Synthesis and characterization of geopolymer-zeolites from Ghanaian Kaolin samples by variation of two synthesis parameters

Two kaolinitic clays from two Regions of Ghana: Western and Volta Regions, were first calcined at 600 °C for 2 h to transform into the amorphous aluminosilicate phases. The effects of kaolin and alkali ratio as well as aging on the amount and types of zeolite in the resultant geopolymers were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transformed spectroscopy, thermogravimetric analysis and specific surface area measurements. Alkali activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different particle size distributions. The results showed that initial kaolin samples were dependent on the concentration of alkali treatment and crystallization time during the activation treatment and produced zeolite type A along with quartz which showed no reactivity regardless of the variation of the synthesis parameter.