Evaluating high pressure milling for liberation enhancement and energy saving

A programme of laboratory based studies has been undertaken to evaluate the extent of liberation enhancement and energy saving that might be expected when utilising high pressure rolls comminution. This route has been compared to that achieved by conventional grinding for the final preparation of a base metal ore for feed to a flotation circuit. rindability tests were undertaken to estimate expectation of energy requirements for a close circuit mill and direct interpolation allowed an estimate of mill energy required for de-agglomeration following high pressure rolls crushing. The energy input to a simulated high pressure rolls mill was measured directly from work input to samples of the ore. The extent of mineral liberation was assessed directly by evaluating the results obtained from flotation release analysis of the ground samples. sults obtained suggest that a similar degree of liberation may be obtained by the high pressure route but at a coarser product size compared to a conventional route. The energy saving as a consequence of a coarser product and the use of high pressure rolls may be as high as 30%. Despite the marginally lower overall recovery obtained the results from a limited test programme suggest that the high compression route may offer significant scope for improved process efficiency.