Limitation of HPGR application

Abstract

Many researchers have discussed the advantages of the pressure breakage mechanism and the importance of high-pressure grinding rolls (HPGR) in the hard minerals industry but the impact of this machine on the final product of the comminution circuit at an industrial scale has been less studied. In this research, the influence of HPGR utilisation on the comminution circuit of the 4th line of the iron ore concentrator at the Golgohar Mining and Industrial Complex, Iran, was investigated. Two series of experiments were carried out: the first was performed with the HPGR in the circuit (ON) while the other was conducted with the HPGR out of the circuit (OFF). The results show that the HPGR had no significant effect on the final product of the comminution circuit from the point of view of particle size. The trommel screen overflow rate decreased by 5.1% of the fresh feed rate when the HPGR was ON. To determine the probable reasons, X-ray computed tomography analyses were carried out. These showed that cracks in the particles entering the grinding circuit were caused not only by the HPGR since some small cracks were present in the HPGR feed. It was also found that coarse particles are more susceptible to failure in the HPGR and that soft materials, such as talc, reduce the HPGR performance.