For decades, flotation has been a cornerstone of mineral processing – an adaptable and efficient method whose importance is only expected to grow.
As ore grades decline and environmental expectations rise, miners are under increasing pressure to recover more metal using less energy, less water, and less space.
Eriez, a global leader in separation technologies, has been at the forefront of this transformation.
With more than 80 years of expertise in magnetic, flotation, and material-handling systems, the company has built a reputation for helping customers achieve the delicate balance between metallurgical performance and environmental responsibility.
The company’s latest breakthrough – the StackCell flotation system – represents a decisive step in that direction. Designed to recover fine and ultrafine particles while reducing energy consumption and plant footprint, StackCell has rapidly emerged as one of the mining industry’s most versatile and sustainable flotation solutions.
According to Eriez senior global product manager Homie Thanasekaran, the technology was born directly from customer feedback.
“At elevations approaching 4000m – as seen across many South American mine sites, or in remote operations across Western Australia’s red-sand deserts – building and installing larger flotation tanks is a constant challenge,” Thanasekaran said.
“What customers really wanted was a compact, energy-efficient system capable of achieving top-tier metallurgical performance, especially in the recovery of fine particles, rather than simply adding more and bigger flotation cells. With many of these remote sites constrained by limited access to energy and water, efficiency had to be engineered into every aspect of the design.”
Originally developed from Eriez’s proven column flotation technology, the StackCell was designed to deliver selective recovery of fine particles within a far more compact and energy-efficient platform, specifically engineered to replace conventional cells in rougher, scavenger, cleaner, and cleaner-scavenger circuits.
Thanasekaran explained that the innovation was shaped by customer demand for flotation systems that are smaller, enclosed and easier to install and maintain, particularly in operations challenged by space constraints, extreme climates or high elevations.
“We took that feedback to heart,” he said. “In regions like North America, where sub-zero temperatures mean most equipment must be housed and heated indoors, there was a clear need for a system that minimised both size and energy use. StackCell evolved through that continuous collaboration with our customers over the past decade.”
The result is a flotation cell that, according to Eriez, consumes roughly one-third of the energy of comparable conventional systems, with a footprint 50 per cent smaller and foundation loads reduced by up to 70 per cent.
With its focus on energy efficiency, fine particle recovery and reduced environmental impact, StackCell exemplifies how technology and innovation can work hand-in-hand to make mineral processing more sustainable, while simultaneously delivering higher recovery of fine and ultrafine particles.
Compact design, big performance
At the heart of StackCell’s success is a deceptively simple idea: separating the particle-collection and phase-separation stages of flotation.
Traditional cells perform both functions in one tank, forcing engineers to compromise between turbulence (required for particle–bubble attachment) and stability, essential for separation.
By decoupling these zones, StackCell focuses energy precisely where it’s needed. The turbulent dissipation rate in its collection chamber can reach 120 watts per kilogram (W/kg), which Eriez said is up to five times higher than in conventional mechanical cells. The result is faster bubble–particle collisions, superior fine particle recovery and higher grade concentrates at minimal residence time.
“Fine particle recovery has taken on new urgency as ore grades drop,” Thanasekaran said. “Where processing one tonne of ore once produced between 0.8 and 1kg of copper, it now yields only about half that. To sustain production levels, miners must process nearly twice as much material, making efficiency and selectivity more important than ever.”
This makes energy-smart flotation essential for miners chasing productivity and environmental, social and governance (ESG) goals simultaneously. Thanasekaran said StackCell delivers that balance.
“We’re seeing sites that need to increase throughput by 15 to 20 per cent just to meet production targets, but they don’t have the real estate or the power capacity to add that within their existing operations,” he said. “StackCell allows them to add capacity at the back end of the circuit with minimal footprint, a key advantage in brownfield operations.
StackCell’s modular, compact design means it can be easily retrofitted into existing circuits as a scavenger or cleaner scavenger unit, enhancing recovery from tailings stream and improving overall circuit performance.
Thanasekaran said many customers are now deploying StackCell in tailings recovery applications, where its ability to capture ultra-fine particles delivers immediate and measurable value.
“When particles get very fine – around 20 microns or even as small as five microns – they tend to escape conventional flotation due to the lack of sufficient turbulent dissipation rate and report straight to tailings,” he said. “StackCell can recover those fine, valuable minerals and return that lost revenue back to the operation.”
The technology also complements Eriez’s HydroFloat coarse-particle flotation system, with the two working in tandem at opposite ends of the particle-size spectrum. HydroFloat handles the coarse material – “the sand on the beach” as Thanasekaran puts it – while StackCell captures the ultra-fine “dust”. Together, they deliver complete recovery coverage across the circuit, maximising overall metallurgical performance
StackCell’s environmental credentials are equally compelling. Lower energy consumption, reduced reagent use, and a smaller installation footprint all contribute to improved sustainability performance. Eriez reports that the design aligns directly with mining companies’ decarbonisation and ESG commitments, including long-term net-zero targets.
Innovation that runs deep
Eriez’s long-standing culture of innovation is deeply embedded in its DNA. Founded in 1942 and headquartered in Erie, in the US state of Pennsylvania, the company now operates in 12 countries, including Australia, where it maintains offices in Victoria and Western Australia and supplies equipment to the nation’s largest mining regions.
Thanasekaran said that culture stems from the vision of Eriez’s leadership team and founder.
“Our CEO Jaisen Kohmuench and VP of technology Mike Mankosa both did their PhDs in flotation at Virginia Tech about 30 years ago,” he said.
“They started the research that became StackCell and HydroFloat in a small laboratory. Today, that same innovation is operating at full industrial scale worldwide.”
Thanasekaran also credits Eriez’s owner Richard Merwin for fostering a research-driven mindset that continues to shape the company’s technological breakthroughs.
“Richard believes in developing technologies that stand out,” he said. “He doesn’t want to buy ideas – he wants us to build them That’s why Eriez has such a strong in-house R&D [research and development] capability.”
This philosophy has paid off, with StackCell installations now spreading rapidly through key global markets. In Australia, the technology is being used across coal operations in Queensland, as well as copper, gold and rare-earth sites in Western Australia.
“In Queensland alone, we have more than 15 StackCell units operating,” he noted. “In Western Australia, we’re seeing strong adoption in copper, gold and rare-earth processing, too.”
Interest is rising fastest in copper and gold projects around the world, where soaring demand meets increasingly complex ore bodies. Thanasekaran expects the next decade to bring continued expansion.
“The demand for copper is projected to remain very strong for at least the next 10 years,” he said. “As ore grades fall, technologies like StackCell that can process higher volumes efficiently will only become more important.”
For Eriez, that combination of market demand, technical innovation and sustainability focus is what defines the company’s purpose. StackCell isn’t just a smaller, faster flotation cell; it represents a shift in how the industry thinks about mineral recovery.
By marrying high-intensity particle collection with low-impact design, the technology shows that superior metallurgical performance and environmental stewardship can truly go hand-in-hand.
“Our goal is to help customers recover more metal with less energy, less water and less waste,” Thanasekaran said. “That’s what StackCell is all about.”