AVZ Minerals Ltd (ASX:AVZ) has provided an update on its preliminary flotation test work program at the Manono Lithium and Tin Project in the Democratic Republic of Congo.
The Phase 2 metallurgical initial test programme (flotation) has been completed and aimed to explore fine lithia recovery for a potential future plant expansion.
- Lithia flotation recoveries averaging 69% recovery after adjusting for losses to slimes, magnetic separation and flotation tailing
- Concentrate grades from 6.1% to 6.4% lithium oxide (Li2O) were all above the company’s target of 6% Li2O spodumene concentrate (SC6.0)
- Iron (Fe2O3) levels were all within a SC6.0 concentrate specification and a marked decrease in Fe2O3 content was achieved by increasing the magnetic field intensity of the wet high intensity magnetic separator (WHIMS) process presenting as a further upside optimisation
AVZ managing director Nigel Ferguson said: “We are pleased to report that the initial results of the flotation test programme have demonstrated extremely positive additional lithia recoveries for lithium.
“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.
“These are early results and further work is required; however this is highly encouraging and the company has committed to complete further test work on this opportunity at the appropriate time.”
Carriere de l’Este metallurgical results
Initial metallurgical test work was also completed on the Carriere de l’Este (CDL) deposit.
Ferguson said: “Whilst this test work continues to focus on the Roche Dure deposit, we have also received the initial metallurgical results from a 100-kilogram bulk diamond core sample from the Carriere de l’Este deposit.
“This concept study used a quarter drill core sample, selected randomly from the high grade sections at Carriere de l’Este that produced a 2.3% Li2O head grade.
“Using the same techniques as the Phase 1 Roche Dure metallurgical study, this material has produced a 6.2% – 6.3% Li2O spodumene concentrate at 5.56 millimetres and 3.35 millimetres crush size respectively.”
The company believes that this result, whilst preliminary in nature, suggests there is a strong possibility that Carriere de l’Este material can be used as a blending feed-stock at the Roche Dure process plant to increase the lithium content and value of the final product needed by potential clients.
Ferguson said: “It also opens up the possibility of this material being used as a feedstock to a downstream processing plant such as a lithium sulphate plant with less tonnages of material being required to produce a value added product, a possibility that we are currently, vigiorously investigating.”
Further work required
Addition floation testwork programs are anticipated after the competition of definitive study activities and investigations will focus on water chemistry, mineral and grinding media chemistry, fine mineral attrition, reagent testing and critical design data for locked cycle or pilot flotation trials.
Further work required at CDL includes:
- Heavy liquid separation and crush size optimisation;
- Improved dense media separation settings and cyclone performance, trial runs at rougher specific gravity up to 2.8 to reject maximum mass before cleaning;
- High pressure grinding rolls crushing optimisation to accommodate the 5.6 millimetre crush which will produce more product in the liberated zone as opposed to a bias toward the coarser end; and
- Crush size optimisation work to target 3.35 to 5.6millimetres.