EVAPORATION RATE OF ZINC IN LIQUID-IRON

An investigation of evaporation rate of Zn from liquid iron has been undertaken at 1 873 K by impinging Ar onto the surface of inductively melted iron containing Zn. The evaporation rate of Zn was found to be first order with respect to Zn content in the metal. No measurable effects of the Ar flowrate and carbon or sulfur content in the metal on the rate were observed with Ar flowrate above 5//min, but the rate was strongly affected by stirring condition of the melt. It was, therefore, concluded that the evaporation rate of Zn was controlled by the liquid phase mass transfer under the condition. The mass transfer coefficient in the liquid phase was estimated to be 0.032 cm/s at 1 873 K. The removal rate of Zn or other tramp elements in the conventional practical operations or vacuum treatment was also discussed based on the present result.