XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2197
UV-Visible Analysis
The SEX adsorption in the presence of mineral samples
under experimental conditions with different pHs is dis-
played in Figure 15. As can be seen from Figure 15 (a) and
(b), the black lines represent the adsorption curves without
adding SEX, which can be treated as a reference. Based on the
previous work of Elizondo-Álvarez et al. (Elizondo-Álvarez
et al., 2021), the adsorption peak appears at approximate
300 nm. According to the trial experiments, the addition
of pentlandite particles, the pH fluctuates in a small scale,
which can be treated as negligible while the addition of
lizardite particles, the pH increases, appearing basic. In
Figure 15 (a), in the presence of pentlandite particles, with
increasing the pH from 3 to 11, the peak area at around
300 nm becomes larger and larger, indicating the concen-
tration of SEX left in the solution is higher and higher. This
is also verified by Millican and Sauers (Millican and Sauers,
1979), SEX easily adsorbs on the surface of sulfide miner-
als, the aqueous solution of SEX is stable at high pH if not
heated, and rapidly hydrolyses at pH less than 9 at room
temperature. In Figure 15 (b), there are no full adsorption
peaks representing the SEX adsorption. However, there are
partial peaks representing the adsorption of left SEX, and
the trend is similar to the trend of Figure 15 (a), increasing
with the increase of pH values.
The influence of CaCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence of
mineral particles is displayed in Figure 16. As can be seen
from Figure 16, there are no obvious peaks for the SEX
adsorption appearing at 300 nm in the diagrams, indicating
with addition of CaCl2 solutions has no obvious influence
on the adsorption of SEX in the presence of mineral par-
ticles. Specially in Figure 16 (b), the change in the CaCl2
concentration does not make changes on the adsorption
curves, and four adsorption curves overlap each other.
The influence of MgCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence
of mineral particles is displayed in Figure 17. As can be
seen from Figure 17 (a), when the MgCl2 concentration
is higher than 0.01 mol/L among all molar concentrations
tested, there are small and shallow peaks appearing at the
300 nm, and with the increase of MgCl2 concentration,
the peak becomes lower and lower. Specially in Figure 17
(b), the change in the MgCl2 concentration does not make
changes on the adsorption curves, and four adsorption
curves overlap each other.
The influence of FeCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence
of mineral particles is displayed in Figure 18. In Figure 18
(a), there are no obvious peaks appearing at 300 nm, indi-
cating there is little SEX left in the presence of FeCl2 solu-
tions with different molar concentrations. It can be seen
from Figure 18 (b), when the FeCl2 concentration is 0.001
mol/L, there is a small peak at 300 nm, while there are
no peaks when the FeCl2 concentrations are increased to 1
mol/L among all concentrations tested.
The influence of NiCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence of
200 300 400 500 600 700
0
2
4
6
8
10
Wavelength (nm)
Influence of pH
P-Cu-SEX
P-Cu+SEX
pH3
pH5
pH7
pH9
pH11
(a) Pentlandite
200 300 400 500 600 700
0
2
4
6
8
10
Wavelength (nm)
Influence of pH
L-Cu-SEX
L-Cu+SEX
pH3
pH5
pH7
pH9
pH11
(b) Lizardite
Figure 15. Effects of pHs on the SEX adsorption in the presence of mineral samples, (a) pentlandite, and (b) lizardite
Absorbance Absorbance
UV-Visible Analysis
The SEX adsorption in the presence of mineral samples
under experimental conditions with different pHs is dis-
played in Figure 15. As can be seen from Figure 15 (a) and
(b), the black lines represent the adsorption curves without
adding SEX, which can be treated as a reference. Based on the
previous work of Elizondo-Álvarez et al. (Elizondo-Álvarez
et al., 2021), the adsorption peak appears at approximate
300 nm. According to the trial experiments, the addition
of pentlandite particles, the pH fluctuates in a small scale,
which can be treated as negligible while the addition of
lizardite particles, the pH increases, appearing basic. In
Figure 15 (a), in the presence of pentlandite particles, with
increasing the pH from 3 to 11, the peak area at around
300 nm becomes larger and larger, indicating the concen-
tration of SEX left in the solution is higher and higher. This
is also verified by Millican and Sauers (Millican and Sauers,
1979), SEX easily adsorbs on the surface of sulfide miner-
als, the aqueous solution of SEX is stable at high pH if not
heated, and rapidly hydrolyses at pH less than 9 at room
temperature. In Figure 15 (b), there are no full adsorption
peaks representing the SEX adsorption. However, there are
partial peaks representing the adsorption of left SEX, and
the trend is similar to the trend of Figure 15 (a), increasing
with the increase of pH values.
The influence of CaCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence of
mineral particles is displayed in Figure 16. As can be seen
from Figure 16, there are no obvious peaks for the SEX
adsorption appearing at 300 nm in the diagrams, indicating
with addition of CaCl2 solutions has no obvious influence
on the adsorption of SEX in the presence of mineral par-
ticles. Specially in Figure 16 (b), the change in the CaCl2
concentration does not make changes on the adsorption
curves, and four adsorption curves overlap each other.
The influence of MgCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence
of mineral particles is displayed in Figure 17. As can be
seen from Figure 17 (a), when the MgCl2 concentration
is higher than 0.01 mol/L among all molar concentrations
tested, there are small and shallow peaks appearing at the
300 nm, and with the increase of MgCl2 concentration,
the peak becomes lower and lower. Specially in Figure 17
(b), the change in the MgCl2 concentration does not make
changes on the adsorption curves, and four adsorption
curves overlap each other.
The influence of FeCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence
of mineral particles is displayed in Figure 18. In Figure 18
(a), there are no obvious peaks appearing at 300 nm, indi-
cating there is little SEX left in the presence of FeCl2 solu-
tions with different molar concentrations. It can be seen
from Figure 18 (b), when the FeCl2 concentration is 0.001
mol/L, there is a small peak at 300 nm, while there are
no peaks when the FeCl2 concentrations are increased to 1
mol/L among all concentrations tested.
The influence of NiCl2 solutions with different molar
concentrations on the adsorption of SEX in the presence of
200 300 400 500 600 700
0
2
4
6
8
10
Wavelength (nm)
Influence of pH
P-Cu-SEX
P-Cu+SEX
pH3
pH5
pH7
pH9
pH11
(a) Pentlandite
200 300 400 500 600 700
0
2
4
6
8
10
Wavelength (nm)
Influence of pH
L-Cu-SEX
L-Cu+SEX
pH3
pH5
pH7
pH9
pH11
(b) Lizardite
Figure 15. Effects of pHs on the SEX adsorption in the presence of mineral samples, (a) pentlandite, and (b) lizardite
Absorbance Absorbance