| Pulp lifter assembly is one of the important components at the discharge ends of grate-discharge grinding mills. It discharges grinded materials out through the discharge trunnion like a centrifugal pump running in the reverse direction to that required by a pump. Though it is widely known conventional pulp lifter design associates with drawbacks that cause inefficient discharge operation, little has been done to understand the causes of this particular happening. With the aim to better understand the effects of different pulp lifter designs on the discharge performance and also establish strategies for future design and operation of such equipment, this work is initiated.;Three types of industry scaled pulp lifter designs, including two conventional designs and a new design, were comparably studied using Discrete Element Method (DEM) modeling technique. The discharge performances of these designs were evaluated against three criteria which include discharge rate, power consumption, and flow-back/carry-over. The results have shown that pulp lifter assembly with spiral designed radial arms possesses better discharge performance than that with straight radial arms. The discharge performances of three types of designs are also found to be sensitive to some specific design and operating parameters, such as number of vanes, mill rotational speed, the size of particle, and the coefficients of friction. Based on the results, five guidelines on future design and operation of pulp lifter assembly were established. |
