A Geochemical Analytical Scheme for the Appraisal of Partitioning and Mobility of Major elements in Weathered Dry Disposed Coal Fly Ash

S. A. Akinyemi, A. Akinlua, W. M. Gitari, R. O. Akinyeye, L. F. Petrik


South Africa is endowed with significant deposits of coal which is utilized in electricity generation to meet the nation’s energy demand. A large volume of waste solid residue from the combustion of pulverized feed coal in power stations is dry disposed in stock piles or dumps. Chemical interactions of dry disposed fly ash with ingressed CO2 from the atmosphere and infiltrating rain water would cause dissolution of the soluble components in the fly ash matrix. Chemical partitioning and mobility of major elements in samples from cores drilled into serially stacked weathered dry disposed fly ash were investigated using a modified five steps sequential extraction scheme. A total acid digestion was carried out on the original ash core samples prior to extraction to validate the extraction procedure. The geochemical distribution of the investigated major elements in 59 drilled core samples was determined by x-ray fluorescence and inductively coupled plasma mass spectrometry. The relationship between SiO2 and chemical index of alteration (CIA) showed 8 year and 20-year-old core samples have a moderate to high degree of weathering. Conversely, 1-year-old cores samples showed characteristics between low and moderate-high degrees of weathering. A cluster and discriminant analysis of the major elements was also able to reveal the subtle chemical alteration differences of the core samples. Functional analysis revealed the disparities in the dissolution patterns of major soluble components in the matrix of the drilled core samples. Modified sequential extractions revealed high concentration of the major species in the leachates for every mineralogical fraction; although the bulk of the major elements are locked up in the insoluble phase of the core samples (i.e. residual fraction) which would not be released under normal environmental conditions. It is noteworthy that the concentration of major elements in the labile fractions (water soluble + exchangeable + carbonate) was high and this has implications for the long-term durability of residual mineral phases. Relative enrichment and depletion trends of major elements are promoted by heterogeneity in the ash dump (i.e. moisture content), gradual reduction of pore water pH and continuous brine and water irrigation.

Key words: Coal fly ash; Weathering; Sequential extraction scheme; Cluster analysis; Factor Analysis 


Key words: Coal fly ash; Weathering; Sequential extraction scheme; Cluster analysis; Factor Analysis

Full Text:



[1] Akinyemi, S. A., Akinlua, A., Gitari, W. M., & Petrik, L. F. (2011a). Mineralogy and Mobility Patterns of Chemical Species in Weathered Coal Fly Ash. Energy Sources, Part A, 33, 768–784. doi: 10.1080/15567030903261881

[2] Akinyemi, S. A., Akinlua, A., Gitari, W. M., Akinyeye, R. O., & Petrik, L. F. (2011b). The Leachability of Major Elements at Different Stages of Weathering in Dry Disposed Coal Fly Ash. Coal Combustion and Gasification Products, 3, 28-40. doi: 10.4177/CCGP-D-11-00005.1

[3] Akinyemi, S. A. (2011c). Geochemical and Mineralogical Evaluation of Toxic Contaminants Mobility in Weathered Coal Fly Ash: as a Case Study, Tutuka dump site, South Africa. Unpublished PhD thesis, University of the Western Cape, South Africa.

[4] Al-Abed, S. R., Jegadeesan, G., Purandare, J., & Allen, D. (2007). Arsenic Release from Iron Rich Mineral Processing Waste: Influence of pH and Redox Potential. Chemosphere, 66, 775-782.

[5] Campos, E., Barahona E., Lachica, M., & Migorance, M. D. (1998). A Study of the Analytical Parameters Important for the Sequential Extraction Procedure Using Microwave Heating for Pb, Zn and Cu in Calcareous Soils. Analytica Chimica Acta, 369, 235-243.

[6] Chang, C., Wang, C., Mui, D. T., & Chiang, H. (2009). Application of Methods (Sequential Extraction Procedures and High-Pressure Digestion Method) to Fly Ash Particles to Determine the Element Constituents: A Case Study for BCR 176. Journal of Hazardous Materials, 163, 578-587.

[7] Cherkauer, D. S. (1980). The Effect of Fly Ash Disposal on a Shallow Ground-Water System. Ground Water, 18, 544-550.

[8] 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 Disposal Mound. Fuel, 81, 1083-1090.

