Industrial Mineral Uses of Coal Combustion Products in Virginia

摘要

The American Coal Ash Association (ACAA) promotes the use of coal combustion products (CCPs) in applications that are commercially effective, technically proven, and environmentally sound (Industry Newswatch, 1994). The ACAA reported that the total production of all coal combustion products in 1999, in the United States, was 107,074,879 short tons (ACAA, 2001, written communication). This figure includes fly ash, bottom ash, boiler slag, and FGD material. The total of fly ash, a finely divided residue that results from the combustion of pulverized coal that is blown into a burning chamber (dry and ponded), was 62.7 million tons; about 20.8 million tons were utilized primarily in flowable fill, structural fill, waste stabilization, and mining applications. Heavier bottom ash is utilized in all these applications as well as for snow and ice control, blasting grit, and roofing granules. Almost 90 percent of boiler slag is utilized for blasting grit and roofing granules, and almost 69 percent of FGD (synthetic gypsum), is utilized in wallboard (ACAA, 2001, written communication). All of these uses are described in detail in the publication by the Office of Technology Applications (1995). Groups such as the Ohio Coal Development Office assert that powerplant owners and operators can save space and cost, reduce delays in new-project permitting and licensing, generate revenue, and help conserve raw materials if they more effectively use CCPs (Coal-Fired Systems, 2002). Major industrial mineral uses/potential uses of CCPs in Virginia include flowable fill, structural and embankment fills, concrete cinderblock, spread-able calcium and sulfur soil amendment, filler in asphalt mixes, fine aggregate in concrete, daily cover at waste facilities, traction material (snow and ice control) for highways, blasting grit, roofing gran- ules, synthetic gypsum (FGD) in wallboard, and as a substitute for expanded slate, and other rock materials in oyster-reef-restoration. Cenospheres (hollow aluminosilicate microspheres produced in fly ashes of coals burnt at power plants) have many uses, mainly as a lightweight filler material. Applications include cement, paint, PVC, polyurethane, resins, and other uses such as brake linings, foundry coatings, insulating refractory bricks, ceramic tile, aerospace materials, marine hulls, piping, and ad-hesives.