Advanced Materials Division, Mintek,
Private Bag X3015, Randburg 2125, South Africa
DST/NRF Centre of Excellence in Strong Materials,
Johannesburg 2050, South Africa
and School of Chemical and Materials Engineering,
University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa;
rainers@mintek.co.za
Advanced Materials Division, Mintek,
Private Bag X3015, Randburg 2125, South Africa
DST/NRF Centre of Excellence in Strong Materials,
Johannesburg 2050, South Africa
and School of Chemical and Materials Engineering,
University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa;
lesley.cornish@wits.ac.za