At the Hanford Site in Richland, Washington, the path to site cleanup involves vitrification of the majority of the wastes that currently reside in large underground tanks. A Joule-heated glass melter is the equipment of choice for vitrifying the high-level fraction of these wastes. Even though this technology has general national and international acceptance, opportunities may exist to improve or change the technology to reduce the enormous cost of accomplishing the mission of site cleanup. Consequently, the U.S. Department of Energy requested the staff of the Tanks Focus Area to review immobilization technologies, waste forms, and modifications to requirements for solidification of the high-level waste fraction at Hanford to determine what aspects could affect cost reductions with reasonable long-term risk. The results of this study are summarized in this report.

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High-Level Waste Melter Study Report

This Investigation was carried out to incorporate fly ash, a waste material generated from thermal power stations, as a replacement of sandstone and to some extent feldspar in the earthenware type glazed wall tile body composition. Test specimens of eight different body compositions incorporating fly ash were prepared and fired at five different test temperatures, viz., 1000°, 1050°, 1100°, 1150° and 1200°C in an electrical furnace. Dry and fired properties like dry MOR, fired shrinkage, fired MOR, apparent porosity, water absorption, bulk density, thermal expansion of the optimized body and glaze etc were determined and compared with those of the specimens of a traditional earthenware tile body used as a standard composition. It was observed that the incorporation of fly ash in the tune of 30 wt% was the optimum In achieving the requisite thermo-mechanical properties In wall tile body.

Development of Glazed Wall Tiles through Optimal Utilization of Fly Ash

An investigation was carried out to incorporate fly ash, a waste material generated from thermal power stations, as a complete replacement of quartz and partial replacement of china clay and potash feldspar in the semi-vitreous tile body composition. Further, a non-conventional flux talc was gradually incorporated in the body mix containing 40 wt% of fly ash. Dry and fired thermo-mechanical properties of the fired specimens were studied and compared with those of a standard body mix. It was observed that the incorporation of fly ash to the tune of 15 wt% in the standard composition led to an increase in the fired strength by 14% without any increase to the maturing temperature of the specimens. The incorporation of talc in a body mix containing 40 wt% fly ash increased the fired strength by 32.4% and decreased the maturing temperature of specimen by 50°C in comparison to those of the parent body.

Utilization of Fly Ash in the Production of Unglazed Semi-Vitreous Tiles

Ecological criteria, design and reaction engineering aspects of fly ash processing to fertilizers

Glasses containing iron oxide (12–15 wt%) have been prepared based on thermal power plant wastes, and their crystallization mechanism studied with the help of XRD, DTA and TEM. In the initial stages of crystallization, phase separation took place which led to the formation of hedenbergite. The glass-ceramic material obtained under optimum conditions had high chemical resistance, microhardness of 7400 MPa and thermal stability. The final product can be recommended for workshop floorings and storage vessels in chemical industries.

C. B. Raju

Papers

Development of Anti-wear and Chemically Durable Tiles from Thermal Wastes