The Potential of Laterite Soils Deposit South Sulawesi as a Precursor for Na-Poly (Ferro-Sialate) Geopolymers

The main objectives of this study was to investigate the potential of lateritic soils deposit South Sulawesi, Indonesia as a precursor for Na-poly(ferro-sialate) geopolymers. The samples of laterite soils were taken from three different regions, namely Sidrap, Bone, and Gowa regency. The soil was clean, grounded, sieves 200 mesh, and dehydroxylated at 750oC for 2 hours. The x-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS) were used to examine the chemical compositions of the soils. The geopolymers was synthesized through alkali activation method by adjusting the molar oxide ratios of SiO 2 /(Al 2 O 3 +Fe 2 O 3 ), Na 2 O/SiO 2 and H 2 O/Na 2 O in accordance with the chemical compositions of the soils. The functional groups of the resulting geopolymers were examined by using Fourier Transform Infra-Red (FTIR). The structure and phase of the resulting material were studied by using x-ray diffraction (XRD). The surface morphology of geopolymers was studied by using scanning electron microscopy (SEM). The mechanical strength of the materials was examined through compressive strength measurement. The results of this study showed that high strength Na-poly (ferro-sialate) geopolymers were successfully produced and characterized.