सीएसआईआर-केंद्रीय काँच एवं सिरामिक अनुसंधान संस्थान

CSIR-Central Glass & Ceramic Research Institute

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Photo: CSIR-CGCRI Naroda Center, Gujarat
Vitreous china sanitaryware is produced in large quantities in Thangadh and Morbi areas of Gujarat state in India. It is estimated that about 170000 pieces or 2380 ton of vitreous china sanitaryware articles are manufactured per day in Gujarat. Considering average 5% fired rejects, generation of vitreous porcelain scrap works out to be 119 ton per day. This is a good amount of any raw material to be considered for some value added application. Plenty of unutilized fired sanitaryware scrap is also available lying in vacant lands around the industrial areas. Ground vitreous china sanitaryware is a good source of mullite crystals, fine quartz and a glassy phase. Ground vitreous porcelain scrap (GVPS) added with talc in gradually increasing quantity was investigated for vitrification behavior in a clay based body. GVPS was added as a major component (50%) in the composition. Talc 0 to 8% and 0.5% barium were added to activate the glassy phase present in GVPS during firing and development of bonding. It is concluded that complete vitrification can be achieved without addition of feldspar in experimental clay bodies at 1160 deg C. Pyro-plasticity is the tendency of body to sag during firing under its own weight and softness created due to high temperature. GVPS body when added with talc in gradually increasing percentage the tendency of sag has increased proportionately. Also the increase in temperature has increased the Pyroplastic index. Lowest pyro plasticity is observed with no addition of talc at the lowest firing temperature. Pyro plasticity is increasing with increase of talc as well as increase of firing temperature. But with achieving maturity by keeping higher talc in the body and firing at lower temperature would favor low Pyroplastic index. The matured body is ultra-high strength porcelain. Further investigations on other aspects are required to develop this body for a complete production technology. However failure of above clay based bodies in crazing resistance test requires further study on body composition and suitably matching glaze composition.

Last Updated on January 28, 2021