Popílky po denitrifikaci metodou SNCR v alkalicky aktivovaných systémech

Abstract

Fly ash is a by-product from coal combustion. Recently, there have been demands to reduce the nitrogen content in flue gases, and this has resulted in the introduction of denitrification processes in practice. This work was addressed to the possibility of using fly ash after denitrification by SNCR method in alkali activated materials. Fly ash used in the experiment was produced by the power plant in Ostrava-Třebovice. Mixtures prepared with fly ash without denitrification and mixtures with fly ash denitrified by SNCR method were compared. Five alkaline activators were chosen for the preparation of mixed alkali-activated mortars and pastes based on blast furnace granulated slag with fly ash. Basic physical and mechanical properties, frost resistance and resistance to the effects of demineralized water were determined on the mortar samples. The hydration processes of the pastes were monitored in a calorimeter and infrared spectroscopy with Fourier transformation was performed on the hardened pastes. Subsequently, three activators were selected to prepare concrete samples from 100% blast furnace granulated slag and with 30% replacement of blast furnace granulated slag with fly ash after denitrification by the SNCR method. For concrete mixtures, the consistency of fresh mixtures was determined, and physical and mechanical properties, frost resistance and shrinkage were tested on hardened samples.