XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2487
The relaxed bulk structures were used to cleave the 2×2
(100) surface (Figure 2a and 2c). As previously reported, the
surface terminations were determined on the basis of mini-
mal surface dipole (McFadzean, Mkhonto and Ngoepe,
2023), and the (100) surface with arsenic termination for
sperrylite (Waterson et al., 2016) and arsenic and sulphur
termination for platarsite has been found as the most stable
surface as shown in Figure 2b and d, respectively. The (100)
surface was constructed with vacuum slab separation of 20
Å for dry adsorption and 30 Å for hydrated adsorption, to
inhibit the interaction of the collector and/or collector-water
with the upper repeating slab. The slab depth were varied
and considered slab model with thickness of twelve atomic
layers (12L) for (100) surfaces of PtAs2 and PtAsS. Prior to
surface adsorption simulations, the (100) surface supercells
of (2×2) cells for PtAs2 and PtAsS were optimized. In the
Figure 2. Crystal structures and side views of the un-relaxed and relaxed 2×2 supercell surface models: (a) PtAs
2 bulk, (b) PtAs
2 (100) surface, (c) PtAsS bulk and (d) PtAsS (100) surface
The relaxed bulk structures were used to cleave the 2×2
(100) surface (Figure 2a and 2c). As previously reported, the
surface terminations were determined on the basis of mini-
mal surface dipole (McFadzean, Mkhonto and Ngoepe,
2023), and the (100) surface with arsenic termination for
sperrylite (Waterson et al., 2016) and arsenic and sulphur
termination for platarsite has been found as the most stable
surface as shown in Figure 2b and d, respectively. The (100)
surface was constructed with vacuum slab separation of 20
Å for dry adsorption and 30 Å for hydrated adsorption, to
inhibit the interaction of the collector and/or collector-water
with the upper repeating slab. The slab depth were varied
and considered slab model with thickness of twelve atomic
layers (12L) for (100) surfaces of PtAs2 and PtAsS. Prior to
surface adsorption simulations, the (100) surface supercells
of (2×2) cells for PtAs2 and PtAsS were optimized. In the
Figure 2. Crystal structures and side views of the un-relaxed and relaxed 2×2 supercell surface models: (a) PtAs
2 bulk, (b) PtAs
2 (100) surface, (c) PtAsS bulk and (d) PtAsS (100) surface