Capital Equipment News October 2021

FLSmidth's double deck vibrating screen with modular panels at the company's Delmas Supercenter.

The significance of screening in processing plants cannot be underestimated and often separates profitable operations from those that struggle to meet production targets

equipment, it will also reduce expensive downtime,” he says. “Efficient screening is also important for environmental reasons. Dewatering screens need to be efficient to limit water losses in arid regions.” It is thus clear, says Fouche, that efficient screening benefits the overall productivity of operations. This is true for all types of screening, whether it is accomplished by vibrating screens, trommel screens or the different types of static screens. Jurgen Cneut, FLSmidth global product manager – mid-market screens & feeders and regional product line manager – mining screens and feeders – ENAR & sub-Saharan Africa, agrees, saying that screening is critical as it affects other equipment downstream, such as crushers and mills. “So if the screens are not working optimally, then the whole operation will be affected,” says Cneut. Selection of a screen Multotec’s Fouche says it is key that the duty for which a screening machine is required is correctly identified before equipment is selected or sized. The various duties include scalping, sizing, desliming and trash removal, among others. Once the duty has been established, the engineer will select an appropriate model to size the vibrating screen or trommel – these include

As screens are the link between many unit processes, they also play a significant role in balancing the production capacity between the comminution circuit and the beneficiation circuit

It is key that the duty for which a screening machine is required is correctly identified before equipment is selected or sized

Efficiency of a screen is a critical parameter that is affected by changes in the particle size distribution, an increase in moisture content, increases in feed tonnage and any material composition changes

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consumption. The recovery of dense medium in the DMS plant relies on the drain and rinse screens performing optimally. The efficient removal of fines prior to flotation will save on the various reagents used in the process,” says Fouche. Furthermore, adds Fouche, as the efficient removal of the fines fraction influences the

recirculating load, efficient screening will increase the capacity of the mill or crusher circuit. While efficient screening prevents over grinding and crushing, it also saves on the electricity bill. “Not only will the duty performed by scalping screens prevent oversize and tramp material damaging downstream process

VSMA, DSM or drainage curves. “Practical factors also need to be considered. In cases where mobile

equipment is required, trommels might be preferred to vibrating screens as they do not

CAPITAL EQUIPMENT NEWS OCTOBER 2021 21