FLOTATION
together for the HydroFloat piloting at a number of projects in South America and Australia .
FLS forges ahead with new innovations
To get an update on its latest flotation developments , IM spoke to Dariusz Lelinski , FLS Global Product Director , Flotation and Lance Christodoulou , FLS Global Product Director – REFLUX™ Technologies . Lelinski began by putting its conventional flotation offerings in context : “ We have two main solutions today – first our well established forced air nextSTEP offering , which demonstrates significant improvement in both metallurgical performance and energy efficiency over existing forced-air designs . We have sold almost 1,000 of these cells in the last eight years .”
When installed , nextSTEP operators note a 15- 40 % reduction of power requirements and see better wear distribution for increased rotor / stator life . These findings have a strong positive impact on total cost of ownership that can benefit both new and existing installations . Wide flow jets produced by the nextSTEP rotor and the cross pattern from the patented slotted nextSTEP stator increase the probability of bubble-particle attachment . Adding slots to the stator increases recovery and boosts overall flotation efficiency . One reason for this improvement is the higher homogenised turbulence dissipation energy . When compared to other forced-air flotation designs , the nextSTEP mechanism exhibits stronger air dispersion near the rotor / stator region , higher air hold-up and a stronger pumping effect below the rotor . CFD analysis shows that the nextSTEP mechanism generates a preferred slurry flow and positive froth movement pattern near the top of the tank . This improves froth mobility and recovery of coarse particles over other competitive designs .
Lelinski said in greenfield projects FLS is very busy with proposals and testwork with customers , plus helping engineering houses on projects . That said , and this affects all the key technology suppliers , a number of major base metals and gold projects have been delayed for various reasons including delays in overall project financing , permitting delays and a general conservatism in capital spending on greenfield . He added though that there is a huge focus today on squeezing more capacity out of existing concentrator plants , which covers refrofits , upgrades and improvements . “ Practically every existing mine in the world is looking to push more tonnes and get better results from existing equipment . This is where we are putting in retrofits of nextSTEP into existing plants , in many cases replacing older Dorr-Oliver cells from us .”
He added that there is also major potential in the retrofit / upgrade market with FLS ’ s new selfaspirated cell - WEMCO II - for which there will be a full market rollout later this year , likely by November , with some orders already in place . This follows an initial product launch in 2022 .
Inside each WEMCO II cell is a newly designed rotor-disperser system that delivers intense mixing and aeration . The WEMCO II design features air control and froth stability , which elevate kinetic performance and lower operational costs . FLS tested multiple iterations to identify the right combination of the rotor stator assembly and hood that would improve hydrodynamics and optimise performance . WEMCO II is designed to be easily retrofitted into all types of existing WEMCO cells . The downtime and cost associated with a retrofit are minimal and produce a quick return on investment .
Lelinski : “ We have finished one set of industrial trials of the WEMCO II technology with a standard WEMCO 1 + 1 rectangular cell . So the product is now commercially ready – we are just making some final tweaks and finishing another WEMCO II testing campaign with 250 m3 large cylindrical cells . We have already made the moulds and are ready to go ahead with production at the FLS factory in Qingado . In addition , we are already working on four retrofits to WEMCO II though I can ’ t name the locations – however they are copper-moly projects in North and South America as well as Central Asia . These all involve retrofitting on one row of WEMCO cells where you have already at least two rows with a common distributor . They are running at the beginning of the row and the end of the row as roughers and rougher-scavengers where we want to see WEMCO II ’ s influence on slow floating and fast floating particles . Once these are up and running we can get solid numbers from
The RFC850 from FLS has now been proven at full scale at a copper mine in Poland
references on the improvements achieved in terms of metallurgical performance . We are already seeing very interesting behaviour with improved overall recovery at the same grade with the main recovery improvement coming in fine particles . It is a huge market and we have many clients waiting for the introduction of WEMCO II .”
Lelinski says it will have four WEMCO II sizes and designs ready for rectangular cells and four for cylindrical cells . “ We will focus on those eight sizes for the first year and then expand across all the WEMCO sizes that we currently offer .” The advantage with WEMCO II is that FLS is retrofitting its own equipment - “ so we know the drives , we know the tanks , we know the arrangement of the dart valves , we know the level control and so there is a high probability of success . When you talk about retrofits to competitor equipment , now talking about nexSTEP , we successfully retrofitted equipment manufactured by Western suppliers , but for the low cost cells , there are always questions about how well nextSTEP will function with a very different , outdated , cell arrangement – so actually we are generally reluctant to do this .”
On to next generation technology in flotation and the REFLUX™ Flotation Cell ( RFC™ ), which was also launched in 2022 in the form of the RFC850 . The RFC operates at a magnitude far beyond the capacity of existing froth flotation
devices , reducing the required installation footprint . Its novel arrangement enhances the hydrodynamics of flotation , with the ability to recover a wide size distribution of minerals at a rate of up to 7-10 times faster than traditional
International Mining | OCTOBER 2024