Use of Catalytic Anodes For Zinc Electrowinning At High Current Densities From Purified Electrolytes

Bestetti, Massimiliano; Ducati, U.; Kelsall, G. H.; Li, G.; Guerra, Eduard

doi:10.1179/cmq.2001.40.4.451

Cited by 21 publications

(16 citation statements)

References 8 publications

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“…Another example was reported using a continuous stripping technique operating with an aluminium alloy belt cathode, which employed DSA anodes running at current densities of over 5 kA m -2 in purified zinc electrolytes [51].…”

Section: Introductionmentioning

confidence: 99%

New oxygen evolution anodes for metal electrowinning: MnO2 composite electrodes

et al. 2009

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Several modifications of manganese dioxide (MnO 2 ) were investigated for use in composite electrode materials for oxygen evolution, the target application being anodes for the industrial electrowinning of metals. It is demonstrated that the performance of this material depends strongly on the modifications of MnO 2 . All modifications investigated were found to be more active than the usual anode of lead alloyed with silver (PbAg) used in zinc electrowinning. A composite sample containing chemical manganese dioxide (CMD) was found to give an oxygen evolution overpotential 0.25 V lower than the standard PbAg anode material. In the second part of the article, we investigate the effect of varying several parameters of the composite electrode assembly, including the size of the catalyst particles and percentage of the catalyst material used. A model is proposed where the performance of the material is proportional to the total length of the boundaries between the lead matrix material and the MnO 2 catalyst particles. Physicochemical processes contributing to the observed data are discussed.

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Section: Introductionmentioning

confidence: 99%

New oxygen evolution anodes for metal electrowinning: MnO2 composite electrodes

et al. 2009

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“…Apart from a few special applications [13][14][15], it is not being used in metal electrowinning. The main drawback of DSA remains its high investment cost, which are due to the high prices of titanium substrates, precious metals, and the coating procedure.…”

Section: Introductionmentioning

confidence: 99%

New oxygen evolution anodes for metal electrowinning: investigation of local physicochemical processes on composite electrodes with conductive atomic force microscopy and scanning electrochemical microscopy

Schmachtel¹,

Pust

Kontturi³

et al. 2009

J Appl Electrochem

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Atomic force microscopy (AFM), conductive atomic force microscopy (CAFM) in air, and scanning electrochemcial microscopy (SECM) in 2 M H 2 SO 4 have been used to investigate model composite electrodes obtained by pressing sieved MnO 2 particles into a Pb matrix. These model electrodes shall resemble new composite electrodes produced by coldspraying and currently being tested for Zn electrowinning. CAFM showed a very uneven distribution of the current path through the matrix electrode with the highest currents measured at the MnO 2 / Pb domain boundary. SECM images in the substrate-generation/tip-collection mode in vertical and horizontal planes could show spatial concentration distribution of H ? , O 2 and H 2 O 2 that could be evaluated qualitatively despite interfering turbulent convection due to raising gas bubbles. There is a concentration overvoltage due to deviations of the H ? and O 2 concentration close to the surface from the bulk value. It amounts to about 40-50 mV for both compounds. H 2 O 2 is formed as an intermediate and is consumed at the MnO 2 catalyst particles.

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“…Zinc is mainly extracted by electrowinning process in hydrometallurgy from its sulfide ores, oxide ores or other secondary resources (Bestetti et al, 2001;Jha et al, 2001). It is well known that electrode process direction and kinetics, structure patterns of electrolytic cell and electric energy consumption, not only are relative with electrolyte characteristics but also depend on characteristics of anode materials in zinc electrowinning.…”

Section: Introductionmentioning

confidence: 99%