M. Madhuchhanda et al., Leaching of deep-sea manganese nodule and base metal sulfide minerals in hydrochloric acid, T I INST ME, 53(1-2), 2000, pp. 71-77
Leaching of manganese nodule in the presence of chalcopyrite. sphalerite an
d galena individually was studied in HCl medium. When leached together, dis
solution of metal values from the nodule as well as each of the base metal
sulfide minerals, was found to be more efficient compared to their leaching
individually under similar conditions. Galvanic interaction between metal
sulfides (MS) and MnO2 and corrosion coupling due to cyclic action of Fe3+/
Fe2+ redox couple were responsible for such increase in dissolution. Chlori
ne gas generated in the system also dissolved the base metal sulfide minera
ls. This approach of combined MS-manganese nodule leaching appears to be ad
vantageous because of more efficeint dissolution and addition of value into
the final product.