SBIR-STTR Award

It is clearly recognized by those associated withenvironmental restoration that coal-fired boiler flyash is asignificant contributor to the increasing shortage of landfillavailability. In general, the landfill requirements for solidwaste products are becoming a major environmental and economicissue. This project addresses a means of mitigating a part of theproblem associated with the disposal of coal-fired boiler flyash bydeveloping one of several likely markets for recycling this wasteinto glass-ceramic construction tiles. The technology plannedfor production of the vitrified product from the flyash is basedon an advanced in-flight suspension glass melting technologycurrently being developed. Phase I will experimentallyinvestigate the feasibility of using vitrified coal-firedboiler flyash as construction tiles. The Phase I effort isdirected toward defining the feedstock and product glasscomposition/property criteria, developing test samples of thetiles being investigated, conducting evaluation tests on thetiles, and reformulating and evaluating the glass batch/flyashcomposition if necessary.Anticipated Results/Potential Commercial Applications as described by the awardee:The anticipated result of this project is thedevelopment of a commercial plant to manufacture construction tilesthat use coal-fired boiler flyash as a feedstock. Nationally, thenet benefits include a positive environmental impact in at leastthree important ways. First, the current disposal of 75 milliontons of boiler flyash generated annually will be decreased. Second, displacing other naturally-occurring feedstocks will notonly conserve them, it will reduce the environmental impact ofmining them as well. Third, glass product reuse in manufacturingindustrial products could also contribute to energy conservation efforts.

The objective of this project is to develop an advanced melting/forming process for the manufacture of high quality, low cost, glassceramic tiles from coal fired boiler flyash and other industrial waste materials. The melting/forming process represents a major technology advancement for the manufacture of floor, wall, and roofing tiles. It has the potential of significantly reducing the costs, energy consumption, and waste associated with existing tile manufacturing operations. Phase I demonstrated the feasibility of using boiler flyash as a primary feedstock in the production of ceramic tiles with advanced glass melting/forming technology. Using laboratory and pilot scale melting operations, suitable feedstock compositions were developed and prototype tiles manufactured for evaluation against existing ceramic tile quality control criteria. Prototype tiles were evaluated using existing tile industry standards and were found to be significantly superior in terms of breaking strength, porosity, dimensional tolerance, dimensional stability, and thermal cycling properties. Cost estimates of the new manufacturing process indicated a potential savings of over 50% relative to existing manufacturing operations. In Phase II, pilot scale manufacturing systems will be developed to demonstrate the capability to form, heat treat, glaze, and decorate glass-ceramic tiles on an industrial scale. Several waste generators and companies involved in the manufacture of glass, ceramic tiles, or tile producing equipment will participate in the Phase II development effort on a cost sharing basis. Anticipated Results /Potential Commercial Applications as described by the awardee:In Phase III, an integrated commercial demonstration should serve as the basis for introducing the technology to the entire ceramic tile industry for manufacturing ceramic based building products from recycled boiler ashes and industrial wastes. Successful development of this technology could also mitigate major problems associated with disposal of boiler ash and industrial wastes, saving an estimated two million cubic yards per year of diminishing landfill space.