The Rotating Cylinder Electrode (RCE) and its Application to the Electrodeposition of Metals

2005 ◽  
Vol 58 (4) ◽  
pp. 246 ◽  
Author(s):  
C. T. John Low ◽  
Carlos Ponce de Leon ◽  
Frank C. Walsh
Keyword(s):  
Rotating Cylinder ◽  
Cathode Current Density ◽  
Vitreous Carbon ◽  
Experimental Investigations ◽  
Rotating Cylinder Electrode ◽  
Expanded Metal ◽  
Cathode Current ◽  
Uniform Current ◽  
Current Densities ◽  
Electrodeposition Of Metals

The application of rotating cylinder electrodes (RCEs) to electrodeposition has progressed significantly over the last decade. New tools for theoretical and experimental investigations have been developed in academia and in industry, with some RCE devices being commercially developed. This paper reviews the continued application of RCEs to quantitative electrodeposition studies of single metals, alloys, and composite, multilayered, and nanostructured electrodeposits with a constant or controlled range of current densities along the RCE under turbulent flow conditions. Rotating cylinder electrode electrochemical reactors, enhanced mass transport, rotating cylinder Hull cell, and uniform and non-uniform current and potential distributions are considered. The applications of ultrasound, porous reticulated vitreous carbon cathodes, expanded metal/baffles, and jet flow around the RCE are also included. The effects of electrolyte flow and cathode current density on electrodeposition have been rationalized. Directions for future RCE studies are proposed.

scholarly journals Influence of Current Density on the Microstructure of Carbon-Based Cathode Materials during Aluminum Electrolysis

2020 ◽  
Vol 10 (7) ◽  
pp. 2228
Author(s):  
Wei Wang ◽  
Kai Sun
Keyword(s):  
Current Density ◽  
Aluminum Electrolysis ◽  
Cathode Current Density ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Aluminum Reduction ◽  
Electrostatic Charging ◽  
Cathode Current ◽  
Current Densities ◽  
Sodium Expansion

Sodium expansion plays an important role in cathode deterioration during aluminum electrolysis. In this work, the sodium expansion of semigraphitic cathode material has been measured at various cathodic current densities using a modified Rapoport apparatus. We have studied the microstructural changes of carbon cathodes after aluminum electrolysis using high-resolution transmission electron microscopy (HRTEM). Because of an increasing trend toward higher amperage in retrofitted aluminum reduction cells, an investigation is conducted both at a representative cathode current density (0.45 A/cm2) and at a high cathodic current density (0.7 A/cm2). The results indicate that the microstructures of carbon cathodes can be modified by Joule heating and electrostatic charging with higher current densities during aluminum electrolysis. With the penetration of the sodium and melt, zigzag and armchair edges, disordered carbon, and exfoliation of the surface layers may appear in the interior of the carbon cathode. The penetration of the sodium and melt causes remarkable stresses and strains in the carbon cathodes, that gradually result in performance degradation. This shows that increasing the amperage in aluminum reduction cells may exacerbate the material deterioration of the cathodes.

The use of a rotating cylinder electrode to recover zinc from rinse water generated by the electroplating industry

2012 ◽  
Vol 65 (8) ◽  
pp. 1406-1411 ◽  
Author(s):  
Sairi Matlalcuatzi ◽  
José L. Nava
Keyword(s):  
Reynolds Numbers ◽  
Rotating Cylinder ◽  
Limiting Current ◽  
Ferric Ions ◽  
Zinc Recovery ◽  
Rotating Cylinder Electrode ◽  
Ph Adjustment ◽  
J 13 ◽  
Current Densities ◽  
Rinse Water

This work concerns the application of a laboratory scale rotating cylinder electrode (RCE) to recover zinc from rinse water generated by the electrolytic zinc process (initially 1,300, 4,400, 50, 20 mg L−1 of Zn(II), Fe(III), Ag(I) and Cr(VI), respectively, at pH 2), although it is also applicable to other electroplating industries. Experimental results demonstrated the convenience of the removal of ferric ions, as (Fe(OH)3(s)) by a pH adjustment to 4, before zinc electro recovery on the RCE. The generation of smooth zinc deposits on the RCE was obtained at Reynolds numbers within the range of 15,000 ≤ Re ≤ 124,000 and limiting current densities (JL) in the interval of −4.8 to −13 mA cm−2. The zinc recovery reached a conversion of 67% in 90 min of electrolysis for Re = 124,000 and J = −13 mA cm−2, 21% current efficiency, and energy consumption of 9.5 kWh m−3. The treated solution can be recycled back through the same rinsing process.

scholarly journals Mechanism of Dy3+ and Nd3+ Ions Electrochemical Coreduction with Ni2+, Co2+, and Fe3+ Ions in Chloride Melts

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7440
Author(s):  
Khasbi Kushkhov ◽  
Zhubagi Ali ◽  
Astemir Khotov ◽  
Anna Kholkina
Keyword(s):  
Intermetallic Compounds ◽  
Cathode Current Density ◽  
Kinetic Regime ◽  
X Ray Diffraction ◽  
Significant Difference ◽  
Cathode Current ◽  
Current Densities ◽  
Electrolysis Potential ◽  
Potentiostatic Regime

