• Hydrometallurgy of the delta sulfide ores, first stage report

      Letwoski, F.; Chous, Kuo-tung; Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1986)
      This report presents the results of hydrometallurgical research carried out from September 16, 1985 to June 30, 1986 on metals recovery from complex sulfide ores from the Delta deposit near Tok, Alaska. The leaching characteristics performed for 6 different ore samples indicate that the most valuable components form the following order: Zn > Au > Pb > Ag > Cu > So. Further study demonstrates that direct leaching of the ore is effective both in chloride as well as in sulfate oxidizing solutions coupled with separating of leached solid components by flotation. Three variants of the ore processing with ferric chloride or fenic sulfate leaching are analyzed: one flowsheet with direct ore leaching in ferric chloride solution followed by leaching-flotation step, with subsequent zinc separation in a solvent extraction step and electrolysis in chloride solution; and two flowsheets of direct ore leaching with ferric sulfate solution followed by a leaching-flotation step, with zinc sulfate electrolysis and other metals recovery in chloride leaching sreps. In two last flowsheets silver is recovered during the chloride leaching steps and gold h m flotation products during the cyanide leaching. Preliminary economic and technical evaluation is presented. The engineering study on apparatus for the fast leaching- flotation processing and on better accumulation of gold and silver in one semi-product are concluded for the next year of research.