8th International Mineral Processing Symposium (IMPS-2000), Antalya, Turkey, 16 - 18 October 2000, pp.47-53
The subject of the investigation was the influence of ball milling and vibratory milling on the reaction kinetics of the digestion of chromite with CaCO3 and Na2CO3 as well as mixtures of these reagents. As opposed to the mainly frictional grinding in the ball mill, the impact stress in the vibratory mill causes the mechanical activation of chromite, which is characterized by lattice defects. The degree of mechanical activation can be quantified by measuring the relative X-ray diffraction intensities at the parent lattice planes of chromite. Each relative X-ray diffraction ratio correlates with a certain degree of digestion. As opposed to vibratory milling, a complete digestion of chromite using a ball mill is impossible, even at extremely long grinding times. A new type of vibratory mill was used, the Eccentric Vibratory Mill. As compared to conventional vibratory mills the Eccentric Vibratory Mill can increase the throughput by the factor 2 while reducing the specific energy demand by 50 %. For the soda digestion the progress made in the mechanical activation of chromite by means of vibratory milling is in the reduction of the mass flows due to a complete digestion, the omission of recycling residues unable of digestion and the improved landfill-suitability of the tailings.