Influence of temperature and current density on oxygen overpotential and corrosion rate of Pb–Co3O4, Pb–Ca–Sn, and Pb–Sb anodes for copper electrowinning: Part I

Hrussanova, A.; Mirkova, L.; Dobrev, Ts.; Васильев, С. Г.

doi:10.1016/j.hydromet.2003.07.004

Cited by 30 publications

(20 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Research on developing methods to produce catalytically active composite coated anodes which can operate as anodes to generate oxygen at a low overpotential and maintain good resistance to corrosion continues (Musiani and Guerriero, 1998;Bertoncello et al, 1999;Bertoncello et al, 2000;Hrussanova et al, 2001Hrussanova et al, , 2002Hrussanova et al, , 2004aHrussanova et al, and 2004bCattarin et al, 2001;Velichenko et al, 2002Velichenko et al, , 2008Velichenko et al, , 2009aVelichenko et al, and 2009b. Prengaman and Siegmund (2007) This paper presents the results of a study which aims to extend the previous work and utilise some of the benefits of cobalt by introducing it directly into the surface layer of the anode, thus avoiding the need to continuously add cobalt ions to the electrolyte.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Electrodeposition of lead–cobalt composite coatings electrocatalytic for oxygen evolution and the properties of composite coated anodes for copper electrowinning

Barmi

Nikoloski

2012

Hydrometallurgy

View full text Add to dashboard Cite

ÔØ Å ÒÙ× Ö ÔØElectrodeposition of lead-cobalt composite coatings electrocatalytic for oxygen evolution and the properties of composite coated anodes for copper electrowinning Please cite this article as: Barmi, Maryam Jozegholami, Nikoloski, Aleksandar N., Electrodeposition of lead-cobalt composite coatings electrocatalytic for oxygen evolution and the properties of composite coated anodes for copper electrowinning, Hydrometallurgy (2012), doi: 10.1016/j.hydromet.2012.08.005 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. , which is significantly less than the 122 mV dec -1 measured on the conventional PbCaSn anodes. The composite anodes exhibited consistently lower oxygen evolution potentials than the conventional type and the potential remained relatively stable throughout the polarisation period. The reduction in the operating anode potential can be attributed to the presence of cobalt in the surface layer while the decrease in the Tafel slope shows that this reduction can be related to a change in the mechanism of the oxygen evolution reaction. Corrosion rates estimated from 16 h tests showed that the composite coated anodes are more stable than the conventional type during short periods of operation. It was also observed that for the Pb-Co coated anode, both the rate of corrosion and the overpotential for the oxygen evolution reaction can be further reduced by the addition of organic additives such as thiourea. : electrowinning, overpotential, anode, lead, cobalt, thiourea A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Keywords INTRODUCTIONLead based anodes have been used in the electrowinning of base metals for more than a century due to their low cost and availability. However, the conventional types of lead based anodes, such as PbCaSn, operate at relatively high oxygen overpotential, which results in significant energy consumption, and suffer from corrosion which takes place at a slow rate during the electrowinning process. It is reported that 20-25% of the overall cell energy consumption in tankhouses using conventional lead based anodes is attributed to oxygen evolution overpotential (Schmachtel et al., 2008). On the other hand, the slow corrosion is adding to the cost of anode replacement but, also, leads to contamination of the cathodes with lead from the corrosion product which lowers the quality of the produced cathodes.The development of anodes that can evolve oxygen from acidic sulphate solutions at lower overpotential than on the conventional lead based anode has a long history in the hydrometallurgical research field. This was revisited in the present study, with particul...

show abstract

Section: Accepted M Manuscriptmentioning

confidence: 99%

Electrodeposition of lead–cobalt composite coatings electrocatalytic for oxygen evolution and the properties of composite coated anodes for copper electrowinning

Barmi

Nikoloski

2012

Hydrometallurgy

View full text Add to dashboard Cite

show abstract

“…This suggests that the formation of a continuous and impermeable oxide film in the presence of cobalt ions acts to protect the underlying metal surface. Hrussanova et al [15] speculated that the porous film consisted of b-PbO 2 and the dense part was composed of PbO t , PbO x and a-PbO 2 and that the oxidation rate increased with the content of b-PbO 2 in the film. The potential was swept at 10 mV s -1 in a negative direction from the potential at *2.1 V. Subsequently the positive scan was measured Figure 7 shows that peak E, which is attributed to the reduction of PbO to Pb, was either not present in the anodic film for cobalt concentrations above 10 ppm or PbO was not produced in the reduction of the PbO 2 layer formed in the presence of cobalt ions.…”

Section: Effect Of Cobalt Concentrationmentioning

confidence: 99%

“…Prior research [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] has shown that a small amount (less than 100 ppm) of cobalt ions in the electrolyte results in a lower oxidation rate of the lead alloy, a lower oxygen overpotential (or at least a lower potential of the lead), a smaller amount of PbO 2 on the lead surface [12] and mainly lead sulphate [19] as the oxidation product. The lower potential at the lead anode could lead directly to a lower oxidation rate.…”

