| The distribution ratios of As and Sb between molten silver alloys and CaO-FeO-CaF₂ slags at 1723K was measured to investigate the thermodynamic behaviors of these elements in steelmaking conditions. The oxygen partial pressure was controlled by the activity of FeO in slags, which was estimated from the Fe/FeO equilibrium. Since the distribution ratio of As decreased with increasing oxygen partial pressure, As would be refined by the reducing refining mechanism. However, the distribution ratio of Sb has a minimum value with variation of the oxygen partial pressure, indicating that Sb can be refined by the reducing refining at lower than Po₂=3.02×10^(-12) atm and by the oxidizing refining at higher than this critical oxygen partial pressure. The capacities of each element, obtained from the distribution ratio and the oxygen partial pressure, were independent of the composition of slags, i.e., X_(FeO)/X_(CaF₂), along the CaO saturated slag. It may be due to the constancy of the activity of CaO, which makes the activity coefficient of each reaction product in stags be constant. The effect of carbon content in molten iron on the distribution ratios of As and Sb was also discussed. |
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