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 rolls (HPGR) is its throughput. The HPGR throughput can be changed by varying the speed of the rolls, but, it is important to determine the effects of changes in the rolls speed together with other variations such as grinding force and feed size, on the overall performance of the HPGR. To that end, the CSIRO laboratory-scale HPGR has recently been modified 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 different surfaces. It was generally found that with increasing rolls speed, the working gap becomes smaller as does the specific throughput. Higher rolls speed tended to produce a steeper product size distribution curve and in some cases size reduction for less energy consumption compared with lower speed. The rolls surface pattern was found to significantly affect the performance of the HPGR. This paper concludes with some possible implications of the results on application of the HPGR. (C) 1997 Elsevier Science Ltd.