Comet Resources Ltd (Comet or the Company) (ASX:CRL) is pleased to provide the results of specialist test work on natural flake graphite from its Springdale Graphite Project (Springdale) located in Western Australia. The results of ICP assay of spherical graphite purified to 99.96% with an intensive alkaline (Sodium Hydroxide - NaOH) method, based on a caustic roasting process, were previously provided in our press release of 21 September 2021. A second sample of spherical graphite was purified using hydrofluoric acid (HF) to 99.99%. The results of ICP assay of the HF purified sample are now provided in this release, with comparison to the results of the sample processed using alkaline purification.


Highlights:
  • As previously announced, spherical graphite produced at a specialist facility in Germany was purified using two methods which produced results of 99.96% and 99.99%
  • Inductively coupled plasma (ICP) assays of both these samples have now been completed

The HF purification worked well as can be seen from the low values returned from the ICP (see table 1). All element values assayed in the ash material are better than the typical specification limits required for use in battery anode material (BAM) for lithium-ion batteries.

As previously advised, assay of the intensive alkaline purified material was also undertaken using the ICP technique (see Table 1). Essentially all elements present in the gangue were at a low level after the purification, especially the critical detrimental elements for use in batteries, such as iron, silicon, chromium and copper, which were measured at levels below the typical specification limits for anode material for lithium-ion batteries. Three element assays were slightly elevated, sodium, nickel and calcium. Sodium is very likely a residue from the alkaline digestion (sodium hydroxide) and can be reduced significantly by further optimisation of the purification process. The same applies for nickel, which is most probably coming from the nickel crucible used during purification. The only element which was found in higher concentration than typical limits for lithium-ion BAM was calcium. Comet believes, a modified alkaline based treatment would lower the calcium value. Often a limit of 25 ppm is given for calcium, versus the result from assay of 32.7 ppm. However, a result within the 25 ppm limit should be achievable with future optimisation work.

Further test work:

Further testing is currently in process on the balance of the concentrate material that was shipped to Germany to optimise the processing of Springdale natural flake graphite into spherical graphite suitable for use as precursor material for the production of anode material used in the manufacture of lithium-ion batteries.

These tests will primarily focus on improvements in yield during the process of spheronisation of the graphite. Once this test program is complete in Germany, which will have exhausted the supply of graphite concentrate, further test work will be paused pending the completion of the proposed transaction with International Graphite. They will then continue with further testing post close of the deal.


Read the full ASX release here.

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