1756 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
their complex composition containing carbonaceous mat-
ter encapsulated in the sulfide matrix of minerals (Konadu
et al., 2020), making conventional methods less effective as
well as having some environmental issues.
This study introduces a novel green-hydrometallurgy
scheme for sustainable Au extraction from DRGO. By
exploiting the principles of green chemistry and engineer-
ing, this scheme aims to minimize environmental impact
while maintaining economic feasibility. The process begins
with the pretreatment of a double refractory carbonaceous
sample, using a ferric solution derived from a bio-oxidation
plant. Subsequently, In significant contrast to traditional
methods, this research employs thiosulfate as an eco-
friendly solvent for gold leaching (Abbruzzese et al., 1995
Aylmore &Muir, 2001 Jeon et al., 2022 Rath R.K. et
al., 2003 XIE et al., 2021). Thiosulfate offers a less toxic
alternative to cyanide and has shown promise in extracting
gold from ores that are difficult to process using conven-
tional methods. The final stage of the process involves the
recovery and upgrading of gold ions utilizing tailings with
thiosulfate decomposition reactions The development of
this sustainable and eco-friendly gold recovery scheme rep-
resents a significant step toward achieving a carbon-neutral
society. By addressing the dual challenges of environmental
sustainability and the growing demand for gold in green
technologies, this research contributes to the broader goals
of sustainable development and climate change mitigation.
MATERIALS AND METHODS
Materials
A flotation concentrate of the DRGO sample obtained
from a hydrometallurgy plant in Uzbekistan was used in
this study.
The chemical composition of the gold flotation con-
centrate was analyzed using X-ray fluorescence (XRF, ZSX
Primus II, Rigaku Corporation, Tokyo, Japan). To deter-
mine the content of gold and silver, the sample was dis-
solved in an aqua regia solution followed by roasting then
analyzed using microwave plasma atomic emission spec-
troscopy (MP-AES, Agilent 4210). The results are pre-
sented in Table 1.
The particle size distribution of the flotation concen-
trate sample was characterized using a particle size analyzer
(Microtrac, MT 3300EXII, Nikkiso Group, Osaka, Japan)
(Figure 1). The main components in the sample identi-
fied using an X-ray diffractometer (XRD, RINT-2200/PC,
Rigaku, Tokyo, Japan) were pyrite (FeS2), quartz (SiO2),
muscovite ((KF)2(Al2O3)3(SiO2)6), and chlorite ((Mg,Fe)3
(Si,Al)4O10(OH)2*(Mg,Fe)3(OH)6), as shown in Figure 2.
Figure 3 shows the SEM image and elemental mapping
Table 1. Chemical composition of the flotation concentrate sample (Refractory Gold Concentrate)
Element Si Fe Al S C K Mg Na Ti
Wt. (%)17.82 8.52 8.07 5.65 3.68 2.22 0.82 0.59 0.55
Element Ca As P Ba Cu Zn Zr V Cl
Wt. (%)0.37 0.17 0.05 0.04 0.03 0.03 0.03 0.02 0.02
Element Sr Mn Sb Ni Co Cd Rb Au Ag
Wt. (%)0.02 0.01 0.01 0.01 0.01 0.01 0.01 10 ppm 7 ppm
0
20
40
60
80
100
0
1
2
3
4
5
6
1 10 100 1000
Particle size (μm)
D
50 =10μm
Figure 1. Particle size distribution of the flotation concentrate (Refractory Gold
Concentrate)
Accumulati
(%)
Frequency
(%)
their complex composition containing carbonaceous mat-
ter encapsulated in the sulfide matrix of minerals (Konadu
et al., 2020), making conventional methods less effective as
well as having some environmental issues.
This study introduces a novel green-hydrometallurgy
scheme for sustainable Au extraction from DRGO. By
exploiting the principles of green chemistry and engineer-
ing, this scheme aims to minimize environmental impact
while maintaining economic feasibility. The process begins
with the pretreatment of a double refractory carbonaceous
sample, using a ferric solution derived from a bio-oxidation
plant. Subsequently, In significant contrast to traditional
methods, this research employs thiosulfate as an eco-
friendly solvent for gold leaching (Abbruzzese et al., 1995
Aylmore &Muir, 2001 Jeon et al., 2022 Rath R.K. et
al., 2003 XIE et al., 2021). Thiosulfate offers a less toxic
alternative to cyanide and has shown promise in extracting
gold from ores that are difficult to process using conven-
tional methods. The final stage of the process involves the
recovery and upgrading of gold ions utilizing tailings with
thiosulfate decomposition reactions The development of
this sustainable and eco-friendly gold recovery scheme rep-
resents a significant step toward achieving a carbon-neutral
society. By addressing the dual challenges of environmental
sustainability and the growing demand for gold in green
technologies, this research contributes to the broader goals
of sustainable development and climate change mitigation.
MATERIALS AND METHODS
Materials
A flotation concentrate of the DRGO sample obtained
from a hydrometallurgy plant in Uzbekistan was used in
this study.
The chemical composition of the gold flotation con-
centrate was analyzed using X-ray fluorescence (XRF, ZSX
Primus II, Rigaku Corporation, Tokyo, Japan). To deter-
mine the content of gold and silver, the sample was dis-
solved in an aqua regia solution followed by roasting then
analyzed using microwave plasma atomic emission spec-
troscopy (MP-AES, Agilent 4210). The results are pre-
sented in Table 1.
The particle size distribution of the flotation concen-
trate sample was characterized using a particle size analyzer
(Microtrac, MT 3300EXII, Nikkiso Group, Osaka, Japan)
(Figure 1). The main components in the sample identi-
fied using an X-ray diffractometer (XRD, RINT-2200/PC,
Rigaku, Tokyo, Japan) were pyrite (FeS2), quartz (SiO2),
muscovite ((KF)2(Al2O3)3(SiO2)6), and chlorite ((Mg,Fe)3
(Si,Al)4O10(OH)2*(Mg,Fe)3(OH)6), as shown in Figure 2.
Figure 3 shows the SEM image and elemental mapping
Table 1. Chemical composition of the flotation concentrate sample (Refractory Gold Concentrate)
Element Si Fe Al S C K Mg Na Ti
Wt. (%)17.82 8.52 8.07 5.65 3.68 2.22 0.82 0.59 0.55
Element Ca As P Ba Cu Zn Zr V Cl
Wt. (%)0.37 0.17 0.05 0.04 0.03 0.03 0.03 0.02 0.02
Element Sr Mn Sb Ni Co Cd Rb Au Ag
Wt. (%)0.02 0.01 0.01 0.01 0.01 0.01 0.01 10 ppm 7 ppm
0
20
40
60
80
100
0
1
2
3
4
5
6
1 10 100 1000
Particle size (μm)
D
50 =10μm
Figure 1. Particle size distribution of the flotation concentrate (Refractory Gold
Concentrate)
Accumulati
(%)
Frequency
(%)