Original paper(Vol.47 No.3 pp.227)
Study on solidification and stabilization of coal ash by steam treatment
Shibata-Yasunori
Abstract:Fundamental study was carried out in order to make use of coal ash as a ground material in large quantities. A series of examination were done by using three kinds of coal ash produced from boilers of which the combustion system differs each other. The properties of coal ash and the characteristics of solidification and stabilization in the solidified coal ash by steam treatment were determined. The main results obtained were as follows:
(1)A solid state reaction takes place between coal ash and CaO at the boiler temperature, generating a large amount of hydraulic substances. The morphology of each particle and the content of amorphous materials in coal ash differ depending upon chemical composition, temperature and pressure in the production atmosphere.
(2)As coal ash, particles becomes denser or amorphous materials become larger in quantity, the compressive strength of the solidified coal ash becomes higher.
(3)The solidified coal ash satisfies a safety standard in leaching by treating it with a saturation steam of proper condition.
Key Words:coal ash, ground material, steam treatment, solidification, stabilization, solid phase reaction, ettringite