Direct Observation of Pure Cu and Cu-Ag Anode Passivation in H2SO4-CuSO4 Aqueous Solution by Channel Flow Double Electrode and Optical Microscopy

Ninomiya, Yuma; Sasaki, Hideaki; Yoshikawa, Takeshi; Maeda, Masafumi

doi:10.1007/s11663-018-1447-9

Cited by 4 publications

(1 citation statement)

References 34 publications

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“…Kucharska-Giziewicz & Mackinnon [5], used cyclic voltammetry to characterize the behavior of silver-containing copper anodes and found that the passivation time decreases with increasing Ag content in the copper anode. In a recent study, Ninomiya et.al [6] also observed that a Cu 5wt%Ag anode passivated with a lower current density than the pure Cu anode, attributing it to the adhesive characteristics of the slime layer. Due to this detrimental behavior of silver in the copper anode, the common copper anode has an upper limit of about 0.75% silver content [1] and this limits refineries in the amount of silver or other precious metals they can recover from e-waste.…”

Section: Introductionmentioning

confidence: 96%

The Role of Lead in Suppressing Passivation of High Silver―Containing Copper Anodes During Electrorefining

Godirilwe

Takasaki

Haga

et al. 2022

Int.J.Soc.Mater.Eng.Resour.

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Passivation behavior of high silver containing copper anodes was investigated using slowly cooled Cu-1%Ag anodes of diff erent lead (Pb) concentrations. The addition of Pb distributes silver in the Pb phase and reduces the amount of silver that is solidly soluble in copper and, thus, generates a fi ne silver powder on the anode surface which is a main contributing factor of passivation. Electrorefi ning experiments were conducted using a synthetic electrolyte containing 40 g/L Cu 2+ and 180 g/L H 2 SO 4 , at 60°C. SEM-EDS analysis was used to study the resulting anode slime and showed that increasing Pb content altered the anode slime structure from fi ne and compact to porous and less adherent to the anode surface. Utilizing a Cu-1%Ag-0.2%Pb anode yielded the longest passivation time with a low and stable cell voltage of 0.1V. The slime morphology was characterized by precipitated metallic silver particles either as inclusion or loosely present on the surface of the abundant complex Cu-Ag-Pb sulfate type of compounds. Because of the economic importance of silver recovery from the anode slime, understanding its behavior during electrorefi ning will enable operating with high impurity anodes especially in secondary copper processing where metallic impurities can result from e-waste and copper alloy scrap.

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Section: Introductionmentioning

confidence: 96%

The Role of Lead in Suppressing Passivation of High Silver―Containing Copper Anodes During Electrorefining

Godirilwe

Takasaki

Haga

et al. 2022

Int.J.Soc.Mater.Eng.Resour.

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Passivation of Cu–Sb anodes in H2SO4−CuSO4 aqueous solution observed by the channel flow double electrode method and optical microscopy

Ninomiya

Sasaki

Kamiko

et al. 2019

Electrochimica Acta

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Challenges for development of technology for prevention of anode passivation during electrorefining of low-grade copper

Sasaki

Okabe

2020

Journal of the Mining and Materials Processing Institute of Jap

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Over the past years, the significance of recycling Cu and its accompanying metals has been increasing. However, the frequency of anode passivation increases during the electrorefining of copper when the copper anode contains a high concentration of impurities. When the amount of secondary materials (scraps) used is increased, the process of electrorefining is frequently troubled because e-waste contains elements that induce anode passivation. Therefore, the development of passivation-prevention technology for low-grade copper anode is essential. This article reviews previous research on the behavior of impurities in the Cu anode and their effects on passivation. The guiding principles for developing passivation-prevention technology are also outlined.

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Direct Observation of Pure Cu and Cu-Ag Anode Passivation in H2SO4-CuSO4 Aqueous Solution by Channel Flow Double Electrode and Optical Microscopy

Cited by 4 publications

References 34 publications

The Role of Lead in Suppressing Passivation of High Silver―Containing Copper Anodes During Electrorefining

The Role of Lead in Suppressing Passivation of High Silver―Containing Copper Anodes During Electrorefining

Passivation of Cu–Sb anodes in H2SO4−CuSO4 aqueous solution observed by the channel flow double electrode method and optical microscopy

Challenges for development of technology for prevention of anode passivation during electrorefining of low-grade copper

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