Section: Introductionmentioning

confidence: 99%

Influence of cobalt ions on the anodic oxidation of a lead alloy under conditions typical of copper electrowinning

et al. 2007

View full text Add to dashboard Cite

The influence of cobalt ions in the solution on the anodic oxidation of a commercial Pb-Ca-Sn alloy under conditions typical of copper electrowinning was studied using cyclic voltammograms and potential decay transients. The cobalt ions changed the structure, morphology and chemical composition of the surface film from a loose porous film to a thin dense film. This change of surface film is the cause for the decreased rate of oxidation for the lead anode in the presence of cobalt ions. The steady state potential of the alloy during anodic oxidation decreased with (i) increasing cobalt ion concentration, (ii) increasing rotation speed, (iii) increasing temperature, (iv) decreasing acid concentration and (v) decreasing current density. The steady state potentials were lower in the presence of cobalt ions. This decrease in the steady state potential may indicate that oxygen evolution is more rapid on the more compact film formed in the presence of cobalt ions. Alternatively, an additional pathway of oxidation may be provided by the cobalt ions.

show abstract

“…It is well established in electrowinning applications that cobalt, added into the electrolyte, or added as an alloying element or on the surface layer of an anode, reduces the operating potential and corrosion rate of lead based anodes, while the lower lead dioxide formation contributed to the quality of the produced cathodes (Bagshaw, 1997;Cachet et al, 1999;Hrussanova et al, 2001Hrussanova et al, , 2004aHrussanova et al, , 2004bRashkov et al, 1999;Yu and O'Keefe 1999). A literature review on the influence of cobalt in the electrolyte solution on the performance of lead based anodes in copper electrowinning was provided by Nikoloski and Nicol (2008), followed by a separate review focusing on the direct addition of cobalt to the lead surface layer (Nikoloski and Nicol, 2010).…”

Section: Introductionmentioning

confidence: 99%

Novel lead–cobalt composite anodes for copper electrowinning

Nikoloski

Barmi

2013

Hydrometallurgy

View full text Add to dashboard Cite

PbO 2 -CoO x and PbO 2 -Co 3 O 4 composite coated anodes, using titanium and nickel substrates, have been successfully prepared and tested under typical copper electrowinning conditions. The aim of depositing a well-adhered composite coating onto the surface of the titanium and nickel substrate materials was pursued using three different coatings. The performance of the produced anodes was examined in terms of oxygen evolution potential and service life. Both of the anodes with PbO 2 -CoO x or PbO 2 -Co 3 O 4 deposited on titanium resulted in reduction of the oxygen evolution potential of 300 to 400 mV compared with a conventional PbCaSn anode. The anodes prepared by applying the same coatings onto a nickel substrate showed poor stability in the acidic electrolyte media used in this experiment to represent typical copper electrowinning conditions. Of the different coatings tested, a combination of thermal deposition of a SnO 2 -Sb 2 O 3 interlayer on the surface of a titanium substrate followed by electrodeposition of the top layer of the composite coating resulted in the best electrochemical activity and service life for the anodes. A Tafel slope of 88 mV dec -1 was recorded for the anode with a top coating of PbO 2 -CoO x and 47 mV dec -1 for the anode with a top coating of PbO 2 -Co 3 O 4 , which both compare favourably to the 122 mV dec -1 which was observed for a conventional PbCaSn anode. Anodisation tests were carried out for a period of 16 hours both in the presence and in the absence of the organic additive thiourea in the electrolyte. Corrosion rates were estimated from these tests and the results showed that the titanium based anode with a SnO 2 -Sb 2 O 3 interlayer and PbO 2 -CoO x coating has a lower corrosion rate than a conventional PbCaSn anode, whereas the corrosion rate of the titanium based anode with same interlayer and PbO 2 -Co 3 O 4 coating might be much greater but this remains to be confirmed. The results also showed that the addition of thiourea appears to increase the corrosion rate of the composite coated anodes although it reduces the corrosion rate of a PbCaSn anode. Thiourea showed no obvious effect on the anode potential.

show abstract

Influence of temperature and current density on oxygen overpotential and corrosion rate of Pb–Co3O4, Pb–Ca–Sn, and Pb–Sb anodes for copper electrowinning: Part I

Cited by 30 publications

References 2 publications

Electrodeposition of lead–cobalt composite coatings electrocatalytic for oxygen evolution and the properties of composite coated anodes for copper electrowinning

Electrodeposition of lead–cobalt composite coatings electrocatalytic for oxygen evolution and the properties of composite coated anodes for copper electrowinning

Influence of cobalt ions on the anodic oxidation of a lead alloy under conditions typical of copper electrowinning

Novel lead–cobalt composite anodes for copper electrowinning

Contact Info

Product

Resources

About