scholarly journals Electrometallurgy: electrochemical, economic and environmental (3E) aspects

2011 ◽  
Vol 30 (1) ◽  
pp. 75 ◽  
Author(s):  
Perica Paunović
Keyword(s):  
Current Efficiency ◽  
Molten Salts ◽  
Cell Voltage ◽  
Aqueous Electrolytes ◽  
Electrolysis Process ◽  
Economic Justification ◽  
Cleaner Technology ◽  
The Impact ◽  
Electrochemical Energetic

This paper is concerned with electrolysis processes aimed for production and refining of metals. This engineering field is named electrometallurgy. The main aspects of electrometallurgy such as electrochemical, energetic/economic and environmental ones are given. The peculiarity of electrorefining and electrowining in both aqueous electrolytes and molten salts are shown. The impact of energetic parameters, such as cell voltage and current efficiency on the economic justification of the electrolysis process is analyzed. It is emphasized that electrolysis is considerably cleaner technology than the pyrometallurgical production and refining of metals.

A ALO-LSSVM Model for the Cell Voltage Optimization in Aluminum Electrolysis Process

2020 ◽  
Author(s):  
Chen-hua Xu ◽  
Jin-zhi Zhang ◽  
Ruo-jun Cheng ◽  
Rui Chen ◽  
Zhu-guang Luo ◽  
...  
Keyword(s):  
Cell Voltage ◽  
Aluminum Electrolysis ◽  
Electrolysis Process

scholarly journals The Effect of Cell Compression and Cathode Pressure on Hydrogen Crossover in PEM Water Electrolysis

2021 ◽  
Author(s):  
Agate Martin ◽  
Patrick Trinke ◽  
Markus Stähler ◽  
Andrea Stähler ◽  
Fabian Scheepers ◽  
...  
Keyword(s):  
Mass Transport ◽  
Cell Voltage ◽  
Water Electrolysis ◽  
Material Design ◽  
Operating Conditions ◽  
Cell Performance ◽  
Membrane Electrode ◽  
Current Densities ◽  
Hydrogen Crossover ◽  
The Impact

Abstract Hydrogen crossover poses a crucial issue for polymer electrolyte membrane (PEM) water electrolysers in terms of safe operation and efficiency losses, especially at increased hydrogen pressures. Besides the impact of external operating conditions, the structural properties of the materials also influence the mass transport within the cell. In this study, we provide an analysis of the effect of elevated cathode pressures (up to 15 bar) in addition to increased compression of the membrane electrode assembly on hydrogen crossover and the cell performance, using thin Nafion 212 membranes and current densities up to 3.6 A cm-2. It is shown that a higher compression leads to increased mass transport overpotentials, although the overall cell performance is improved due to the decreased ohmic losses. The mass transport limitations also become visible in enhanced anodic hydrogen contents with increasing compression at high current densities. Moreover, increases in cathode pressure are amplifying the compression effect on hydrogen crossover and mass transport losses. The results indicate that the cell voltage should not be the only criterion for optimizing the system design, but that the material design has to be considered for the reduction of hydrogen crossover in PEM water electrolysis.

Effect of Flow Pattern on Energy Consumption and Properties of Copper Powder in the Electrolytic Process

2018 ◽  
Vol 279 ◽  
pp. 77-84 ◽  
Author(s):  
Wen Tang Xia ◽  
Xiao Yan Xiang ◽  
Wen Qiang Yang ◽  
Jian Guo Yin
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Flow Pattern ◽  
Copper Powder ◽  
Dendritic Structure ◽  
Electrolysis Cell ◽  
Powder Size ◽  
Low Oxygen ◽  
Electrolysis Process ◽  
Electrolytic Process

Because of distinctive properties, such as dendritic structure, high green strength, and low oxygen content, electrolytic copper powder has been widely used in aviation, aerospace, national defense industry and other domains. But at present, energy consumption of the electrolysis process in copper powder production is high, and the current efficiency is only about 90%. Therefore,the decrease in energy consumption of the electrolysis process has become the major bottlenecks in the development of the enterprises. In this paper, a new electrolysis cell with different electrolyte inlet arranged on the cell was manufactured. Then, the effect of flow pattern of electrolyte on the current efficiency, energy consumption and properties of copper powder was investigated. The experimental results showed that the electrolytic process had the higher current efficiency, lower energy consumption and smaller copper powders when the flow rate is 0.5l/min in the paralleled inlet and 1.5 l/min in the traditional inlet. Under the optimal conditions, the current efficiency, energy consumption and copper powder size were 99.10%, 712.90kw∙h/t and 47.80um respectively. This means an obvious rise in current efficiency and decrease in energy consumption compared to traditional feeding method.

