Effect of feed size on residence time and energy consumption in a stirred mill: An attainable region method

In mineral processing, stirred mills have become a common device due to their high energy efficiency. In this work, the kinetics of batch wet grinding studies were studied using six mono-sized fractions of quartz. The population balance model (PBM) was used to simulate the evolution behavior of the particle size distribution in a laboratory scale stirred mill. The parameters of PBM were obtained by calculations performed on experimental data. The results showed that the breakage behavior of each class followed a first-order model in the grinding process. Furthermore, the particle size distribution was back calculated from the determined parameters of the PBM. The simulated results were analyzed by the attainable region (AR) method to maximize the volume fraction of the desired size (-45 + 10 mu m) in grinding products. The results obtained indicated that the turning point and switch point were largely dependent on the feed size. These results suggest that a finer feed size is a better choice if the objective is to maximize the volume fraction of the desired size in the shortest residence time possible in a grinding circuit with a classifier. In addition, at the initial stage of grinding, the influence of the specific energy input on the yield of the desired size and overgrinding size for different feed sizes was significant. (C) 2020 Published by Elsevier B.V.