Vitrification and neomineralisation of bentonitic and kaolinitic clays for possible ceramic applications

  • Georges-Ivo E Ekosse Department of Geology, University of Botswana, P/Bag 0022 Gaborone, Botswana
  • Antoine Mulaba-Bafibiandi Department of Metallurgy, School of Process and Mechanical Engineering, Technikon Witwatersrand, PO Box 526, Wits 2050, Johannesburg, South Africa
  • John S Nkoma Department of Physics, University of Botswana, P/Bag 0022 Gaborone, Botswana


The bulk mineralogy of selected raw and fired bentonitic and kaolinitic clays from Botswana, Mozambique, Pakistan, Senegal, South Africa and the United States of America was determined by X-ray powder diffraction (XRPD) technique. Each sample was fired at 950°C, and 1250°C, for 35 minutes in order to study the effects of firing on them. It was noticed that the samples vitrified, and neomineralization was realised. These processes are found to be similar to those of transformation of sedimentary rocks into metamorphic and/or igneous rocks. Resultant fired mineral phases depicted mineral compositions of ceramic bodies, and the study suggested that these clays could be gainfully utilized in the making of ceramic wares, subject to selected beneficiation processes.

Keywords: kaolin, bentonite, vitrification, neomineralization, ceramic, firing

Global Journal of Geological Sciences Vol. 3(2) 2005: 153-161

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eISSN: 1596-6798