Perth-listed lithium developer, AVZ Minerals, has achieved an impressive average of 69% fine lithia recoveries from stage two metallurgical flotation test work at its giant Manono lithium and tin project in the Democratic Republic of Congo.
Recoveries were calculated after accounting for any lithia lost to “slimes”, magnetic separation and flotation tailings, meaning the mass balance recovery resulted in a lithium oxide concentrate of 6.2%, which is above AVZ’s target of 6.0%.
The new results are important because they indicate that the project may well hang together metallurgically, a key hurdle for every pending operation.
Whilst there is some level of variability depending on end use, lithium chemical manufacturers generally seek a lithium concentrate of over 6% lithium oxide, which is then converted to lithium hydroxide or lithium carbonate chemicals for use in lithium-ion batteries.
With EV markets going gangbusters at the moment, there has been some anticipation by analysts such as S&P Global that declining upstream investment will potentially create an under-supply of lithium in the market.
AVZ’s stage two results represent an improvement of 21.5% on its phase one test work and actively demonstrate the scalable upside of its metallurgical flow sheet at Roche Dure.
AVZ said the metallurgical results still require more work, however the company’s Managing Director Nigel Ferguson said: “this demonstrates at an early stage, there is significant upside for the potential maximisation of spodumene recovery by the flotation treatment of the undersize material from the planned Roche Dure crushing circuit.”
Elsewhere, the nearby Carriere de l’Este, or “CDL” ore deposit could emerge as the Manono project’s biggest pegmatite, extending for about 5.5 kilometres, according to AVZ.
The company has made an initial metallurgical bulk test work evaluation of CDL and found that randomly sampled high grade sections from diamond core produced a 2.37% lithium oxide sample head grade.
Dense media cyclone separation of the CDL samples generated a lithium concentrate of 6.2% with a recoveries of 55% at a coarser 5.6mm crush size and a concentrate of 6.3% lithium at 66% recovery at a finer 3.35mm crush size.
A very fine fraction of the ore performed really well through the dense media separation process, with an average recovery over 87% for a 6% lithium oxide product.
The company said that it might even be possible to add as much as 10% recovery to the CDL ore via further optimisation work.
Mr Ferguson said: “this opens up the possibility of this material being used as a feed stock to a downstream processing plant such as a lithium sulphate plant with less tonnages of material being required to produce a valued added product, a possibility that we are currently vigorously investigating."
It’s still early days at CDL, however, these results will only add value to the company’s impending DFS, with the secondary source providing a potential high-grade source of ore to blend with Roche Dure - adding to the overall lithium content and value of its final lithium product.
The upside of the intensive Roche Dure metallurgical test work, is that most of the DSF hard yards have been achieved now and AVZ can simply apply the parameters of its Roche Dure flow sheet to the CDL ore.
With a bit of fine tuning, the CDL deposit should be able to seamlessly integrate with the DFS.
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