Coal-derived unburned carbons in fly ash: A review

摘要: Abstract Unburned carbon (UC) in fly ash indicates inefficiency combustion and may be an impediment to the beneficial use of or products a variety applications. The characteristics coal-derived UC are function rank type coal, as well size feed coal conditions. At any rank, inertinite macerals inherently more difficult combust than associated vitrinite, some will have tendency appear less unchanged from their appearance coal. nature UCs resulting vitrinite is dependent upon rank. Low-rank huminite/vitrinite tend form isotropic char; bituminous anisotropic cokes; anthracite naturally anisotropic, observed partially combusted fragments ash. absorption air entraining agents by limits high-UC ashes Portland cement substitute, with both standards organizations regulatory bodies imposing on acceptable concentrations. can used adsorb organic compounds (such phenols, dyes, herbicides, polychlorinated biphenyls, petroleum constituents) capture trace elements (particularly Hg) flue gas. also sources activated carbons, manufacture graphite, cokes metallurgical industry, source back into boiler. Beneficiation segregate relatively UC-free UC-rich splits for re-use done classification, electrostatic separation, froth flotation, density acid digestion, incipient fluidization. Thermal processing burn off UC, leaving product.