[9] Comans, R. N. J. Meima, J. A., & Geelhoed, P. A. (2000). Reduction of Contaminant Leaching from MSWI Bottom Ash by Addition of Sorbing Components. Waste Management, 20, 125-133.

[10] Donahoe, R. J. (2004). Secondary Mineral Formation in Coal Combustion Byproduct Disposal Facilities: Implications for Trace Element Sequestration. In: Gieré R, Stille P Editors. Energy, Waste and the Environmental: a Geochemical Perspective, Geological Society, London. Special Publications, 236, 641–658.

[11] Fernández-Turiel, J. L., Cabañas, M., Querol, X., & López-Soler, A. (1994). Mobility of Heavy Metals from Coal Fly Ash. Environ. Geol., 23, 264-270.

[12] Fraser, J. L., & Lum, K. R. (1983). Availability of Elements of Environmental Importance in Incinerated Sludge Ash. Environ. Sci. Technol., 17, 52-54.

[13] Galbreath, K. C., & Zygarlicke, C. J. (2004). Formation and Chemical Speciation of Arsenic-Chromium-, and Nickel-Bearing Coal Combustion PM 2.5. Fuel Proc. Technol., 85, 701-726.

[14] Garavaglia, R., & Caramuscio, P. (1994). Coal Fly-Ash Leaching Behaviour and Solubility Controlling Solids. In: Goumans, J. J. M., van der Sloot, H. A., and Aalbers, Th. G. Editors, Environmental Aspects of Construction with Waste Materials, Amsterdam: Elsevier Science.

[15] Gitari, W. M., Petrik, L. F., Key, D. L., & Okujeni, C. (2010). Partitioning of Major and Trace Inorganic Contaminants in Fly Ash Acid Mine Drainage Derived Solid Residues. Int. J. Environ. Sci. Tech., 7 (3), 519-534.

[16] Gitari, M. W., Fatoba, O. O., Nyamihingura, A., Petrik, L. F., Vadapalli, V. R. K., Nel, J., October, A., Dlamini, L., Gericke, G., Mahlaba, J. S. (2009). Chemical Weathering In a Dry Ash Dump: An Insight from Physicochemical and Mineralogical Analysis of Drilled Cores. World of Coal Ash (WOCA) Conference in Lexington, KY, USA.

[17] Gleyzes, C., Tellier, S., & Astruc, M. (2002). Fractionation Studies of Trace Elements in Contaminated Soils and Sediments: A Review of Sequential Extraction Procedures. Trends in Analytical Chemistry, 21, 451-467.

[18] Grisafe, D. A., Angino, E. E., & Smith, S. M. (1988). Leaching Characteristics of a High Calcium Fly Ash as a Function of pH: A Potential Source of Selenium Toxicity. Applied Geochem., 3, 601-508.

[19] Goodarzi, F., & Huggins, F. E. (2001). Monitoring the Species of Arsenic, Chromium and Nickel in Milled Coal, Bottom Ash and Fly Ash from a Pulverized Coal-Red Power Plant in Western Canada. J. Environ. Monit., 3, 1-6.

[20] Go´mez Ariza, J. L., Gira´ldez, I., Sa´nchez-Rodas, D., & E. Morales, E. (2000). Selectivity Assessment of a Sequential Extraction Procedure for Metal Mobility Characterization Using Model Phases. Talanta, 52, 545–554.

[21] Helena, B. A., Vega, M., Barrado, E., Pardo, R., & Fernandez, L. (1999). A Case of Hydrochemical Characterization of an Alluvial Aquifer Influenced by Human Activities. Water Air Soil Pollut., 112, 365–387.

[22] Horowitz, A. J. (1991). A Primer on Sediment-Trace Element Chemistry. Chelsea: Lewis Publication Incorporation.

[23] Iwashita, A., Sakaguchi, Y., Nakajima, T., Takanashi, H., Ohki, A., & Kambara, S. (2005). Leaching Characteristics of Boron and Selenium for Various Coal Fly Ashes. Fuel, 84, 479-485.

[24] Jegadesaan, G., Al-Abed, S. R., & Pinto, P. (2008). Influence of Trace Metal Distribution on Its Leachability from Coal Fly Ash. Fuel, 87, 1887-1893.

