MechChem Africa February 2019

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How does global engineering company FLSmidth do it? Delivering high levels of recovery, while managing large throughput efficiently in mining operations? REFLUX Classifier increases mining productivity

Atlas Copco.......................................................................3 BI (Bearings International).....................................IBC Bosch Rexroth SA (Hytec)........................................ 21 Endress+Hauser....................................................... OFC Flexicon........................................................................OBC Hägglunds....................................................................... 25 Lanxess............................................................................. 24 MMRisk............................................................................ 12 Pragma............................................................................IFC Wearcheck...................................................................... 13 ZebraTube....................................................................... 15 Zest WEG Group.......................................................... 11 Index to advertisers Process Control Valves and Actuators 27-29 March 2019 Park Inn Hotel, Sandton, Johannesburg +27 11 074 5916 michael@luthandoskills.co.za www.luthandoskills.co.za Industry diary March 2019 RAIL LIVE! 5-7 March 2019 Bilbao Exhibition Centre, Bilbao, Spain marketing@terrapinn.com PROPAK Africa 2019 12-15 March 2019 Expo Centre, NASREC, Johannesburg A recent innovation is the modular RC plant, for which FLSmidth carefully selected the associated equipment – including pumps, screens, dewatering equipment and convey- ors – for optimal performance. Thesemodular plants are also automated, using advanced in- strumentationand control equipment tokeep operations consistent and recoveries high. q www.propakafrica.co.za svens@specialised.com fastest midway between the channel walls. The lightest particles are carried by the faster flow before they can settle and they overflow at the top of the channel. They fall intointernallaundersandaredischargedfrom the RC. The higher density particles tend to slide back along the topside of the lamella channel, where the flow is slower. These par- ticles slide down the slope, back to form the autogenous dense media zone. Pressure probes monitor the bed density andautomaticallycontroltheunderflowvalve to optimise the bed level and density. The fluidised bed keeps particles in suspension and rejects the lighter material upwards and out of the bed, while the denser particles sink and flow out through the underflow valve. The valve’s four-link system moves the plug vertically, which reduces wear and provides protection against splashing.

T he key design element of REFLUX Classifiers (RC) is its slurry based gravity separator in the top portion, which consists of a system of la- mella plates or inclined channels and internal overflow launders that upgrade fineminerals – generally finer than 2.0 mm. The other two main components are an Autogenous Dense Medium Separator un- derneath the lamella chamber, andaFluidised Bed Separator beneath that. How it works Material from the process plant enters through the slurry inlet and passes over an internal over-size protection screen, which removes any tramp or debris that may cause damage to the ceramic underflow valve. Large, high-density solids quickly sink

and settle in the mixing chamber that is in the middle section of the classifier, forming a fluidised bed of dense material. The fluidised bed is created by a series of water jets at the base of themixing chamber, which rejects any trapped lighter particles. Lighter and finer particles rise in the RC, through the autogenous zone to the lamella section. The autogenous section consists of fine suspended solids and this zone helps convey lighter particles to the lamella section. This upper section contains the crucial sloping lamella channels that are typically placed 6.0 mm apart – although this distance can be reduced for finer materials. Low- density particles rise up through these chan- nels, driven by the upward water flow from the feed. The narrow sloping channels cause a parabolic flow pattern, where the flow is

The overflow of Reflux Classifier in a coal application. This upper section contains the crucial sloping lamella channels that are typically placed 6.0 mm apart.

Power and Electricity World Africa Power and Electricity World Africa 2019 will bring together 100+ expert speakers from across the power industry to provide insight, showcase innovation, share best practice and discuss ideas on trends in the power sector.

effective solutions to some of the technical engineering challenges the industry faces on a daily basis. These seminars will cover: solar tech, installing renewables, genera- tion and smart electricity. The event takes place at the Sandton Exhibition Centre in Johannesburg from March 26 to 27. q

Through a host of free seminars, the show aims to find innovative and cost-

32 ¦ MechChem Africa • February 2019