1. Arsenopyrite is separated from a mixture with pyrite by contacting the mixture with a sulfitic agent providing HSO 3 - ions at elevated temperature and pH below about 8 for a period sufficient to impart a selective depression property to the Arsenopyrite

2. Arsenopyrite is separated from a mixture with pyrite by contacting the mixture with a sulfitic agent providing HSO3- ions at elevated temperature and pH below about 8 for a period sufficient to impart a selective depression property to the Arsenopyrite