FLOTATION
less preference for graphite , despite being a critical raw material , due to lower economic incentives . Flotation is a suitable and costefficient process for graphite recovery before downstream processing , however its effective separation from the black mass is hindered by the ( ultra ) fine particles . To address this challenge , a pneumatic Maelgwyn Mineral Services Imhoflot™ cell has tested in this application . The cell utilises high-shear turbulence to generate fine bubbles , facilitating dispersion / de-agglomeration of particles and removal of adhered slimes , enhancing reagent selectivity , and reducing dosing requirements . Maelgwyn says the Imhoflot cell offers advantages over mechanical and column flotation , including increased recovery of fine particles , rapid flotation kinetics , and high attachment rates and reducing the fine entrained metal oxides particles into the concentrate . The company states : “ This research presents a promising approach for efficient graphite recovery from spent Li-ion batteries , securing the sustainable recycling of critical raw materials .”
Jord ’ s NovaCell gets closer to multiple pilots at customer sites
In collaboration with world renowned expert Laureate Professor Graeme Jameson , Jord International believes its NovaCell™ represents the next generation of coarse particle flotation technology . Early results indicate NovaCell™ could unlock a 40 % reduction in comminution energy and a 12 % reduction in overall site operating cost .
Jord ’ s patented NovaCell™ flotation technology recovers a wide particle size range , from the lower limit of flotation to the upper limit of coarse particle flotation . This ensures maximum product yield . Jameson explains that “ the finest particles are contacted with bubbles in the high-shear aerator , while the coarse particles are captured in the gentle environment within the fluidised bed .”
NovaCell™ combines a high shear and a low shear zone in the one flotation cell . This allows Novacell™ to produce high grade froth products from the overflow of the cell and a secondary coarse product from within the fluidised bed . By incorporating the NovaCell™ into a flow sheet , dry stacking of tailings can now come into consideration , further turning the dial towards eliminating traditional tailings dams .
Following an order , Jord is in the process of fabricating a pilot scale NovaCell unit for testing at multiple customer sites . This will be ready in early 2024 , and it is expected that the pilot plant will confirm the positive laboratory results and provide confidence for some its clients to progress to plant-scale implementation .
Jord is also undertaking an engineering study for the plant-scale implementation of the
NovaCell technology . Given the potential revenue increase , this project is expected to progress to implementation without further testing ( ie piloting ). In December 2022 , Jord was announced as one of the winners of the NSW Critical Minerals and High-Tech Activation Fund ( Stream 2 ). This funding will enable this plant-scale installation which will be at an existing copper operation in regional NSW , Australia and is expected to be completed in 2025 .
Finally in 2022 , Jord ( backed by funding from ACARP ) broke ground on a full-scale XtractOre™ 500 m 3 per hour demonstration plant at a site in NSW . Based largely on work led by the University of Newcastle ’ s ARC Centre for Excellence for Enabling Eco-Efficient Beneficiation of Minerals ’ Director , L / Prof Kevin Galvin , XtractOre™ is a novel agglomeration technology that could ultimately “ deliver a 10 to 100 fold increase in the speed of fine particle separation ” compared to traditional flotation technology . The demonstration plant is expected to become operational this year .
Flotation chemicals – dealing with NaSH
In Cu-Mo separation , Cu sulphides and pyrite are depressed using inorganic reagents such as NaSH and Nokes while floating molybdenite selectively . However , these inorganic depressants have serious safety and health hazards due to potential formation of toxic H2S gas during use . Solvay previously introduced AERO ® 7260 HFP depressant several years ago as a safer alternative to NaSH . This technology is in commercial use globally , but it is only able to replace up to 60 % of the NaSH . Solvay ’ s latest innovation is AERO ® NR-7361 depressant , which replaces 70-100 % of the NaSH . This technology is chemically stable and safer to apply under a wide pH range , with air or nitrogen , without concern for product degradation or H2S formation .
The development process involved microflotation and batch flotation screening of various ligands for Cu sulphide depression using chalcopyrite and chalcocite as model systems . Molybdenite was used to screen ligands for selectivity . In-house electrochemistry methods were used to study the interaction of various molecules with chalcopyrite , chalcocite and molybdenite . Results from these fundamental and practical studies were used to design a prototype sulfur-based organic depressant . The mechanism of the depressant action of the new molecule is mainly via chemical complexation of the functional group with Cu or Fe on the Cu sulphides or pyrite respectively while the remaining group on the molecule provides hydrophilicity to the mineral surfaces after the molecule has adsorbed . The prototype depressant underwent rigorous process
development and scale up optimisation with a specific focus on eliminating any degradation or offgassing that could generate toxic gases .
The new depressant , AERO NR-7361 , was then tested on various global Cu-Mo bulk concentrates containing various mineralogies ranging from single chalcopyrite to more complex bulk concentrates containing a mixture of chalcopyrite , chalcocite , bornite , tennantite , and covellite . These lab tests were conducted in plant process water , using air or N2 under various pHs in order to evaluate the efficacy of the new depressant under real plant conditions .
A recent commercial application of AERO ® NR- 7361 at a large Cu-Mo operation in North America achieved 100 % NaSH replacement at an overall consumption in the range of 1-2 kg / t of molybdenum plant feed compared to > 10 kg / t NaSH dosage . Metallurgical results indicated that AERO ® NR-7361 provided advantages in terms of better Cu and Fe depression resulting in higher Mo concentrate grades , more efficient removal of Pb impurities from the final Mo concentrate , and overall stable Mo plant operation . Positive results have also been seen at a large copper-moly mine in Chile .
Clariant has also developed a new , efficient solution for copper and molybdenum separation that fully replaces NaSH in the flotation process . FLOTICOR™ DP sulphide depressants are already being used in commercial production of molybdenum concentrate , allowing operators to eliminate the risk of H2S generation while maintaining molybdenum recovery and grade . FLOTICOR™ DP sulphide depressants can work at a lower dosage than NaSH , providing a costeffective alternative . The main benefits in switching to FLOTICOR™ DP sulphide depressants it says include elimination of the risk of H2S exposure in all process conditions , maintaining the molybdenum recovery and grade ; the product being odourless , readily biodegradable and water soluble ; it has no pH restrictions , with no need to avoid acidic pHs , as there is no potential for H2S generation ; it allows complete replacement of NaSH under continuous operational conditions ; and it is easy to implement using existing plant equipment and flowsheets , requiring only minimal training .
Patricio Zarate , Global Sulfides Technology Manager for Clariant Mining Solutions comments : “ FLOTICOR™ DP sulphide depressants are unique in this application because they allow for complete replacement of NaSH . Many other products available as NaSH replacements are only effective as partial replacements for NaSH on an industrial scale , and they need some NaSH in order to minimise molybdenum losses in the flotation process .”
An operating molybdenum producer based in Mexico is currently using Clariant ’ s FLOTICOR ™
International Mining | OCTOBER 2023