Graphite material purification process

A graphite material purification process, the process comprising the steps of:

• (i) Passing a concentrate of the graphite material to be purified to a pelletisation step providing a pelletised material;
• (ii) Baking the pelletised material of step (i) in caustic conditions providing a sintered product and whereby one or more impurity minerals are rendered soluble;
• (iii) Passing the sintered product of step (ii) to a water leach step whereby at least a portion of the impurity minerals from step (ii) are solubilised, forwarded for effluent treatment, and separated from leach solids;
• (iv) Passing the leach solids of step (iii) to a first sulphuric acid leach step wherein impurity minerals partially leached in step (iii) are solubilised, forwarded for effluent treatment, and separated from leach solids;
• (v) Passing the leach solids of step (iv) to a hydrofluoric acid leach step, wherein partially leached impurity minerals are solubilised, forwarded for effluent treatment, and separated from leach solids;
• (vi) Passing the leach solids of step (v) to a second sulphuric acid leach step wherein impurity minerals or components precipitated during step (v) not leached in previous steps are solubilised, forwarded for effluent treatment, and separated from leach solids;
• and
• (vii) Passing the leach solids of step (vi) to one or more washing stages wherein at least a portion of any remaining soluble impurities are separated, and whereby a purified graphite material is produced.