Issue link: http://resourceworld.uberflip.com/i/1099276
A P R I L / M A Y 2 0 1 9 www.resourceworld.com 55 MININGWORLD minution circuits and is becoming ever more popular in minerals processing." HPGRs employ two counter-rotating grinding rolls to exert high pressure on material distributed across the gap between the rolls. The company explains that, "Inter-particle comminution is the HPGR specific grinding process in which material particles are crushed and ground within the compressed material bed and not by contact with the roll surface." TAKRAF also points out that, unlike conventional crushers, HPGRs do not require that the feed material be larger than the gap in order to be reduced. "The high pressure comminution process causes micro-cracks in the particles, which leads to the liberation of minerals and a higher portion of fines." Additionally, the company says that HPGRs can be usefully employed in brownfield projects to de-bottleneck conventional crushing/milling circuits resulting in an increase in total plant capacity. "Furthermore, they can also be used as tertiary and/or quaternary crush - ing stages or in the pebble-crushing stage to improve downstream milling perfor- mance," says TAKRAF. Another significant advantage is that HPGR treated minerals, "show better leaching performance, because the micro- cracks increase the particle contact surface for the leaching liquid. Flotation efficiency is also further enhanced through the use of HPGR comminution." "Grinding of material in HPGRs has proven to be more cost efficient as com - pared to conventional crushers and mills. Especially downstream processing stages, such as ball milling, are more energy-effi- cient using HPGRs as a result of the finer product size distribution coming out of the HPGR and the additional effect of micro- cracks in the product particles. In essence, the main motivation to use HPGRs is to save energy and production costs," states TAKRAF. TAKRAF continues to further develop its capabilities within the comminution industry with an expanded range of roll presses, sizers and HPGRs. In fact, cur - rently two HPGR machines are being manufactured at the company's special- ized fabrication facility in Lauchhammer, Germany. The factory is equipped to han- dle rolls of a diameter up to 2,600 mm and a roll weight of up to 130 tons. In order to meet the challenging longev- ity requirements of such a machine, each roll surface is protected from wear by weld hardfacing for cement applications, and with tungsten carbide inserts for ore pro- cessing. n SOME OF THE MAIN HPGR ADVANTAGES INCLUDE: • Outstanding size reduction as result of inter-particle comminution between the rolls • High throughput rates at comparably low operating costs • Low specific energy demand • Proven alternative to SAG mill in SAG/ ball mill circuits • Improves energy efficiency or throughput in existing ball mill plants • Proven alternative to tertiary and quaternary crushers and rod mills • Can perform final grinding duty in fine grinding circuits (iron ore pellet feed) • Enhances leaching performance and flotation efficiency • Type of roller surface customized for different applications • Throughput rates up to 5,100 t/h. REGISTER TO ATTEND TODAY WWW.CANADAGASLNG.COM/RW2 @canadagaslng #CGLNG2019 THE ONLY CANADIAN EXHIBITION AND CONFERENCE DEDICATED TO THE GLOBAL GAS AND LNG INDUSTRIES Supported by CONNECT WITH BUYERS AND PRODUCERS IMPORTANT TO THE FUTURE OF YOUR BUSINESS 5,000 VISITORS 300 CONFERENCE DELEGATES 200+ EXHIBITION BOOTHS 75 GLOBAL EXPERT SPEAKERS DMG507 Canada Gas VISITOR_4.875'' x 4.7''_V1.indd 1 26/03/2019 08:38