Red Metals - Sybella Rare Earth Project Review, page-10

Thanks for that BPP
Looks like the other geologist should have done some more homework.
Below is one of the testing/extraction reports of VMM you recommended reading.
Fe and Al removed with sodium carbonate(very cheap I assume), with minimal losses of REE.


MREC Metallurgical Process
Rare earth elements were extracted from 50kg of material taken from as-received 31 AC drill samples
collected from 12 holes from North Stanmore (JORC Table 1), using a blend of ammonium sulphate
and weak sulphuric acid leaching at pH 1, ambient temperature and pressure and with a 4-hour
residence time.
Impurities, including aluminium (Al) and iron (Fe), were first removed from the leach liquor by
neutralising with commercial grade sodium carbonate (soda ash) at ambient temperature. The low
levels of aluminium and iron extraction exhibited by North Stanmore samples (refer to ASX
announcement dated 1 May 2023) indicates a very high removal rate of Al and Fe with minimal
losses of REE (Table 2). This allows a high downstream recovery rate of REE from the leach liquor to
the MREC test product. Further work is underway to optimise the impurity removal step to decrease
REE and copper reporting to the precipitate.
Impurity Removal Precipitation Extent (Liquor Basis)
Al Fe TREE HREE LREE Ni Co Cu
% % % % % % % %
99.3 > 99.9 17.2 16.9 18.6 3.0 2.4 62.1
Table 2: Bulk Impurity Removal Precipitation Extents (pH adjusted with sodium carbonate, ambient temperature)