The effect of quartz content on the mechanical activation of dolomite

Dolomite surface and structure was modified by mechanical activation in a planetary mill. The attention was mainly directed to the role of quartz content (<1, 49, and 72 wt.%) in the modification of dolomite. The mechanically activated samples were studied by X-ray diffraction, thermal analysis, scanning electron microscopy and determination of the quadratic square mean diameter. The increased quartz content accelerated the mechanochemical deformation and amorphization of dolomite phase. While the amorphization reduced primarily the relative peak area of the (0 1 5) reflection, the deformation mostly increased the lattice strain in the (1 0 4) lattice plane. After grinding the dolomite/quartz mixtures, the thermal decomposition of dolomite showed a four- or three-step weight loss, instead of the original two- or one-step one. The mechanical activation of the mixtures produced a favourable state for the formation of calcium magnesium silicates at temperature even as low as 880 °C.