スラグ-溶銅間シリコン酸化反応系における物質移動速度

抄録

A kinetic study has been investigated on the reaction between molten Cu-0.1%Si alloy and a Li₂O-SiO₂-Al₂O₃-FeO slag. The explored reaction was Si+2FeO=SiO₂+2Fe. The metal-slag melt was stirred by an alumina rod. The experimental temperature was 1250°C.
In one series of experiments, initial FeO contents of slag were varied from 5 to 15% at a constant rotational speed of the stirrer (200 rpm). The rate data could be represented apparently by linear relationship between log[%Si] and the time (t). Apparent mass-transfer coefficients of Si in metal, k'_Si, were calculated. At initial FeO contents, (%FeO)0, below 9%, the reaction rate is controlled both by Si transport in the metal phase and Fe0 transport in the slag phase. At (%FeO)₀_??_9%, the reaction rate is controlled only by Si transport in the metal phase.
In another series of experiments, the stirring speed was varied as 70400 rpm at (%FeO)₀=9%. The mass-transfer coefficients, k'_Si, were found to be proportional to the 0.5 power of rpm of the stirrer. This experimental finding can be ascribed to the fact that the reaction is of mass-transfer controlled.
The present reaction system has been established as a suitable model for the purpose of investigating the role of stirring in slag-metal reactions at high temperatures.