Mineralogical Characterization of Anode Slimes: Part V—Nickel-Rich Copper Anodes from the CCR Division of Noranda Minerals Inc.

Abstract

Nickel-rich copper anodes from the CCR Division of Nor and a Minerals Inc. have been examined chemically and mineralogically to identify the phases present. Cuprous oxide, Cu₂O, is the principal impurity phase, and this occurs either as spheroidal particles at the copper grain boundaries or as tubelike inclusions oriented perpendicular to the upper surface of the anode. Nickel exists in solid solution in the copper matrix, as NiO crystal inclusions, and as kupferg1immer (Cu–Ni–Sb oxide) inclusions in selenides; the presence of NiO and kupferglimmer depends on the Ni and Sb contents of the anodes. Iron is present in amounts ranging from 14–81 ppm, and the iron occurs in solid solution in the NiO inclusions or as rare NiFe₂O₄ (ferrite) crystals. Silver occurs mostly in solid solution in the copper matrix although lesser amounts are present in solid solution in copper selenide inclusions which are the dominant selenium, and tellurium, carrier in all the anodes studied. Anodes rich in As and Bi contain numerous inclusions of Cu–Bi–As oxide and Cu–Bi oxide as well as As– and Bi–rich complex Cu–Pb– As–Sb–Bi oxides. Notable is the presence of thin rims of metallic silver which surround copper selenides associated with the oxide inclusions, and especially, the bismuth-rich oxides. Although some of the lead is in solid solution in the copper matrix, the majority of this element exists as complex inclusions of Cu–Pb oxide, Cu–Pb–As oxide or Cu–Pb–As–Sb–Bi oxide. All of the impurities are present principally as tiny inclusions concentrated at the copper grain boundaries; in many instances the inclusions are <1 μm in size.