The grinding charateristics and the structural lattice irregularity of sericite powder ground by a vibration ball-mill were studied. From measurement of the particle size distribution and the observation of scanning electron micrographs, it was found in dry grinding that the granulation of fine particle occurred after over three hours of grinding. Although the mean particle size of the ground product was increased gradually with increase in grinding time, the specific surface area was clearly increased. In wet grinding, granulation did not occur, and sericite powder was delaminated.
From X-ray powder diffraction analysis, thermoanalysis and infrared absorption spectroscopy of the product ground 45 and 100 hours in air, it was suggested that the structural lattice irregularty of the sericite powder was induced by the grinding operation. In particular, the characteristics of the structual water and/or the surface adsorbed water of the ground product were affected by the mechanochemical activation with fine grinding.
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