Removal of manganese and iron from the alloy obtained from direct smelting of sea nodules

Abstract

The alloy obtained from smelting of polymetallic sea nodules contains a substantial amount of iron and manganese. For subsequent processing to obtain a sulphide matte from this alloy for the recovery of pure copper, nickel and cobalt, the iron and manganese content needs to be reduced to a manageable level. For achieving this objective, initially few trials were conducted for oxidation of the molten alloy by blowing oxygen in an induction furnace. However, due to slow kinetics of oxidation as well as wear of furnace lining, further trials were conducted by the addition of an oxidizing agent such as pyrolusite. A substantial amount of iron and almost complete manganese could be decreased in the resultant alloy, making the same suitable for the preparation of sulphide matte and subsequent hydrometallurgical processing for recovery of copper, nickel and cobalt.