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

Coal fly ash is a spherical fine powder by-product discharged from coal-fired power plants. When coal fly ash is used as raw materials for the synthesis of geopolymers, there are practical problems associated with the stable surface of the particles that do not allow the production of geopolymers wi...

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Bibliographic Details
Published in:Minerals (Basel) 2019-12, Vol.9 (12), p.791
Main Authors: Matsuoka, Mitsuaki, Yokoyama, Kaho, Okura, Kohei, Murayama, Norihiro, Ueda, Masato, Naito, Makio
Format: Article
Language:English
Subjects:
Acceleration
Acid resistance
Aluminum
Brownfields
Coal
Coal-fired power plants
Compressive strength
Curing
Curing (processing)
Densification
Electrons
Fly ash
Fossil fueled power plants
Geopolymers
Grinding mills
Industrial plant emissions
Mechanical properties
Morphology
Particle size
Power plants
Raw materials
Spherical powders
Synthesis
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Summary:Coal fly ash is a spherical fine powder by-product discharged from coal-fired power plants. When coal fly ash is used as raw materials for the synthesis of geopolymers, there are practical problems associated with the stable surface of the particles that do not allow the production of geopolymers with sufficient strength. A long-time is also required for the curing. In this study, we aim to promote the curing reaction of geopolymers by activating the surface of coal fly ash particles. By mechanically activating the surface of coal fly ash particles using an attrition-type mill, the dissolution of Si4+ and Al3+ in coal fly ash is promoted, and the acceleration of the reaction taking place during curing is also anticipated. The surface morphology and crystal phase of coal fly ash particles change with the use of an attrition-type mill. The mechanical activation results in improvement of the compressive strength and the acid resistance under milder curing conditions by the densification of the hardened body. Thus, it is clearly shown that mechanical activation is effective for the production of geopolymers with beneficial mechanical properties under milder curing conditions.
ISSN:2075-163X
2075-163X
DOI:10.3390/min9120791