The rate of transfer of manganese from slag to liquid iron was investigated by measuring the change of manganese and oxygen contents of liquid iron under MnO-(CaO+Fe_tO +MgO)-SiO₂ slag in a magnesia crucible. Experiments were carried out with slags of basicity from 0.66 to 1.19 at 1 600°C.
The results are as follows :
1) The equilibrium between liquid iron and slag was attained after about 30 min.
2) The rate of reaction and manganese content of final liquid iron increased with decrease of oxygen potential of the system and with increase of manganese oxide content of initial slag.
3) The experimental results were interpreted by the rate equation derived from the assumptions that the reaction rate was controlled by the transfer of Mn, O, (MnO) and (FeO) in the boundary layers and that the distribution-ratio of manganese and oxygen varied with proceeding of the reaction. Values of mass-transfer-coefficient of (MnO) were nearly the same with those obtained in the previous study on the rate of oxidation of manganese in liquid iron at the same temperature.