Characterization of fly ash from coal-fired power plants

White, Steve; Case, Eldon D.

doi:10.1007/bf00580153

Cited by 84 publications

(37 citation statements)

References 4 publications

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“…Crystalline quartz amounts depend on cooling rates [9], while iron and quartz mineral proportions are influenced by varying coal mineral quantities. Glass fraction composition, indicated by a hump in XRD patterns [9], has also been found to vary by ash property [10]. The study regarding microstructural observations using SEM is in good agreement with phase transformations investigated by XRD [11].…”

Section: Introductionsupporting

confidence: 55%

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A Study on Factors Affecting Geopolymerization of Low Calcium Fly Ash

Tajunnisa¹

2017

GEOMATE

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This paper presents some factors affecting geopolymerization of low calcium fly ash for geopolymeric matrices. Low calcium fly ash samples were collected from two different coal-powered facilities: an Indonesian fertilizer plant and a Japanese power plant. Several series of tests were conducted using various ratios of fly ash to activator as well as ratios of activators to sodium hydroxide molarity. Each matrix consisted of a set molar ratio of three variations of Si/Al (1.5, 2, 2.5), Na2O/SiO2 (0.3-0.38), H2O/SiO2 (2.8 to 3.5), H2O/Na2O (9 to 10.6), and mass ratio of water/solid (0.31 to 0.45). The setting time of Japanese ash-matrices were longer than Indonesian ash. The compressive strength revealed that the Japanese and Indonesian matrices with activator ratios of 1.5 achieved 47.7 and 57.5 MPa respectively, while activator ratios of 2.5 reached 50.9 and 50.5 MPa. In addition, microstructural characterizations-XRF, XRD, SEM, EPMA-were performed. This study concludes that even ashes categorized as the same class, their mineral composition is different. Furthermore, coal combustion techniques modify ash particles, which in turn causes differences in setting time, while strength is not significantly affected.

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Section: Introductionsupporting

confidence: 55%

“…Just as ash properties affect geopolymer properties [16] [17], wide variations in mineral proportions of coal affect ash characterization [10] [14]. Thus, several micro-analyses have been conducted to investigate ash [13,18]: scanning electron microscopy (SEM), X-ray Diffraction (XRD), and X-ray Fluorescence (XRF).…”

Section: Introductionmentioning

confidence: 99%

A Study on Factors Affecting Geopolymerization of Low Calcium Fly Ash

Tajunnisa¹

2017

GEOMATE

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“…This is mainly ascribed to the combustion of residual carbon. 13) A small exothermic peak is observed at 678°C. Although the original sample was heated at 700°C for 1 h and subjected to powder XRD, no change was observed on the XRD pattern.…”

Section: Jcs-japanmentioning

confidence: 97%

Formation of linde F zeolite by KOH treatment of coal fly ash

Miyaji

Murakami

Suyama

2009

J. Ceram. Soc. Japan

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“…In addition, spectral features suggest that all fly ash samples have exposed edge sites with Al-OH and Si-OH bond terminals, [43] which is consistent with literature reports of silica and mullite (3Al 2 O 3 Á2SiO 2 ) content in fly ash. [44] The formation of mullite and silica in fly ash has been suggested to follow a two-step mechanism during the combustion process, where kaolinite (Al 2 where the loss of the well-crystallised aluminosilicate clay minerals leading to mullite and silica has been suggested to decrease the stability of the mineral, which can lead to faster dissolution rates in an acidic media. [13] Overall, the differences between ATR-FTIR spectra are a reflection of the variations in mineralogy due to the difference in power-plant efficiency and their coal source.…”

mentioning

confidence: 99%

Comparative evaluation of iron leach from different sources of fly ash under atmospherically relevant conditions

et al. 2016

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Environmental context. Iron, a limiting nutrient of plankton in the ocean, is deposited to the sea from atmospheric aerosols. In particular, atmospheric acidic conditions promote dissolution of iron from fly ash, a byproduct of coal-fired power plants. Here, we report that the iron leached from fly ash depends on its source region, and that the type of combustion process may influence the iron species mobilized.Abstract. Fly ash, an iron-containing by-product of coal-fired power plants, has been observed in atmospheric aerosol plumes. Under the acidic atmospheric conditions resulting from the uptake of atmospheric gases, iron leached from fly ash can impact global biogeochemical cycles. However, the fly ash source region, as well as its generating power plant, plays an important role in the amount, speciation and lability of iron. Yet no comparative studies have been made on iron leached from fly ash from different sources. This study reports the iron mobilisation by proton-promoted dissolution from wellcharacterised fly ash samples from three distinctive locations: the USA Midwest, north-east India and Europe. In addition, pH dependency was also investigated. Proton-promoted dissolution showed a variability between source regions with a relative iron leach in the order USA Midwestern . north-east Indian . European ash. In addition, the initial rate of iron leach suggests that source region is indeed a determining factor in the iron leaching capacity of fly ash, because dissolution from Midwestern fly ash is also faster than both European and Indian ash. Finally, the combustion process of fly ash proved to be significant for the iron speciation, given that well-combusted fly ash samples leached mostly Fe 3þ rather than bioavailable Fe 2þ . The role of fly ash should therefore be taken into account in order to better understand the effects of combustion particles in atmospheric iron deposition.

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Characterization of fly ash from coal-fired power plants

Cited by 84 publications

References 4 publications

A Study on Factors Affecting Geopolymerization of Low Calcium Fly Ash

A Study on Factors Affecting Geopolymerization of Low Calcium Fly Ash

Formation of linde F zeolite by KOH treatment of coal fly ash

Comparative evaluation of iron leach from different sources of fly ash under atmospherically relevant conditions

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