Effect of rheology and dispersion degree on the regrinding of an iron ore concentrate

This investigation addressed the study of the effects of the slurry's rheological behavior and the state of aggregation and dispersion on wet ultrafine grinding of an iron ore concentrate. Regrinding tests were conducted under different conditions of dispersion (pH 7.3, 8.5 and 10.0) and with the addition of 300 g/t of lime. The increase of pH from 7.3 to 10.0 increased the slurry dispersion degree, providing lower values of yield stress and apparent viscosity, and a reduction in specific energy consumption of 17.4%. So, sodium hydroxide, added at previous processing steps, has acted as a grinding aid. The addition of 300 g/t of lime caused an increase of 27% in specific energy consumption, with significant increase in yield stress and consistency index of the fluid, especially for the condition of 18 kWh/t.