1. Thermodynamics Research Unit, School of Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4041, South Africa
2. Minerals Processing Division, Mintek, Private Bag X3015, Randburg 2125, South Africa
3. Department of Chemical and Metallurgical Engineering, University of the Witwatersrand, 1 Jorissen St, Johannesburg 2000, South Africa
4. Department of Chemical Engineering, Banhoekweg, Stellenbosch University, Stellenbosch 7600, Western Cape, South Africa