DEVELOPMENT OF GLASS CERAMICS USING KAOLIN PROCESSING WASTE, SODALIME AND BOROSILICATE GLASS WASTES

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Department of Environmental Design

ABSTRACT
The utilisation of waste materials to producea useful product is highly encouraged to avoid its disposal on land fields so as to safeguard the environment. Kaolin waste, soda lime and borosilicate glass wastes were used to develop glass ceramic. The oxides content of the raw materials were determined using the X-Ray Florescence machine while the moisture content and loss on ignition were determined by the weight loss method and the following results were obtained; SiO? 80.50% for borosilicate 77.63% in soda lime and 46.80% in kaolin, Fe?O? content in borosilicate was O.22%, 0.30%in soda lime and 0.01% in kaolin .V?O5 was found in kaolin and soda lime glass wastes and B?O? only in borosilicate glasswaste.CaO content of 7.46% in soda lime with value less than 1.0% in kaolin and borosilicate. Loss on ignition of 10.13% was found in kaolin, 0.30% in soda lime and 1.34% in borosilicateAl?O? content of kaolin is 31.41%, 0.60% in soda lime and 0.52% in borosilicate, the MgO content of 0.20% in kaolin, 2.63% soda lime and 0.03% in borosilicate waste glass. Particle sizes of 90 μm, 125 μm and 250 μm of the waste glasses were used to formulate batches. which were compressed into pellet shape of 20mm in diameter with a thickness of 5mm.Hydraulic pressing machine at a pressure of 10metric tones using the polyvinyl chlorine (PVC) organic binder was used to produce pellets.Then sintered at 750c°, 850°c and 950°c in a furnace at a heating rate of 50C /min with residence time of one hour and cooled gradually. The composition containing kaolin, soda lime, borosilicate with 90μm particle size sintered at 950°Cgave the highest shrinkage in diameter with value of 17.36% and a batch containing kaolin, borosilicate and Na?SO? with 250 μm particle size sintered at 750°C gave average of 0.94% in diameter. The physical properties of porosity, water absorption and bulk density were measured at all sintered temperatures for all the batches. The highest bulk density was found to be 2.54g /cm3 in the batch K?B?SL?? with 90 μm particle size at 850°C sintering temperature.The least bulk density is 1.34g/cm3 and the highest porosity of 26.84% were observed in batch K?? B? SL?? with 250μm particle size at 750°C.The least value of 0.68% in batch K?? B?? NS? with 125μm particle size at 950°C.The highest value of 18.02% water absorption was recorded for batch K? B? SL?? with 250μm at 750°C with the least value of 0.34% at 950°C .The highest hardness value was recorded for batch K5B?? NS? with 90μm particle size at 950°Cwas81.5 Nm2 Rock well superficial scale and the least value of 70.5Nm2 was found in batches K10B?? NS? with 125 μm particle size and K10B? SL8? with 125μm particle size sintered at 950° C. The most acid resistance batch was K?? B??NS? with 250μm sintered at 750°C, 850°C and 950°C. The least acid resistance batch was K?? B?? NS? with 7.85% loss sintered at 950°C with 125 μm. The most alkali resistance batch was found to be K? B? SL?? with 90 μm particle size with value of 0.35% sintered at 850 °C and 950°C and the least alkali resistance batch was observed in K5 B95 NS0 with 90 μm particle size with value of 8.87% sintered at 850°C. The X-Ray Diffraction (XRD) result for batch K? B? SL?? with 90 μm particle size showed thatCrystallisation occurs at 750°C and for batch K5 B95NS0 of same particle size, amorphous peaks were observed at the same sintering temperature. Scanning Electron Microscopy (SEM) appearance of a square pillar like crystals for batches K15 B80 NS5 at 125 μm and 250 μm sintered at 850°C and 950°C revealed sharp XRD peaks which correspond to that of diopside crystalline phase (CaO .MgO.Al?O-SiO8) .The SEM appearance of feathery crystals for batches K5B5SL90 with 90 μm sintered at 850?C, K10 B5SL85with 125 μm sintered at 850°C and 950°Cindicated an anorthite( CaO .Al?O?SiO8) crystal phase - The results obtained in this study showed that the glass ceramic developed can be used as lining for materials in construction and communication, heat and wear-resistance appliances for thermo-chemical, biomedical and ceramic coatings.