Abstract: A terrestrial disposal of the fly ash has been regarded as a potential source of contamination due to the enrichment and surface association of trace elements in ash particles. In laboratory conditions the leaching of soluble components existing in ashes proceeds in a different way than in land deposits. On the landfill site coal combustion by-products are under the pressure of atmosphere agents, especially water, sun and rain activity (drying and wetting alternately), freeze/thaw (in cold climate) and gases included in the air. Also the time of exposition is an important parameter. In the presented experiment the observed dynamics of ash solubility over a long period of time provides the evidence that in the ash-water system, a variety of precipitation processes dominate the solubility of solid mass. Simulating the weathering by the freeze/thaw test approximates the effectuated changes in ash particles structure. The leaching of a particular ash component depends on reactions in the ash-water systems. Solidification by compaction of the material is often favoured because of the cementitious properties of ashes being in contact with water. Secondary hydrated minerals such as ettringite, portlandite and calcite are formed during a contact with water. Calcium -silicate hydrates, aluminate-hydrates and gypsum can occur as secondary minerals. The solubility of such new phases and the solidification process determine the leaching characteristics of the ash mass
B I B L I O G R A F I A1. Choi, S. K., Lee, S., Song, Y. K. & Moon, H. S. (2002). Leaching characteristics of selected Korean fly ashes and its implications for the groundwater composition near the ash mound, Fuel, 81, 1083-1090. http://www.fuelfirst.com http://www.fuelfirst.com
2. Fitianos, K., Tsanikiidi, B. & Voundrias, E. (1998). Leacibility of heavy metals in Greek fly ash from coal combustion, Environ. Int., 24, 477-486.
3. Jankowski, J., Ward, C. R., French, D. & Groves, S. (2006). Mobility of trace elements from selected Australian fly ashes and its potential impact on aquatic ecosystems, Fuel, 85, 243-256.
4. Mehtap, P. et al. (2006). Acid leaching of ash and coal: Time dependence and trace element occurrences, Int. J. Miner. Process, 79, 27-41. http://www.elsevier.com/locate/ijminpro http://www.elsevier.com/locate/ijminpro
5. Miravet, R., Fer Lopez-Sanchez, J. & Rubio, R. (2006). Leachability and analytical speciation of antimony in coal fly ash, Analytica Chemica Acta, 576, 200-206. http://www.sciencedirect.com, http://www.elsevier.com.locate.aca http://www.sciencedirect.com http://www.elsevier.com.locate.aca
6. Mudd, G. M. & Kodikara, J. (2000). Field studies of the leachability of aged brown coal ash, J. Hazardous Materials, 159-192. http://www.elsevier.nl/locate/jhazmat http://www.elsevier.nl/locate/jhazmat
7. Querol, X. et al., (1996). Mobility of trace elements from coal and combustion wastes, Fuel, 75, No 7, 821-838.
8. Querol, X., et al. (2001), Extraction of soluble major and trace elements from fly ash in open and closed leaching systems, Fuel, 80, 801-813. http://www.elsevier.com/locate/fuel http://www.elsevier.com/locate/fuel
9. Oter-Rey, J. et al. (2005). Influence of several experimental parameters on As and Se leaching from coal fly ash samples, Analytica Chemica Acta, 531, 299-305.
10. Paul, M., Seferinoglu, M., Aycik, G. A., Sastrom, A., Smith, M. L. & Paul, J. (2006). Acid leaching of ash and coal, Time dependence and trace element occurrences, Int. J. Miner. Process, 79, 27-41.
11. Praharaj, T., Powell, M. A., Hart, B. R. & Tripathy, S. (2002). Leachability of elements from sub-bituminous coal fly ash from India, Environmental International, 27, 609-615. http://www.elsevier.com/locate/envint http://www.elsevier.com/locate/envint
12. Wang, J. et al. (2006). Impacts of pH and ammonia on the leaching of Cu(II) and Cd(II) from coal fly ash, Chemosphere 64, 1892-1898. http://www.elsevier.com/locate/chemosphere http://www.elsevier.com/locate/chemosphere
13. Xu, M., Yan, R. & Zheng, Ch., et al. (2003). Status of trace element emission in coal combustion process: a review, Fuel Processing Technology, 85, 215-237.
14. Hasset, D. J., Pflughoeft-Hassett, D. F. & Heebink, L. V. (2005). Leaching of CCBs: observations from over 25 years of research, Fuel 84, 1378-1383. http://www.sciencedirect.com http://www.sciencedirect.com
15. Seidel, A. & Zimmels, Y. (1998). Mechanism and kinetics of aluminium and iron leaching from coal fly ash by sulphuric acid, Chemical Engineering Science, 55, 22, 3835-3852. PII
S009-2509(98)00201-2
16. Stefanowicz, T., Napieralska-Zagozda, S., Osińska, M. & Szwankowski, S. (1994). The leacheabilty test as a criterion of hazardousness of deposited industrial wastes - in Polish, Test wymywalności zanieczyszczeń jako kryterium oceny szkodliwości składowanych odpadów przemysłowych, Archiwum Ochrony Środowiska, nr 1-2
17. Ugurlu, A. (2004), Leaching characteristics of fly ash, Environmental Geology, 46, 890-895. DOI 10.1007/S))254-004-1100-6
18. Reijnders, L. (2005). Disposal, uses and treatments of combustion ashes: a review, Resources, Conservation and Recycling, 43, 313-336. http://www.elsevier.com/locate/resource http://www.elsevier.com/locate/resource
19. Twardowska, I. & Szczepanska, J. (2002). Solid waste: terminological and long-term environmental risk assessment problems exemplified in a power plant fly ash study, The Science of the Total Environment, 285, 29-51. http://www.elsevier.com/locate/scitoenv http://www.elsevier.com/locate/scitoenv
20. Egemen, E. & Yurteri, C. (1996). Regulatory leaching tests for fly ash: a case study, Waste Management & Research, 14, 43-50.
21. Kim, A. & Kazonich, G. (2004). The silicate / monosilicate distribution of metals in fly ash and its effect on solubility, Fuel, 83, 2285-2292. http://www.fuelfirst.com http://www.fuelfirst.com
22. Steenari, B. M., Schelander, S. & Lindqvist, O. (1999). Chemical and leaching characteristics of ash from combustion of coal, peat and wood in a 12 MW CFB - a comparative study, Fuel, 78, 249-258.PII-S0016-2361(98)00137-9
23. Reardon, E. J. et al. (1995). Determining controls on element concentrations in fly ash leachate, Waste Management & Research, 13, 435-450.
24. Iyer, R. (2002). The surface chemistry of leaching coal fly ash, J. Hazardous Materials B 93, 321-329. http://www.elsevier.com/locate/jhazmat http://www.elsevier.com/locate/jhazmat
25. Iyer, R. S., Stanmore, B. R. & Pullammanappallil, P. C. (2001). The role of the diffuse double layer in leaching of calcium from the surface of fly ash particles, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 177, 69-74.
26. Łączny, J. M. (1979). The solubility of ash in water - in Polish, Rozpuszczalność popiołów lotnych w wodzie, Energetyka, 12, 1979, 485-486. http://www.elsevier.nl/locate/colsurfa http://www.elsevier.nl/locate/colsurfa
27. Cheerarot, A. & Jaturapitakkul, R. (2004). A study of disposed fly ash from landfill to replace Portland cement, Waste Management 24, 701-709. http://www.elsevier.com/locate/wasman http://www.elsevier.com/locate/wasman 
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