Modelling of silver anode dissolution and the effect of gold as impurity under simulated industrial silver electrorefining conditions

An anode dissolution of binary metallic lead–bismuth alloys with different concentrations of components has been studied in the KCl–PbCl2 molten eutectic. The dissolution of lead is found to be a basic process for the alloys of Pb–Bi (59.3–40.7), Pb–Bi (32.5–67.5), Pb–Bi (7.0–93.0) compositions in the whole interval of studied anode current densities. A limiting diffusion current of lead dissolution was observed at 2 A/cm2 and 0.1 A/cm2 for the alloys of Pb–Bi (5.0–95.0) and Pb–Bi (3.0–97.0) compositions, respectively. The dissolution of bismuth takes place at the anode current densities exceeding the mentioned values. The number of electrons participating in the electrode reactions is detected for each mechanism. Based on the theoretical analysis, the experimental electrolysis of bismuth was performed in the laboratory-scale electrolytic cell with a porous ceramic diaphragm. The final product contained pure bismuth with a lead concentration of 3.5 wt.%.

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Principles of the express method for controlling interelectrode space condition during wire electrochemical processing

Journal of Electrochemical Science and Engineering ◽

10.5599/jese.660 ◽

2019 ◽

Vol 9 (4) ◽

pp. 269-280

Author(s):

Vasyl Osypenko ◽

Oleksandr Plakhotnyi ◽

Oleksii Timchenko

Keyword(s):

Electrical Discharge Machining ◽

Electrochemical Machining ◽

Practical Implementation ◽

Movement Trajectory ◽

Electrode Tool ◽

Space Condition ◽

Electrochemical Processing ◽

Electrode Space ◽

Anode Dissolution ◽

Adaptive Adjustment

In the practical implementation of the sequential wire electrical discharge machining – pulsed electrochemical machining (WEDM – PECM) technology and in order to perform high quality electrochemical processing, there is a need for the real-time operational control of electrical parameters of inter-electrode space and corresponding adaptive correction of amplitude-frequency power supply parameters (AFPSP). In the context presented by the authors, a mathematical apparatus and an algorithm of operational galvanostatic mode monitoring of anode dissolution using wire electrode-tool are proposed. This will allow adaptive adjustment of AFPSP to ensure controlled passage of electrochemical reactions and significantly increase process stability, dissolved surface layer thickness uniformity along entire electrode tool movement trajectory and resulting surface quality.

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Anode dissolution of nickel in segregating oxide systems

Russian Metallurgy (Metally) ◽

10.1134/s003602951208006x ◽

2012 ◽

Vol 2012 (8) ◽

pp. 685-691

Author(s):

A. I. Mikhailov ◽

A. N. Vatolin

Keyword(s):

Oxide Systems ◽

Anode Dissolution

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First principles investigation of zinc-anode dissolution in zinc–air batteries

Physical Chemistry Chemical Physics ◽

10.1039/c3cp50349f ◽

2013 ◽

Vol 15 (17) ◽

pp. 6416 ◽

Cited By ~ 23

Author(s):

Samira Siahrostami ◽

Vladimir Tripković ◽

Keld T. Lundgaard ◽

Kristian E. Jensen ◽

Heine A. Hansen ◽

...

Keyword(s):

First Principles ◽

Zinc Anode ◽

Anode Dissolution ◽

Zinc Air Batteries

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Micro Electrochemical Milling of Micro Metal Parts with Rotating Ultrasonic Electrode

Sensors ◽

10.3390/s20226617 ◽

2020 ◽

Vol 20 (22) ◽

pp. 6617

Author(s):

Yong Liu ◽

Haoran Chen ◽

Shenghai Wang ◽

Kan Wang ◽

Minghao Li ◽

...

