Submitted to: Coal Ash Utilization Workshop
Publication Type: Abstract Only
Publication Acceptance Date: October 23, 1995
Publication Date: N/A
Technical Abstract: Coal combustion by-products consist of many different types depending on the coal and burning technology used. The Clean Air Act (CAA) of 1976 as amended in 1990 mandates that coal burning facilities reduce the amount of SO**2 delivered to the atmosphere. Burning low-sulfur coal or using Clean Coal Technologies (CCT) are common. Because of the CAA and the use of the CCT, a growing tonnage of high Ca and S residues are produced. The wet limestone FGD systems are the most widely used today and except for small amounts used in making dry wall, most of the material is land- filled. While FGD is the most common method chosen for retrofitting existing combustors, newer plants often choose fluidized bed combustion (FBC) due to lower costs. FBC fly ashes and bottom ashes contain a considerable amount of calcium sulfate and have a high pH due to the presence of calcium oxide. Because of the high pH and the presence of beneficial alkaline oxides, FBC has been evaluated for its potential for agricultural land application. This work focused mainly on the beneficial effects of liming, as well as the loading of heavy metals. Some work has been conducted to look at the effect of adding these materials on the physical properties of the soil, particularly those related to infiltration and soil loss. Similar FGD, FBC residues are generally land-filled and their use in agriculture at this point is limited. The objective of this paper is to review different commonly produced high Ca and S coal combustion by-products as electrolyte sources for reduction of surface sealing and erosion.