Use of Polystyrene Nanoparticles as Collectors in the Flotation of Chalcopyrite

Abstract

This study proposes the use of polymeric nanoparticles (NPs) as collectors for copper sulfide flotation. The experimental phase included the preparation of two types of polystyrene-based NPs: St-CTAB and St-CTAB-VI. These NPs were characterized by Fourier-Transform Infrared (FTIR) spectroscopy and dynamic light scattering (DLS). Then, microflotation tests with chalcopyrite under different pH conditions and nanoparticle dosages were carried out to verify their capabilities as chalcopyrite collectors. In addition, the zeta potential (ZP) measurements of chalcopyrite in the presence and absence of NPs were carried out to study their interaction. Lastly, some Atomic Force Micrographs (AFM) of NPs and Scanning Electronic Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis of NPs on the chalcopyrite surface were conducted to analyze the size, the morphology and their interaction. The results obtained at pH 6 and pH 8 show that the NPs under study can achieve a chalcopyrite recovery near or higher than that obtained with the conventional collector. In this study, it was possible to observe that the NPs functionalized by the imidazole group (St-CTAB-VI) achieved better performance due to the presence of this group in its composition, allowing to achieve a greater affinity with the surface of the mineral.

On the Use of Styrene-Based Nanoparticles to Mitigate the Effect of Montmorillonite in Copper Sulfide Recovery by Flotation

“…Figure 5 shows the zeta potential of chalcopyrite, montmorillonite, and St-CTAB-VI NPs as a function of pH (Figure 5a). In the figure, it can be observed that the St-CTAB-VI NPs have a positive surface charge throughout the pH range studied (6-10), with a maximum value of 50 mV at pH 8 and a minimum value of 42 mV at pH 10, which is consistent with the report by Murga et al (2022) [33]. In the case of the chalcopyrite, it had a negative potential in the range of pH studied, obtaining values between −6.06 mV (pH 6) and −40.69 mV (pH 10).…”

“…However, Yang et al, 2011 showed that nanoparticles functionalized with imidazole groups (VI) are designed to cause selective adsorption onto sulfide minerals, even in the presence of glass beads, which have a more negative charge than montmorillonite [ 32 ]. In this case, the interaction was due to electrostatic forces, considering that the nanoparticles had cationic charges and the presence of the imidazole group contributed a more stable deposition of nanoparticles onto the copper-rich surface In addition, considering the presence of NPs and montmorillonite in the system, NPs can be deposited faster on the surface of the chalcopyrite than the clay minerals, as the NPs have higher attractive forces and higher eletrophoretic mobility than montmorillonite [ 33 ].…”

“…The preparation of the polystyrene-based organic St-CTAB-VI NPs used the following chemical reagents supplied by Sigma-Aldrich (St. Louis, MO, USA): styrene as monomer, VI (vinylimidazole) as binder, CTAB (cetyltrimethylammonium bromide) as cationic surfactant, and V50 as starter. The manufacturing process of these nanoparticles involves a series of steps, described by Murga et al (2022) [ 33 ]. The nanoparticles were characterized at pH 8 using dynamic light scattering (DLS) and electrophoretic light scattering (ELS) techniques to determine their hydrodynamic radius, electrophoretic mobility, and surface charge.…”

“…Recently, nano/collectors have attracted a lot of interest because they have the potential to give much more efficient attachment to air bubbles than molecular collectors [31,32]. In relation to the behavior of nanoparticles, it has been demonstrated that polystyrene nanoparticles (NPs) functionalized by the imidazole group (St-CTAB-VI) as collectors resulted in higher recoveries of sulfide minerals like pentlandite [13] and chalcopyrite [33]. In relation to the presence of clay minerals and the slime coating phenomenon it has been reported that large nanoparticles adsorbed on pentlandite surfaces may be less susceptible to the slime coating produced by serpentine than conventional collectors (a kaolin group clay mineral) [13].…”