Engineering & Mining Journal

APR 2013

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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Its disc-stack centrifuges are available with bowl diameters of 200-1,050 mm, handling up to 500,000 liter/h and separating out particles as small as 0.5 µm. Its decanter centrifuges, meanwhile, come with bowl diameters from 200 to 1,030 mm, with throughput capacities of up to 350,000 liter/h and have separation capabilities for plus-5 µm particles. "Manufacturing these centrifuges involves high-precision engineering, since these are heavy, stainless-steel bowls rotating at speeds of around 5,000 rpm," Hartmann explained. "We do all of our own milling to shape each bowl to the exact dimensions for each application, and wear-protection of the centrifuges for these applications is very important." One of the main uses for these centrifuges is in separating "crud" from solvent-extraction liquids. Crud is the stable emulsion that can form along the interface between the organic and aqueous phases during solvent leaching which, if not removed, can reduce the process efficiency significantly. Today, Hartmann said, companies such as BHP Billiton, Anglo American, Vale and Impala Platinum are using its centrifuges for crud removal in copper and PGM operations, while in 2012 alone, it received orders from Talvivaara Mining and Cameco (uranium), and AngloGold Ashanti and Grupo México (copper) for new systems for their solvent-extraction plants. Centrifuges from GEA Westfalia Separator Group not only remove the solids responsible for crud formation, but also produce cleanly separated organic and aqueous phases, Hartmann noted. And, uniquely in this market, he said, its patented DControl system allows operators to adjust the separation parameters in response to changing physical, chemical and even climatic conditions. In addition, either standard, super-duplex or even hastelloy grade can 2013 • VDMA MINING SUPPLEMENT be used for bowl production, depending on the corrosion characteristics of the fluids being handled. The improved recovery of the organic phase, and reduced losses, have given investment payback periods of less than six months, he added. Major advantages of these separators include the speed of operation, with typical process times of less than 10 seconds, their small footprint, their ability to be installed as "plug-and-produce" units within an existing plant and—since they are fully enclosed— their minimal environmental impact. Aside from crud treatment, other potential applications include clarifying tailings wastewater. VDMA German Crushing Technology Used World-wide Sandvik Mining & Construction Crushing Technology GmbH has supplied a broad range of crushing solutions for applications in the mining sector for nearly 60 years. As a major supplier to the global mining market, Sandvik Mining says it places great importance on the incorporation of Environmental Health and Safety (EHS) principles into the design, manufacture, operation and maintenance of every machine. This commitment has earned it a broad customer base with varied crushing requirements in the mining sector; from copper and iron ore mines in Australia and Africa to coal processing equipment in China and throughout Europe, the company states. The Sandvik CR810 Hybrid is a unique machine in its offering, combining the benefits of a classic double-roll crusher with sizer technology to create a compact machine that achieves high throughputs with low power consumption. Its aggressive teeth configuration is capable of crushing lumps of up to 2,000 mm in size with a reduction ratio ranging from 1:4 to 1:6, depending on the VDMA 39

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