Effects of non-thermal plasma treatment on the geopolymerization of kaolin clay

Abstract Cameroonian kaolin samples were used to produce geopolymer cements. Prior to its application, the raw kaolin samples were activated trough the gliding arc plasma treatment in both spatial post-discharge and direct mode. A mixture of sodium hydroxide and silicate was used as the alkaline solution. The materials produced were tested by X-ray diffraction, thermogravimetric analysis, differential scanning calorimeter and Fourier transform infrared spectroscopy in order to study the influence of the modifications generated by the gliding arc plasma treatment on the geopolymerization process. The scanning electron microscopy analyses, nitrogen physisorption analyses and compression tests were also carried out on the materials produced for assessing and understanding their mechanical performance. The results showed that the geopolymerization process remained partial at the curing temperature of 90 °C. Plasma spatial post-discharge mode treated kaolin led to 20.48% increase in compressive strength when compared with the geopolymer prepared from raw kaolin.