Mineralogical Characterization of Anode Slimes—I. Anode Copper from Inca's Copper Cliff Copper Refinery

Abstract

Anode copper from Inco's Copper Cliff Copper Refinery was characterized mineralogically to determine the composition, morphology and relative abundance of the phases present. The anode consists of a copper matrix containing numerous oxide and selenide inclusions, mostly present at the copper gram boundaries but also occurring within individual copper grams. Most of the 0.67% Ni content of he anode is in solid solution in the copper although some is present as tiny NiO crystals Which occur primarily in the upper half of the anode. Virtually all the silver is in solid solution in the copper, and <1% of he total occurs in the inclusion phases. The inclusions present in the anode are mostly Cu2O containing persistent traces of Ni and Se, and NiO containing ∼ 3% Cu in solid solution. The Cu2O occurs as spheroidal or irregular masses ∼10 μm in diameter, whereas the NiO occurs invariably as euhedral crystals <10μm in size. Copper selenide with minor amounts of Te and traces of Pb and Ag is present in complex inclusions with Cu2O, and the selenide is the dominant Te carner. Traces of Pb-Cu-Bi oxide and Pb-Cu oxide were observed in some of the complex inclusions. Many ∼10 μm inclusions of Cu-Ni Silicate and Ca-Cu-Ni silicate also were present, especially in the upper half of the anode. The mineralogical characterization suggests that most of the nickel will dissolve during. copper electrorefining and that the anode slimes will consist predominantly of selenides, NiO, PbSO4, Silicates and possibly stiver telluride.