スラグ-溶銅間シリコン酸化反応における反応帯

抄録

An experimental study had been made on the mechanism of mass-transfer between molten Cu-Si alloy and Li₂O-SiO₂-Al₂O₃-FeO slag at 1523 K. The explored reaction was the oxidation of silicon by FeO in slag taking place under the condition of rate-controlling by transport of silicon in the metal phase. By examining rate data influenced by the concentration of Si in the metal phase, a new concept on the reaction zone in metal-slag reactions has been proposed.
It is presumed that the zone of reaction between Si and O is located within the metal-side boundary layer. The location of the zone is supposedly controlled by mass-tranfer fluxes of O from the slag-metal interface to the reaction zone and Si from the bulk metal to the zone. When the initial concentration of Si is high (≥0.08 mass%), the reaction zone is located in the vicinity of the slag-metal interface until Si concentration is lowered considerably. In this case, the apparent mass-transfer coefficient of Si (k_Si′) is constant. When the initial concentration of Si is low (≤0.02 mass%), the reaction zone moves away from the interface during the reaction so that the distance through which Si is diffusing decreases, resulting in the increase in the mass transfer coefficient.