Use of coal fly ash to manufacture a corrosion resistant brick

Moyo, V.; Mguni, N.G.; Hlabangana, N.; Danha, Gwiranai

doi:10.1016/j.promfg.2019.05.072

Cited by 12 publications

(6 citation statements)

References 4 publications

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“…It is noted from the review of available literature that the weight per unit area of CA bricks is lower than that of conventional burnt clay bricks [7,31,63,64]. These studies reported that CA bricks have up to 10% lower weight per unit area compared to conven-tional clay bricks.…”

Section: Weight Per Unit Areamentioning

confidence: 99%

“…The various steps involved in brick preparation are screening of clay to remove debris; manual mixing of clay, sand, and water to make a homogenous mix; molding of brick into the desired shape and size; the drying of brick in the open air; burning of brick in brick kilns at temperatures ranging between 850 and 950 • C to achieve the required hardness, color, and strength [6][7][8]. The production of burnt clay bricks involves the use of beneficial clayey soil, which is important for the cultivation of valuable crops [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of Using Coal Ash for the Production of Sustainable Bricks

et al. 2022

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In this research study, environmentally friendly unburnt coal ash (CA) bricks were investigated as an alternative to conventional burnt clay bricks. In this research study, various physical and mechanical properties of unburnt CA bricks were investigated. The unburnt CA bricks were prepared by using 60% CA and 10% lime by weight. In these unburnt CA bricks, varying cement contents (5%, 10%, and 15%), sand contents (10% and 15%), and quarry dust contents (5% and 10%) by weight were used. A forming pressure of 29 MPa was applied through an automatic pressure control system either for 3 s or 6 s. The prepared bricks were moist cured for 28 days. The experimental results exhibited that unburnt CA bricks with 10% cement, 10% sand, and 10% quarry dust subjected to forming pressure for 3 s exhibited the highest compressive strength of 19 MPa and flexural strength of 2.1 MPa. The unburnt CA bricks exhibited reduced water absorption, reduced efflorescence, and lower weight per unit area than the conventional clay bricks. A cost comparison of unburnt CA bricks and clay bricks exhibited that unburnt CA bricks are cost-effective compared to clay bricks.

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Section: Weight Per Unit Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Feasibility of Using Coal Ash for the Production of Sustainable Bricks

et al. 2022

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“…During the high-temperature combustion process of lignite, arsenic and scarce metals are simultaneously volatilized in the form of oxide into CFA. , In addition to arsenic, the CFA also contains about 0.01–0.1% of the scarce metals of germanium and tungsten, which are far higher than that of coal. , Huge environmental and economic costs need to be paid to dispose them. Currently, under the impetus of the world’s major demand for clean coal utilization and recycling of the residue, there are some new technologies for recycling of CFA with high-value-added utilization, such as synthesis of zeolites/geopolymers, , ceramic/glass ceramic manufacture, , fire-resistant materials, recovery of valuable metals, etc. However, it is imperative to detoxify or harmlessly treat the CFA to remove the poisonous arsenic element before reutilization.…”

Section: Introductionmentioning

confidence: 99%

“…6,7 Huge environmental and economic costs need to be paid to dispose them. Currently, under the impetus of the world's major demand for clean coal utilization and recycling of the residue, there are some new technologies for recycling of CFA with high-value-added utilization, such as synthesis of zeolites/geopolymers, 8,9 ceramic/glass ceramic manufacture, 10,11 fire-resistant materials, 12 recovery of valuable metals, 13 etc. However, it is imperative to detoxify or harmlessly treat the CFA to remove the poisonous arsenic element before reutilization.…”

Section: Introductionmentioning

confidence: 99%

Arsenic Removal and Recovery of Germanium and Tungsten in Toxic Coal Fly Ash from Lignite by Vacuum Distillation with a Sulfurizing Reagent

Zhang

Song

2021

Environ. Sci. Technol.

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Every year, billions of tons of lignite are burnt to generate electricity, meanwhile generating large amounts of coal fly ash (CFA) that is regarded as an industrial waste. During lignite combustion, arsenic and scarce metals are simultaneously volatilized in the form of oxide into CFA. This study proposed an effective vacuum distillation method to remove As and recover Ge and W from CFA. The feasibility of separating As and recycling Ge and W from CFA was verified by the theoretical analysis. The experimental result indicated that the removal ratio of As was 96 ± 1% and the contents of Ge and W reached 0.75 ± 0.023 and 0.24 ± 0.016 wt % in the residue, which were enriched 17.2 and 1.2 times, respectively, at a temperature of 550 °C, with 50 wt % sulfurizing agent added under pressure of 1 Pa and 240 min of heating. For the condensed product, chemical species As 2 S 3 and As 4 S 4 were detected by X-ray photoelectron spectroscopy analysis. For Ge and W in the residue, GeO x (x < 2), GeS, WO x (x < 3), and WS 2 were the main chemical species. The potential mechanism involved in the release of arsenic from CFA, vacuum sulfurization, evaporation, and condensation was proposed. The kinetic analysis indicated that the apparent activation energy (E α ) was 31.24 kJ mol −1 . Those results encourage further exploration of vacuum separation technology to environmentally friendly recycle CFA.

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“…High levels of arsenic (2.8-6300 ppm), mercury (0.02-0.36 ppm), molybdenum (1.2-236 ppm) and selenium have been reported [4]. Several scientists have proposed the use of fly ash in agriculture, mostly as soil fertilizing additives [5][6][7][8][9], as additive in concretes [10][11][12][13][14], building materials such as bricks [15][16][17][18] and asphalts [19][20][21][22]. Utilisation via the synthesis of zeolite materials is one of the researched and considered possibilities of using fly ash [23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Impact of Fly Ash Fractionation on the Zeolitization Process

et al. 2020

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Coal combustion product in the form of fly ash has been sieved and successfully utilised as a main substrate and a carrier of silicon and aluminium in a set of hydrothermal syntheses of zeolites. The final product was abundant in zeolite X phase (Faujasite framework). Raw fly ash as well as its derivatives, after being sieved (fractions: ≤ 63, 63–125, 125–180 and ≥ 180 µm), and the obtained zeolite materials were subjected to mineralogical characterisation using powder X-ray diffraction, energy-dispersive X-ray fluorescence, laser diffraction-based particle size analysis and scanning electron microscopy. The influence of fraction separation on the zeolitization process under hydrothermal synthesis was investigated. Analyses performed on the derived zeolite X samples revealed a meaningful impact of the given fly ash fraction on synthesis efficiency, chemistry, quality as well as physicochemical properties, while favouring a given morphological form of zeolite crystals. The obtained zeolites possess great potential for use in many areas of industry and environmental protection or engineering.

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Use of coal fly ash to manufacture a corrosion resistant brick

Cited by 12 publications

References 4 publications

Feasibility of Using Coal Ash for the Production of Sustainable Bricks

Feasibility of Using Coal Ash for the Production of Sustainable Bricks

Arsenic Removal and Recovery of Germanium and Tungsten in Toxic Coal Fly Ash from Lignite by Vacuum Distillation with a Sulfurizing Reagent

Impact of Fly Ash Fractionation on the Zeolitization Process

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