21/06/2016 · 90% of Manganese metal production is consumed by the iron and steel industries (10 kg of Mn per metric ton of steel,13 million metric ton of Mn per year consumed for steel production). High grade Mn ore ( >35% Mn by wt.) is processed conventionally by high temperature roasting ( ̊ C) of Mn(III), Mn(IV) ores to MnO for leaching with Sulphuric acid and subsequent Electrowinning to ...