A study of the grinding of magnetite/limestone mixture in a stirred mill by the attainable region method

Abstract

The ore processed by grinding in the minerals industry is generally composed of two or more minerals, and thus multicomponent formulations are commonly used to simulate the grinding process. In this paper, batch studies were carried out by grinding magnetite, limestone, and magnetite/limestone mixture at different mixing ratios in a laboratory-scale stirred mill. The impact of mixing ratios on the volume fraction of the desired size (−45 + 10 μm) in the ground products, energy consumption, and residence time of the feed in the grinding chamber was studied. The breakage parameters of the material were predicted by the population balance model (PBM). The results indicated that the back-calculated particle size distribution (PSD) of ground products by PBM fitted well with the measured data. The correlation of breakage parameters and mixing ratio were discussed and then compared to the single mineral grinding results. In addition, the predicted PSD was analyzed and discussed by the attainable region (AR) method. A significant effect of specific energy input on the yield of the desired size in the ground products was elucidated. The energy consumption and residence time of one component in the grinding chamber were compared to the single mineral grinding results at the turning point and switch point.