COAL COMBUSTION PRODUCTS - RECOVERED MINERAL RESOURCES THAT SUPPORT SUSTAINABILITY

The U.S. electric utility industry burns more than a billion tons of coal annually, producing in excess of 123 million tons of coal ash and air emission control residues. Though these materials were historically considered wastes, their perception is changing. Fly ash, boiler slag, bottom ash and flue gas desulfurization (FGD) material are collectively referred to as “coal combustion products,” or CCPs. Their “product” status evolved with proven commercial and environmental benefits. CCPs offer equal or superior performance over many commonly accepted materials. For example, by substituting fly ash for portland cement, landfill space and disposal costs are reduced. CCPs may be used to produce portland cement and can serve as fillers in asphalt concrete paving and in paints, metals castings and other specialty processes. CCPs have proven invaluable in numerous geotechnical and land applications as well. Nearly 30 percent of the gypsum wallboard produced in the U. S. is manufactured from power plant FGD gypsum. A number of CCPs are used in agricultural and agronomic processes to improve soils and to support agribusiness. This paper provides an overview of the CCP industry, the materials it produces and discusses a variety of CCP applications. It will address some federal and state regulatory opportunities and challenges impacting management and use. It will briefly describe ways to minimize the impact of air emission controls, which may be detrimental to fly ash use. Partnerships between the CCP industry, academia, federal and state agencies and the general public help increase awareness of how CCPs can have a positive environmental and economic impact on communities. Demonstration projects and outreach supported by the EPA, the Departments of Energy and Agriculture, and the Federal Highway Administration have allowed many CCPs to become widely accepted. The large volume of CCPs and other industrial materials produced annually represents a tremendous opportunity for the United States to greatly increase its sustainable and green practices. Reducing an industry's carbon footprint by increasing the use of recovered mineral resources pays environmental, economic and social dividends, while still maintaining the required quality of engineering and construction standards.