High Volume Utilization of Fly Ash Containing Mercury-Impregnated Activated Carbon

79234S In January of 2004, the EPA published draft regulations for the control of mercury emissions from coal-fired power plants, and one of the most promising technologies for controlling mercury involves the treament of flue gas with activated carbon. As a consequence, the fly ash collected from power plants contains high concentrations of mercury-impregnated activated carbon, which would make the fly ash unusable for concrete manufacturing. This would result in reduced revenues and increased disposal costs, creating a significant economic burden for electric utilities. It also would produce another environmental problem for society, because approximately 68 million tons of fly ash is produced annually in the United States. This project will develop chemically-bonded materials, which incorporate fly ash that contains mercury-impregnated carbon, for concrete applications. These chemically-bonded materials will encapsulate the mercury, allowing the material to be used as an additive or binder in concrete manufacturing. In addition, the material will prevent the leaching of mercury into the environment. In Phase I, several compositions will be prepared from fly ash with and without mercury-impregnated carbon. The encapsulation of mercury by the chemically-bonded material under different leaching conditions will be carefully examined. The feasibility of using this material in concrete will be established by characterizing key parameters using compression tests, foam index tests, and other standard industrial criteria. Commercial Applications and other Benefits as described by the awardee: The fabrication of chemically-bonded concrete material, which uses fly ash containing mercury-impregnated activated carbon, should result in a useful and marketable product. This technology will solve an economic problem for coal-fired power plants after they implement the mercury emission control regulations. Environmental benefits include reductions in mercury emissions, in the number of landfills needed for the disposal of fly ash, and in carbon dioxide emissions through the replacement of Portland cements in concrete manufacturing.