Abstract

In mineral crushing operations, the feed rate and feed size distribution affect the crushing rate and particle size distribution of the crushed products. In the present study, copper ore feed charges of different size distributions were prepared. These feed charges were fed to the jaw, cone, and roll crushers at different feed rates in the laboratory scales. The effects of these parameters on the crushed particle size distributions and crushing rates were investigated and described using the fractal geometry by the calculation of the product fractal dimensions. The fractal dimension was calculated based on a proportional relation between the size and weight of the particles. The obtained fractal dimensions of the particle size distributions for the particles crushed by the jaw, cone, and roll crushers were in the range of (2.16–2.38), (2.13–2.31), and (2.23–2.46) respectively. In all of three types of crushers, the fractal dimensions and crushing rate of the ore were increased with an increase in feeding feed size distribution and by increasing the amount of particles with sizes bigger than the setting size. Increasing the feed rate at the permitted capacity had an inverse relation with the fractal dimension and led to a reduction in both the fractal dimension and the crushing rate. However, an increase in the feed rate at the unpermitted capacity, having a direct relationship to the fractal dimension, was resulted an increase in crushing rate and fractal dimension of the ore due to the choke feeding.

摘要

在矿物破碎作业中，进料速率和进料粒度分布影响被粉碎产品的破碎速率和粒度分布。在本研究中，制备了不同粒度分布的铜矿石进料。这些进料以实验室规模的不同进料速率喂入颚式破碎机、圆锥破碎机和辊式破碎机。通过计算产品分形维数，使用分形几何来研究和描述这些参数对粉碎粒度分布和粉碎速率的影响。分形维数是根据颗粒的大小和重量之间的比例关系计算的。由颚式破碎机、圆锥破碎机和辊式破碎机破碎的颗粒获得的粒度分布分形维数在（2.16-2.38）、（2.13-2.31）、和 (2.23–2.46) 分别。在所有三种类型的破碎机中，矿石的分形维数和破碎率都随着给料粒度分布的增加和大于设定粒度的颗粒数量的增加而增加。在允许的容量下增加进料速率与分形维数成反比，并导致分形维数和破碎率都降低。然而，在不允许的容量下增加进料速率，与分形维数有直接关系，由于阻塞进料导致矿石的破碎速率和分形维数增加。矿石的分形维数和破碎率随着进料粒度分布的增加和粒度大于设定粒度的颗粒数量的增加而增加。在允许的容量下增加进料速率与分形维数成反比，并导致分形维数和破碎率都降低。然而，在不允许的容量下增加进料速率，与分形维数有直接关系，由于阻塞进料导致矿石的破碎速率和分形维数增加。矿石的分形维数和破碎率随着进料粒度分布的增加和粒度大于设定粒度的颗粒数量的增加而增加。在允许的容量下增加进料速率与分形维数成反比，并导致分形维数和破碎率都降低。然而，在不允许的容量下增加进料速率，与分形维数有直接关系，由于阻塞进料导致矿石的破碎速率和分形维数增加。