Characteristic and Sinterability of Alumina-Zirconia-Yttria Nanoparticles Prepared by Different Chemical Methods

2014 ◽  
Vol 87 ◽  
pp. 30-35
Author(s):  
Janis Grabis ◽  
Dzidra Jankovica ◽  
Ints Steins ◽  
Krisjanis Smits ◽  
Inta Sipola
Keyword(s):  
Phase Transition ◽  
Spark Plasma Sintering ◽  
Molten Salts ◽  
Preparation Method ◽  
Bulk Materials ◽  
Chemical Methods ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact ◽  
Sintering Method

The characteristics and sinterability of the Al2O3-ZrO2(Y2O3) nanoparticles produced by simple and effective microwave and molten salts methods and processed by using spark plasma sintering were studied and compared. The crystalline powders with the specific surface area in the range of 72–108 m2/g and crystallite size of 5–13 nm were obtained by calcination of samples prepared by both methods at 800 °C. The content of t-ZrO2 phase depends on concentration of Al2O3, Y2O3 and on calcination temperature but the impact of the preparation method is insignificant. The phase transition of tetragonal ZrO2 to monoclinic for the samples without Y2O3 started at 1000 °C though it was incomplete in the case of high content of Al2O3. The bulk materials with relative density of 86.1–98.7% were fabricated by the spark plasma sintering method at 1500–1600 °C depending on the content of Al2O3 and Y2O3.

Metal Instabilities and its Effect on Cell Performance during Aluminium Smelting

2013 ◽  
Vol 828 ◽  
pp. 45-54 ◽  
Author(s):  
Anupam Agnihotri ◽  
Shail Umakant Pathak ◽  
Jyoti Mukhopadhyay
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Cell Voltage ◽  
Aluminum Electrolysis ◽  
Cell Performance ◽  
Consumption Pattern ◽  
Magnetic Current ◽  
Zero Current ◽  
Aluminium Smelting ◽  
Rolling Noise

The Hall-Heroult process for the production of aluminium is based on the electrochemical reduction of alumina (Al2O3) dissolved in a cryolite (Na3AlF6) based electrolyte. Instability in cell voltage is referred to as noise. Normal voltage noise is inevitable due to bubble evolution and it has little effect on performance parameters such as, current efficiency and power consumption. Metal rolling noise (wavy noise) is caused by the disturbances in cell magnetic field and it affects the cell current efficiency adversely. Investigating the causes of the cell instability in the aluminium smelting cells can lead to better cell performance. Understanding the variation in cell voltage is critical for cells, because magnitude of voltage determines the energy consumption pattern in the process and hence, any saving on voltage can save energy. Voltage affects the current efficiency of the cell and an optimum cell voltage leads to higher current efficiency without compromising on energy consumption. Magnetic, current distribution, heat loss and voltage at zero current measurements along with online current and voltage signal can help to identify the problems and their combined effects on the performance of the cells. In order to estimate the loss in current efficiency of the aluminum electrolysis cells due to metal instabilities, measurements were performed and data analyzed. The present paper analyses the effect of voltage fluctuations (noise) during metal instability along with cause of instability and its effect on current efficiency of the cell. Measurements carried out to estimate the deviations from the normal cell operations are also discussed.

scholarly journals Preparation of V–4Cr–4Ti Alloys from Mixed Oxides via Electro-Deoxidation Process in Molten Salt

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1067
Author(s):  
Xiaozhou Cao ◽  
Qiuyue Li ◽  
Yuanyuan Shi ◽  
Dong Wu ◽  
Xiangxin Xue
Keyword(s):  
Fusion Reactor ◽  
Mixed Oxides ◽  
Reduction Rate ◽  
Cell Voltage ◽  
Perovskite Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrolysis Process ◽  
Solid Mixture ◽  
Deoxidation Process

V–4Cr–4Ti alloys exhibit important advantages as a candidate structural materials for fusion reactor first-walls and blanket applications. V–4Cr–4Ti alloys were prepared by direct electrochemical reduction of the solid mixture of V2O3, Cr2O3 and TiO2 in the molten CaCl2–NaCl eutectic at 1073 K. The influence of cell voltage, sintering temperature and electrolysis time on the electrolysis process are reported. The microstructure and phase compositions of the products were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) during the electrolysis process. The results showed that V–4Cr–4Ti alloys can be obtained at the voltage of 3.1 V and the time of 0.5 h. Cr2O3 was first reduced to Cr metal, while V2O3 and TiO2 was reduced to low-valence oxide of vanadium and titanium. The reduction rate increases with increasing cell voltage, with much perovskite oxide formed during the electrolysis process.

scholarly journals PEM Fuel Cell Voltage Neural Control Based on Hydrogen Pressure Regulation

