1. Chemical Resource Beneficiation, North-West University, Potchefstroom, South Africa
2. Centre of Excellence in Carbon-based Fuels, Potchefstroom Campus, Potchefstroom, South Africa
3. School of Chemical and Minerals Engineering, North-West University, Potchefstroom, South Africa
4. School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney NSW, Australia
5. Sustainability Division, Research, Testing and Development, Eskom, South Africa