Modern Quarrying Q3 2020

The Combo allows Ground Breakers to produce two high- quality sands simultaneously from the raw feed including plaster sand and river sand.

WET PROCESSING

Problems encountered when washing and dewatering sand include the discharge of wet product; product-sized sand sent to waste; too much time spent cleaning out settling ponds, and water usage. Wet processing equipment provider CDE has developed an alternative for construction and materials companies, in the form of cyclone-based solutions. By Mark Botha REPLACING BUCKET WHEEL SYSTEMS WITH CYCLONE TECHNOLOGY U ntil recently, construction and materials companies had to rely on bucket wheel wet processing technology to separate materials into different grades of sand. Although bucket wheels have been Bucket wheel technology “Bucket wheel technology, in its prime when resources were abundant and the price of sand was high, is fast becoming a much less attractive proposition when compared to new systems,” says Du Plooy.

essential to the quarrying industry over the years, increasing demand for sand and aggregates prod- ucts, as well as increasingly stringent regulatory requirements, mean that operators must produce a wider range of materials in larger quantities and in less time to protect their return on investment and to turn a profit. Global wet processing equipment provider CDE has developed an alternative for construction and materials companies, in the form of cyclone-based solutions which, according to Willem du Plooy, the company’s business development manager, “guar- antee a strong competitive edge and fast return on investment”.

He says bucket wheels accept material either directly from the aggregates screening operation, or are fed from classification tanks in applications where there is excess fine material in the -75/-63 micron range, which must be removed. The operation of the screw pushes the sand fraction up the elevated chamber while the water and finer particles pass through the overflow weir. The overflow weir, which is closer to the feed point, then provides the mechanism for fines removal. In bucket wheel classifiers, sand slurry is intro- duced near the wheel, where the coarse sand set- tles, and is lifted by the rotating wheel. The rotary

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MODERN QUARRYING QUARTER 3 - 2020