COPPER PROCESSING negatively affect microbial activity , according to BASF .
LixTRA reduces the surface tension of the lixiviant , resulting in a droplet with a lower contact angle , which increases the wetting area on the mineral surface . This effect improves interstitial lixiviant flow through the ore , increasing the rate of copper recovery . Deeper intra-particle permeation is also observed , significantly increasing the diffusion of copper from the ore particle .
Moleaer ’ s nanobubble generators , meanwhile , help with creating the ideal oxygen-rich environment to facilitate ferric oxidation and ensure maintenance of a healthy microbial community , plus increase the kinetic rate of copper recovery , according to JJ Taute , BASF ’ s Head of Global Segment Hydrometallurgy .
“ First , they provide very high dissolved oxygen transfer rates ( up to 85 %, versus 1-3 % for traditional aeration ) so can significantly increase the concentration of dissolved oxygen in the aqueous phase ,” he told IM . Second , Moleaer ’ s nanobubble generators have “ neutral buoyancy ” and lack the ability to float to the surface and
Moleaer ’ s technology ( on the right ) provides the opportunity to considerably increase lixiviant oxygen levels within heaps and accelerate sulphide leaching kinetics , while BASF ’ s LixTRA reagent ( graphic on the left ) facilitates improved intra and inter-lixiviant ore permeation and significantly increases copper recovery levels
“ pop ”, meaning they are highly stable and long lasting , so , when added to the lixiviant in a leaching process , can ensure high levels of oxygen reach all parts of the heap .
“ This is especially of interest for run of mine and dump heaps with tall lifts where high compaction of the ore can lead to areas of poor permeability and low oxygen ,” Taute said .
Moleaer ’ s technology provides the opportunity to considerably increase lixiviant oxygen levels within heaps and accelerate sulphide leaching kinetics , while BASF ’ s LixTRA reagent facilitates improved intra and inter-lixiviant ore permeation and significantly increases copper recovery levels .
“ When combining the two technologies , we have seen a synergistic effect , which potentially offers a step change in sulphide leaching
efficiencies ,” Taute said .
The combined LixTRA-Moleaer offering for leaching copper sulphides is not the only solution billed as offering a processing breakthrough in the copper space ; several companies – some from within the mining company fraternity – have come to the table with solutions targeting recovery of copper from hardto-leach deposits .
Taute says the technology combination he is focused on is complementary to these .
“ Many of these technologies focus on overcoming the passivation layer associated with chalcopyrite leaching by employing novel catalysts and lixiviants ,” he said . “ Although we see a catalytic effect with LixTRA on primary sulphides , we predominantly see both LixTRA and Moleaer ’ s nanobubbles as potentially complementary technologies , as all leaching technologies would benefit from greater ore lixiviant contact and higher oxygen levels within the heaps .”
Initial work carried out at BASF ’ s Hydrometallurgy Centre of Excellence in Tucson , Arizona , on a chalcopyrite ore , demonstrated a quantifiable increase in copper recovery with LixTRA and Moleaer alone , and a synergistic effect when combined , Taute says .
The pair are conducting more detailed validation and optimisation test work in Tucson , as well as at customer sites around the globe , to verify these findings across a wider range of orebodies .
Once the companies are in receipt of a wider bank of test results , Taute is optimistic the mining industry will look at adopting the combined solution .
“ Historically , introducing new chemical innovation to the industry has been a long , slow process , but with the demand for copper set to increase significantly , there appears to be a real focus to improve efficiency at mines , and especially around existing leach processes ,” he said . “ The result has been several customers reaching out to us to learn more about our technology , which is not usually the case .”
Despite this new openness , he did acknowledge a remaining reticence within the
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MARCH 2023 | International Mining 19