XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2153
tetrahedral structure after the xanthane is adsorbed on the
sphalerite (110) surface.
From the state density (DOS) analysis, we can give
the observation of the electron level of interaction between
the collector and different minerals, which directly reflects
the electron orbital coupling between the 3d orbit of Cu,
Zn and the p orbit of sulfur atoms in xanthane. The DOS
before and after adsorption of xanthane on sphalerite and
Cu-activated sphalerite was calculated and the Fermi level
was set to 0 eV (EF= 0) in the DOS curve. It can be seen
from Figures 6 and 7 that the 3d orbital of Zn is far away
from the Fermi level, while the 3d orbital of Cu is near the
Fermi level, indicating that the activity of Cu 3d orbital is
greater than that of Zn 3d orbital. The part of the xanthane
functional group at the Fermi level before adsorption con-
sists of S 3p orbit, which indicates that the S 3p orbit is
very active. Further, the DOS of the S atom having a single
bond is identical to the DOS of the S atom having a double
bond, indicating that the two S atoms in the xanthane have
similar chemical reactivity, which is consistent with chemi-
cal principles. The absorbance of xanthane changed after
it was adsorbed on the mineral surface. Xanthate primar-
ily absorbs Zn atoms onto mineral surfaces through the
interaction between the S orbital of the xanthate molecule
and the s orbital of Zn. Meanwhile, Cu atoms are mainly
adsorbed by xanthate on mineral surfaces through inter-
actions between the S atom and Cu s orbital, as well as
between the S 3p orbital and Cu 3d orbital in xanthate.
The COHP parameter is employed to characterize the
bonding properties between two atoms, where a negative
value signifies the formation of a bonding orbital and a
positive value indicates the formation of an anti-bonding
orbital. It can be observed from Figure 6 and Figure 7 that
when xanthate adsorbs Zn atoms onto mineral surfaces,
the involvement of Zn 3d orbital in bonding is negligible,
with bonding primarily occurring in Zn s and p orbitals.
Conversely, when xanthate adsorbs Cu atoms onto mineral
surfaces, the Cu 3d orbital actively participates in bonding,
demonstrating that the primary interaction responsible for
bonding arises between the Cu 3d orbital and the S s orbital
within xanthate. This observation highlights the inertness
of Zn 3d orbital compared to Cu’s ability to readily interact
with S within xanthate through its own 3d orbital, thereby
playing a significant role in the overall bonding process.
Correlation Between the Adsorption Energy and d
Band Center
According to previous research, the s and p orbitals of the S
atomvs in xanthane are coupled to the electronic orbitals of
the Zn and Cu atoms on the face of sphalerite (110). The
overlap of the electronic orbitals of the S and Cu atoms in
the lower energy states suggests an interaction between the
S 3s orbitals and the Cu 3d orbitals. In contrast, the lack
of overlap between the electronic orbitals of the S and Zn
atoms implies that there is no interaction between the S 3s
orbital and the Zn 3d orbital.
Based on the above results, the d-band centers of Zn
atoms on the sphalerite (110) surface and Cu atoms on the
sphalerite (110) surface following Cu activation were cal-
culated and are presented in Figure 8. The d-band centers
Figure 5. Optimized adsorption geometries of (a) sphalerite (110) surface and (b) Cu-activated
sphalerite (110) surface
tetrahedral structure after the xanthane is adsorbed on the
sphalerite (110) surface.
From the state density (DOS) analysis, we can give
the observation of the electron level of interaction between
the collector and different minerals, which directly reflects
the electron orbital coupling between the 3d orbit of Cu,
Zn and the p orbit of sulfur atoms in xanthane. The DOS
before and after adsorption of xanthane on sphalerite and
Cu-activated sphalerite was calculated and the Fermi level
was set to 0 eV (EF= 0) in the DOS curve. It can be seen
from Figures 6 and 7 that the 3d orbital of Zn is far away
from the Fermi level, while the 3d orbital of Cu is near the
Fermi level, indicating that the activity of Cu 3d orbital is
greater than that of Zn 3d orbital. The part of the xanthane
functional group at the Fermi level before adsorption con-
sists of S 3p orbit, which indicates that the S 3p orbit is
very active. Further, the DOS of the S atom having a single
bond is identical to the DOS of the S atom having a double
bond, indicating that the two S atoms in the xanthane have
similar chemical reactivity, which is consistent with chemi-
cal principles. The absorbance of xanthane changed after
it was adsorbed on the mineral surface. Xanthate primar-
ily absorbs Zn atoms onto mineral surfaces through the
interaction between the S orbital of the xanthate molecule
and the s orbital of Zn. Meanwhile, Cu atoms are mainly
adsorbed by xanthate on mineral surfaces through inter-
actions between the S atom and Cu s orbital, as well as
between the S 3p orbital and Cu 3d orbital in xanthate.
The COHP parameter is employed to characterize the
bonding properties between two atoms, where a negative
value signifies the formation of a bonding orbital and a
positive value indicates the formation of an anti-bonding
orbital. It can be observed from Figure 6 and Figure 7 that
when xanthate adsorbs Zn atoms onto mineral surfaces,
the involvement of Zn 3d orbital in bonding is negligible,
with bonding primarily occurring in Zn s and p orbitals.
Conversely, when xanthate adsorbs Cu atoms onto mineral
surfaces, the Cu 3d orbital actively participates in bonding,
demonstrating that the primary interaction responsible for
bonding arises between the Cu 3d orbital and the S s orbital
within xanthate. This observation highlights the inertness
of Zn 3d orbital compared to Cu’s ability to readily interact
with S within xanthate through its own 3d orbital, thereby
playing a significant role in the overall bonding process.
Correlation Between the Adsorption Energy and d
Band Center
According to previous research, the s and p orbitals of the S
atomvs in xanthane are coupled to the electronic orbitals of
the Zn and Cu atoms on the face of sphalerite (110). The
overlap of the electronic orbitals of the S and Cu atoms in
the lower energy states suggests an interaction between the
S 3s orbitals and the Cu 3d orbitals. In contrast, the lack
of overlap between the electronic orbitals of the S and Zn
atoms implies that there is no interaction between the S 3s
orbital and the Zn 3d orbital.
Based on the above results, the d-band centers of Zn
atoms on the sphalerite (110) surface and Cu atoms on the
sphalerite (110) surface following Cu activation were cal-
culated and are presented in Figure 8. The d-band centers
Figure 5. Optimized adsorption geometries of (a) sphalerite (110) surface and (b) Cu-activated
sphalerite (110) surface