Mineral Partitioning by Sulfidation.
Paper in Process Mineralogy IX: Applic to Mineral Benefic Met Gold Diam 1990 :311-322
The U.S. Bureau of Mines is investigating the feasibility of partitioning complex sulfide minerals to simpler sulfide phases by sulfidation reactions. Such partitioning can afford opportunity to improve selective extraction of mineral constituents of value. This report describes initial research involving sulfidation partitioning of chalcopyrite concentrates. Small chalcopyrite samples were sulfidized with elemental sulfur in glass capsules sealed after evacuating and backfilling with helium, by heating for 1 to 24 h at specific temperatures in the range of 250 to 500 deg. C, which extends from below to above the boiling point of sulfur ( 445 deg. C). Above the boiling point of sulfur, the overall reaction with adequate sulfur (13.9 Wt pct of cufes2) is 5cufes2 + 4sog->cu5fes6 + 4fes2. The reaction below the boiling point of sulfur, with adequate sulfur (17.4 Wt pct of cufes2), results in partitioning to the simple copper sulfide, covellite, according to the reaction cufes2 + sol->cus + fes2. The covellite forms as a crust on particulate pyrite cores. Larger amounts of concentrate have been sulfidized to the covellite-pyrite product in a tube furnace reactor.
Paper in Process Mineralogy IX: Applic. to Mineral Benefic, Met, Gold, Diam., 1990, Pp 311-322