Trevor T. Chiweshe, Walter Purcell
Complete fusion of the reference material (SARM 131), UG2 chromitite and the Meresky Reef
mineral ores was achieved using a mixture of NaH2PO4 and Na2HPO4 salts/flux in the ratio of 1:25.
Quantitative analysis of Cr in the SARM 131 samples were found to be 28.64 % compared to the
certified value of 28.62 % whilst Cr content in the UG2 chromite and Merenky Reef were found to
be 64.85 and 16.61 % respectively. Isolation of Cr from the resultant green solution was achieved
using the basic mediums of NaOH, KOH and NH4OH (pH 6.5 – 6.9) to yield grey-green gelatinous
precipitates. Similar SEM and EDX results were obtained for all the grey-green precipitates, which
showed the presence of Cr, P and O as the major elements. Further increase in pH (7.0 – 9.5) of the
grey-green precipitates using the above bases isolated Cu and Ni as a blue solution. Quantitative
analysis of Cu and Ni in the isolated blue solutions of the reference material (SARM 131), Merensky
Reef, UG2 chromitite ore shows Cu (0.29 % or 90.63 % of original content), (0.02 or 100 %),
(0.02 or 100 %) and Ni (0.26 or 86.67 %), (0.09 or 100 %) and (0.12 or 100 %) respectively. Possible
separation of Ni from Cu in the blue filtrate through crystallization yielded Ni (0.06 or 20.00 %)
in the crystals compared to higher a percentage Cu content (0.18 or 56.25 % of original content)
that remained in the filtrate after the isolation of the Ni.