FLOTATION
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 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
Inside each WEMCO II cell is a newly designed rotordisperser system that delivers intense mixing and aeration
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 methods . This frothless system allows for stable and froth flotation , enhanced gangue rejection , and quicker kinetics – pushing the boundaries on concentrate grade , recovery , and throughput well beyond the performance of conventional open tank systems .
Christodoulou told IM : “ The RFC commercialisation journey is going very well – we just completed a full scale test project at a copper mine in Poland where we were testing a full scale RFC850 . The main purpose of this was to see the scale up and if we would get the same
results as we had at lab and pilot scale . I am happy to report we have seen this , if anything there has been a slight improvement when scaling up to the larger size unit .”
Plots of the copper recovery versus flotation time were generated to compare continuous operation of the RFC850 to the batch operation of the pilot RFC100 unit . These initial plots showed that although the RFC850 was treating unreagentised feed the performance of the fullscale machine was matching that of the pilot machine . Copper recoveries ranging from 15 % to 35 % in a single pass were achieved with retention times ranging from 26 seconds to 45 seconds .
Once a baseline of performance was established a later test campaign was executed at operating conditions such that recoveries were improved . Feed to the industrial machine was reagentised for this campaign . Again , recovery versus retention times were plotted . Results from this campaign showed that the full-scale RFC outperformed the pilot batch runs in terms of recoveries achieved at comparable retention times . Copper recoveries ranging from 20 % to 54 % in a single pass were achieved at residence times ranging between 43 and 60 seconds utilising the RFC-850 . Results from the test campaigns showed that the industrial scale equipment performed equally well when compared to the pilot scale equipment . Upgrade ratios for the industrial machine treating scavenger feed material ranged from 2.6 to 5.2 , producing concentrate grades ranging from 4 to 12 % Cu in a single pass .
He added that FLS has secured a purchase order for industrial RFC850 units in North America in an industrial minerals applications , with commissioning expected in early 2025 following completion of fabrication in early November 2024 .
54 International Mining | OCTOBER 2024