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FLSmidth shakes up flotation

ALEXANDRA EASTWOOD March 31, 2023

Faster and more powerful flotation technology has arrived in the Australian mining industry courtesy of FLSmidth and the University of Newcastle.

FLSmidth has developed its patented Reflux Flotation Cell (RFC) – a new technology that delivers superior grades and improved recoveries.

The RFC was pilot tested at an Australian copper mine and delivered concentrates at 28 – 30 per cent copper grade with an average recovery of 80 per cent. When compared with the first two rougher cells of the existing operation, this could have improved the recovery by 5 – 8 per cent, and provided a 10 per cent throughput increase.

With no direct power input required apart from slurry pumping and compressed air, the RFC can deliver up to 60 per cent reductions in energy consumption and carbon dioxide equivalent (CO2e) emissions compared to those from conventional flotation.

FLSmidth regional product line manager – separation and sedimentation Harrison Law said the RFC was delivering ​“a step change in flotation”.

“With our patented RFC, you end up with a very small footprint, better grade, less energy input, less capital costs, less operational cost, and hence improved ESG (environmental, social and governance) performance,” he told Australian Mining.

“It is an extremely fast flotation machine with a highly efficient washing system. This means what is typically processed in 20 – 30 minutes, an RFC can treat and achieve superior grades in 2 – 3 minutes.”

The RFC is smaller than conventional flotation devices but it is also more efficient, with the ability to operate at gas and wash water fluxes above what is possible with existing mining flotation methods.

In fact, the RFC can cut residence time requirements by up to a factor of 10, reducing the installation footprint of a processing plant and streamlining plant operations.

Law said the RFC celebrates the best aspects of FLSmidth’s broader product portfolio.

“We’ve combined some of the best practices from other technologies and adapted an existing FLSmidth technology – the Reflux Classifier – into flotation,” he said.

“The Reflux Classifier is a highly successful gravity separator. Both it and the RFC have stemmed from FLSmidth’s collaboration with inventor, Laureate Professor Kevin Galvin.”

Galvin, who developed the Reflux Classifier and the RFC with FLSmidth, is an esteemed figure in the mineral processing industry, having invented technologies that improve grade and recovery of valuable materials.

Known for its high capacity and compact design, the Reflux Classifier has become one of FLSmidth’s most advanced fine-particle, specific gravity-based separators.

And its best attributes complement the RFC.

“In the RFC, the lamella chamber separates mineral-loaded bubbles from unwanted gangue. This allows the unit to operate at feed fluxes well above what is typically of conventional flotation machines, improving kinetics while reducing entrainment.”

The RFC also operates as a frothless system, which enables stable flotation, enhanced gangue rejection and quicker kinetics, facilitating improved performance across all quality and productivity metrics.

As Law highlighted, inclined channels enhance the segregation between bubbles and downward flowing liquid, which means the RFC can operate at elevated internal gas fractions.

With an RFC operating at full-scale for a Tier 1 mining client in NSW, Law said ESG has been a key driver of the machine’s uptake.

“If they (operators) don’t innovate, they don’t achieve their ESG targets,” Law said. ​“Like FLSmidth, Tier 1 miners have sustainability goals. These companies have identified that the only way they are going to achieve these goals is by becoming an innovator-slash-early-adopter of technology rather than being a late adopter.

“This is a step change in mentality from what has historically been a conservative approach.”

Having graduated through research and development, design and concept, and full-scale on-site trials, the RFC is ready to shake up flotation in the Australian mining industry.

And with more products being developed under the Reflux banner, it looks like the sector will have more advanced flotation technologies at its disposal in the years to come.

This feature appeared in the April 2023 issue of Australian Mining.