ASSESMENT OF THE SUITABILITY OF SAW DUST ASH AS FLUXING RAW MATERIAL IN SODA LIME SILICA GLASS PRODUCTION

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Department of Environmental Design

ABSTRACT
This research was conducted to study the suitabilty of saw dust ash in glass preparations. Saw dust from Isoberlinea doka (doka), Terminalia superba (Afara), Anogeissus leiocarpus (marke) and the mix saw dust (without taking note of the wood type) were used. They were collected from local market Sabon Gari, Zaria. The saw dusts were ashed using muffle furnace at 5500C and analysed using affluent absorption spectrophotometer and percentage oxides were calculated. The following results were obtained: Terminalia superba (Afara) 7.85% SiO2, 1.89% Al2O3, 18.00% K2O, 24.80% CaO, 5.40% Na2O, 5.07% MgO, 1.97% Fe2O3. Anogeissus leiocarpus (marke) 7.31% SiO2, 2.27% Al2O3, 22.80% K2O, 19.05% CaO, 9.17% Na2O, 9.04% MgO, 1.37% Fe2O3. Isoberlinea doka (doka) 7.10% SiO2, 6.42% Al2O3, 21.50% K2O, 8.42% CaO, 7.55% Na2O, 24.21% MgO, 1.92% Fe2O3. Mixed saw dust 7.27% SiO2, 7.56% Al2O3, 29.90% K2O, 24.47% CaO, 5.40% Na2O, 15.61% MgO, 4.57% Fe2O3. Four glass batches containing these ashes were prepared and melted in refractory crucibles at 13000C for five hours where two batches 1 and 4 melted and formed glasses while 2 and 3 sintered. Some properties of the two glasses obtained was determined, the density was determined by measurement and by calculation. The result from measurement was found to be 2.46gdm-3 while by calculations, the result was 2.42gdm-3. The variation in densities might be as a result of foreign inclutions from refractory crucibles or the introduction of excess K2O into the glass batches. Chemical durability test of the glasses was found to be in compliance with standard soda lime silica glass. The Xray diffraction of the melt showed the formation of amorphous phase in sample 1 and 4, which indicated the formation of glass while that of 2 and 3 indicated the formation of crystalline phase which confirmed the formation of sintered bodies. The electron dispersive spectroscopy from scanning electron microscopy (SEM) of glasses from batch 1 and 4 showed the consistency of major elements forming the glass compositions, Si, Na and O, indicating the homogeinity of the melts and accuracy of the temperature range. While the external morphology of the glasses showed rough surfaces as a result of not subjecting the glasses into mechanical stirring or any of the forming processes, and also presence of pores but not large enough to cause any form of deformity to the glasses. Based on the results obtained, saw dust ash can best be used as sources stabilizers in glass making due to high percentage of CaO and K2O.