Zeta Potential of Pyrite Particles in Concentrated Solutions of Monovalent Seawater Electrolytes and Amyl Xanthate

Abstract

Charge screening and adsorption capacity of monovalent ions onto pyrite (Py) in aqueous suspensions and the effect of potassium amyl xanthate (PAX) has been studied by measuring the changes in zeta potential (zp) versus pH with streaming potential. PAX addition in the absence of salts leads to an increase in |zp| suggesting dissolution of the surface ferric hydroxides and recovery of bare Py, corroborating existing theories. In the presence of salt, addition of PAX at pH > 6, for which hydroxides interference in not expected, has little effect over the zp, except when Li is present. The water network around the polar head of PAX is expected to be similar to that of hydrated Li+ facilitating the linkage between them and, thus, the formation of Li-mediated Py–PAX bridges. We speculate that these bridges lead to a xanthate shield around anionic sites on Py, decreasing |zp|. An increased PAX dose amplifies the effect of Li as a Py activator but only at low salt. At high salt concentrations, >0.01 M, PAX molecules do not find room to percolate to the surface of Py. Results for monovalent cations should improve our understanding of copper flotation processes in the presence of Py in saltwater.

AFM Study of Pyrite Oxidation and Xanthate Adsorption in the Presence of Seawater Salts

“…Again, it was verified that the salt cations reached the surface of the pyrite and covered it, even if PAX was in a high dose. In previous work [27], we analyzed the effect of alkali metal ions, such as Na + , on the zeta potential of pyrite in the presence of PAX. The results showed for low salt concentrations that the cations were adsorbed on the pyrite leaving few sites for the adsorption of the PAX molecules; therefore, at 0.5 M of salt it was expected that the PAX molecules would not penetrate the thick layer of cations that covered the surface of the pyrite and, therefore, little or no PAX was adsorbed.…”

“…The new complexities that must be addressed include the effect of saltwater cations on the surface of the pyrite, the association of cations with collector molecules, and the adsorption of collector on pyrite carpeted by cations. Recently, Paredes et al [27] studied the effect of alkali metal ions on the zeta potential of pyrite at different salt concentrations, as well as the effect on the potential of the addition of potassium amyl xanthate to a previously conditioned pyrite solution. In this study, contact mode atomic force microscopy (AFM) is used to analyze the topography of pyrite surfaces subjected to treatments including oxidation and exposure to xanthate and solutions of seawater salts and xanthate at a pH typical of seawater.…”

Effects of Digestion, Cell Culture Media, and Mucous on the Physical Properties, Cellular Effects, and Translocation of Polystyrene and Polymethacrylate Nanoparticles

“…The particles are immobilized on the walls of the PTFE chamber, and the liquid flow causes charge separation. As the mobile cloud of the double layer of the immobilized particles is pushed up and down, that oscillating ion cloud produces an alternating voltage at the two electrodes—the streaming potential—which is proportional to the zeta potential of the particles” [ 33 ]. The isoelectric points (pI) for each nanoparticle and media were determined from the pH-mV plots.…”

Impact of organic phosphates on the structure and composition of short-range ordered iron nanophases

“…For this, all solids were suspended in 10 mM NaCl at a solid concentration of 0.4 g L −1 and then titrated in triplicate to pH 10 (±0.2) with 0.1 M NaOH. 66 For particle size distribution, SAXS measurements were conducted using the MOUSE (Methodology Optimization for Ultrane Structure Exploration) instrument at the Bundesanstalt für Materialforschung und-prüfung (BAM), and at Diamond Light Source Beamline I22. 67,68 See ESI † for more details.…”