Abstract
As a fundamental study for treating fused oxides containing antimony and arsenic components relating to metallurgical and recycling processes, volatility, a, and vapor pressure of the oxide species evaporating from the CaO-SiO2-FeO1.5 slags with Q (%CaO / (%CaO + %SiO2)) of 0.37, 0.53 and 1 were determined at 1,573 K in a range of mole fraction, N, of SbO1.5 , SbO2.5 and AsO2.5 in the slag between 0.005 and 0.05 by using the transpiration method with a vertical volatilization chamber. It was found that the volatility of the antimony and arsenic components in each slag increases with decreasing Q and suggested that control and adjustment of the slag basicity are very important for eliminating these components from the slag by means of volatilization. The log α versus log N plots represented a nearly straight line with a gradient, which is very close to that predicted by the thermodynamic consideration, and it was concluded that Sb4O6 and As4O6 are the predominant gas species evaporating from the slags. Raoultian activity coefficients, γ, of SbO1.5, SbO2.5 and AsO2.5 in the slags, which were derived from the measured volatility, decrease with increasing Q, and γSbO2.5 and γAsO2.5 are less than unity for the slags with Q of 0.53 and 1.
