Grinding Kinetics of Vanadium-Titanium Magnetite Concentrate in a Damp Mill and Its Properties

The grinding behavior of the as-received (5 pct moisture) vanadium-titanium magnetite concentrates in a damp mill was investigated in this paper. A grinding kinetics equation was established based on a population balance model using size distribution data obtained from a laser diffraction technique. X-ray diffraction results show that a loss in crystallinity occurs when the grinding time is increased. The crystallite size of the materials decreased, whereas their structural microstrain increased with increasing grinding time. The wettability increased because the surface roughness increases with increasing grinding time. The moisture capacity of the solids increased during the first 3 minutes of grinding and then remained roughly constant with further increases in grinding time. The water transfer coefficient of the particles increased at grinding times of 3 and 6 minutes and then decreased at grinding times of 9 and 12 minutes. The compressive strength of oxidized pellets increased with increasing grinding time; longer grinding times can compensate for the effects of lower roasting temperature or shorter roasting time on the strength of the pellets. Lowering the roasting temperature and shortening the roasting time by grinding appeared to be possible.