Phosphate Capacities of CaF2-MgO and CaF2-CaO-MgO Slags

Abstract

Previously published sulphide capacity data and thermodynamic arguments have been employed to calculate the phosphate capacities and the phosphorus partition ratios between a molten carbon saturated iron alloy and binary CaF2-MgO slags and also ternary CaF2 -CaO-MgO slags at 1450 °C. For the CaF2-MgO binary system, a linear relationship was found between the phosphate and the sulphide capacities as follows: log = 1.2 log Cs + 25.2. For the ternary CaF2-CaO-MgO system at 1450 °C, the logarithm of the calculated phosphate capacities ranged from 19.47 to 20.15. With the addition of CaO, the phosphate capacities initially increased, reached a maximum and then decreased slightly. The addition of MgO to the CaF2-CaO system resulted in a decrease in the phosphate capacity. The calculated phosphorus partition ratios increased slightly with increasing mole fraction of CaO in the ternary system.

Keywords

• phosphate
• capacities
• slags
• 81.20.ym