The present paper is devoted to the study of the processes of the mechanism of electrochemical coreduction of Dy3+ and Nd3+ ions with Ni2+, Co2+, and Fe3+ ions in the equimolar NaCl-KCl melt at 973 K and characterization of the synthesized samples. The performed voltammetry analysis of the electrochemical coreduction processes elucidated a significant difference in the values of the extraction potentials of the studied metals. This melt testifies that intermetallic compounds of Dy and Nd with Ni, Co, and Fe may be synthesized in the kinetic regime. The intermetallic phases of Dy and Nd with Ni, Co, and Fe are found to be formed along with the phases of metallic Ni, Co, and Fe either during electrolysis at the cathode current densities exceeding the limiting diffusion current of Ni2+, Co2+, and Fe3+ ions or in the potentiostatic regime at the potentials of the corresponding voltammetry curves. Therefore, the following interrelated key parameters affecting the electrochemical synthesis of Dy and Nd intermetallic compounds with Ni, Co, and Fe were determined: (i) composition of the electrolyte, i.e., concentrations of FeCl3, CoCl2, NiCl2, DyCl3, and NdCl3; (ii) cathode current density or electrolysis potential and (iii) electrolysis time. The obtained samples were characterized by micro-X-ray diffraction analysis, cyclic voltammetry, and scanning electron microscopy methods.

Bituminous Insulations Durability of Underground Metallic Pipelines I Field investigations

2017 ◽  
Vol 68 (3) ◽  
pp. 581-585 ◽  
Author(s):  
Gabriela Oprina ◽  
Ladislau Radermacher ◽  
Daniel Lingvay ◽  
Dorian Marin ◽  
Andreea Voina ◽  
...  
Keyword(s):  
Cathode Current Density ◽  
Induced Voltage ◽  
Cathodic Current ◽  
Field Investigations ◽  
Operation Period ◽  
Cathode Current ◽  
Protection Potential ◽  
Cathodic Protection System ◽  
Corrosion State ◽  
Good Agreement

The corrosion state of an underground metallic pipeline of �161 mm and 565 m length was assessed by specific electrical and electrochemical measurements. The investigated pipe, buried in 1997, was protected against corrosion by successive layers of bituminous material with a total thickness of 1 to 1.2 mm. The pipeline crosses three electrified railway lines (50 Hz - 28 kV), and then its route is approximately parallel to these lines; thus, the induced AC voltages between line and ground were calculated obtaining values between 4.05 and 7.1 Vrms, in good agreement with the values measured in the accessible points. The measurements regarding the insulation capacity against corrosion of the bituminous insulation, performed at one month and after 19 years of burial, showed an increase of the average cathode current density needed for obtaining the protection potential in the range �1.00 � �1.28 VCu/CuSO4 of approx. three times (from 6.65 up to 19.96 mA/m2), in good agreement with the evolution of the insulation resistance measured between the steel pipe (having a contact area with the ground of 270.5 m2) and a ground socket of 4 W, which decreased from 995 to 315 kW. Following the analysis and processing of the field collected data, it is considered that, by implementing a cheap cathodic protection system (without cathodic current power supply), based on the rectification of the AC induced voltage, the safe operation period of the investigated pipeline may be extended by at least 50 years.

RESTORATION OF MACHINE PARTS WITH GALVANIZED ZINC COATINGS

2020 ◽  
Vol 4 (141) ◽  
pp. 140-147
Author(s):  
MIKHAIL VIKHAREV ◽  
◽  
VLADIMIR YUDIN ◽  
VESELOVSKIY NIKOLAY ◽  
◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
Zinc Coating ◽  
Cathode Current Density ◽  
Research Purpose ◽  
Cathode Layer ◽  
Properties Of Coatings ◽  
Chemical Polarization ◽  
Cathode Current ◽  
Zinc Coatings

The article shows the role of electroplating in the restoration of parts, indicates the advantages of restoring parts with electroplating over other methods, and gives the characteristics and properties of coatings obtained by electroplating. (Research purpose) The research purpose is in increasing the speed of application of zinc electroplating when restoring parts. (Materials and methods) The cathode current density has a decisive influence on the coating speed. The main reason for limiting the cathode current density during galvanizing from sulfuric acid electrolytes is the chemical polarization of the cathode. The article presents a study on the designed installation for the application of galvanic coatings. When applying coatings to the internal surfaces of parts, there was used a device with activating elements having an electromechanical rotation drive. This device prevents depletion of the near-cathode layer of the electrolyte and reduces the chemical polarization of the cathode. Elements made of moisture-resistant skin were used as activators. (Results and discussion) The article presents the results of experiments as a dependence of the coating speed on the speed of the activator relative to the restoring surface. It also presents the relationship between the size of the abrasive grains of the activating elements, the force of their pressing against the cathode surface, the speed of movement of the activator and the speed of applying the zinc coating, as well as its quality. By activating the cathode surface, it was possible to raise the operating current density to 100-150 amperes per square decimeter. The speed of application of zinc coatings is 16-25 micrometers per minute. (Conclusions) In the course of research, authors determined the conditions of electrolysis during galvanizing, which provide a significant increase in the cathode current density and the rate of application of these coatings during the restoration of parts.

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