Synthesis of Geopolymers from Mechanically Activated Coal Fly Ash and Improvement of Their Mechanical Properties

Matsuoka, M.; Yokoyama, Katsutoshi; Okura, Kohei; Murayama, Norihiro; Ueda, Mikito; Naito, Makio

doi:10.3390/min9120791

Cited by 16 publications

(4 citation statements)

References 27 publications

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“…In this context, both terms, "MA" and "milling", denote the same process of mechanical treatment a solid raw material in a planetary mill. Researchers have extensively studied the impact of milling on FA reactivity and geopolymer strength, as evidenced by numerous studies [18][19][20][21][22][23][24][25][26]. Secondly, various Ca/Mg-containing additives have been introduced into the FA, including abundant and cost-effective carbonate minerals such as calcite (CaCO 3 ) and dolomite (CaMg(CO 3 ) 2 ).…”

Section: Introductionmentioning

confidence: 99%

Composite Geopolymers Based on Mechanically Activated Fly Ash Blended with SrCO3 (Strontianite) and BaCO3 (Witherite)

Kalinkin,

Kalinkina,

Kruglyak

et al. 2023

Minerals

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In this study, geopolymers based on mechanically activated mixtures of fly ash (FA) with SrCO3 (strontianite) and BaCO3 (witherite) were synthesized. NaOH solution was used as an alkaline agent and curing was carried out under ambient conditions. XRD, FTIR spectroscopy, thermogravimetry, and SEM were used to study the geopolymerization process and microstructure. The product of geopolymerization of the milled (FA + SrCO3) and (FA + BaCO3) blends was X-ray amorphous N-A-S-H gel. The beneficial impact of mechanical activation on the compressive strength of geopolymers was most evident during the initial stages of the curing process. The strength of geopolymers based on the (FA + carbonate) blends after 7 d was either less than the corresponding strength of geopolymers based on the 100% FA or, within the measurement accuracy, equal to it. With increasing curing time, the strength development of geopolymers synthesized from (70% FA + 30% carbonate) blends exceeded the strength growth of geopolymers containing less carbonates; after curing for 180 d, these geopolymers showed the highest compressive strength (20–27 MPa). This trend was more pronounced for the geopolymers based on the (FA + SrCO3) blends. The influence of SrCO3 and BaCO3 addition to the FA on the strength of composite geopolymers was explained by dilution and microfiller effects. The geopolymers based on the FA blended with SrCO3 and BaCO3 exhibit potential applications in immobilizing radioactive strontium and producing radiation shielding materials.

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Section: Introductionmentioning

confidence: 99%

Composite Geopolymers Based on Mechanically Activated Fly Ash Blended with SrCO3 (Strontianite) and BaCO3 (Witherite)

Kalinkin,

Kalinkina,

Kruglyak

et al. 2023

Minerals

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“…An effective way to improve the physical and mechanical properties of geopolymers based on FA is mechanical activation (MA). [25][26][27][28][29][30][31][32][33] The effect of MA on the reactivity of FA in the synthesis of geopolymers and on the characteristics of the geopolymers has been scarcely investigated. In this work, the effect of MA on the processes occurring during alkaline activation of iron-rich (19.3% Fe 2 О 3 ) Class F FA as well as on the microstructural and strength characteristics of the obtained geopolymers has been studied.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of geopolymers based on mechanically activated low‐calcium iron‐rich fly ash

Калинкин

Гуревич

Калинкина

et al. 2021

Env Prog and Sustain Energy

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“…Another approach that is used to improve the performance of the FA-based geopolymers is the mechanical activation (MA) of FA in mills [29][30][31][32][33][34][35]. Here, the terms "mechanical activation" (MA) and "milling" refer to the same process of mechanical treatment of a solid material.…”

Section: Introductionmentioning

confidence: 99%

Geopolymers Based on Mechanically Activated Fly Ash Blended with Dolomite

et al. 2021

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This study reports the effect of natural dolomite addition to fly ash and the mechanical activation of this blend on the geopolymerization process. Dolomite was replaced with fly ash at 1, 3, 5, and 10 wt.%. Geopolymers were synthesized at ambient temperature using NaOH solution as an alkaline agent. The geopolymerization process, reactivity of the raw material, compressive strength, and microstructure were studied using X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetry, and scanning electron microscopy. It was shown that blending fly ash with dolomite and mechanical activation improved the geopolymer strength, especially during the early age of curing. For geopolymers prepared using a 90% fly ash + 10% dolomite blend cured for 7 d, the strengths were 8.2-, 2.3-, and 1.4-fold higher than those for geopolymers prepared using 100% FA for 30 s, 180 s, and 400 s milling times, respectively. A simple method for evaluating the increments of mechanical activation, carbonate additives, and the synergistic effect in the increase in the compressive strength of the composite geopolymer is proposed.

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Synthesis of Geopolymers from Mechanically Activated Coal Fly Ash and Improvement of Their Mechanical Properties

Cited by 16 publications

References 27 publications

Composite Geopolymers Based on Mechanically Activated Fly Ash Blended with SrCO3 (Strontianite) and BaCO3 (Witherite)

Composite Geopolymers Based on Mechanically Activated Fly Ash Blended with SrCO3 (Strontianite) and BaCO3 (Witherite)

Synthesis of geopolymers based on mechanically activated low‐calcium iron‐rich fly ash

Geopolymers Based on Mechanically Activated Fly Ash Blended with Dolomite

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