FLOTATION
Outotec , remains available , but TankCells are more often selected . However , Metso Outotec added that there is still market space for RCS cells such as in legacy operations using that technology .
What about coarse particle flotation ? Rinne added that Metso Outotec is working with various projects looking at recovery of coarse particles as the industry is moving towards larger and larger throughputs along comminution flowsheets that require high capital and operating cost . “ Grinding required for low grade valuable minerals liberation has opened the door for coarse particle flotation solutions . The right flotation technologies will play very significant roles in supporting achievement of current and future ESG targets . A positive change in the flotation circuit can significantly decrease energy and water consumption across the whole concentrator . New innovations such as coarse particle flotation allows to directly reduce energy and water per metal production .”
Metso Outotec has also recently been highly successful with retrofits and upgrades , including Center Launder Upgrades . Bermudez comments : “ Recent advances in flotation cell technology can be implemented into existing flotation cells through retrofit projects to improve equipment efficiency . In recent years , the Center Launder Upgrade has been a successful solution to enhance metallurgical performance by optimising the open froth area in a flotation cell . The upgrade can result in quick turn-around projects . For example , recent Center Launder Upgrades in North America have resulted in return on investment from two to six months . Metso Outotec has engineered various retrofit packages to optimise existing cells ’ efficiency on all fronts . Upgrading flotation equipment can result in increased metallurgical recovery whilst using the same installed equipment . The new increased production of valuable material is a surplus to typical energy-to-tonne ratio , improving in this way the plant ’ s overall energy consumption per tonne of concentrate .”
Finally , regarding the bigger picture , Rinne and Bermudez add : “ Metso Outotec has launched Metrics to provide advanced connected analytics and expertise for our customers . We are soon expanding the Metrics offering to TankCell as a solution to improve sustainability , increase asset availability and lower maintenance costs . The new Metso Outotec Metrics for TankCell will ensure digitalised mechanical and metallurgical performance of the flotation equipment .”
Metso Outotec has also launched a sciencebased digital twin , Metso Outotec Geminex™ , for managing variability and optimising resources . “ The unique solution simulates and optimises seamless sustainable operations in minerals , pyro- and hydrometallurgical processes by combining operational data from both internal and external data sources . With Geminex , alternative operational scenarios and parameters can be efficiently simulated and tested based on accurate process models and real data . It provides invaluable information for short- and long-term decision-making and allows operations to use resources in an optimal way while considering both impacts and constraints .”
FLSmidth refines existing technologies & introduces new ones
At FLSmidth , IM spoke in-depth to Global Product Director , Dariusz Lelinski and Lance Christodoulou , Global Product Line Manager – REFLUX™ Technologies .
Lelinski says that today FLSmidth has two main conventional forced air and self aspirated cells in its offer : “ With our WEMCO cells we have the WEMCO II design coming online which is essentially an upgrade to the original WEMCO technology . Then nextSTEP , introduced about six years ago is an upgrade to our original Dorr- Oliver cells . With the old Dorr-Oliver forced air machine , we redesigned it with a new rotor stator mechanism .”
In terms of the tanks themselves , Lelinski added that the vast majority of the market ( for both FLSmidth and others ) is now using cylindrical tank type cells for metallic sulphide flotation including copper and nickel but interestingly for FLSmidth its older rectangular design remains very popular in the industrial minerals market such as phosphate , silica , potash , fluorspar , barytes and graphite – but also coal ; here it refers to the original cells as WEMCO I + I ; which perhaps surprisingly still represent about a third of its self-aspirated cells sales . With WEMCO II FLSmidth is finalising industrial trials – “ two plants are currently running , one at a mine in Nevada where we have retrofitted two 70 m 3 rectangular WEMCOs ; then at a mine in Peru we have replaced mechanisms on two 250 m 3 cells . WEMCO II was designed to be able to insert the whole new mechanism using a dedicated stand during scheduled maintenance , to minimise disruption for the customer . While of course we offer the technology for greenfield flotation plants , the potential retrofit market is huge – there are in excess of 40,000 WEMCO cells running today , many of which are small sizes . But WEMCO II was designed to be able to be installed on any cell size .”
With mixedROW , nextSTEP and WEMCO II come together and Lelinski says it is continuing to do research using scaled down versions – not using pilot Denver type cells which has been typical in flotation technology testing . “ We also run exactly the same slurry . We have found that forced air nextSTEP is much better at fast floating
FLSmidth is now in the process of scaling up its REFLUX Flotation Cell technology with testing to start at KGHM and LKAB
material – WEMCO II is better at slow floating non-liberated material including fines and coarse particles . This is shown in the attached graph and is the main reason why nextSTEP works so well . We hit the slurry with the nextSTEP at the beginning and clean the slow floating material with WEMCO II at the end .”
Notable greenfield nextSTEP installations include Teck ’ s QB2 copper mine , which has deployed nextSTEP 650 m 3 cells . But again , a lot of retrofits of Dorr-Oliver cells are also being done – plus they are also being applied as refrofits to competitor cells . Interestingly , since nextSTEP ’ s launch , FLSmidth has sold well over 700 units within which the greenfield-retrofit market share has been about 50:50 .
So for greenfield what are the main factors determining selection of nextSTEP or WEMCO II or the mixedROW combined approach ? Lelinski : “ It is mainly based on the type of materials you are recovering – easy flotating porphyry copper ore for example is best suited to nextSTEP ; and if there is some more challenging slow floating material then it is better suited to WEMCO II or mixedROW ie a combination of WEMCO II and nextSTEP . We believe mixedROW to be by far the most effective solution where you have a combination of easier and harder to float material , but there is an element of customer preference as well – mainly relating to not wanting two cell types from a spare parts and spare parts point of view . As an example , Cerro Verde and KAZ Minerals Aktogay have all WEMCOs ; whereas Toquepala , Las Bambas and Antapaccay all have mixedROW installations .”
Beyond WEMCO II and nextSTEP FLSmidth also has column cells , where it offers now improved external recirculating sparging system as well as insertion style spargers . But the real new technology focus is the REFLUX suite .
First off is the CoarseAir , FLSmidth ’ s approach to handling coarse particles . Christodoulou says its exact application is site specific but it can be
50 International Mining | OCTOBER 2022