Power consumption management and simulation of optimized operational conditions of ball mills using the Morrell Power model: A case study

Abstract

The amount of comminution or fineness of minerals in a mill can be described by various parameters, the most important of which is d80 (80% passing size). The purpose of this study is to investigate and simulate the optimal operating conditions of a ball mill in a copper processing plant. The actual operating conditions in the intended mill are performed with a 300 tph tonnage, a 267 second retention time, and a discharge d80 = 53 μm. Laboratory studies showed that the optimal economical and metallurgical recovery of copper in this plant is achieved in 65 μm ≤ d80 ≤ 75 μm with Flotation Recovery (R) = 90.16%, Economical Efficiency (EE) = 93.04% and Separation Efficiency (SE) = 88.64%. In this study, having the optimal d80 for the concentration unit, the mill data, and utilizing Excel Software and the Morrell method, first the total power for the optimal set of d80 was calculated, which is equal to 7790 to 8005 kW. Then, according to these power values, the corresponding retention times were calculated, which are equal to 236 and 247 seconds respectively. Finally, utilizing the retention time-tonnage relationship and taking into account the specific filling of the mill, the optimal corresponding tonnages to the obtained retention times were calculated, ranging from 324 to 340 tph. The results of these studies showed that by reducing the level of comminution from d80 = 53 μm to 65 μm ≤ d80 ≤ 75 μm, in addition to increasing flotation efficiency to R = 90.16%, EE = 93.04% and SE = 88.64%, about 4.21% to 7.09% energy savings and an 8.00% to 13.33% tonnage increase will occur.