FLOTATION
Paul Moore spoke to Alejandro Yanez , Senior Manager , Concorde Technology and Paul Sohlberg , VP Separation at Metso Outotec
You now have your Concorde Cell™ – are we entering a new era of innovation in flotation addressing issues such as more efficient fine and coarse particle flotation ? AY : Metso Outotec leads flotation technology development for the past 50 years by continuously pushing the limits and successfully bringing new technologies to the market that cater to the needs at that time . The extensive installed base allows us to get first direct input to respond to market needs and new industry challenges . Substantial in-house research work and mineral processors feedback revealed the need for having dedicated technologies for specific particle sizes . Introducing Concorde Cell™ technology for improving fine and ultrafine particle recovery is our proposition for more finely disseminated and complex orebodies .
New technologies bring new challenges starting from concept to product development , along with scale up , predicting plant performance as well ensuring the technology can keep high performance against normal plant operating and process variabilities . Combining well proven TankCells ® with new technologies is a low risk and high benefit approach for minerals processing flowsheets .
Is this being driven by existing mines seeking greater efficiencies from plants they already have ? AY : Global industry trend towards efficient use of Earth ' s resources with more environmentally efficient technologies under ore grades declining and increasing demand for metal production , place a major challenge for every operation , both in greenfield and brownfield environments . We see that both existing and planned mines will want to deliver efficiencies , coupled with ESG improvements . Every mineral processing flowsheet reports making greater effort for improved efficiencies in certain particle sizes classes . There is a value available to capture when looking at recovery by size fraction . Current flotation cells work well for particles ranging ~ 25 up to ~ 250 microns . Outside that range there are challenges to address . Ultrafines tend to float slowly and recovery fall as particles diminish , demanding high capital and operating cost with conventional flotation technology . Recovery losses in plants occur and concerns about overgrinding inhibit grinding for required liberation aiming to improve flotation selectivity . Concorde Cell as an easy standalone addition to any existing operation is one of our compelling value propositions for greater plant efficiencies . The technology can easily be applied as a new standalone addition at any operation , or as retrofit to operating suitable flotation cells . At the same time Metso Outotec has various projects looking at recovery of coarse particles as the industry is moving for larger and larger throughputs along comminution flowsheets that requires high capital and operating cost . Grinding required for low grade valuable minerals liberation has opened the door for coarse particle flotation solutions .
What has the market response been to your cPlant offering – in this regard do you still see a lot of potential in more modular flotation plants that can be quickly set up ? Can these be used as pilot plants and test plants as well as full scale plants ? PS : The cPlant Flotation offering is a costeffective , flexible solution for tackling challenges with project budget or tight project schedule , constantly changing capacity needs , or operations in remote locations . We see the market response to the cPlant offering continuing to be positive . The plant has been developed for projects handling up to 3 Mt of ore per year , with cell capacities of 1.5 , 3 , 6 , or 11 m 3 so it allows selection of technology to be used as pilot plants or test plants for miners to conduct different ore types evaluation as well as flowsheet development before selecting a business case around full scale operation . One recent example is a cPlant delivery for an Asia graphite application where different ores will be treated aiming to develop a full-scale plant .
How is the flotation market playing out in high demand high tech minerals such as cobalt , lithium , graphite etc in terms of customised designs and future development focus ? PS : In the current high market demand for battery metals , Metso Outotec can provide technology and equipment for the entire lithium , nickel and cobalt production chain from the mine to battery materials with project scope ranging from equipment packages to turnkey plant delivery . Due to the project size and complexity of the battery metals ore bodies , Metso Outotec conventional flotation cells have been delivered to lithium , cobalt , and graphite flotation technology around the globe in recent years . Thanks to our unique in-house capabilities on testing , flowsheet development , process design , and customised conditioning and flotation technology for the duty have allowed us to lead the market with significant well proven flotation installed base in lithium spodumene oxide flotation in Australia and Brazil . Medium size mechanical flotation cells have been selected for recent cobalt contained flotation flowsheets in DRC , USA and China .
What role does flotation play in helping mines meet their current and future ESG targets in relation to water and energy use etc ? PS : Declining ore grades over the last decades in an increasing demand for metals , pushed minerals processing flowsheets to treat higher and higher tonnages rates aiming to remain economic . Large flotation cell development has helping mines to meet ESG targets by providing footprint , capital , and operation cost to remain at competitive level as well as to achieve high valuable metal efficiencies . Back in 2018 , large flotation TankCell 630 m 3 cells helped to improve copper and molybdenum recovery at Buenavista del Cobre concentrator in Mexico . Late in 2020 , Metso Outotec was awarded a major order to deliver TankCell 630s for a new
It also includes a reagent preparation and dosing system , two DELKOR high-rate thickeners , two DELKOR horizontal belt filters , a slurry holding tank agitator and various other ancillaries .
The order was received following the development of a process solution by DELKOR India to reduce the high levels of limestone and water that the plant was losing in the tailings discharged from the limestone washing plant into the tailings pond . Besides the loss of valuable minerals , the water loss meant that the tailings ponds were filling up at an unacceptably fast rate , while also contributing to water scarcity .
The process solution was developed based upon extensive laboratory and pilot scale test work by specialists at its Bengaluru lab centre , which demonstrated the advantages of the MAXGen mechanism in optimising recovery of limestone from the washing plant tailings . In addition , bench scale tests with high-rate thickeners and a vacuum belt filter demonstrated the potential for water recovery . The resulting process flowsheet includes flotation , dewatering and filtration equipment . The flotation plant will thus minimise limestone loss into the tailings , while the dewatering equipment will provide between 85 and 90 % water recovery . The tailings cake generated from the flotation plant will be dry enough to be stacked , after filtering , for use as mine backfill .
As a result of this environmentally-friendly solution , both the mine and tailings pond life will be significantly increased , with the water that is recovered being re-used in the process immediately , thus reducing the fresh / make-up
44 International Mining | OCTOBER 2021