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This research focuses on the potential use of fly ash (WAf) from a Chinese pulverized-coal combustion (PCC) power plant for manufacturing foam glass. The influences of fly ash properties, fly ash/recycled glass proportion in the raw materials, addition of fluxing and foaming agent, firing temperature, and residence time at the peak temperature on the final properties (apparent density, compressing strength and leachable potential of major and trace elements) of the foam specimens are investigated. The optimal foaming products were obtained consuming up to 33.3–43.3% fly ash, adding 9–11% Na 2 CO 3 fluxing agent and 0.5% SiC foaming agent, firing at 865–915 °C during 15 min residence time at the peak temperature. The obtained fly ash-based product revealed comparable compressive strength but slightly higher densities than commercial foam glass, with low CO 2 emissions and low leachable potential for environmentally relevant trace elements within the limits for inert/no-hazardous material established by the European Council Decision 2003/33/EC for land waste disposal. The large porosity of the foam glass indicates a high potential of thermal and acoustic insulation. The foaming behavior and the final properties the foam glass are strongly influenced by properties of fly ash (mainly fluxing temperature and organic C content), fly ash/recycled glass proportion in the raw materials, addition of Na 2 CO 3 fluxing agent and SiC foaming agent, firing temperature, and residence time at the peak temperature. The low C content and high refractory character of WAf give rise to poor foaming of the specimens when only fly ash and Na 2 CO 3 mixtures are used. The consumption of relatively high proportions of recycled glass and SiC is essential to produce foaming. [ABSTRACT FROM AUTHOR]

The present study investigates the geochemical characteristics of the flue gas desulfurization gypsum (FGD Gp) generated from a pulverized-coal combustion (PCC) power plant in Xinjiang, Northwest China, with special emphasis on manufacturing fire-resistant panels using this FGD Gp as well as the fly ash collected from the same power plant. The physical, mechanical and insulating properties of the manufactured panels are also determined. The FGD Gp is characterized by low trace element concentration and low leachable potential for environment-concerned trace elements, indicating it can be reused with low environmental implication. Fire-resistant panels were successfully made from pure FGD Gp, pure commercial gypsum (CGp) and different FGD Gp/fly ash and CGp/fly ash mixtures. With the same gypsum/fly ash proportion, the FGD Gp/fly ash panels present relatively lower density, lower water absorption and lower mechanical strength, but higher moisture contents and better insulating capacities than the CGp/fly ash panels. The pure FGD Gp panel presents the best insulating capacity (52 min), much higher than that of the pure CGp panel (42.8 min). The mechanical and insulating properties of the panels are reduced with the increasing of fly ash proportion in the mixtures, but even prepared with 80% fly ash, the manufactured panels can still be used as benign fire-resistant panels with no significantly physico-chemical, and mechanical limitations. Therefore, manufacture of fire-resistant panels from FGD-Gp and fly ash is a very promising application for these coal combustion by-products which are substantially being generated in large amounts from Xinjiang power plants. The manufactured fire-resistant panels can be used in large amount as insulating construction and building materials with low environmental implication and high economic value. [ABSTRACT FROM AUTHOR]