A Mathematical Description of the Thermodynamic Behaviour of Multi-Component Slag Systems with the use of Solution Species

For a better understanding and control of the chemistry of smelting processes, the importance of adequate descript-ion of the thermodynamic behaviour of slag, metal and matte solutions has been increasingly realized. In this regard, the concept of associated solution species has gained wide acceptance over the past two decades for its efficacy and flexibility in representing the properties of complex slag and matte solutions.

This paper reviews the highlights of this approach and the author's experience in applying it for describing the thermodynamic properties of iron silicate slag systems wherein the hypothetical chemical species are considered to behave in a non-ideal manner. The activity coefficients of the solution species are described with the help of three-suffix Margules equations with zero ternary inter-actions which correspond, in the author's opinion, to a generalized form of the regular solution behaviour. Examp-les from the lime containing iron silicate quaternary and the nickel containing quinary and their subsystems are examined briefly.