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This research is about nanoparticles hematite (NPH) synthesized and characterized from natural iron sands using co-precipitation method and its potential applications as extrinsic semiconductor materials type-N. The aims of this study is to determine the process parameters to obtain hematite of high purity degree and to observe its physical characteristics as an extrinsic semiconductor materials type-N. The iron sand was first separated by magnetic technique and then dissolved into HCl solution before conducting the precipitation process. Precipitation was done by dripping ammonium hydroxide (NH4OH). Precipitated powder was dried at 80°C for 2 hours, and then calcined at 500°C, 600°C 700°C for 2 hours respectively. The composition of iron sands, purity degree, hematite mineral grain size, and space group were analyzed by XRF, XRD, FTIR and SEM. The XRF analysis result of raw material, showed that dominant element and composition in the sample is Fe with purity degree is 90.51%. The XRD result before and after precipitation showed Fe3O4 and α-Fe2O3. Fe3O4 purity degree was obtained 85%, and α-Fe2O3 in NPH500, NPH600, NPH700 were 63%, 83%, and 76%, respectively. FTIR spectral showed crystalline hematite characteristics stong band of 472.07 to 559.62 cm-1. SEM image showed the morphology of agglomeration particulates, when the calcinaton temperature increases, the agglomeration will be seperated due to thermal energy. Based on the charaterization results it was found that the natural iron sand synthesized has the potential to be applied as an N-type extrinsic semiconductor material.

In this study, zeolite-geopolymer hybrid bulk materials were fabricated by using laterite soils deposit Gowa regency, South Sulawesi, Indonesia as a precursor for possible heavy metal absorbent. Laterite soils was calcined at 750°C for 6 hours to transform it into the amorphous aluminosilicate phase. Zeolite-geopolymer materials were produced through alkali activation method with curing temperature around 70°C for 2 hours. There were two different oxide molar ratios of SiO2/Al2O3 used to produce zeolite-geopolymer hybrid bulk materials and the specimens were designated as K1 and K2. The presence of zeolitic phase within geopolymer network was examined by using of XRD, FTIR, and SEM-EDS technique. The mechanical properties of the resulting material were studied by means of compressive and tensile strength. The results showed that Gowa laterite soil was succesfully fabricated as zeolite-geopolymer hybrid bulk materials, and the type of zeolite coined with geopolymers were zeolite A in sample K1 and un-named zeolite in sample K2. The mechanical strengths of zeolite-geopolymers produced in this study were below to those of pure geopolymers.