5020
Nihal Ahmed Mohamed Tawfik El-Mahalawy
Preparation and Characterization of Ceramic Bodies based on Some Phosphate containing Wastes
bone china / fish bone / technological properties
This work aimed to study the recycling of fish bone ash by using it in the manufacturing of stoneware tiles and bone china bodies. In addition, studying the effects of addition of fish bone ash by measuring the physical, mechanical and thermal properties of sintered tile bodies. Three different groups were designed; each comprised four batches to satisfy the aim of the thesis.Group one was designed in order to study the effect of substitution of Hafafit feldspar for bone ash. While in group two, the effect of weathered feldspar substitution for Hafafit feldspar was shown. And group three was designed to study the possibility of manufacturing bone china bodies based on fish bone ash.Results of the first group showed that the addition of more than 10 mass-% fish bone ash accelerated the formation of anorthite phase and hindered the formation of mullite in sintered tiles. Partially replacement of potash feldspar by fish bone ash resulted in lowering of the thermal expansion than conventional tiles and displayed greater porosity and reduced bulk density as their fish bone ash content increased.The study demonstrated that the microstructure and technological properties of the tiles containing fish bone ash are strongly affected by the fish bone ash content.A decrease in bending strength, attributed to greater porosity and lower quartz content, was observed as fish bone ash content increased more than 10 masspercent. Substitution of Hafafit feldspar by weathered feldspar increased the bulk density of the tile samples andshortened the firing range of the samples. Samples based on weathered feldspar are composed mainly of anorthite, mullite and quartz and possessed relatively low thermal expansion coefficient due to its content of silicate glassy phase and improved mechanical properties due to low porosity.The bone china fired bodies are composed of anorthite, ß- tricalcium phosphate and quartz. Identification of mullite was very difficult in the fired samples. The addition of feldspar on the expense of bone ash in the bone china bodies has a negative effect on the bodies’ whiteness and translucency.
2015
Ph.d
Ain Shams
Science