Electrochemical noise analysis of chalcopyrite carbon paste electrodes by Acidithiobacillus ferrooxidans

• Autor(a) principal: Horta, Daniela G. [UNESP]
• Data de Publicação: 2007
• Outros Autores: Bevilaqua, Denise [UNESP], Acciaric, Heloisa A. [UNESP], Garcia Jr., Oswaldo [UNESP], Benedettie, Assis V. [UNESP]
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.4028/www.scientific.net/AMR.20-21.83; http://hdl.handle.net/11449/31779
• topic: chalcopyrite; Acidithiobacillus ferrooxidans; carbon paste electrodes; electrochemical noise analysis; bioleaching

The electrochemical response of chalcopyrite was studied using electrochemical noise analysis (ENA). The assay was carried out under constant aeration using 30 mL in two electrochemical cells containing iron-free mineral salts solution. These cells were initially monitored for 56 hours, After 72 hours, 7.25x 10(10) cells mL(-1) of A, ferrooxidans strain LR were added in both cells and monitored until 128 h. Subsequent to this period, 0.927 mmol L-1 of silver ions and 400 mmol L-1 of chloride ions were added each one separately. Both conditions were monitored until 168 hours. According to results obtained, it was observed that Cl- ions addition induced an accelerated corrosion process. However, there is a tendency of the system to reach the stationary state due to repassivation of the electrodic surface. In the other side, the Ag+ addition contributed for the maintenance of the oxidant atmosphere, in spite of controversial effect caused by considerable variations in the R-n values, resulting in a instability in the chalcopyrite reactivity.