2016 年 63 巻 1 号 p. 3-11
It is well known that galvanic interaction between sulfide minerals and manganese oxides in manganese nodules accelerates the leaching of sulfide minerals. Zinc-carbon batteries contain a moist paste (hereafter, black paste) of manganese oxides and graphite powder as cathode mix. We have investigated the feasibility of galvanic leaching of chalcopyrite using chemical reagent MnO2 and black paste. Addition of MnO2 enhanced the leaching of chalcopyrite in sulfuric acid media with pH 1.0 and Mn concentration also increased remarkably. Extraction yields of Cu and Mn were 52% and 23% respectively at a MnO2 to chalcopyrite mass ratio of 4 in 24 days. In the presence of black paste the kinetics of chalcopyrite leaching was accelerated dramatically and 83% of Cu in the concentrate was extracted in 40 hours. The graphite powder contained in black paste could play an important role in the galvanic leaching of chalcopyrite in the presence of MnO2.