Structural and thermal behavior of proclay kaolinite using high energy ball milling process

• Ball milling efficient to achieve amorphous kaolinite structure
• Nanocrystalline quartz preserved during processing
• XRD, DSC, infra-red spectroscopy and DTG quantifys major structural changes
• Ball milling is an alternative to avoid calcination process

Planetary ball mill is used to process kaolinite clay powder under a commercial name of proclay kaolinite. Influence of milling time on structure and thermal behavior of proclay kaolinite are presented and discussed. X-ray powder diffraction shows that peak intensities, at kaolinite characteristic positions, decrease gradually and decay after 3 hours of milling. Amorphous structure of kaolinite forms with a nanocrystalline quartz. The mean crystallite size of nanocrystalline quartz is found to decrease from D = 30 ± 2 nm for unmilled powder to D = 7 ± 1.5 nm after 9 hours of processing. For the same time shift, thermal analysis shows that specific heat capacity of unmilled powder increases from 0.93 J/g.K to 1.65 J/g.K for milled powder.

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