Contributed by FLS
As the world faces potential bottlenecks in strategic minerals that are critical for a low carbon future, FLS is allowing mines to optimise production and recoveries while keeping their ESG targets on track.
Alistair McKay, FLS vice president for Capital Sales in Europe, Arabia and Africa. All images supplied by FLS
The manufacture of battery-powered vehicles, for instance, will demand orders of magnitude for more graphite, cobalt, manganese, nickel, lithium and copper, explains Alistair McKay, FLS vice president for Capital Sales in Europe, Arabia and Africa. The European Union’s Critical Raw Materials Act has highlighted the challenge facing both producers and consumers of mined commodities. It defines strategic resources as those whose current production is difficult to increase – and for which the demand is expected to grow significantly. At the same time, it also points to 16 critical minerals, a shortage of which could derail economic activity.
“An example is copper, which is essential for a vast array of decarbonising technologies,” says McKay. “A sustainable future is reliant on these technologies, as they could account for two-thirds of global greenhouse gas emissions’ abatement by 2050.”
With these factors front of mind, FLS invests over half its research and development budget on technology that will have a noticeable impact on reducing emissions, water and energy, he says. As a global technology provider with contributions across the process flow sheet, FLS has recently introduced a range of innovations. These include the rail-running belt conveyor, Eccentric Roll Crusher (ERC®) and the Pro generation of its High Pressure Grinding Rolls (HPGRs) as well as the coarseAIR™ coarse particle flotation technology and REFLUX™ Flotation Cell (RFC™).
“These are all part of our ongoing MissionZero strategy to support our mining customers’ commitments to meet carbon emissions and sustainability goals,” he says.
FLS’s rail-running belt conveyors have provided a breakthrough in sustainable conveying from mine to plant, across the plant and in other applications.
Eco-efficient rail-running belt conveyors
McKay highlights how rail-running belt conveyors have provided a breakthrough in sustainable conveying from mine to plant, across the plant and in other applications. The energy efficiency of this technology has been reliably calculated to reduce the carbon footprint of operations by between 20% and 90% – when including all embodied carbon in the system.
He points out that while friction losses in a traditional belt conveyor are between 0.070 and 0.110 kilowatt-hours per tonne per kilometre, these can be reduced to between 0.015 and .,030 in a rail-running conveyor.
“It is remarkable to consider how this innovation – being essentially a combination of the two well-known mobility systems of belt conveyors and rail wagons – can deliver such immediate and game-changing benefits,” he says. “The merging of these two proven technologies has enabled the most eco-efficient haulage mode now available in mining, by combining the best of each.”
Large rocks in the run-of-mine feed material entering the crushing chamber.
The rail-running belt conveyor features carriages and rails installed between the head and tail ends of the conveyor system, allowing the belt to be carried on light-wheeled carriages while maintaining the conventional configurations. A host of idler-related maintenance problems are eliminated thanks to this new way of carrying the belt.
“In addition to the energy efficiency and cost savings of 30% to 60% in running the system, there are also CAPEX savings,” he says. “Since tensions are usually far lower due to the reduced friction, and much tighter curves are possible, the conveyor alignment and drive locations can be dramatically optimised, reducing expenditure in earthworks, civils, electrical supply and erection.”
There are operational benefits too, as the rail-running conveyor accommodates tighter curves and steeper angles; this makes it more flexible in replacing trucks in open pits, while also allowing more efficient routes between shovel and plant.
Primary crushing circuit solutions
Moving on to FLS’s ERC® in the primary crushing circuit, McKay highlights how improved crushing kinetics allows this technology to boost production capacity – while reducing energy consumption by up to 40% and extending liner lifespan.
A cutaway view of the ERC® crusher showing the screening and crushingchamber process.
“With its compact, simple and robust design, the ERC® has an integrated grizzly that can boost crusher throughput by up to 20% at the same product size,” he says. “The units boast a higher reduction ratio of 1:6, which compares well to the 1:4 ratio that the industry usually considers as acceptable.”
He explains how the integrated design ensures that the system avoids the excessive energy resulting from high drop heights between the grizzly and the crusher – a challenge for most other primary crushing configurations. The ERC® also boasts an adjustment range for close side setting (CSS) from 50mm to 300mm; a fully automatic gap setting system allows for compensation of liner wear and the easy release of tramp metals.
Next generation grinding technology
Well-known for its HPGR solutions, FLS has developed the HPGR Pro – the next generation of grinding technology. McKay notes that HPGR technology has already made significant energy-saving advances on the traditional combination of semi-autogenous (SAG) and ball mills.
“Emerging from the well-established presence of the HPGR in the mining market, the HPGR Pro is now taking that progress another step forward,” he says. “The continuous improvement has focused on aspects such as improved feeding of material onto the rolls, ensuring a uniform pressure profile across the full width of the roll.”
The FLS HPGR Pro takes grinding to the next level of efficiency.
This reduces concentrated wear in the mid-sections of the grinding roll, and further improves the overall capacity, energy efficiency, roll wear life and maintenance requirements. At the heart of this advance has been the application of rotating side plates; this is a particularly valuable aspect of the technology as existing HPGRs can be upgraded to include these rotating plates.
“This all contributes not only to the energy savings but also to the production capacity,” he explains. “Our concept of sustainability goes beyond savings on energy and water consumption; we also believe it must include production benefits, which is clearly the case here.”
Flotation circuit innovation
Further downstream in the flow sheet are other innovations that promote the company’s MissionZero imperatives. The achievement of the FLS coarseAIR™ technology is to allow coarser particles to be floated at a lower mineral liberation – reducing the amount of grinding necessary. This cuts down on the energy cost and the grinding media consumed, as well as high material throughput in the flotation circuit.
“This paves the way for mill capacity to be increased by more than 30%,” says McKay. “Another benefit is that a coarser tailings particle size improves water drainage, so that tailings can be placed through hydraulic deposition to improve sustainability.”
FLS coarseAIR™ technology allows coarser particles to be floated at a lower mineral liberation reducing energy and boosting sustainability.
Once again, it is the cumulative progression of technology through ongoing R&D that makes this all possible, he points out. The concept of laminar plates from the original reflex classifier, for example, has been incorporated in the coarseAIR™ – as well as into another recent innovation: the REFLUX Flotation Cell (RFC™).
“What is significant about the REFLUX flotation cell is the way it contributes to developing the industry trend toward ‘staged flotation’ to improve overall flotation kinetics,” he says. “This helps us to focus on the critical differential in particle size, to more effectively separate gangue from valuable minerals.”
This has allowed the RFC™ to reduce the residence time of material from an average of over 30 minutes to between three and four minutes – while an increase in recoveries of 1 to 3% has been achieved. This has been done while cutting energy consumption by 27%.
The REFLUX™ Flotation Cell pushes performance to new extremes
“These are the kinds of innovations which are central to our MissionZero strategy,” concludes McKay. “We believe that the mining sector is a vital player in the planet’s quest for a lower carbon future; these technologies are paving the way to achieve sufficient production of critical minerals while still allowing mines to meet their sustainability targets.”