C S Prasad

Effect of rice husk ash in whiteware compositions

Quartz was progressively replaced by ground active silica obtained from rice husk ash (RHA) in a traditional whiteware composition and the effect of this replacement on the vitrification behaviour and mechanical and thermal properties in relation to the microstructure of specimens has been investigated. It has been found that the complete replacement of quartz by RHA drastically reduced both the maturing temperature and the percentage of thermal expansion, and increased the strength marginally. The improvement in the properties is attributed to sharp changes in the microstructural features as a result of significant reduction in the content of quartz phase and the simultaneous increase in glassy phase.

Effect of Particle Size on the Vitrification Temperature and Fired Properties of Conventional White Stonewares

Five-samples of a conventional stoneware composition have been prepared with variations in grinding time. A body mix having identical composition but produced under factory conditions was also collected for the study. Physico-chemical characteristics of raw materials used in the body mix were evaluated. Physical and fired properties of prepared body samples fired at various test temperatures were measured and their relationship with the particle size of mixed bodies was examined. It was observed that the gradual reduction in particle size of the mixed bodies improved the fired properties with the gradual increase in test temperatures until vitrification. On optimization of properties, it emerged that the conventional white stonewares containing particles in the range of 60 to 65% below 10 micron not only matured at a lesser temperature than that of the factory body containing about 50% particles below 10 micron, but also had improved ceramic properties and were found suitable for successful industrial pro...

Effect of Firing Schedule on the Properties of Flooring Tiles

The mechanical properties of flooring tiles fired in a conventional down draft kiln were compared with those produced commercially following the fast firing schedules. It has been observed that the conventional long firing operation favours dissolution of quartz, recrystallization of the secondary mullite and reduction in the amount of closed pores in the structure, thus enhancing the strength and toughness of the body as well as the resistance towards abrasion of the glazed surface.

Psysico-chemical Characterization of Some Common Clsys of Nizamabad, UP and their Utilization in the Production of Black Pottery

Physico-chemical characteristics of some common clays of Nizamabad were studied with the objective of determining their suitability in the manufacture of high strength black pottery. The study also revealed that the alternative raw material, namely, Nasirpur field clay could be used even up to 100% in complete replacement of the existing plastic clays like Dhuripur, Bhairopur and Nasirpur pond clays for the production of black pottery. The products developed also possessed the highest fired strength of about 400 kg.cm−2 at the firing temperature of about 850°C.

Characterization and utilization of some Indian pyrophyllites

The physical, chemical and mineralogical characters of twelve pyrophyllite samples collected from three states, namely, Uttar Pradesh, Madhya Pradesh and Rajasthan are described. The investigations show that the deposits mainly fall into three categories: low, medium and high alkali content pyrophyllites. Possible utilization for these three categories of pyrophyllites have been mentioned.