Capital Equipment News October 2020

SCREENING

Screen technology is penetrating into ever finer size ranges.

Dry separation gains traction in finer size ranges

Diverse classification methods are used in quarrying and mining applications. Traditionally, hydrocyclones have most often been preferred to meet fine separating cut requirements, while screen systems and other separation methods have generally been used for the size range above that. However, this convention now appears to have lost its validity, with dry technologies such as screens and air classifiers gaining the edge in finer size ranges. By Munesu Shoko .

H ydrocyclones have historically been the go-to solution for fine separating cut requirements. However, other technologies such as fine screen technology and air separators are challenging the status quo, and are penetrat- ing into ever finer size ranges. Jorge Abelho, director – Technical Support at Pilot Crushtec International, reasons that traditional mining makes use of wet processing technologies such as hydrocyclones to remove fines from products. With the global push to reduce the environmental impact, he says, new and more efficient dry technology is gaining favour. “Hydrocyclones make extensive use of water, which is already a scarce natural resource in most areas of the

world. Then there are challenges and costs associated with the treatment of the contaminated water,” says Abelho. Wet processing, he says, is significantly more efficient in removing fines than screening. There are, however, improvements in fine screening, but there also are challenges associated with blinding of screens as well as the significantly larger screen areas required for similar production rates if compared to wet processing. As far as wet processing is concerned, governments are also reviewing or implementing regulations which further control the use and disposal of water in mining applications. “I believe that in future, air separation will play a

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