There is a fast-growing installed base of Cavex hydrocyclone technology in coal processing in both classification and dense-media separation (DMS) applications, according to mining equipment supplier Weir Minerals Africa.

“This is as a result of the lower total cost of ownership achieved by clients using the Cavex hydrocyclones in their operations,” Weir Minerals Africa cyclones product manager Sheldon Gabriel tells Mining Weekly.

He notes that the Cavex CVXT ceramic tile-lined hydrocyclone, designed exclusively for DMS applications, features a laminar 360º inlet scroll, which provides a natural flow path into the hydrocyclone. Its unique shape has no sharp edges or square corners and allows for the feed stream to blend smoothly with rotating slurry inside the chamber of the hydrocyclone.

This reduces turbulence and friction in the hydrocyclone and, therefore, improves its efficiency, as a greater hydraulic capacity is achieved and the wear life of the hydrocyclone is also improved, Gabriel explains.

He adds that Weir Minerals Africa has developed slip-cast radius tiles that are inserted into the feed chamber, further improving the hydrocyclones’ wear life. “The tiles were developed to maintain the Cavex hydrocyclone profile within the feed chamber; this also results in less turbulence generated, compared with that generated by standard tiles that are currently used in industry,” he advises.

Applications and Achievements
Weir Minerals Africa achieved a 15% yield percentage increase in a DMS application at a coal wash plant in the Emalahleni coalfields, in Mpumalanga, using its Cavex CVXT hydrocyclone in 2017.

The Cavex CVXT hydrocyclone achieved an overall average of 75% yield in this application, compared with the previous competitor hydrocylone that achieved 65% yield.

“In the same application, a higher production output of 116 t/h, versus 78 t/h of the competitor hydrocyclone, was achieved using the Cavex CVXT hydrocyclone,” Gabriel highlights.

Moreover, the Cavex CVXT hydrocyclone needed only a spigot replacement over a nine-month period, whereas the competitor hydrocyclone required a complete refurbishment after six months of operation in the same DMS application.

In another dense media application at a major coal mine in Emalahleni, Weir Minerals Africa installed a 1 150-mm Cavex CVXT hydrocyclone. The hydrocyclone only needed to be replaced after 18 months, compared with the competitor hydrocyclone which needed to be replaced after nine months.

“This is a 100% wear-life improvement demonstrating the lower total cost of ownership achieved by the client,” Gabriel enthuses.

Client Support
Weir Minerals Africa provides dedicated process engineering support for clients in the coal sector, which involves assistance with commissioning and optimising their processes.

Support is provided with each installation in line with the long-term relationships the company establishes with clients and it assists them in adding real value to their processes, Gabriel notes.

“Our dedicated process engineering support ties in with Weir Minerals Africa’s strategy of being a process solutions provider rather than just an equipment supplier,” he concludes.