A MODIFIED SULFIDE CAPACITY FUNCTION

The sulphide capacity as originally defined by Fincham and Richardson is a strong function of composition in pseudobinary oxide melts of int erest in extractive metallurgy. From an analysis of data available in the literature, it is shown that sulphide capacity is directly proport ional to the activity of the basic oxide in the melt, within the uncer tainty of experimental data. A single parameter is sufficient to descr ibe the sulphide capacity of a binary slag system under isothermal and isobaric conditions. The correlation indicates that the activity coef ficient of the sulphide ion or the neutral base metal sulphide dissolv ed in the melt is independent of composition in pseudobinary melts wit hin experimental uncertainty. Structural variations in the melt with c omposition do not seem to affect the activity coefficient of the sulph ide. A modified sulphide capacity function is defined which makes the treatment more elegant and greatly simplifies data storage and retriev al. The modified function is not based on any model for the melt.