XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2151
sphalerite (110) were examined using the DFT approach
in this research.
Figure 2 depicts the optimum bulk sphalerite and
sphalerite (110) surfaces. As seen in Figure 2, the Zn atoms
in the sphalerite lattice are coordinated with four S atoms
and are positioned in the core of the orthotetrahedron
produced by the four S atoms. The Zn-S bond is broken
during the process of breaking, and the Zn atoms transi-
tion from bulk phase coordination with four S atoms to
surface coordination with three S atoms. On the sphalerite
(110) surface, after geometry optimization, a pronounced
relaxation phenomenon occurs. The Zn atoms on the
sphalerite (110) surface transform a tetrahedral coordina-
tion structure to a planar triangular coordination structure.
The angles formed by the Zn atom with the coordinating S
atoms are 120.445°, 120.443°, and 117.385°, and the sum
of the three angles is 358.273°. Thus, the Zn atom is situ-
ated in the planar triangle formed by the three S atoms.
This calculation is consistent with Chen’s and Duke’s previ-
ous findings.
As illustrated in Figure 3, there are two types of Zn
atoms at the top (T) and bottom (B) of the sphalerite (110)
face. As a result, the mechanism of Cu in the activation
of sphalerite has two options: substitution of Zn atoms
at the T-site of sphalerite (110) face or substitution of Zn
atoms at the B-site of sphalerite (110) face. DFT calcula-
tions show that the substitution energies of Cu at the T-site
and Cu at the B-site are –82.09 kJ/mol and –66.81 kJ/
mol, respectively. From the results, it is clear that T-site Zn
atoms on the sphalerite (110) face have a greater substitu-
tion energy than B-site Zn atoms on the sphalerite (110)
face. This implies that Cu is more likely to displace the Zn
atoms at the T-site of the sphalerite (110) face. Therefore,
this paper focuses on Cu which substitutes at the T-site on
the surface of sphalerite (110). After the copper-activated
sphalerite (110) face, the angles formed by the Cu atom
Figure 2. Schematic diagrams of bulk ZnS(a), ZnS (110) surface side view(b), ZnS (110) surface side view top view(c)
Figure 3. Schematic diagrams of ZnS (110) surface(a), Cu-activated ZnS (110) surface side view(b), Cu-activated ZnS (110)
surface top view(c)
sphalerite (110) were examined using the DFT approach
in this research.
Figure 2 depicts the optimum bulk sphalerite and
sphalerite (110) surfaces. As seen in Figure 2, the Zn atoms
in the sphalerite lattice are coordinated with four S atoms
and are positioned in the core of the orthotetrahedron
produced by the four S atoms. The Zn-S bond is broken
during the process of breaking, and the Zn atoms transi-
tion from bulk phase coordination with four S atoms to
surface coordination with three S atoms. On the sphalerite
(110) surface, after geometry optimization, a pronounced
relaxation phenomenon occurs. The Zn atoms on the
sphalerite (110) surface transform a tetrahedral coordina-
tion structure to a planar triangular coordination structure.
The angles formed by the Zn atom with the coordinating S
atoms are 120.445°, 120.443°, and 117.385°, and the sum
of the three angles is 358.273°. Thus, the Zn atom is situ-
ated in the planar triangle formed by the three S atoms.
This calculation is consistent with Chen’s and Duke’s previ-
ous findings.
As illustrated in Figure 3, there are two types of Zn
atoms at the top (T) and bottom (B) of the sphalerite (110)
face. As a result, the mechanism of Cu in the activation
of sphalerite has two options: substitution of Zn atoms
at the T-site of sphalerite (110) face or substitution of Zn
atoms at the B-site of sphalerite (110) face. DFT calcula-
tions show that the substitution energies of Cu at the T-site
and Cu at the B-site are –82.09 kJ/mol and –66.81 kJ/
mol, respectively. From the results, it is clear that T-site Zn
atoms on the sphalerite (110) face have a greater substitu-
tion energy than B-site Zn atoms on the sphalerite (110)
face. This implies that Cu is more likely to displace the Zn
atoms at the T-site of the sphalerite (110) face. Therefore,
this paper focuses on Cu which substitutes at the T-site on
the surface of sphalerite (110). After the copper-activated
sphalerite (110) face, the angles formed by the Cu atom
Figure 2. Schematic diagrams of bulk ZnS(a), ZnS (110) surface side view(b), ZnS (110) surface side view top view(c)
Figure 3. Schematic diagrams of ZnS (110) surface(a), Cu-activated ZnS (110) surface side view(b), Cu-activated ZnS (110)
surface top view(c)