THE EFFECT OF ROLLS SPEED AND ROLLS SURFACE PATTERN ON HIGH-PRESSURE GRINDING ROLLS PERFORMANCE

An important aspect in the performance of the high pressure grinding r olls (HPGR) is its throughput. The HPGR throughput can be changed by v arying the speed of the rolls, but, it is important to determine the e ffects of changes in the rolls speed together with other variations su ch as grinding force and feed size, on the overall performance of the HPGR. To that end, the CSIRO laboratory-scale HPGR has recently been m odified to extend its circumferential speed up to 3.6 m/s. This paper reports on a study examining the effects of rolls speed variations on the CSIRO HPGR from 0.38 m/s up to 3.1 m/s on a number of ores. It was complemented by some studies performed on pilot-scale machines with d ifferent surfaces. It was generally found that with increasing rolls s peed, the working gap becomes smaller as does the specific throughput. Higher rolls speed tended to produce a steeper product size distribut ion curve and in some cases size reduction for less energy consumption compared with lower speed. The rolls surface pattern was found to sig nificantly affect the performance of the HPGR. This paper concludes wi th some possible implications of the results on application of the HPG R. (C) 1997 Elsevier Science Ltd.