Amorphization of aluminosilicate mineral during micronization process

Physicochemical changes of minerals present in kaolin concentrate (kaolinite, illite, quartz, and feldspar) were investigated as a function of grinding time in a laboratory vibration mill. The techniques used (granulometry, DTA, TGA, XRD, IR analysis, and cation exchange capacity) indicate the presence of intensive structural changes of clay minerals (amorphization) and less intensive changes of quartz and feldspar grains. HF acid treatment did not affect the ground kaolinite and illite, but returned the stucture of the quartz quality and feldspar to what it was before grinding.