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

Sasaki, Hideaki; Okabe, Toru H.

doi:10.2473/journalofmmij.136.77

Cited by 3 publications

(6 citation statements)

References 117 publications

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“…The insoluble SbAsO 4 is known to be formed and promote the passivation when a certain amount of As 5+ and Sb 3+ ions are present in the electrolytic solution in the forms of H 3 AsO 4 and SbO + , respectively. 1,31) In this study, the low-grade Cu contains a significant amount (5.6 mass%) of Sb. During electrolysis, Sb, in addition to Cu, dissolves in solution as SbO + ions.…”

Section: Discussionmentioning

confidence: 83%

“…Cu anode passivation has been reported to be directly caused by the precipitate of CuSO 4 at the interface between Cu substrate and slime in previous research. 1,19,22) That is, the slime formed on the surface of Cu inhibits the diffusion of Cu 2+ ions dissolved from the anode, and the concentration of Cu 2+ ions exceeds the solubility of CuSO 4 at the interface between Cu substrate and slime. As a result, CuSO 4 precipitates on the Cu substrate, the passivation appears to occur, and the Cu dissolution reaction immediately shifts to oxygen evolution.…”

Section: Discussionmentioning

confidence: 99%

“…Bi 2 O 3 and Bi 2 (SO 4 ) 3 are known to be formed in slime in an electrolytic solution containing Bi 3+ ions, 7) whereas BiAsO 4 is reported to be formed on Cu anode and promote the passivation in a solution containing a certain amount of As 5+ and Bi 3+ ions. 1,31) The areas where Bi, S, and O (Fig. 9) and As, Bi, and O (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…As a result of this situation, the concentration of impurities included in crude Cu produced by pyrometallurgy has been increasing. 1,2) Electrorefining of crude Cu obtained by pyrometallurgy produces Cu with a purity of above 99.99 mass%, which is used for electrical wire and rolled products. The anode for this electrorefining is usually crude Cu with a purity above 99 mass%.…”

Section: Introductionmentioning

confidence: 99%

“…The concentrations of impurities above were set using data from a practical electrolytic solution of a Japanese Cu electrorefining. 1,28,29) When the recycled low-grade Cu is used as an anode, the concentration of Ni 2+ ions in solution is expected to rise due to increase in dissolution of Ni from the anode. As a result, even though the concentration of Ni 2+ ions in a practical electrolytic solution is around approximately 0.34 mol•dm ¹3 , the concentration in this study was set to be high.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

et al. 2023

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Cu electrorefining using a low-grade copper anode is desirable from the standpoint of electric power savings. Cu electrolysis was carried out in an unagitated sulfate solution with a low-grade copper anode, and the effect of impurity ions and additives in the solution on the passivation of the anode was investigated. The time when anode passivation firstly occurs shortened significantly in a solution containing 0.596 mol•dm ¹3 of Ni 2+ ions as impurity and shortened somewhat in a solution containing As 5+ (0.053 mol•dm ¹3 ) or Bi 3+ (0.0005 mol•dm ¹3 ) ions. Sn 2+ (0.0004 mol•dm ¹3 ) and As 3+ (0.053 mol•dm ¹3 ) ions slightly decreased the time to passivation, but Sb 3+ (0.004 mol•dm ¹3 ) ions did not. The viscosity coefficient of the solution increased when the 0.596 mol•dm ¹3 of Ni 2+ ions were added to the solution, while the diffusion coefficient of Cu 2+ ions decreased. The compound of the AsSbO or AsBiO system was formed in anode slime when the As 5+ (0.053 mol•dm ¹3 ) or Bi 3+ (0.0005 mol•dm ¹3 ) ions were added to the solution, which seemed to increase the compactness of slime. The time to passivation was slightly longer in thiourea-free solution but shortened when the concentration of thiourea was increased from 0.525 to 2.24 mmol•dm ¹3 . The time to passivation was constant in solutions containing 0 to 1.13 mmol•dm ¹3 of Cl ¹ ions, but significantly decreased as the concentration of Cl ¹ ions increased above 1.13 mmol•dm ¹3 . Cl ¹ ions formed CuCl at the upper area of anode slime, which increased the compactness of slime and promoted the passivation.

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

et al. 2023

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Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

Mori

Yamakawa

Oue

et al. 2022

J. Japan Inst. Metals and Materials

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The Cu electrorefining using low-grade copper anode is desired from the view point of reduction of electric power. Cu electrolysis was performed using a low-grade copper anode in an unagitated sulfate solution, and the effect of impurity ions and additives in solution on the passivation of anode was investigated. The time when anode passivation firstly occurs shortened significantly in solution containing 0.596 mol•dm −3 of Ni 2+ ions as impurity, and shortened somewhat in solution containing As 5+ (0.053 mol•dm −3 ) or Bi 3+ (0.0005 mol•dm −3 ) ions. Sn 2+ (0.0004 mol•dm −3 ) and As 3+ (0.053 mol•dm −3 ) ions slightly decreased the time to passivation, but Sb 3+ (0.004 mol•dm −3 ) ions rarely decreased the time. When the 0.596 mol•dm −3 of Ni 2+ ions were added in solution, the viscosity coefficient of solution increased and the diffusion coefficient of Cu 2+ ions decreased. When the As 5+ (0.053 mol•dm −3 ) or Bi 3+ (0.0005 mol•dm −3 ) ions were added in solution, the compound of As-Sb-O or As-Bi-O system was formed in anode slime, which seemed to increase the compactness of slime. The time to passivation was slightly longer in thiourea-free solution, but shortened with increasing the concentration of thiourea from 0.525 to 2.24 mmol•dm −3 . In the solutions containing 0 to 1.13 mmol•dm −3 of Cl − ions, the time to passivation was constant, but significantly shortened with increasing the concentration of Cl − ions at the region above 1.13 mmol•dm −3 . Cl − ions formed CuCl at the upper area of anode slime, as a result, increased the compactness of slime and promoted the passivation.

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酸性硫酸銅水溶液中における銅と銀および亜鉛のガルバニック対の電気化学的挙動とその場観察

TAKASAKI,

KAWAKAMI,

KUBO

et al. 2023

Journal of the Mining and Materials Processing Institute of Jap

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Electrochemical behavior and in situ observation of galvanic couples of copper and silver or zinc wires in acidic copper sulfate solutionsThe anodic dissolution reaction of copper in copper electro-refining was studied by considering the reaction of galvanic couples with different metals as impurities. In this study, zinc was chosen as a typical anodic impurity and silver as a cathodic impurity, and electrochemical measurements of galvanic couples with silver or zinc wires winding around a copper wire and in situ observation of the electrode surface using a stereo microscope were carried out. For comparison, copper wire with zinc or silver plating was used.As a result, even the simple method of winding silver or zinc wire around copper wire was able to capture the characteristic behavior of the galvanic reaction of silver and zinc on copper wire. It was also confirmed that zinc dissolution was accelerated by copper and copper dissolution was accelerated by silver, and that the effects were more promoted under anodic polarization. The crystallization and passivation of copper sulfate on the copper electrode surface and the dissolution behavior of silver were also observed. These results indicate that the experimental method presented in this study is an effective way to investigate the effects of impurities on the solubility and passivation of crude copper metal.

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

Cited by 3 publications

References 117 publications

Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

Effect of Impurity Ions and Additives in Solution of Copper Electrorefining on the Passivation Behavior of Low-Grade Copper Anode

酸性硫酸銅水溶液中における銅と銀および亜鉛のガルバニック対の電気化学的挙動とその場観察

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