The recent launch by Weir Minerals of its second-generation Cavex 2 hydrocyclone marks a new era in separation technology, according to LERATO RAMANALA, hydrocyclones product manager for Africa and the Middle East at Weir Minerals Africa.
“Built on the global success of our first Cavex hydrocyclone, which we introduced in the 1990s, we can now offer customers increases in their operational and circuit capacity of up to 30%,” says Ramanala.
She highlights the worldwide success achieved by the pioneering Cavex model, based on its 360⁰ laminar spiral inlet delivering reduced turbulence and improved separation. This has led to the rapid growth of its installed base globally, including throughout Africa.
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The laminar spiral inlet geometry design provides a natural flow path into the Cavex hydrocyclone. Its unique shape has no sharp edges or square corners, allowing the feed stream to blend smoothly with rotating slurry inside the chamber. The result is greatly reduced turbulence throughout the entire hydrocyclone, creating even wear, long life and increased classification efficiency.
“The Cavex 2 hydrocyclone has further improved on this design,” she says. “The LIG+ advanced laminar spiral inlet – together with the size of the feed chamber – reduces turbulence and allows the hydrocyclone to classify considerably more feed slurry.”
Longer residence time for the slurry and lower turbulence are key to the performance of the Cavex 2 hydrocyclone. The increased slurry capacity – combined with the benefits of having an unchanged footprint – gives the Cavex 2 an enhanced performance that is unmatched by any hydrocyclone in operation today, she asserts.
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Having the same footprint as the original Cavex or competitor cyclones allows Cavex 2 upgrades and retrofits to be easily applied without requiring changes to plant infrastructure.
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“This means, for instance, that a plant does not need a new cluster, distributor, overflow launder or underflow launder when retrofitting for higher throughput,” she says. “With spools and the new hydrocyclone, the upgraded system is ready to deliver.”
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Ramanala emphasises that operational flexibility is another important benefit from the added capacity of the Cavex 2 hydrocyclone, especially where plants are required to push their production and run all cyclones to their limits.
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“Taking the example of a system in which 12 hydrocyclones are nested, it is preferable that only nine to 10 are operational at a time, so that maintenance can be carried out on two to three of them without disrupting the operation of the plant,” she says.
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“Now, with the extra throughput enabled by the Cavex 2 hydrocyclones, there are always some units which can be taken offline for maintenance while plant throughput requirements are still being met.”
This means that a Cavex 2 upgrade is not just relevant for plants wanting to increase their throughput, she argues. It is equally applicable for a plant that needs to regain its standby capacity, so that it is able to take certain items offline on a regular basis for planned maintenance.
With the recent buoyancy of certain commodity prices, she expects more mineral plants will be looking for ways to boost production and maximise returns.
“This is certainly a good time for a plant to extract more value through improved separation and throughput, and Weir Minerals Africa can help them do this,” she says.
The company’s hydrocyclones are currently well employed in gold, platinum, chrome, coal, minerals sands, iron ore, manganese, potash, lithium, diamonds, zinc and copper mining operations. While new projects such as gold mines in West Africa have been an important customer for Cavex cyclone units over the past decade, there has also been significant take-up of retrofits in Brownfields projects, notes Ramanala.
The Cavex 2 hydrocyclone maximises plant recovery by reducing the quantity of misclassified particles. Empirical evidence to date has shown an average improvement of the alpha parameter in excess of 10%, while the bypass has improved by an average of over 15%.
“Efficiency is further enhanced by fewer fines being returned to the mill,” she says. “Our latest technology also assists mines with their efforts to reduce their carbon footprint, as less energy is consumed for small particle reduction.”
As mines look to leverage digital technology in pursuit of more streamlined and productive operations, Weir Minerals Africa can also add value on this front through Synertrex technology, which makes the Cavex 2 hydrocyclone an intelligent product.
Synertrex is the company’s in-house industrial internet of things (IIOT) technology which detects sub-optimal operating conditions in real time and improves its overall performance.
“For our new hydrocyclone, this means that performance can be further enhanced through a Synertrex-enabled monitoring system to detect sub-optimal conditions such as roping and semi-roping,” she says. “Synertrex facilitates the continuous and efficient operation of the hydrocyclone as it can foresee risk and enhance performance.”
Using cloud computing, the system draws data from smart sensors on the equipment, gathering critical operating data for advanced analysis. The data is transformed into powerful insights of the discharge condition which are relayed to the customer through a digital interface.
This allows for the identification of potential problems before they occur, reducing downtime and optimising equipment performance. It also paves the way for more remote management and simplified maintenance.
When dealing with highly abrasive substances, heat or pressure, the durability of the materials used in the hydrocyclone is critical to the longevity of equipment’s wear components.
Liners are available in a range of materials including industry-leading Linatex premium rubber and other robust Weir Minerals natural rubbers – such as R55 – which are known to outlast competitors’ elastomers in similar applications. The inclusion of metal and ceramic liners that are suited to the most aggressive applications can further extend hydrocyclone wear life.
An important factor in minimising turbulence has been the fine-tuning of the liner shape, resulting in longer life, less downtime for maintenance and lower total cost of ownership.
Liners can be replaced using a ‘snap-in’ system which requires no adhesive. Smaller models (400CVD and below) are also available with moulded fibreglass housings.
“The Cavex 2 hydrocyclone can be customised to suit almost any application, with a variety of spigots, vortex finders and liners,” says Ramanala. “Our expert team tailors the units to suit customers’ particular applications, while using the existing footprint.”