Bioleaching of ocean manganese nodules in the presence of reducing agents

Abstract

The key for successful and efficient dissolution of copper, nickel and cobalt from the ocean manganese nodules depend on prior reduction of manganese and ferric oxides with which the above valuable nonferrous metals are interlocked. The present work is relevant to bioleaching of ocean manganese nodules using autotrophic microorganisms, such as Thiobacillus ferrooxidans and Thiobacillus thiooxidans in the presence of pyrite and sucrose which resulted in significant dissolution of copper, nickel and cobalt from the ocean manganese nodules. Electrochemical means of creating reducing conditions in situ are also brought out. Various biochemical and electrochemical mechanisms in the leaching process are outlined.