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Pulverised Coal Ash-Requirements for Utlisation

AUTHOR: Lesley Sloss, Irene Smith, Deborah Adams
DATE: June 1996

Coal ash is an inherently variable material due to the differences in the mineral content of the source coal, combustion conditions, and ash collection and handling methods. This affects the marketability of pulverised coal ash. Markets in different countries are discussed with respect to the opportunities and the obstacles to their development.

Recent publications on applications for pulverised coal ash are reviewed briefly. A knowledge of the chemical, mineralogical, and physical properties of fly ash and bottom ash are reviewed. Standards and specifications used in various countries for use of coal ash in different applications are discussed along with appropriate test methods. Quality assurance procedures which suppliers use to ensure fly ash meets these specifications are also included.

The marketability of fly ash may be improved by a number of benefication processes. Processes such as dewatering, blending, agglomeration, grinding, sieving, air classification, flotation, carbon burnout and electrostatic separation are discussed, including some examples of processes which are being actively developed.