Galvanic Leaching of Cobalt-Rich Ferromanganese in the Presence of Pyrite

Cobalt-rich ferromanganese crusts (cobalt crust) contain strategic metals such as copper, nickel and cobalt. In order to recover cobalt, the reduction and dissolution of manganese oxide in crusts is required because cobalt is interlocked in manganese oxide. It is known that galvanic interactions between metal sulfide minerals and manganese nodule cause oxidation-reduction reactions on them. In this study, galvanic leaching of chemical analytical MnO2 and cobalt crust has been examined in the presence of pyrite. The measurement of rest potential indicated that MnO2 was nobler than pyrite. The dissolution of the MnO2 was accelerated in the presence of pyrite because MnO2 could act as cathode to be reduced in the galvanic couple MnO2/FeS2 . The dissolution of manganese and cobalt from the cobalt crust was enhanced in the presence of pyrite, and 84% of cobalt was extracted in three days while about 1% in the absence of pyrite in sulfuric acid solution of pH0.8. The leaching of the cobalt crust has been studied under various experimental parameters such as pH, amount of pyrite and particle size.