[25] 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. doi:10.1016/j.fuel.2005.05.028

[26] Kalembkiewicz, J., Sitarz-Palczak, E., & Zapala, L. (2008). A Study of the Chemical Forms or Species of Manganese Found in Coal Fly Ash and Soil. J. Microchem., 90, 37-43.

[27] Khanra, S., Mallick, D., Dutta, S. N., & Chaudhuri, S. K. (1998). Studies on the Phase Mineralogy and Leaching Characteristics of Coal Fly Ash Water, Air, and Soil. Pollution, 107, 251–275.

[28] Kheboian, C., & Bauer, C. F. (1987). Accuracy of Selective Extraction Procedures for Metal Speciation in Model Aquatic Sediments. Analytical Chemistry, 59, 1417-1425.

[29] Kim, A. G., Kazonich, G., & Dahlberg, M. (2003). Relative Solubility of Cations in Class F Fly Ash. Environmental Science Technology, 37, 4507–4518.

[30] Kirby, C. S., & Rimstidt, J. D. (1994). Interaction of Municipal Solid Waste Ash with Water. Environmental Science and Technology, 28 (3), 443-451.

[31] Kukier, U., Ishak, C. F., Summer M. E., & Miller, W. P. (2003). Composition and Element Solubility of Magnetic and Non-Magnetic Fly Ash Fractions. Environ. Pollut., 122, 255-266.

[32] Liu, C. W., Lin, K. H., Y. M., & Kuo, Y. M. (2003). Application of Factor Analysis in the Assessment of Ground Water Quality in the Blackfoot Disease Area in Taiwan. Sci. Total Environ., 313, 77–89.

[33] Massart, D. L., Vandeginste, B. G. M., Deming, S. N., Michotte, Y., & Kaufman, L. (1988). Chemometrics, A Textbook. Amsterdam: Elsevier.

[34] Mester, Z., Cremisini, C., Ghiara, C., & Morabito, R. (1998). Comparison of Two Sequential Extraction Procedures for Metal Fractionation in Sediment Samples. Anal. Chim. Acta., 359, 133-142.

[35] Nesbitt, H. W., & Young, G. M. (1982). Early Proterozoic Climates and Plate Motions Inferred from Major Element Chemistry of Lutites. Nature, 299, 715-717.

[36] Ojo, O. I. (2009). Mineralogy and Chemical Mobility in Some Weathered Ash Dump Sites, South Africa, Unpublished M.Sc Thesis, Earth Sciences Department, University of the Western Cape, South Africa.

[37] Pe´rez-Bendito, D., Rubio, S., et al. (1999). Environmental Analytical Chemistry. Comprehensive Analytical Chemistry Series (vol. 32, pp. 709). Amsterdam: Elsevier.

[38] Petit, M. D., & Rucandio, M. I. (1999). Sequential Extractions for Determination of Cadmium Distribution in Coal Fly Ash, Soil and Sediment Samples. Anal. Chim. Acta., 401, 283-291.

[39] Querol, X., Juan, R., Lopez-Soler, A., Fernandez-Turiel, J. L., & Ruiz, C. R. (1996). Mobility of Trace Elements from Coal and Combustion Wastes, Fuel, 75, 821-838.

[40] Rao, C. R. M., Sahuquillo, A., & Lopez Sanchez, J. F. (2008). A Review of the Different Methods Applied in Environmental Geochemistry for Single and Sequential Extraction of Trace Elements in Soils and Related Materials, Water Air Soil Pollut., 189, 291–333.

[41] Schramke, J. A. (1992). Neutralization Of Alkaline Coal Fly Ash Leachates by CO2 (g). Applied Geochemistry, 7, 481–492.

[42] Shan, X.Q., & Chen, B. (1993). Evaluation of Sequential Extraction for Speciation of Trace Metals in Model Soil Containing Natural Minerals and Humic Acid. Anal. Chem., 65, 802–807.

[43] Smeda, A., & Zyrnicki, W. (2002). Application of Sequential Extraction and the ICP-AES Method for Study of the Partitioning of Metals in Fly Ashes. Microchemical, 72, 9-16.

[44] Smichowski, P., Polla, G., Gomez, D., Fernandez Espinosa, A. J., & Lopez, A. C. (2008). A Three Step Sequential Metal Fractionation Scheme for Fly Ashes Collected in an Argentine Thermal Power Plant. Fuel, 87, 1249-1258.

