Geopolymerisation of Mechanically Activated Lignite and Brown Coal Fly Ash

Geopolymers have been synthesized from mechanically activated lignite and brown coal y ash. Mechanical activation of y ash has been carried out using laboratory ball mill. To determine the structural changes in both, the y ash and the resulted geopolymer, Fourier transform infrared spectroscopy measurements were performed. Isothermal conduction calorimetry method was applied to study the geopolymerisation reactions in mechanically non-activated (raw) and activated y ash samples. The isothermal conduction calorimetry results showed similar peak intensity for mechanically activated (5 30 min) y ash samples. However, the intensity of peak for 120 min milled brown coal y ash was the highest. The compressive strength of the specimen was found to be dependent on the grinding residence time as well as composition/type of y ash.