Recovery of manganese as ferro-silico-manganese alloy from leached sea nodule residue

The leached residue contains a considerable amount of manganese along with iron and silicon. Attempts have been made to recover manganese as ferro-silico-manganese through smelting with coke as reductant. To improve the Mn/Fe ratio in the alloy produced, three blending materials viz. Fe-Mn slag, Mn ore and electrolytic manganese metal were used. Two stages smelting of washed residue was also tried to produce directly standard grade Fe-Si-Mn alloy.