by Kathrine Moore
Leveraging more than 295 years of experience in the engineering, design, fabrication, installation and commissioning of mining, bulk handling and minerals processing equipment and systems, Tenova TAKRAF is a major supplier to the global resource industry.
The company’s competence covers overburden removal, raw material extraction, conveying, processing, comminution, homogenizing, blending, storage, transport and shipment.
In the minerals processing industry, comminution is the act of reducing the size of raw material. This is accomplished by using powerful crushers and grinders. Conventionally, crushers of various types ranging from jaw to hammer, gyratory and cone crushers are employed to break down or crush ore using force, compressing raw material so as to generate enough energy within the material being crushed that its molecules separate from (fracture), or change alignment in relation to (deform), each other.
HPGRs are modern and efficient comminution machines, which, according to TAKRAF, are becoming more and more popular within the minerals processing field and are an interesting crushing alter-native, where appropriate. In fact, the company states that HPGR technology “is a qualified alternative for large-scale com-
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 crushing stages or in the pebble-crushing stage to improve downstream milling performance,” 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-efficient 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, currently two HPGR machines are being manufactured at the company’s special-ized fabrication facility in Lauchhammer, Germany. The factory is equipped to handle rolls of a diameter up to 2,600 mm and a roll weight of up to 130 tons.
In order to meet the challenging longevity 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 processing.