MechChem Africa November-December 2024

⎪ Innovative engineering ⎪

The largest FLS VRM sets benchmarks in production capacity and energy efficiency.

FLS has re-engineered a trommel solution based on lightweight tubing to reduce its weight.

overland conveyors. We are now looking to incorporate our new Rail-Running Conveyor system to achieve significantly better ef ficiencies and wear life. Instead of loading all of the rom ore onto a conveyor belt running on rollers, we use rail haulage principles – a carriage supported on wheels and running on rails – to transfer the ore over long distances. “Compared to a belt conveyor that is con stantly running over rollers, we have been able to reduce ongoing transport costs by between 30% and 60%, just because of the reduced friction from a steel on steel rail application. And we are sure there are significant wear life and maintenance advantages over and above the reduced running costs,” suggests Alistair McKay, adding that towards the end of next year, FLS should have two of these systems up and running in Zimbabwe. He says that on a long overland belt con veyor, there might be 30 000 static rollers to lubricate, inspect and replace across the length of the belt. This makes maintenance and monitoring very difficult to manage. “With the Rail-Running Conveyor, only the rail is static and all the moving parts are travel ing in a loop. This makes a digital monitoring station for all the individual wheels easy to set up. What is really innovative is that the monitoring station is linked to a ‘wagon’ swap out station, where if a fault on a wheel is de tected, the whole wagon can be decoupled and replaced by a new one in a matter of minutes,” he explains. “And in terms of curvatures and inclines, the rail-based system can significantly out perform belt conveyors, enabling inclines of up to 20° to be comfortably managed. This can often reduce the number of trucks that need to be used to bring material up from a pit,” he adds. On the milling side, he says that FLS is moving away from the traditional SAG and Ball mill combination for fine milling, which

FLS’s Rail-Running Conveyors offer significant operational advantages, most notably, reduced running costs.

pany’s new coarseAIR™ flotation technology, an innovative system used for the recov ery of coarse particles in flotation circuits that is based on the REFLUX™ Classifiers. “Traditional flotation cells rely on rising air bubbles to float value stream material. But coarse sinking particles tend to disrupt the bubble particle interaction and impede this recovery. coarseAIR is a low turbulence, aer ated fluidised bed separator combined with the lamella plate innovation used in FLS’s REFLUX™ Classifier. This technology combi nation is able to float larger particle sizes of up 850 µm, enabling the target grind size to be increased to deliver significant sustainability and process benefits. “This provides excellent efficiency through improved resource utilisation – not only in terms of air, water and energy use, but of the mineral resource itself: more value is recov ered, while less grinding is required. “Using our coarseAIR is an ultimate ex ample of an innovative sustainability solution from FLS,” concludes Alistair McKay. www.flsmidth.com/en-za

is known to be inefficient in terms of energy and water consumption. “We have introduced our new Vertical Roller Mill (VRM), which we are very excited about. We have been using VRMs for many years in the cement industry and we have one of the largest vertical roller mill in the world operating at a cement plant in Bangladesh.” Coupled with HPGRs (high-pressure grind ing rolls), VRM technology brings a new level of size classification control to a mill circuit. Successful replacements have been done, where traditional tertiary and secondary mills are removed and the ore is taken directly from a tertiary HPGR crusher into a single VRM. Describing the difference between the FLS VRM and traditional VRM technology, he says that instead of having smooth rolls, FLS’s VRM has a carefully designed studded roll that moves over a static table – and it incorporates a dynamic air classifier that separates out the milled fines at the preset size. “And it is not untested. It has been used in the cement industry for many, many years,” McKay adds. Finally, he cites the com

November-December 2024 • MechChem Africa ¦ 47