MATERIALS HANDLING
hydrocyclone. Te solution involves utilising tailings to construct TSF dam walls, thereby turning what’s usually a waste product into a usable, valuable product. Ensuring the structural integrity of the
wall is obviously paramount, which means that the sand must have relatively free- draining characteristics – or, in other words, sand that’s 15% passing minus 200 mesh (75µm). Tis requirement helps prevent liquefaction, the process by which water- saturated, unconsolidated sediments are transformed into a substance that acts like a liquid. Typically, tailings would have to pass
through several stages of hydro-cycloning to achieve this sand quality; however, with the Cavex DE hydrocyclone, it can be achieved in a single stage.
GREATER EFFICIENCY With a conventional hydrocyclone, around 35-40% of mass is usually sent to the underflow, but, with the Cavex DE hydrocyclone, it is around 45-55% – making it 10-15% more efficient than some other hydrocyclones on the market.
Weir Minerals is commited to optimising its equipment to help miners produce more with less. Te Cavex DE hydrocyclone’s design epitomises this approach.
Te first classification stage is performed in a cylindrical hydrocyclone and terminated in the expansion zone, which features the wash water injection and an inverted conical body. As the coarse particles travel down the hydrocyclone and migrate to the outside wall of the hydrocyclone, fine particles are trapped and move with the coarse particles into the expansion zone. Te expansion zone creates conditions for the fine particles to be dragged to the first-stage overflow by the ascendent air cone. Te probability of fine particles being released from the coarse particles and reporting to the hydrocyclone overflow is further increased when water is injected into the cleansing chamber or expansion zone. Te decreasing coarse material is washed, providing an adequate dilution for the classification in the second stage. Te hydrocyclone’s improved efficiency also has benefits in terms of reducing water consumption.
With the rising cost of water in many
parts of the world, water efficiency is increasingly becoming a precondition of being able to operate. Although these challenges are site- and region-specific, mines in arid parts of the world – where low rainfall and high evaporation is the norm – are already experiencing acute water-related challenges.
Te total water consumption will
vary from site to site, but, based on research carried out by Weir Minerals, the savings are significant. Compared with conventional hydrocyclones, the Cavex DE hydrocyclone can reduce water consumption by up to 70%. Tis holistic aporoach to sustainability – in which equipment and challenges aren’t viewed in isolation and each operator’s specific requirements are addressed on their merits – is what’s needed if the mining industry is going to reduce its carbon footprint.
Debra Switzer is with Weir Minerals.
www.global.weir
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