Sulphur Dioxide Emissions during the Firing of Ceramic Bodies Based on Class C Fly Ash

Sokolar, Radomir; Nguyen, Martin

doi:10.4028/www.scientific.net/ssp.296.149

Cited by 3 publications

(2 citation statements)

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“…When the milled CCFA was used, the decomposition of anhydrite started at lower temperatures (about 1040 °C). Sulfur dioxide appears in the flue gases from low temperatures close to 940 °C (milled fly ashes) or 990 °C (unmilled fly ashes) due to the decomposition of anhydrite CaSO 4 in dry-pressed clay-fly ash bodies [ 24 , 25 ]. Haüyne Na 4 Ca(Si 3 Al 3 )O 12 (SO 4 ) = 2Na 2 O·CaO·3SiO 2 ·Al 2 O 3 (SO 4 ) [ 26 ] is a tectosilicate sulfate mineral from the sodalite group (feldspathoids).…”

Section: Introductionmentioning

confidence: 99%

“…Despite abundant laboratory research [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], there are no examples of a broad application of CCFA within the production of fired building materials because the decomposition of anhydrite and the resulting re-release of sulfur dioxide (SO 2 ) into the atmosphere has not been solved. The previous research only provides information about the temperature ranges of the SO 2 content in the flue gas during the firing of pure CCFA bodies or the mixtures containing CCFA [ 24 , 25 ]. The finding of new ways for the utilization of CCFA is important for the environment and sustainable development since the CCFA is produced in very large quantities all over the world, and this number is predicted to continue to grow due to the transition from conventional high-temperature coal burning to fluidized bed reactor coal burning due to the efforts to reduce emissions released into the air.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Process for the Containment of SO2 Emissions from Class C Fly Ash in the Fired Materials by Haüyne Formation

Sokolar

Nguyen

2022

Materials

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Class C fly ash has been receiving increasing attention due to the gradual transition of thermal power plants all over the world to the fluidized bed combustion technology with sulfur dioxide emissions capture. This research investigates the utilization of class C fly ash in fired ceramic materials with simultaneous efficient and novel containment of sulfur dioxide emissions in the flue gas during firing. A number of experiments were conducted by addition of sodium water glass with different molar ratios of SiO2:Na2O, sodium carbonate, and different ratios of sodium carbonate to water glass to the class C fly ash to examine the optimal combination and quantity for the creation and formation of the mineral phase haüyne which resulted in reduction and containment of SO2 emissions. Results revealed that a 12% dose of sodium water glass with a low molar ratio of 1.7 (SiO2:Na2O) combined with class C fly ash was more effective in the formation of haüyne and the resulting decrease of SO2 in the flue gas was more substantial. The newly formed mineral phase haüyne was identified by an X-ray diffraction analysis and scanning electron microscopy with energy dispersive X-ray spectroscopy. Outcomes reveal a potential for utilization of class C fly ash in the fired materials by containment of sulfur dioxide into their structure.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Novel Process for the Containment of SO2 Emissions from Class C Fly Ash in the Fired Materials by Haüyne Formation

Sokolar

Nguyen

2022

Materials

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Size fraction characterisation of highly-calcareous and siliceous fly ashes

Delihowski,

Izak,

Wójcik

et al. 2024

J Therm Anal Calorim

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The properties of coal fly ash vary significantly depending on factors such as coal type, combustion conditions, and flue gas emission reduction methods. This study investigates the influence of particle size fractionation on the chemical composition, mineralogical structure, and thermal behaviour of two types of fly ash: high calcium ash derived from lignite (S1) and silica-rich ash from bituminous coal (S2). Dry aerodynamic separation was used to obtain distinct size fractions, which were then subjected to a comprehensive characterisation including X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and thermal analysis. The results reveal notable differences between the S1 and S2 ashes and between their size fractions. The finer fractions (< 20 μm) of S1 showed an increased calcium and sulphur content, while the coarser fractions (> 100 μm) contained more silica and alumina. The S2 ash exhibited a higher overall silica content, with alkali metals concentrated in finer fractions. Thermal analysis demonstrated distinct behaviours for each type and fraction of ash. Fine fractions of S1 ash showed SO2 emission at elevated temperatures, while S2 ash exhibited greater CO2 gas emission. After thermal treatment, the recrystallisation of the glassy phase was observed for S1, while the S2 ashes were more prone to melting and agglomeration. The study highlights the potential for the customised utilisation of specific ash fractions in various applications, such as geopolymer synthesis, adsorbent materials, and refractory products. This comprehensive characterisation contributes to a better understanding of fly ash properties and their dependence on particle size, providing valuable insights to optimise fly ash utilisation in various industries. The findings suggest strategies for a more efficient use of fly ash resources, particularly relevant in the context of decreasing fly ash availability due to the phase-out of coal power plants.

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Thermal Studies of Fractionated Lignite and Brown Coal Fly Ashes

Delihowski,

Gajek,

Izak

et al. 2024

Materials

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Coal fly ash (CFA), a by-product of coal combustion, is a valuable raw material for various applications. However, the heterogeneous nature of the composition and properties of CFA provides challenges to its effective usage and utilisation. This study investigates the thermal behaviour of the fly ashes of lignite (FA1) and brown coal (FA2) and their fractions obtained by dry aerodynamic separation. Thermal analysis techniques, including thermogravimetry (TG), differential scanning calorimetry (DSC), and evolved gas analysis (EGA), were used to characterise the behaviour of the fly ash fractions while heating up to 1250 °C. The results reveal distinct differences in the thermal behaviour between ash types and among their different size fractions. For the FA1 ashes, the concentration of calcium-rich compounds and the level of recrystallisation at 950 °C increased with the decrease in particle size. The most abundant detected newly formed minerals were anhydrite, gehlenite, and anorthite, while coarser fractions were rich in quartz and mullite. For the FA2 ashes, the temperature of the onset of melting and agglomeration decreased with decreasing particle size and was already observed at 995 °C. Coarser fractions mostly remain unchanged, with a slight increase in quartz, mullite, and hematite content. Recrystallisation takes place in less extension compared to the FA1 ashes. The findings demonstrate that the aerodynamic separation of fly ashes into different size fractions can produce materials with varied thermal properties and reactivity, which can be used for specific applications. This study highlights the importance of thermal analysis in characterising fly ash properties and understanding their potential for utilisation in various applications involving thermal treatment or exposure to high-temperature conditions. Further research on advanced separation techniques and the in-depth characterisation of fly ash fractions is necessary to obtain materials with desired thermal properties and identify their most beneficial applications.

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Sulphur Dioxide Emissions during the Firing of Ceramic Bodies Based on Class C Fly Ash

Cited by 3 publications

References 9 publications

A Novel Process for the Containment of SO2 Emissions from Class C Fly Ash in the Fired Materials by Haüyne Formation

A Novel Process for the Containment of SO2 Emissions from Class C Fly Ash in the Fired Materials by Haüyne Formation

Size fraction characterisation of highly-calcareous and siliceous fly ashes

Thermal Studies of Fractionated Lignite and Brown Coal Fly Ashes

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