engleski

APPLIANCE OF RAPID METHOD FOR DETERMINATION REACTIVE SILICA IN FLY ASH

Thermal power plants produce large amounts of fly ash (FA), which must be disposed in landfills and is a significant environmental problem. Researches suggest that FA can be converted into geopolymers, which are good binders for construction. Reactive silica (SiO2) is the main active constituent located in the glass phase of the fly ash and the fraction of the total silica participating in the pozzolanic reactions. It controls the use of FA in cement and building materials. The aim of this work was to determine reactive silica in the fly ash by acid treatment followed by alkali digestion in a digestion bomb under pressure. The SiO2 content so obtained was precipitated as potassium hexafluorosilicate (K2SiF6). The precipitate was filtered, washed and hydrolyzed with warm water and finally titrated with NaOH. The percentage of reactive silica is calculated using equation[1]. [1] N.K. Katyal, J.M. Sharma, A.K. Dhawan, M.M. Ali, K. Mohan, Cem. Concr. Res, 38 (2008) 104-106.

reactive silica; fly ash; geopolymers

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