Influence of the co-firing on the leaching of trace pollutants from coal fly ash

Izquierdo, María; Moreno, Natàlia; Font, Oriol; Querol, Xavier; Álvarez, Esther; Antenucci, Diano; Nugteren, Henk; Luna, Yolanda; Fernández‐Pereira, Constantino

doi:10.1016/j.fuel.2007.11.002

Cited by 59 publications

(28 citation statements)

References 31 publications

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“…According to previous studies, some elements such as Ca, Cr and Mg are reported to the surface of the fly ash particles, while Al, Si, K, Pb and many other trace elements are distributed throughout the particle [40,41]. Most of the cationic elements including Mg, Cu, Mn and Ni, show lower leaching rates due to their chemical behavior in solution below pH 10.…”

Section: Results Of the Toxicity Test Proceduresmentioning

confidence: 98%

Leaching behavior of selected trace elements in coal fly ash samples from Yenikoy coal-fired power plants

Akar

Polat

Galecki

et al. 2012

Fuel Processing Technology

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Keywords:Coal fly ash Coal-fired power plants Trace element leaching Short-term leaching test results of alkaline fly ash from Yenikoy coal-fired power plant were reported in this paper. ASTM D-3987-85 and TCLP-1311 test methods were applied to determine leaching behavior of selected elements namely, Fe, Ca, Cu, Co, Cd, Mn, Ni, Pb Zn, and Cr (VI) at different particle size fractions and test conditions. Chemical, mineralogical and morphological characterizations of ash samples were also performed using chemical, XRD and SEM-EDS analysis methods. The results showed that CaO dominates in the Yenikoy fly ash sample which directly affects the mobility of trace elements by determining the pH of the leaching medium. Higher mobility values of Cd, Co Cu, Pb, Ni and Zn elements were observed for TCLP-1311 procedure. The concentration of these elements in leachates showed a tendency to increase by decreasing particle size. Overall results suggested that the amount of the selected elements in the final leachates of both tests was lower than the limit values of landfill regulations except Cr (VI).

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Section: Results Of the Toxicity Test Proceduresmentioning

confidence: 98%

Leaching behavior of selected trace elements in coal fly ash samples from Yenikoy coal-fired power plants

Akar

Polat

Galecki

et al. 2012

Fuel Processing Technology

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“…In environmental conditions, reduced S species are generally present in negligible quantities and SO 4 2-is the dominant species (Fruchter et al, 1990). Iwashita et al (2005) and Izquierdo et al (2008) noted that the leached concentrations of S in water are correlated to its concentration in fly ash. With water only, 40-80% of SO 4 2-was removed from alkaline fly ash from Australia, the Netherlands and Spain, whereas up to 90% was removed from acidic fly ash (Nugteren et al, 2001;Querol et al, 2001;Ward et al, 2003).…”

Section: Sulphurmentioning

confidence: 99%

Leaching behaviour of elements from coal combustion fly ash: An overview

Izquierdo

Querol

2012

International Journal of Coal Geology

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625

379

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Coal-based power generation produces over 750 Mt of coal ash per year globally, but under 50% of world production is utilised. Large amounts of fly ash are either stored temporarily in stockpiles, disposed of in ash landfills or lagooned. Coal ash is viewed as a major potential source of release of many environmentally sensitive elements to the environment. This paper encompasses over 90 publications on coal fly ash and demonstrates that a large number of elements are tightly bound to fly ash and may not be easily released to the environment, regardless of the nature of the ash. This review provides an extensive look at the extent to which major and trace elements are leached from coal fly ash. It also gives an insight into the factors underlying the leachability of elements and addresses the causes of the mobility. The mode of occurrence of a given element in the parent coal was found to play an important role in the leaching behaviour of fly ash. The amount of calcium in fly ash exerts a dominant influence on the pH of the ash-water system. The mobility of most elements contained in ash is markedly pH sensitive. The alkalinity of fly ash attenuates the release of a large number of elements of concern such as Cd, Co, Cu, Hg, Ni, Pb, Sn or Zn among others, but at the same time, it enhances the release of oxyanionic species such as As, B, Cr, Mo, Sb, Se, V and W. The precipitation of secondary phases such as ettringite may capture and bind several pollutants such ash As, B, Cr, Sb, Se and V.

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“…Several studies have been carried out on ashes from coals co-fired with petroleum coke, sewage sludge, and different types of biomass (e.g. Izquierdo et al, 2007Izquierdo et al, , 2008Hower et al 2005b;Jia et al 2002;Steenari and Lindqvist 1999;Diaz-Somoano et al, 2006;Wolski et al 2004;Lapa et al 2007), but little attention has been paid to the effects of co-firing with oil during start-up, even though this process may also have a significant impact on fly ash characteristics (Navarrette et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Mineralogy and Leaching Characteristics of Coal Ash from a Major Brazilian Power Plant

Silva¹,

Ward²,

Hower³

et al. 2010

CCGP

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A B S T R A C TThe feed coals, fly ashes and bottom ashes collected from seven different units in a major Brazilian PF power plant have been subjected to comprehensive mineralogical, geochemical, and petrographic studies, to investigate the links between feed coal and ash characteristics. Ashes from two of the units were collected while the coal was being co-fired with oil as part of the boiler start-up procedure, allowing the impact of oil co-firing on ash characteristics also to be evaluated. High proportions of unburnt carbon and high proportions of retained sulphur were found in the fly ashes produced during oil co-firing, probably reflecting less efficient combustion and associated lower combustion temperatures. Higher concentrations of a number of relatively volatile trace elements were also noted in these fly ashes, compared to the fly ashes collected from units under normal operating conditions.The fly ashes produced during oil co-firing gave rise to acid pH conditions in water-based leaching tests, in contrast to the alkaline pH associated with fly ashes produced during normal operations. This probably reflects higher SO 3 contents relative to total CaO + MgO for the co-fired ash samples. Many trace elements that are typically mobilised as cations were also more abundant in leachates from the co-fired fly ashes. This is due, most likely, to the more acid pH conditions involved. Despite similar or even higher total concentrations, however, elements that are typically released from coal ash as oxy-anions were less mobile from the co-fired fly ashes than from the normally-fired fly ash materials.

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Influence of the co-firing on the leaching of trace pollutants from coal fly ash

Cited by 59 publications

References 31 publications

Leaching behavior of selected trace elements in coal fly ash samples from Yenikoy coal-fired power plants

Leaching behavior of selected trace elements in coal fly ash samples from Yenikoy coal-fired power plants

Leaching behaviour of elements from coal combustion fly ash: An overview

Mineralogy and Leaching Characteristics of Coal Ash from a Major Brazilian Power Plant

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