The potential of Sudanese Refractory Gold Ores Characterization and Pre-treatment in Ariab Mines (VMS) in Red Sea (Sudan)

with optimal parameters. Characterization studies were performed by
AAS, XRF and XRD analysis to assess the abundance of elements
and mineral phases. In addition, the acidity of the ore was examined
to estimate the effective amount of lime. The ore was subjected
directly to cyanidation without any pre-treatment. High oxidation
reagent processes were carried out to pre-treat the ore. Chemical
analysis results show the gold grade to be 1.37 g/t. In addition, the
ore contained 51.78% Fe2O3, 43.40% SO3, 2.39% CuO, 1.47% SiO2,
0.35% Cr2O3, 0.17% CaO, 0.08% As2O3, 0.06% ZnO and 0.06%
MnO. The XRD result shows that the ore phases are Pyrite (FeS2),
Chatkaite (Cu6Fe+2Sn2S2) and Quartz (SiO2). The investigations of
direct cyanidation elucidated that the ore can consume a high amount
of cyanide with unsatisfactory recoveries for gold (Exgold ≤39.41%).
The influence of the cyanide concentration, pulp density (% by
weight), leaching time hr, agitator speed and pH were examined in
direct cyanidation experiments. In pre-treatment experiments, the
effect of hydrogen peroxide (H2O2) and concentrations on gold
recovery was studied. The pre-treatment of the ore with H2O2
achieved a good impact on the gold extraction performance. The
higher gold extraction was obtained at hydrogen peroxide (H2O2) 300
ppm, cyanide concentration 3500 ppm, leaching time 10 hr, pH=10.5
and pulp density 40%.