MechChem Africa March-April 2021

⎪ Minerals processing and materials handling ⎪

Cyclone evolution improves coal fines recovery

Continuous improvement of Multotec classification cyclones is helping customers meet both commercial and environmental imperatives in the coal sector. Ernst Bekker, product specialist for cyclones at Multotec explains why. O ngoing design evolution and continuous improvement initia- tives of Multotec’s classification cyclones is helping customers in at Multotec. “Today, there is an intense focus on the beneficiation of coal fines, which in the past were generally discarded,” says Bekker. “There is greater awareness of the environmental impact, and it alsomakes good economic sense to recover more.” the coal mining sector to meet commercial and environmental imperatives, according to Ernst Bekker, product specialist for cyclones

Hehighlights, however, that dewateringof fines canbe costly.Multotec’s efforts tomake theprocessmore cost effectivehave included the investigation of alternative inlet designs, whichachievemoreefficient separation, espe - cially with fine coal. Also important has been the incorporation of alternativewearmateri- als to extend the lifespan of these cyclones. “Our focus is on the mechanical life of our units and their physical ability to last, but we alsowant toextend their efficiency across the lifecycle, so they perform well for longer,” he says. Ongoing wear creates undulations on the inner surface of a cyclone, for instance, and this causes separation inefficiencies. “Ceramic tiles tend to last longer, but other materials can retain a smoother surface for better separation,” he says. “Using these be replaced if necessary. As it rotates, the screw self-centres, providing ample space between itself and the tubewall tominimise or eliminate grinding. The gentle rolling action imparted by the screw prevents the separation of blends, while the enclosed conveyor tube prevents product and plant contamination. Supplied as standard with a durable industrial coating, the unit is available with an optional start-stop control panel and a range of flow-promotion devices. Flexicon also manufactures other flex - ible screw conveyors, as well as pneumatic conveying systems, tubular cable conveyors, bulk bag dischargers, bulk bag conditioners, bulk bag fillers, manual dumping stations, drum/box/container tippers, weighbatching systems and automatedplant-wide systems integrated with new or existing process equipment. www.flexicon.co.za

alternative materials, we can design custom solutions to suit the application, thus ensur- ing the customer is always getting optimal value throughout aMultotec cyclones’ entire lifespan.” He also notes that the company’s overall sensor development programme is giving at- tention to monitoring wear lining thickness and performance conditions in classification cyclones. “With sensor technology, wewill be able topick up roping conditions in the spigot, for example,” he says. “We believe there is even scope, with these units, to leverage ar- tificial intelligence to help us achieve optimal operating conditions,” Bekker concludes. www.multotec.com

All-steel flexible screw conveyor resists abrasion

Flexicon has introduced a wear-resistant flexible screw conveyor with a carbon steel conveyor tube, a heavy-duty flexible screw, and a heavy-gauge floor hopper and dis- charge housing, which is capable of moving crushedglass, garnet, aluminiumoxide, silica sand, aggregate, cement and many other abrasive materials. The screw is available in lengths of up to 12 m in round, square, flat or bevelled profiles to optimise conveying efficiency for each application. The 115 mm diameter conveyor tube is available curved tovertical, to horizontal or at any angle. The screw is the only moving part contacting material. Its lower end has no bearing, while its upper end is driven beyond thematerial discharge point, preventing material contact with the upper seal or bearing. This configuration facilitates simple maintenance in harsh environments since the single moving component can quickly

Flexicon’s all-steel flexible screw conveyor conveys crushed glass, garnet, aluminium oxide, silica sand, aggregate, cement and other abrasive materials – dust-free.

March-April 2021 • MechChem Africa ¦ 27