XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1177
Quantum Chemical Calculations
The crystal and electronic structures of ideal mineral crys-
tals were investigated through first-principles calculations.
Except for the highest occupied molecular-orbital/lowest
unoccupied molecular-orbital (HOMO/LUMO) compu-
tations, all spin-polarized density functional theory (DFT)
calculations were implemented in the Vienna Ab-initio
Simulation Package (VASP)[15]. Three-layer slab models
were constructed for CaWO4 (112), MnWO4 (010), and
SnO2 (100). The Brillouin zone was modeled using the
gamma-centered Monkhorst–Pack scheme. CaWO4 (112),
MnWO4 (010), and SnO2 (100) were modeled on grids
of sizes 3×4×1, 5×5×1, and 5×8×1, respectively. Denser K
points were employed for the density of states calculations
and the Dmol3 package was used for the HOMO/LUMO
computations. Most of the parameters were those of VASP,
but the van der Waals interactions and solely employ-
ing Gamma point were described by the Tkatchenko–
Scheffler method. The quantum chemical properties of the
ligand and ML–MOF collectors were calculated using the
Gaussian 16 procedure with the DFT method[16]. The
complex configuration was optimized by employing the
B3LYP functional and def2SVP basis set.
RESULTS AND DISSGUSSIONS
The Flotation Behavior of Scheelite, Wolframite, and
Cassiterite
The pH influences on the recovery of scheelite, wolframite,
and cassiterite are first investigated from 8.0 to 10.5. As
shown in Figure 5, the recovery rates of these minerals first
increase and then decrease as pH increases. The primary
growing tendency is mainly because the formation of the
Pb-BHA complex requires the participation of OH–. The
optimal pH for scheelite flotation is 9.0 while 9.5 for wol-
framite and cassiterite. The actual flotation production is
a process involving multiple operations, so this unobvious
difference in optimal pH will gradually cycle and accumu-
late in the process, resulting in a large impact on the differ-
ent recovery in these minerals. It is not entirely reasonable
to utilize a single process to simultaneously recover these
three minerals.
Figure 4. The chemical structural formulas of BHA(a) and MBHA(b)
Figure 5. The pH influence on the recovery of scheelite(a), wolframite(b), and cassiterite(c)
Quantum Chemical Calculations
The crystal and electronic structures of ideal mineral crys-
tals were investigated through first-principles calculations.
Except for the highest occupied molecular-orbital/lowest
unoccupied molecular-orbital (HOMO/LUMO) compu-
tations, all spin-polarized density functional theory (DFT)
calculations were implemented in the Vienna Ab-initio
Simulation Package (VASP)[15]. Three-layer slab models
were constructed for CaWO4 (112), MnWO4 (010), and
SnO2 (100). The Brillouin zone was modeled using the
gamma-centered Monkhorst–Pack scheme. CaWO4 (112),
MnWO4 (010), and SnO2 (100) were modeled on grids
of sizes 3×4×1, 5×5×1, and 5×8×1, respectively. Denser K
points were employed for the density of states calculations
and the Dmol3 package was used for the HOMO/LUMO
computations. Most of the parameters were those of VASP,
but the van der Waals interactions and solely employ-
ing Gamma point were described by the Tkatchenko–
Scheffler method. The quantum chemical properties of the
ligand and ML–MOF collectors were calculated using the
Gaussian 16 procedure with the DFT method[16]. The
complex configuration was optimized by employing the
B3LYP functional and def2SVP basis set.
RESULTS AND DISSGUSSIONS
The Flotation Behavior of Scheelite, Wolframite, and
Cassiterite
The pH influences on the recovery of scheelite, wolframite,
and cassiterite are first investigated from 8.0 to 10.5. As
shown in Figure 5, the recovery rates of these minerals first
increase and then decrease as pH increases. The primary
growing tendency is mainly because the formation of the
Pb-BHA complex requires the participation of OH–. The
optimal pH for scheelite flotation is 9.0 while 9.5 for wol-
framite and cassiterite. The actual flotation production is
a process involving multiple operations, so this unobvious
difference in optimal pH will gradually cycle and accumu-
late in the process, resulting in a large impact on the differ-
ent recovery in these minerals. It is not entirely reasonable
to utilize a single process to simultaneously recover these
three minerals.
Figure 4. The chemical structural formulas of BHA(a) and MBHA(b)
Figure 5. The pH influence on the recovery of scheelite(a), wolframite(b), and cassiterite(c)