, leaching, pretreatment, fused sodium