New synthesis method for the production of coal fly ash-based foamed geopolymers

Böke, Nuran; Birch, Grant D.; Nyale, Sammy M.; Petrik, Leslie

doi:10.1016/j.conbuildmat.2014.07.041

Cited by 102 publications

(34 citation statements)

References 62 publications

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“…After the reaction with alkali silicate solution, the diffuse hump of fly ash shifted slightly towards higher degree (20°–40° 2θ). This was the typical characteristic of aluminosilicates matrix and the shift indicated the formation of geopolymer matrix after the geopolymerization reaction32. Mineral phases of quartz, hematite and magnetite were still present in geopolymers but with slightly reduced intensity.…”

Section: Resultsmentioning

confidence: 89%

“…This band shifted to lower wavenumber (~950 cm −1 ) after the geopolymerization reaction33. This inferred the incorporation of Al atoms in the silicate geopolymer network and increasing non-bridging oxygen in structure3247. The shifting of the band also indicated formation of larger molecular structure and higher cross-linking2148.…”

Section: Resultsmentioning

confidence: 92%

“…The foam could be introduced through air bubbles20 or endogeneous gas generation (e.g. aluminium powder29, hydrogen peroxide3031 or sodium hypochlorite3233). In this study, hydrogen peroxide was used as the gas-forming agent.…”

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confidence: 99%

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Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Cheng-Yong

Yun-Ming

Abdullah

et al. 2017

Sci Rep

114

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This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200–800 °C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2 MPa and degraded 34% to 15 MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5 MPa with increasing temperature up to 800 °C. Foamed geopolymers behaved differently whereby they deteriorated to 3 MPa at 400 °C and increased up to 11 MPa at 800 °C. Even so, the geopolymers could withstand high temperature without any disintegration and spalling up to 800 °C. The formation of crystalline phases at higher temperature was observed deteriorating the strength of unfoamed geopolymers but enhance the strength of foamed geopolymers. In comparison, foamed geopolymer had better thermal resistance than unfoamed geopolymers as pores provide rooms to counteract the internal damage.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 92%

See 1 more Smart Citation

Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Cheng-Yong

Yun-Ming

Abdullah

et al. 2017

Sci Rep

114

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“…Although South Africa has been actively involved in research and development for CFA beneficiation and/or utilization [2,[10][11][12][13][14][15][16], research on the recovery of aluminium from South African CFA [5,[17][18][19] is limited. It is also mostly restricted to acid leaching methods, which are unlikely to be adopted at large scale.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical processing of a South African ultrafine coal fly ash using ammonium sulphate as extracting agent for aluminium extraction

et al. 2016

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“…Lim et al [28] investigated the effects of waste ceramic powder on both the mechanical and microstructural properties of mortar. Böke et al [29] and Wen et al [30,31] studied the method of preparing solidified foam filling materials using fly ash, and they analyzed the influence of factors such as the watercement ratio and foaming multiple on the foam. e use of fly ash foam cement in plugging air leakages has greatly reduced coal dust pollution on the ground.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Application of LASC Foamed Concrete to Create Airtight Walls in Coal Mines

Zhang

Wang

Deng

et al. 2020

Advances in Materials Science and Engineering

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If an airtight wall in a coal mine leaks air, it may cause spontaneous combustion of residual coal in the gob and even cause a full-blown fire or gas explosion. In this study, we developed a new type of foamed concrete, low-alkalinity sulphoaluminate cement (LASC), to control air leakage. The performance of filling materials that were prepared by adding various dosages of foam to LASC was studied. The longer the curing period for the foam filling material of LASC, the better the crystallinity of the hydrated product. With an increasing foam dosage, the initial setting time gradually extends while the fluidity of the foam slurry decreases. The bubble rate of the filling material increases and the density decreases with increasing foam dosage. The compressive strength of the LASC filling material decreases with increasing foam dosage and increases with increasing curing time. In the LASC filling materials, the optimal volume ratio of foam dosage to gel slurry is 2. The crystallinity, initial gel time, and compressive strength of the LASC foaming materials are better than those of ordinary Portland cement (OPC) foaming materials. When the crossheading is filled with LASC foam cement, the deformation of the surrounding rock is less than 19 cm, and the air leakage prevention is better than that achieved with loess and fly-ash-cement foam. Thus, the proposed LASC foam material can be applied to the filling of the crossheading to efficiently prevent leakage in underground coal mines.

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New synthesis method for the production of coal fly ash-based foamed geopolymers

Cited by 102 publications

References 62 publications

Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Thermochemical processing of a South African ultrafine coal fly ash using ammonium sulphate as extracting agent for aluminium extraction

Experimental Study and Application of LASC Foamed Concrete to Create Airtight Walls in Coal Mines

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