608 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
g(RVC)–1 min–1. The SRRCu/C0(Cu) value is 9 times lower
than that of the electro-deposition in a synthetic Cu2+ solu-
tion in Na2SO4 [25] (Figure 5). Such a low rate can be
explained by the passivating effect of the continuous insu-
lating Al hydroxide layer (Figure 4) [25].
At –0.50 V, the uptake becomes faster, removing 99%
Cu and Al in already 30 min (Figure 3c). However, the Cu
and Al selectivities degrade due to the co-uptake of 80%
U, 70% Y, 50% Ce, 30% Nd, and 10% Zn, while the
co-uptake of the other elements is below 5%. The uptake
rates further increase at –0.75 V (Figure 3d). Within 3.2
min, when pH reaches 7.40, the electrode uptakes 92% Al,
82% Cu, 64% Zn, ca. 70% TREE, 64% U, 35% Co&Ni.
At 7 min, the electrode uptakes 99% of Cu, Al, U, and
REE, along with 80% Co&Ni, with 40% Mn and 50%
Si. In contrast to the steady increase of pH at –0.30 V
(Figure 3a), pH at –0.50 V and –0.75 V reaches a plateau
in 30 and 7 min, respectively (Figure 3c,d). This picture
Cu Al
Figure 4. SEM/EDS of RVC after electrolysis at –0.30 V in AMD1 in the experiment shown in Figure 3a,b. The scale bar is
8 mm in EDS maps in the bottom row. Copyright © 2023 Chernyshova, Suup, Kihlblom, Kota, Ponnurangam
0.008
0.045
0.054
0.16
0.083
0.13
0
0.036
0.0066
0.046
0.081
0.13
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
Cu
Zn
e-dpt of Cu
SEP of Zn
0.30 V 0.75 V 0.30 V 0.75 V 0.75 V 0.30 V
AMD1 AMD1 AMD1 AMD2
Al-depleted -0.3 V
Figure 5. Specific recovery (uptake) rates of Cu and Zn (SRR
Cu /C
0(Cu) and SRR
Zn /C
0(Zn) ,respectively) at –0.30 V and –0.75 V
from initial AMD1 and AMD2, as well as Al-depleted AMD1 (depleted in Al by chemical precipitation) and AMD1 depleted
in Al, Cu, and U by SEP at –0.30 V. Horizontal dashed lines show SRR
Cu /C
0(Cu) of (7.5±0.2) × 10–2 L g(RVC)–1 min–1 for the
diffusion-controlled Cu electrodeposition in a synthetic Cu solution in 0.1 M Na
2 SO
4 ,as well as SRR
Zn /C
0(Zn) of (4.6±0.2) ×
10–2 L g(RVC)–1 min–1 for the SEP of Zn in a synthetic Zn solution in 0.05 M Na
2 SO
4 reported in Ref. [25]
SRR
Cu/Zn
/C
0(Cu/Zn) ,
L
g(RVC)-1min-1
g(RVC)–1 min–1. The SRRCu/C0(Cu) value is 9 times lower
than that of the electro-deposition in a synthetic Cu2+ solu-
tion in Na2SO4 [25] (Figure 5). Such a low rate can be
explained by the passivating effect of the continuous insu-
lating Al hydroxide layer (Figure 4) [25].
At –0.50 V, the uptake becomes faster, removing 99%
Cu and Al in already 30 min (Figure 3c). However, the Cu
and Al selectivities degrade due to the co-uptake of 80%
U, 70% Y, 50% Ce, 30% Nd, and 10% Zn, while the
co-uptake of the other elements is below 5%. The uptake
rates further increase at –0.75 V (Figure 3d). Within 3.2
min, when pH reaches 7.40, the electrode uptakes 92% Al,
82% Cu, 64% Zn, ca. 70% TREE, 64% U, 35% Co&Ni.
At 7 min, the electrode uptakes 99% of Cu, Al, U, and
REE, along with 80% Co&Ni, with 40% Mn and 50%
Si. In contrast to the steady increase of pH at –0.30 V
(Figure 3a), pH at –0.50 V and –0.75 V reaches a plateau
in 30 and 7 min, respectively (Figure 3c,d). This picture
Cu Al
Figure 4. SEM/EDS of RVC after electrolysis at –0.30 V in AMD1 in the experiment shown in Figure 3a,b. The scale bar is
8 mm in EDS maps in the bottom row. Copyright © 2023 Chernyshova, Suup, Kihlblom, Kota, Ponnurangam
0.008
0.045
0.054
0.16
0.083
0.13
0
0.036
0.0066
0.046
0.081
0.13
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
Cu
Zn
e-dpt of Cu
SEP of Zn
0.30 V 0.75 V 0.30 V 0.75 V 0.75 V 0.30 V
AMD1 AMD1 AMD1 AMD2
Al-depleted -0.3 V
Figure 5. Specific recovery (uptake) rates of Cu and Zn (SRR
Cu /C
0(Cu) and SRR
Zn /C
0(Zn) ,respectively) at –0.30 V and –0.75 V
from initial AMD1 and AMD2, as well as Al-depleted AMD1 (depleted in Al by chemical precipitation) and AMD1 depleted
in Al, Cu, and U by SEP at –0.30 V. Horizontal dashed lines show SRR
Cu /C
0(Cu) of (7.5±0.2) × 10–2 L g(RVC)–1 min–1 for the
diffusion-controlled Cu electrodeposition in a synthetic Cu solution in 0.1 M Na
2 SO
4 ,as well as SRR
Zn /C
0(Zn) of (4.6±0.2) ×
10–2 L g(RVC)–1 min–1 for the SEP of Zn in a synthetic Zn solution in 0.05 M Na
2 SO
4 reported in Ref. [25]
SRR
Cu/Zn
/C
0(Cu/Zn) ,
L
g(RVC)-1min-1