Analyses on uniformity of particles under HPGR finished grinding system

Abstract

In order to deal with the disadvantages of excessive grinding and non-uniformity in finished particle under high-pressure grinding rolls (HPGR) finished grinding system, four aspects were investigated, including evaluating indicators, effects of operating factors, effect of particle uniformity on the flotation and formation mechanism of particle uniformity. Experiment of HPGR finished grinding system, cationic reverse flotation experiment and simulation test of particle bed comminution under the condition of quasi-static were carried out. Theoretical analyses indicated that both of uniformity coefficient and average particle size should be included in the uniformity analysis of the mineral particles. The results show that the effect of circulation fan impeller speed on particle uniformity is the most evident, HPGR working pressure and roll gap are second and HPGR roller speed is the last. Average particle size has a more obvious effect on the grade of flotation concentrate while uniformity coefficient has a more obvious effect on the flotation recovery. Considering the two aspects of grade and recovery, the optimal uniformity coefficient for flotation is 1.1–1.2 and the optimal average particle size for flotation is 50–55 μm. The operating factors which promote the shielding effect and compact effect in the HPGR finished grinding system should be strengthened based on the uniformity of particles.

Keywords

high-pressure grinding rolls / particle uniformity / uniformity coefficient / average particle size / flotation / shielding effect / compact effect

References

[1] MutzeT. Energy dissipation in particle bed comminution [J]. International Journal of Mineral Processing, 2015, 136: 15-19

[2] KhanalM, SchubertW, TomasJ. Discrete element method simulation of bed comminution [J]. Minerals Engineering, 2007, 20(2): 179-187

[3] TavaresL M. Particle weakening in high-pressure roll grinding [J]. Minerals Engineering, 2005, 18(7): 651-657

[4] SesemannY, BroeckmannC, HofterA. A new laboratory test for the estimation of wear in high pressure grinding rolls [J]. Wear, 2013, 302(12): 1088-1097

[5] GaoH, QuL G. 3D design and analysis of the crushing roller of a high-pressure grinding roller [J]. Journal of Materials Processing Technology, 2002, 129(1–3): 649-652

[6] ZengY-c, XuH-l, ChenQ, WuBo. Research on influence of high pressure grinding rollers’ hydraulic system parameters on roll cap deviations [J]. Journal of Vibration, Measurement & Diagnosis, 2015, 35(5): 841-848

[7] DundarH, BenzerH, AydoganN A. Application of population balance model to HPGR crushing [J]. Minerals Engineering, 2013, 50–51: 114-120

[8] SaramakD. Mathematical models of particle size distribution in simulation analysis of high-pressure grinding roll operations [J]. Physicochemical Problems of Mineral Processing, 2013, 49(1): 121-131

[9] XuP-y, LiJ, LuoH, YeH-qi. Models for the particle size distribution of high-pressure grinding rolls based on fractal theory [J]. Journal of China University of Mining & Technology, 2016, 45(5): 1030-1037

[10] AydoganN A, ErgunL, BenzerH. High pressure grinding rolls (HPGR) applications in the cement industry [J]. Minerals Engineering, 2006, 19(2): 130-139

[11] CamalanM, OnalM A R. Influence of high-pressure grinding rolls on physical properties and impact breakage behavior of coarsely sized cement clinker [J]. Particulate Science and Technology, 2016, 34(3): 278-288

[12] ZhuD-q, YuW, ZhouX-l, PanJian. Strengthening pelletization of manganese ore fines containing high combined water by high pressure roll grinding and optimized temperature elevation system [J]. Journal of Central South University, 2014, 21(9): 3485-3491

[13] KodaliP, DhawanN, DepciT, LinC L, MillerJ D. Particle damage and exposure analysis in HPGR crushing of selected copper ores for column leaching [J]. Minerals Engineering, 2011, 24(13): 1478-1487

[14] JankovicA, SutherS, WillsT, ValeryW. Evaluation of dry grinding using HPGR in closed circuit with an air classifier [J]. Minerals Engineering, 2015, 71: 133-138

[15] YuanZ-t, LiL-x, HanY-x, LiuL, LiuTing. Fragmentation mechanism of low-grade hematite ore in a high pressure grinding roll [J]. Journal of Central South University, 2017, 23(11): 2838-2844

[16] AltunO, BenzerH, DundarH, AydoganN A. Comparison of open and closed circuit HPGR application on dry grinding circuit performance [J]. Minerals Engineering, 2011, 24: 267-275

[17] LanJ-w, JinW-x, WangJun. Performance studies of finished mill with roller press in cement production process [J]. Journal of Xi’an University of Architecture & Technology: Natural Science Edition, 2012, 44(4): 597-604

[18] YinW-z, WangJ-zhen. Effects of particle size and particle interactions on scheelite flotation [J]. Transactions of Nonferrous Metals Society of China, 2014, 24(11): 3682-3687

[19] RahmanA, AhmadK D, MahmoudA. Nanomicrobubble flotation of fine and ultrafine chalcopyrite particles [J]. International Journal of Mining Science and Technology, 2014, 24(4): 559-566

[20] XieG-y, WuL, OuZ-s, ZhangX-p, WangW-ping. Research on fine coal classified flotation flow sheet [J]. Journal of China University of Mining & Technology, 2005, 34(6): 756-760

[21] ThellaJ S, MukherjeeA K, SrikakulapuN G. Processing of high alumina iron ore slimes using classification and flotation [J]. Powder Technology, 2012, 217: 418-426

[22] YangX-l, AiG-hua. Effects of surface electrical property and solution chemistry on fine wolframite flotation [J]. Separation and Purification Technology, 2016, 170: 272-279

[23] ErgulerZ A. A quantitative method of describing grain size distribution of soils and some examples for its applications [J]. Bulletin of Engineer Geology and the Environment, 2016, 75(2): 807-819

[24] HouY, YinW-z, ZhuJ-j, YaoJ, WangY-l, WuKai. Relationship between parameters of size characteristic and uniformity of particle size distribution [J]. Journal of Central South University: Science and Technology, 2015, 46(9): 3183-3187

[25] MatijašicG, KurajicaS. Grinding kinetics of amorphous powder obtained by sol-gel process [J]. Powder Technology, 2010, 197(3): 165-169

[26] LiuS-h, LiQ-l, XieG-s, LiL-h, XiaoH-lin. Effect of grinding time on the particle characteristics of glass powder [J]. Powder Technology, 2016, 295(3): 133-141