The technology, dubbed Rapid Oxidative Leach, can leach more than 98% of copper from concentrates containing as low as 8% copper in less than six hours – a vast productivity improvement from the 95% rate other systems can take between 20-60 hours to leach.
A key differentiating factor of Rapid Oxidative Leach is that it operates at atmospheric pressure and temperature of around 80C, making it possible to leach directly at the mine and hence provide a seamless transition from oxide ore to sulphide concentrates.
“For a copper mine with remaining low quality copper deposits producing around 200,000 tonnes of copper per year, our 3% output increase would mean an extra $US40 million per year with a copper price around $US6600 per tonne,” FLSmidth’s head of group R&D Jens Almdal said.
“That is indeed a significant contribution to profitability in an industry that normally chases 0.1-0.2% increase in copper recovery by design modifications of flotation machinery.”
For copper producers, the new technology could mean a renewed business case for remaining deposits, where existing mines have lost the ability to make copper concentrates suitable for smelting in the later stages of development.
Rapid Oxidative Leach also has the potential to be deployed at mineral deposits which are yet to be developed and have been deemed unsuitable for smelting but adequate for leaching.
These include mineral deposits, including copper, gold and silver that contain arsenic.
Since the technology operates at atmospheric pressure, FLSmidth minerals division president Manfred Schaffer said a concentrate could be treated at the mine location, with complete control over the arsenic-bearing residues generated after leaching.
This makes it possible to avoid the potential of arsenic contamination of sea, air and land while hauled from the mine to the smelter.
“A lot of existing mines have piles of copper concentrate with more than 0.5% arsenic concentrations which is too high for smelting,” he said.
“Our technology can be used to process these piles of high arsenic concentrate or even make it possible to develop new mineral deposits high in arsenic.”
FLSmidth has patents pending for the new technology and expects to implement it in large scale in 2017.
