MTA-AUS 2014

CONEXPO-CON/AGG VIP SHOW GUIDE contains Floor Plans and a complete listing of companies exhibiting at the ConExpo-Con/Agg 2014 trade show in Las Vegas March 3-7, 2014. It also contains 2014 forecasts for the Aggregate, Concrete and Cement industries

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2014 VDMA MINING SUPPLEMENT | VDMA 65 VDMA final product. We can do a pre-concentration to make the down- stream process smaller and more economical." Eliminating the waste rock ahead of the liberation process lightens the load on the mill and all of the downstream processes. Improving the Efficiency of Solid-liquid Separation Decanter centrifuges are an effective means of separating solid- liquid mixtures. Similar to most areas, constant improve ments have consistently increased the performance of these decanters. The GEA Westfalia Separator Group builds decanters for the mining business. Some of it largest machines can process 200 m 3 /h. The company has recently identified and implemented technological changes that will help it reduce energy consumption on these machines by as much as 30%. The decanter mainly consists of a bowl with a scroll. Both ends of the bowl are supported by roller bearings. The scroll rotates at a lower speed relative to the bowl, conveying the solids to the discharge ports. The liquid is discharged through holes in the bearing hub. In addition to supplying idling power, a primary motor, connected to a rotor by a V-belt, supplies the power to discharge the clarified liquid in a traditional arrangement. A secondary motor dri ves the scroll. GEA performed a power study on its ma- chines. They determined that the ejection power of the clarified liquid is the most significant ele- ment, representing 45% of the machine's total power requirement. Idling consumed 26% of the power. The power to transport solids was 7%. The losses through the frequency converter and the gearing amounted to 30%. To improve this situation, GEA developed the summation- drive concept. The power for conveying the solids is provided by the sec- ondary motor. A frequency converter is used to control the secondary motor, which means the speed of the motor can be varied between 1 and 25 rpm. If a higher differential speed is required, a hollow shaft connected to the scroll may be driven by the primary motor by a belt. The differential speed range is shifted to 25 to 50 rpm. By using a different set of pulleys, the differential speed could be fur- ther increased to 70 rpm. A flowsheet shows how Wolfram includes the X-ray ore sorter in its process. I N V E N T O R A N D W O R L D M A R K E T L E A D E R O F T Y R E P R O T E C T I O N C H A I N S Erlau AG Erlau 16 73431 Aalen Germany Tel. +49 7361 595-0 Fax +49 7361 595-3214

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