MINERAL SEPARATION
a low capital outlay, small and flexible footprint, compact support structure, and operating cost comparable with conventional magnetic separation technologies. Plus they bring simple commissioning and a reliable and robust mechanical design with a significant redundancy capability. They can also increase capacity of existing thickener plants
Magnetite can be lost at various transport / recovery points in the plant, so when designing a magnetic circuit, the three main criteria are strong magnetic field at the feed point; high magnetic gradient at the feed point and smooth magnetic field around the drum circumference.“ The STEINERT WDH will recover the magnetite or ferrosilicon in dense media plants eg coal wash plants. Therefore recovering the medium used in these dense( heavy) media separation( DMS) plants with STEINERT’ s WDH makes it a more cost-effective process.”
Hydrocyclone highs – FLS KREBS ® gMAX ®
Hydrocyclones are static, cone-shaped device that separates solid particles from a liquid or liquids of different densities using centrifugal force instead of gravity. They create a high-speed, vortex-driven, inward-upward flow, where lighter materials exit through the top( overflow) and heavier, denser materials exit through the bottom( underflow).
IM spoke to Kofi Baah, FLS Global Product Manager Cyclones, about its major product- the KREBS ® gMAX ®. The company has had some big project wins recently, including the cyclones for a large copper project in Australia plus the cyclones as part of a large package including 18 tower mills, HPGRs and a range of pumps for a customer in India. These will be deployed in 2026 / 2027 in a 45 Mt / y plant, which will upgrade banded haematite quartzite into a high-grade iron concentrate, unlocking its potential as a valuable resource for the steel industry. The project will also use Wet High Intensity Magnetic Separation( WHIMS) extensively plus FLS’ s nextSTEP™ flotation cell technology. The KREBS gMAX ability to operate with a higher density feed helped in its selection for this project.
On the attributes of KREBS gMAX, Baah told IM:“ There are two main design parameters when you want to design a cyclone- the first is to ensure that you are reducing turbulence in the inlet head- the inlet head takes all of the feed coming into the cyclone and this is also where most of the pre-classification happens. Turbulence can lead to misclassification and displaced coarse particles which can then find their way to the overflow. The gMAX outer wall involute design entrance pre-classifies
24
With improved geometry of the inlet head, cylinder section, cones, and apex, FLS says KREBS gMAX hydrocyclones deliver sharper particle separation
the feed solids prior to entering the main body of the cyclone. The inlet head of the gMAX also includes an improved vortex finder and top cover plate liner design. This technology we have shown in testing reduces a lot of turbulence relative to competitor cyclone designs. So it brings a finer separation and less displaced particles. The gMAX wear life is also very good based on the materials we use, which contributes to a lower operating cost.”
He added:“ The second thing I would highlight and where I would say gMAX is a market leader is with our compound cones and resulting angles we have developed. Most OEMs rely on typical angles like 20 degree and 10 degree plus 30 degree and flat bottom angles. At FLS we offer compound cones which is a combination of two or more cones – this helps us in two ways – it increases tangential velocities plus it increases the residence time as well. So, whilst we generate tangential velocities due to the centrifugal forces applied to the particles from the cyclone head, we want to be able to sustain that for as long as possible – as that gives us the ability to achieve a sharper separation, plus it also allows us to handle much higher density feeds coming from the pump. Using the compound cones also translates to a lower capital cost as the cyclone footprint is lower.”
What are the most in demand cyclone markets in mining today? Obviously, mill discharge remains the number one – ie sizing mill discharge slurry.“ However, I would say number two, and becoming more important all the time, is tailings applications. We have seen a real upsurge both for new plants and for plant expansions requiring large numbers of cyclones to dewater or deslime the fine particles from tailings before tailings disposal in the TSF.” Baah specifically referenced the South American market but also North America.
Baah cites tighter governmental and global regulatory standards with regard to tailings disposal- specifically related to how much-75 micron material that is allowed to go to the TSF. For mines transitioning to underground, they are also having to deslime tailings before it can be used for backfilling.
He also said the KREBS ® CycloWash™ technology is increasingly being used for desliming purposes, normal classification takes place in the upper portion of a cyclone; this can be thought of as the first stage of desliming. The CycloWash™ permits the injection of elutriation( cleaning) liquor or water into the lower section of the hydrocyclone, so that fine particles in the underflow or solubles in the liquid phase of the hydrocyclone feed stream can be displaced and discharged with the hydrocyclone overflow. The injection liquid serves as the displacement agent of fine particles that are entrained in the underflow pulp. With creation of a“ secondary classification” within the hydrocyclone, displaced fines rise within the centre of the hydrocyclone, joining the overflow pulp. For separation of soluble values, or contaminants, fresh injection liquor can be used in the CycloWash™ as a washing agent to help displace liquid-containing solubles with the hydrocyclone overflow. The CycloWash™ device can be installed on single cyclones or manifold systems.
Looking at new technologies to come, Baah said FLS is set to launch some new cyclone designs but among its most significant launches this year relevant to hydrocyclones is a new onstream particle analyser.“ The product is what we are calling the KREBS ® OSA – or KREBS ® OnStream Analyser. Cyclone performance today is based largely on intermittent manual sampling in terms of P80 output. KREBS ® OSA gives us the technology and the capability to measure hydrocyclone performance in real time. This means that as the plant runs you are able to know in real time if you are hitting your P80 target for each individual cyclone- plus this gives you a much better idea of what is going through to flotation. Also the P80 knowledge from the cyclones allows you to make adjustments upstream and downstream with mills for example, to make sure that you are always on target.”
FLS will also be able to install the technology with cyclones in tailings applications to be able to determine in real time how much of the slimes, the-75 micron fraction, remains in the cyclone output. For both mill discharge and tailings
International Mining | MARCH 2026