Modern Mining September 2020

COVER STORY

Maximising efficiency in separation Hydrocyclones play a pivotal role in mineral processing and have a large effect on the overall efficiency and cost of processing. As mines continue to demand increased efficiency in their separation processes, Weir Minerals Africa reports increased demand for its range of Cavex ® hydrocyclones. Featuring a laminar spiral inlet geometry, Cavex hydrocyclones are engineered to deliver greater efficiency, capacity and long wear life – parameters of sheer significance to every miner. By Munesu Shoko .

D eclining ore grades are driving an increased focus on efficient separation processes in the mining industry, so says Sheldon Gabriel, prod- uct manager hydrocyclones at Weir Minerals Africa. Mining companies are consequently re-exam- ining old concepts to contend with the sector-wide grade decline and improve profitability. While a hydrocyclone is a fairly basic piece of equipment, its role in the overall economic efficiency of the separa- tion process cannot be underestimated. To this end, Weir Minerals Africa’s range of Cavex hydrocyclones are available in a wide variety of sizes and linings to meet each operation’s specific requirements. The range is suited for grinding cir- cuits, tailings and single or multiple stage desliming applications. “Traditionally, Cavex hydrocyclones were largely

Sheldon Gabriel, product manager hydrocyclones at Weir Minerals Africa.

used in classification duties, but over the years the scope of applications has broadened to include dense medium separation (DMS), tailings and dewa- tering stacker applications,” explains Gabriel. Key differentiator A key differentiator of the Cavex hydrocyclone, says

Installation of 8 Cavex CVXT ceramic tiled hydrocyclones in a cluster in a coal mine saw a 49% increase in solids to the underflow.

Gabriel, is the unique laminar spiral inlet geometry designed to deliver sharper separation, maximum capacity and a lon- ger wear life than conventional involute or tangential feed inlet designs. “The innovative design provides a natural flow path into the cyclone body, allowing the feed stream to blend smoothly with the rotating slurry inside the chamber. The result is greatly reduced tur- bulence through the whole hydrocyclone, dramatically improving the separation effi- ciency,” says Gabriel. This is because the residence time in the separation zone is increased. Another advantage when compared with con- ventional cyclones is the reduction in misplaced particles in both the overflow and underflow streams. Key successes The marked reduction in turbulence and friction significantly reduces wear. In coal applications, for example, where highly abrasive slurries are transported, ceramic tiles are engineered specifi- cally for use in the inlet section of the

8  MODERN MINING  September 2020