1. The Waste Farmework Directive (Council Directive 75/442/EEC, as emended by Council Directive 91156/EEC).
2. EN 450-1, Fly ash for concrete. Definitions, specifications and conformity criteria.
3. H. Ban, An experimental study of particulate charge relating to electrostatic dry coal cleaning, Ph.D. Dissertation, University of Kentucky, Lexington, KY, 1994.
4. Triboelectrostatic removal of unburned carbon matter from coal combustion fly ash;Stencel,1997
5. STI's Six Years of Commercial Experiences in Electrostatic Beneficiation of Fly Ash;Bittner,2001