OXYGEN AND SULFUR SOLUBILITIES IN NI-FE-S-O MELTS

Oxygen and sulfur solubilities were determined in Ni-Fe-S-0 melts unde r the following conditions: 10(-11.50) less-than-or-equal-to P(O2) les s-than-or-equal-to 10(-8.50) atm; 10(-3.0) less-than-or-equal-to P(S2) less-than-or-equal-to 10(-2.00) atm; 0.19 less-than-or-equal-to Ni/(N i + Fe) less-than-or-equal-to 0.85; and 1473 K less-than-or-equal-to T less-than-or-equal-to 1573 K. The oxygen solubility was found to incr ease with increasing partial pressure of oxygen up to a maximum value at oxide saturation and to decrease with increasing equilibrium partia l pressure of sulfur. The ferrous metal content enhanced oxygen solubi lity. The trends in dissolution behavior of sulfur were opposite to th ose of oxygen with respect to changing P(O2) and P(S2) and to the Ni/( Ni + Fe) ratio; however, at high matte grades {Ni/(Ni + Fe) > approxim ately 0.5}, sulfur solubility appeared to decrease as a function of th e Ni/(Ni + Fe) ratio, as did oxygen solubility. The standard Gibbs ene rgy of oxygen dissolution in Ni-Fe-S-0 melts {Ni/(Ni + Fe) = 0.47} in the temperature range 1473 to 1573 K can be described by DELTAG-degree s = -202.5 + 0.0660 T (K) (+/- 1.5 kJ/mol)