Influence of the character of input materials on formation and properties of sintered fly ash body

konferenční sborník (ne článek)

angličtina

Artificial aggregate from sintered fly ash is an example of material, which can be used solely on the basis of fly ash without any additions. However, to ensure optimal progress of firing and high quality aggregate, it is necessary to study influence of the characteristic of fly ash on properties of fly ash body. The aim of the research work is evaluation of influence of characteristic of fly ash on formation, structure and properties of sintered fly ash body using laboratory firings of testing samples and also using the heating microscopy. The main difference as regards behavior is between fly ash originating from high temperature and fluidized bed combustion. While the first type of fly ash contains mainly mullite and other high temperature minerals, fluidized bed combustion fly ash contains mainly anhydrite and free lime. These increase for example manipulation strength of fly ash mix, but they also increase the amount of mixing water, emissions, content of extractable sulphur and weaken the sintered fly ash body. Content of Fe2O3 and its modifications and proportion of SiO2 in amorphous phase or mullite are important parameters for evaluation of various types of high temperature combustion fly ash. Content of Fe2O3 together with carbon caused reduction to FeO, which consequently works as a very effective fluxing agent. Thus, the surface of the specimen was sintered and swelling was considerable due to product gases CO and CO2. After exceeding the melting point, melting begins. Higher proportion of SiO2 contained in amorphous phase increase strength and quality of fly ash body.

Fly ash, power plant, artificial aggregate, clinkering.

ČERNÝ, V.; DROCHYTKA, R.

24. 11. 2014

IOS Press BV

Amsterdam

978-1-61499-465-7

Construction Materials and Structures

703

708

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