Studied on the mechanically activated and thermally treated dolomite for adsorption application

Abstract

Dolomite from Chuping, Perlis was mechanically activated at different parameters of planetary milling (ball:powder ratio, miiling time and revolution speed) and thermally treated within temperature range 600-1000 °C. The changes of structural and modifications undergone by dolomite, inherent to the mechanical activation and thermal treatment, were investigated from X-ray diffraction patterns. The chemical composition and elemental constituents of the raw dolomite samples was determined using X-ray fluorescence (XRF) and energy dispersive X-ray spectroscopy (EDX). The results were also discussed using scanning electronic microscopy and nitrogen adsorption. Thermogravimetric and differential thermal analyses indicated that the dolomites undergo two stages of decomposition during the calcination process. Results obtained showed that high revolution speed and longer grinding duration have pronounced effect on the grindability, increase in fineness, decrease in crystallite sizes and amorphization of Perlis dolomite. . SEM analysis of calcined dolomite indicated that the morphological properties were profoundly affected. SEM images of D-1000 (sample treated at 1000 °C) indicated that the original particle shape of dolomite (presence of discrete grains having sharp edges with presence of cleavages) was totally destroyed, leading to small spherical particles. From BET analysis, it shows that the surface area and pore size increases as calcination temperature increases. As the conclusion, structural and morphology of dolomite undergo changes and modifications due to the mechanical activation process and thermal treatment.