Electrochemical behavior of galena in the presence of calcium and sulfate ions

• Published in: Minerals engineering 2017-09, Vol.111, p.158-166
• Main Authors: Flores-Álvarez, José Manuel, Elizondo-Álvarez, Martha Araceli, Dávila-Pulido, Gloria Ivone, Guerrero-Flores, Angel Daniel, Uribe-Salas, Alejandro
• Format: Article
• Language: English
• Subjects: Calcium; Carbon paste electrodes; Galena; Sulfate; Xanthate
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2017.06.014

•Calcium interacts with the oxidized sites of the galena surface.•Sulfate appears to passivate further oxidation/reduction of the mineral.•At acidic pH a layer of lead sulfate appears to form, partially covering the surface of the mineral.•At alkaline pH, the passive layer that forms on the mineral surface is composed by several lead species.•The CaOH+ species creates a stronger bond with the mineral, compared to Ca2+. A study of the electrochemical behavior of galena and the effect of the Ca2+ and SO42− species on the mineral behavior at different pH, was carried out using carbon paste electrodes. The Ca2+ and SO42− ions were used to simulate the species that are most concentrated in the recycled water of sulfide mineral flotation processes. By means of electrochemical and SEM analysis, it was possible to identify the chemical species that are generated on the mineral surface by means of redox reactions. In the same way, it was observed that depending on the pH, Ca2+ and CaOH+ species interact with the oxidized species of galena. Furthermore, at acidic pH, sulfate reacts with lead ions to form a passivating layer on the surface of the mineral, while at alkaline pH more than one species is generated on the mineral, which passivate its surface.