The contents of impurities, especially that of phosphorus, in manganese metal or in ferromanganese used in steelmaking are an important factor that affects product quality. More than 80% of phosphorus in the manganese products is introduced from manganese ore, the rest coming from coke and lime. Once it is absorbed into a molten manganese ore ferromanganese phase, it cannot be easily removed by smelting, and thus, ferromanganese must generally be low in phosphorus to begin with. As good quality ores of low phosphorus are depleted, the phosphorus content in manganese ores increases, and thus, the development of a new dephosphorization technology is needed.

For this purpose, the removal of phosphorus compounds by vaporization directly from manganese ores using a plasma system was investigated in this study. For the removal of phosphorus, the effects of argon gas flow rate, hydrogen gas content in the plasma gas, and plasma torch power were analyzed. In addition, based on the thermal decomposition of hematite in the ores into magnetite at a high temperature, a magnetic separation was conducted after plasma treatment aiming to upgrade manganese ores. For the removal of phosphorus, a low argon gas flow rate and a high torch power were found to be effective, and the use of hydrogen gas as a reducing agent was more favorable than without. Magnetic separation after plasma treatment improved the ore grade with a decrease of iron content in the ore.