Minimization and Use of Coal Combustion By-Products (CCBs): Concepts and Applications

Abstract

During coal-fired electric power production, four main types of coal combustion by-products (CCBs) are produced: fly ash, bottom ash, boiler slag, and flue gas desulfurization (FGD) material (1,2). In 1998, 97.7 million metric tons of CCBs were produced in the United States (see Figure 1). Fly ash was generated in the largest quantity (57.1 million metric tons), with FGD material the second most abundant CCB (22.7 million metric tons). Roughly 15.1 million metric tons of bottom ash were generated and 2.7 million metric tons of boiler slag were produced. Although the majority of CCBs produced currently enters landfills and surface impoundments, there is great potential for the effective and environmentally sound utilization of these materials.