1784 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
with rapid leaching for 8 hours and steady recovery until
the end of the test. At 24 hours, gold recovery was 78.3%
at 0.5 mM, 78.7% at 1 mM, and 75.5% at 2 mM of Cu.
Figure 6 (b) highlights that all copper concentrations
decreased by nearly 50% at the beginning of the leach test.
While the 2 mM copper sample decreased slowly over time,
the other samples remained relatively constant (0.5 and 1
mM). Figure 6 (c) demonstrates that pH levels were stable
across all conditions at the initial pH.
However, the decomposition behavior of thiosulfate
showed variation. Figure 6 (d) illustrates that increasing
Cu concentration resulted in a decrease in thiosulfate con-
centration. Thiosulfate concentration decreased from the
initial concentration (0.1 M) to 0.08 M at 0.5 mM and
0.06 M at 2 mM of Cu. Some studies have investigated the
effect of copper concentration on gold leaching and discov-
ered that increasing the initial copper concentration could
decompose high concentration of thiosulfate [16,24,24] .
Figure 4. Kinetic plots of leaching at various thiosulfate concentration, a) pH 10 b) pH 10.3, and, c) pH 11.5 (Test condition:
0.05-0.2 M S2O32–, 1 mM Cu, 0.01 gMg(OH)2/gOre Mg(OH)2, 20±3°C)
Figure 5. Variation of a) Au leaching efficiency and b) final Cu concentration at 24 h (Test condition: 0.05-0.2 M S
2 O
3 2–,
1 mM Cu, 0.01 g
Mg(OH)2 /g
Ore Mg(OH)
2 ,20±3°C)
with rapid leaching for 8 hours and steady recovery until
the end of the test. At 24 hours, gold recovery was 78.3%
at 0.5 mM, 78.7% at 1 mM, and 75.5% at 2 mM of Cu.
Figure 6 (b) highlights that all copper concentrations
decreased by nearly 50% at the beginning of the leach test.
While the 2 mM copper sample decreased slowly over time,
the other samples remained relatively constant (0.5 and 1
mM). Figure 6 (c) demonstrates that pH levels were stable
across all conditions at the initial pH.
However, the decomposition behavior of thiosulfate
showed variation. Figure 6 (d) illustrates that increasing
Cu concentration resulted in a decrease in thiosulfate con-
centration. Thiosulfate concentration decreased from the
initial concentration (0.1 M) to 0.08 M at 0.5 mM and
0.06 M at 2 mM of Cu. Some studies have investigated the
effect of copper concentration on gold leaching and discov-
ered that increasing the initial copper concentration could
decompose high concentration of thiosulfate [16,24,24] .
Figure 4. Kinetic plots of leaching at various thiosulfate concentration, a) pH 10 b) pH 10.3, and, c) pH 11.5 (Test condition:
0.05-0.2 M S2O32–, 1 mM Cu, 0.01 gMg(OH)2/gOre Mg(OH)2, 20±3°C)
Figure 5. Variation of a) Au leaching efficiency and b) final Cu concentration at 24 h (Test condition: 0.05-0.2 M S
2 O
3 2–,
1 mM Cu, 0.01 g
Mg(OH)2 /g
Ore Mg(OH)
2 ,20±3°C)