Effect of Silicon and Carbon on the Evaporation Rate of Copper in Molten Iron

In order to increase the evaporation rate of copper in molten iron, the addition of silicon or carbon, which has a strong affinity with the solvent metal, iron, is considered to be effective, because the activity coefficient of copper can be expected to increase. Accordingly, the effects of silicon and carbon on the evaporation rate of copper in molten iron have been investigated. It is found that the rate constant of copper evaporation has a maximum value at the silicon content of about 3 mass%. The apparent rate constant at 3 mass% Si is about 1.4 times larger than that for Fe-Cu alloy. The apparent rate constant of copper evaporation for Fe-C-Cu alloy monotonically increases with increasing the carbon content. The rate constant at 2 mass% C is about 1.7 times larger than that for Fe-Cu alloy. At a practical reduced-pressure of 133 Pa, the rate constant of copper evaporation which is large enough to be equivalent to that in the case of the chemical reaction rate-limiting for Fe-Cu alloy was attained in the present study.