Positive Cyclone & Leach Results For Bitterwasser Lithium Clays

Philip le Roux, the CEO of Arcadia stated: “We are encouraged by these unprecedented particle size distribution results confirming that undemanding cyclones could offer a viable option to significantly increase Bitterwasser clay grades before leaching take place. An additional boost to our confidence in the project’s potential economic possibilities comes from the University of Stellenbosch’s leach results, which confirmed that industry standard recoveries can be achieved by using potentially low- cost and environmentally friendly organic acids. This forecasts well for our ambitions to establish Bitterwasser as a potential environmentally friendly source of Lithium and the globe’s next economic Lithium-bearing mineral province. We are looking forward to improved results on leaching results with optimisation measures with the second phase of test work on post-cyclone feedstock”.

Cyclone Test Work Results

Multotec Process Equipment (Pty) Ltd was appointed by Arcadia to conduct cyclone test work on 800kg Bitterwasser representative clay samples from the Eden Pan. The aim of the program was to identify if the fine clay fraction of < 10μ fraction, could be separated from the remaining larger material that consist mainly of calcite, dolomite and quartz, and by doing so, the lithium grade in the feedstock material could be increased.

The composite 800 kg auger drilled core sample represents a clay sample combining all the different zones (both the brown and green clay) and from all the boreholes drilled as part of the 2022 drilling campaign (refer to Annexure 1). This sample is regarded a truly representative sample of the Eden Pan clays covering the complete stratigraphy from surface to approximately twelve meters below surface.

After the sample was received by Multotec, the material was blended, and a representative sub-sample was taken to be analysed for particle size distribution (PSD) through a Malvern master-sizer, and specific gravity (SG) through a pycnometer (refer to Annexure 2) for the PSD results. The SG of the material was measured to be 2.4 t/m³.

Based on the PSD, SG as well as the pulp relative density (RD) information, the following cyclone configuration was simulated: An FC40 cyclone with 5° cone and 1 barrel was tested. The operating pressure was kept constant at 105kPa. The cyclone sump was filled with water up to 500 litres. The stirrer and cyclone pump were then started with the feed bypassing the cyclone. The sample was gradually added to the sump. The RD of the feed was measured, and water was added to obtain the desired feed RD’s for the test work. Once the desired RD’s of the feed slurry were obtained, it was sampled three times (referred to as the actual feed). The main valve was opened while closing the bypass valve, where the feed slurry was then fed through the cyclone at the operating pressure as per the simulation. The spigot is optimised by changing the size until optimum flaring is achieved. Once the spigot was properly optimised, the cyclone was allowed to run for 10 minutes to reach steady state before commencing with the RD measurements of the overflow and underflow streams. The necessary RD checks were done and were repeated three times to ensure consistency and repeatability. The cyclone was allowed to reach steady state before sampling the overflow and underflow streams three times (the cyclone products). All the samples collected were prepared to complete the mass balance and the associated PSD analyses and chemical analyses.

The cyclone results indicated that 30.4% of the feed material reported to the underflow (coarse material) and 69.6% of the material to the overflow (fine material). The overflow is showing a cumulative % passing 10µm of 96.9%, which states that majority of the -10µm material is reporting to the underflow stream.

The cyclone test work therefore indicates that if a 14-micron cut size is used, about 70% of the material would report to the overflow and around 97% of this overflow material would be below 10 microns.