Keyword(s):

Surface Quality ◽

Ultrasonic Vibration ◽

Rapid Development ◽

Three Dimensional ◽

Machining Performance ◽

Good Surface ◽

Anode Dissolution ◽

Compound Method ◽

Metal Microstructure ◽

Electrochemical Milling

With the rapid development of MEMS, the demand for metal microstructure is increasing. Micro electrochemical milling technology (MECM) is capable of manufacturing micro metallic devices or components based on the principle of electrochemical anode dissolution. To improve the capacity of MECM, this paper presents a compound method named ultrasonic vibration-assisted micro electrochemical milling technology (UA-MECM). Firstly, the simulation and mathematical model of UA-MECM process is established to explain the mechanism of ultrasonic vibration on micro electrochemical milling. Then, the effects of ultrasonic parameters, electrical parameters and feedrate on machining localization and surface quality are discussed considering sets of experiments. The surface roughness was effectively reduced from Ra 0.83 to Ra 0.26 µm with the addition of ultrasonic vibration. It turns out that ultrasonic vibration can obviously improve machining precision, efficiency and quality. Finally, two- and three-dimensional microstructures with good surface quality were successful fabricated. It shows that ultrasonic vibration-assisted electrochemical milling technology has excellent machining performance, which has potential and broad industrial application prospects.

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Electrorefining of High Carbon Ferromanganese in Molten Salts to Produce Pure Ferromanganese

Archives of Metallurgy and Materials ◽

10.1515/amm-2017-0233 ◽

2017 ◽

Vol 62 (3) ◽

pp. 1505-1509 ◽

Cited By ~ 1

Author(s):

S. J. Xiao ◽

W. Liu ◽

L. Gao ◽

J. Zhang

Keyword(s):

Electron Microscope ◽

Molten Salts ◽

Reference Electrode ◽

X Ray Diffraction ◽

High Carbon ◽

X Ray ◽

Anode Dissolution ◽

High Carbon Ferromanganese ◽

Scanning Electron ◽

Main Impurity

AbstractHigh carbon ferromanganese is used as a starting material to prepare pure ferromanganese by electrorefining in molten salts. High carbon ferromanganese was applied as the anode, molybdenum was the cathode and Ag/AgCl was the reference electrode. The anodic dissolution was investigated by linear polarization in molten NaCl-KCl system. Then potentiostatic electrolysis was carried out to produce pure ferromanganese from high carbon ferromanganese. The cathodic product was determined to be a mixture of manganese and iron by x-ray diffraction (XRD). The content of carbon in the product was analyzed by carbon and sulfur analyzer. The post-electrolysis anode was characterized by scanning electron microscope (SEM). The mechanism of the anode dissolution and the distribution of the main impurity of carbon and silicon after electrolysis were discussed.

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Electrochemical Machining—Prediction and Correlation of Process Variables

Journal of Engineering for Industry ◽

10.1115/1.3672681 ◽

1966 ◽

Vol 88 (4) ◽

pp. 455-461 ◽

Cited By ~ 26

Author(s):

J. Hopenfeld ◽

R. R. Cole

Keyword(s):

Flow Rate ◽

Metal Removal ◽

Electrochemical Machining ◽

Electrolytic Cell ◽

Process Variables ◽

Electrode Gap ◽

Electrolyte Flow ◽

Normal Current Density ◽

Anode Dissolution ◽

Bubble Layer

The relationship between total current, applied potential, electrolyte flow rate, electrolyte conductivity, and electrode gap in electrochemical machining was investigated experimentally and analytically. An electrolytic cell was designed permitting the electrode gap to be observed and photographed. A 0.25 × 0.375-in. rectangular 1100F aluminum anode was used. Electrode gap varied between 0.013 and 0.033 in. The electrolyte was potassium chloride in concentrations from 0.67 normal to 1.7 normal. Current density range was 40–450 amp/in. and electrolyte flow rate was 0.22 to 0.98 gal/min. The photographs taken of the electrode gap during operation clearly show development of a hydrogen bubble layer next to the cathode. Based upon a mathematical model incorporating the bubble layer, an equation in a nondimensional form has been derived describing the functional relationship between process variables. This equation correlates the experimental data within plus or minus 15 percent. An equation which predicts the local current distribution, and hence anode dissolution rate, along the electrode gap in the direction of electrolyte flow is also presented. Based on the theoretical analysis, optimum operation in electrochemical machining from the standpoint of uniformity of metal removal is discussed.

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