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 434 ◽  
Author(s):  
Andrés Morán-Durán ◽  
Albino Martínez-Sibaja ◽  
José Pastor Rodríguez-Jarquin ◽  
Rubén Posada-Gómez ◽  
Oscar Sandoval González
Keyword(s):  
Fuel Cell ◽  
Output Voltage ◽  
Neural Control ◽  
Principal Component ◽  
Cell Voltage ◽  
Cell Performance ◽  
Fuel Cell Performance ◽  
Model Control ◽  
And Control ◽  
The Impact

Fuel cells are promising devices to transform chemical energy into electricity; their behavior is described by principles of electrochemistry and thermodynamics, which are often difficult to model mathematically. One alternative to overcome this issue is the use of modeling methods based on artificial intelligence techniques. In this paper is proposed a hybrid scheme to model and control fuel cell systems using neural networks. Several feature selection algorithms were tested for dimensionality reduction, aiming to eliminate non-significant variables with respect to the control objective. Principal component analysis (PCA) obtained better results than other algorithms. Based on these variables, an inverse neural network model was developed to emulate and control the fuel cell output voltage under transient conditions. The results showed that fuel cell performance does not only depend on the supply of the reactants. A single neuro-proportional–integral–derivative (neuro-PID) controller is not able to stabilize the output voltage without the support of an inverse model control that includes the impact of the other variables on the fuel cell performance. This practical data-driven approach is reliably able to reduce the cost of the control system by the elimination of non-significant measures.

scholarly journals Impact of Different Electrolytes on the Machining Rate in ECM Process

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
K. G. Saravanan ◽  
R. Prabu ◽  
A. R. Venkataramanan ◽  
Eden Tekle Beyessa
Keyword(s):  
Metal Removal ◽  
Electrochemical Machining ◽  
Tool Material ◽  
Electrochemical Process ◽  
Machining Process ◽  
Complexing Agents ◽  
Workpiece Material ◽  
Electrolysis Process ◽  
Machining Rate ◽  
The Impact

Electrochemical machining is a nonconventional machining process in which the metal removal is achieved by the electricity and chemical solution known as an electrolyte. It is the reverse electrolysis process where the application of electricity facilitates the current travel in between anode and cathode. The mechanism of the ion movement is similar to the electrolysis process. Electrochemical machining (ECM) is a type of advanced machining process which employs electricity to perform the machining process on the workpiece. It is also known as a reverse electroplating process where metal removal is achieved instead of metal deposition on the metal surface. There are various parameters that affect the metal removal process in the ECM process, such as electrolyte, power supply, workpiece material, and tool material. The electrolyte is one of the key factors impacting the machining rate, surface finish, and reliability of the produced parts. In this project, a brief study is carried out regarding the electrochemical process and the electrolytes where the properties, functions, merits, and demerits are evaluated. The impact of the various electrolytes and their suitability for machining of various metals is also discussed. The findings of the effect produced by using the mixture of the electrolyte in the electrochemical machining process are discussed in this project. The effects of the complexing agents on the electrolyte and the electrochemical process as a whole are also reviewed.

Electrophoretic deposition and electro-codeposition in nanoparticle-containing molten inorganic salts

2021 ◽  
Author(s):  
weiliang jin ◽  
saijun xiao ◽  
qian kou ◽  
desheng ding ◽  
jun zhang ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Molten Salts ◽  
Cell Voltage ◽  
Nanocomposite Coating ◽  
Inorganic Salts ◽  
Homogeneous Distribution ◽  
Uniform Dispersion ◽  
A Cell ◽  
Molten Fluorides ◽  
Efficient Heat Transfer

Abstract Molten inorganic salts containing solid nanoparticles with a stable and uniform dispersion have attracted great attention as efficient heat transfer and storage materials1,2 and for catalysis for chemical reactions3-5. Compared with those in aqueous suspensions6,7, electrophoretic deposition and electro-codeposition in molten inorganic salts containing nanoparticles, have not been reported in the literature. Here we report the possibility of electrophoretic deposition of nanoparticles and electro-codeposition of nanoparticles and metal ions in high-temperature molten salts. In molten fluorides and chlorides, a cell voltage of 1.2-1.5 V below the decomposition voltage of the electrolytes, was applied to perform the electrophoretic deposition of nanoparticles (e.g., TiB2 and ZrB2), resulting in compact and adhesive coatings. In molten chlorides containing TiB2 nanoparticles, with the introduction of electroactive specimen MoO3, the electro-codeposition of TiB2 nanoparticles and Mo-containing ions has been achieved to yield a dense and adhesive Mo/TiB2 nanocomposite coating with homogeneous distribution of Mo and TiB2, without the assistance of stirring of molten salts. These findings should present opportunities to synthesize various coatings and films via the proposed processes.

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