[45] Patricia Smichowski, P., Polla, G., & Go´mez, D. (2005). Metal Fractionation of Atmospheric Aerosols via Sequential Chemical Extraction: A Review. Anal Bioanal Chem., 381, 302–316.

[46] Soˇco, E., & Kalembkiewicz, J. (2007). Investigations of Sequential Leaching Behavior of Cu and Zn from Coal Fly Ash and Their Mobility in Environmental Conditions. J. Hazard. Mat., 145, 482–487.

[47] Theis, T. L., & Wirth, J. L. (1977). Sorptive Behavior of Trace Metals on Fly Ash in Aqueous Systems. Environmental Science & Technology, 11, 1096-1100.

[48] Tessier, A. (1992). Sorption of Trace Elements on Natural Particles in Oxic Environments. In: Buffle, J. and Van Leeuwen, H.P., Editors (pp. 425–453). Environmental Particles, Environmental Analytical and Physical Chemistry Series, Boca Raton, F L: J. Lewis Publishers.

[49] Tessier, A., Campbell, P. G. C., & Bisson, M. (1979). Sequential Extraction Procedure for the Speciation of Particulate Traces Metals. Analy. Chem., 51, 844-850.

[50] Van der Hoek, E. E., Bonouvrie, P. A., & Comans, R. N. J. (1994). Sorption of As and Se in Mineral Components of Fly Ash, Relevance for Leaching Processes. Appl. Geochem., 9, 406-412.

[51] Van der Hoek, E. E., & Coman, R. N. J. (1999). Speciation of As and Se During Leaching of Fly Ash. Stud. in Environ. Sci., 60, 467-476.

[52] Wang, J., Wang, T., Burken, J. G., Chusuei, C. C., Ban, H., Ladwig, K., & Huang, C. P. (2008). Adsorption of Arsenic (V) onto Fly Ash: A Speciation-Based Approach. Chemosphere, 72, 381-388.

[53] Wang, T., Su, T., Wang, J., & Ladwig, K. (2007). Calcium Effects on Arsenic (V) Adsorption onto Coal Fly Ash. Covington, Kentucky: World of Coal Ash (WOCA).

[54] Willet, P. (1987). Similarity and Clustering in Chemical Information Systems. Chichester: Wiley, Research Studies Press.

[55] Yinghui, L., Chuguang, Z., & Quanhai, W. (2008). Speciation of Most Volatile Toxic Trace Elements During Coal Combustion. Dev. in Chem. Eng. and Min. Proc., 11, 381-394.

[56] Yuan, C. G. (2009). Leaching Characteristics of Metals in Fly Ash from Coal-Fired Power Plant by Sequential Extraction Procedure. Microchimica Acta, 165, 91-96.

[57] Zevenbergen, C., Vander Wood, T., Bradley, J. P., Van Der Broeck, P. F. C. W. Orbons, A. J., & Van Reeuwijk, L. P. (1994). Morphological and Chemical Properties of MSWI Bottom Ash with Respect to the Glassy Constituents. Hazardous Waste and Hazardous Materials, 11, 371–383.

[58] Zielinski, R. A., Foster, A. L., Meeker, G. P., & Brownfield, I. K. (2007). Mode of Occurrence of Arsenic in Feed Coal and Its Derivative Fly Ash, Black Warrior Basin, Alabama. Fuel, 86, 560-572.

DOI: http://dx.doi.org/10.3968/j.est.1923847920110202.109

DOI (PDF): http://dx.doi.org/10.3968/g2085


  • There are currently no refbacks.

Copyright (c)

Share us to:   


If you have already registered in Journal A and plan to submit article(s) to Journal B, please click the CATEGORIES, or JOURNALS A-Z on the right side of the "HOME".

We only use three mailboxes as follows to deal with issues about paper acceptance, payment and submission of electronic versions of our journals to databases: caooc@hotmail.com; est@cscanada.net; est@cscanada.org

 Articles published in Energy Science and Technology are licensed under Creative Commons Attribution 4.0 (CC-BY).


Address: 9375 Rue de Roissy Brossard, Québec, J4X 3A1, Canada 
Telephone: 1-514-558 6138 
Website: Http://www.cscanada.net Http://www.cscanada.org 
E-mailest@cscanada.net; est@cscanada.org

Copyright © 2010 Canadian Research & Development Centre of Sciences and Cultures