International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
Vol. 5, No. 4, 2008, pp. 485-494
Bioline Code: st08054
Full paper language: English
Document type: Research Article
Document available free of charge
International Journal of Environment Science and Technology, Vol. 5, No. 4, 2008, pp. 485-494
© Copyright 2008 IRSEN, CEERS, IAU
Particle size distribution and dissolution properties of metals in cyclone fly ash|
Rönkkömäki, H.; Pöykiö, R.; Nurmesniemi, H.; Popov, K.; Merisalu, E.; Tuomi, T. & Välimäki, I.
The particles in the examined cyclone fly ash were all smaller than 0.25 mm. in diameter, and particles smaller than 0.075 mm. in diameter accounted for 88.4 % of the ash weight. This result indicates that cyclone fly ash consists of particles with a small diameter. The metals in the cyclone fly ash were enriched in small particles. The highest concentrations for zinc, copper, lead, cadmium and molybdenum in the cyclone fly ash were found in the smallest particle size fraction (< 0.075 mm.) and for Barium, chromium, nickel, Vanadium and Cobalt in the second to smallest particle size fraction (0.0750.125 mm.). From an environmental and toxicological standpoint, the smallest particles are of the greatest concern when ash is handed at landfill disposal sites (transport and disposal especially in stormy weather conditions), and some studies have reported risks to workers from prolonged exposure to ash. The results of the comparison of various dissolution methods for metals showed that the digestion procedures with nitric acid alone (USEPA 3051) or with a mixture of nitric acid + hydrogen peroxide (USEPA 3050B) slightly underestimated the metal concentrations in the cyclone fly ash. Although the use of hydrofluoric acid is often necessary for the determination of a number of elements associated with siliceous minerals, its use can result in loss of trace elements during dissolution.
Bark, forest residues, grate-fired boiler, waste, wood
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