2025 Hyun Jae Kim Evaporation of Cu from Molten Steel Containing C and S Under Reduced Pressure at 1650 C for Developing Refining Process of EAF Steel s40831 024

The evaporation of Cu from molten steel containing C and S was investigated by employing high-temperature gas–liquid reaction and kinetic mechanism analysis. To continue the development of the tramp element removal process by evaporation, the investigation was extended to reduced pressures in the present study. A systematic study was carried out with well-controlled steel chemistry in order to avoid uncontrolled impurity effects. An electromagnetic levitation technique with a rapid-evacuation chamber was developed. The experiments were carried out under a chemical reaction-controlled regime to elucidate the evaporation mechanism, mostly at 1650 °C. Apart from the previous findings (acceleration of Cu evaporation by increasing temperature, surface blocking of S, simultaneous evaporation of Cu(g) and CuS(g), and coupled effect of C and S), it was found that Cu evaporation was significantly accelerated by decreasing pressure. The previous reaction rate model of Cu evaporation from molten steel surface was extended to take into account the evacuation. The intrinsic rate constants of each gas species were obtained as functions of pressure. It was proposed that the evaporation of Cu via residual sites was accelerated under reduced pressure.