Effects of Mn ore on the Dephosphorization and Desulphurization in Hot Metal Pretreatment

In order to examine the possibility of utilizing Mn ore in the pretreatment process of liquid iron, experiments were carried out in a system with liquid iron and CaO‐SiO₂‐MgO‐Al₂O₃‐FeO slag with additives (Mn ore and Fe₂O₃+MnO₂) in a magnesia crucible at 1673K. When Mn ore was added to the pretreatment slag, decarburization, desiliconization, dephosphorization and desulphurization proceeded simultaneously with the reduction of Mn ore. The reduction rate of MnO and the Mn concentration in the melt increased with increasing initial Si content. The maximum dephosphorization was obtained when the additive consisted of 66.6 mass% Fe₂O₃ and 33.4 mass% MnO₂. The desulphurization ratio increased with increasing the relative amount of MnO₂ in the additives. The amount of additives comprising Fe₂O₃ and MnO₂ required for a targeted manganese content could be predicted using the mass balance. Effects of the additives on dephosphorization were also estimated.