Effects of process conditions on cell voltage, current efficiency and voltage balance of a chlor-alkali membrane cell

Desalination ◽  
2009 ◽  
Vol 237 (1-3) ◽  
pp. 126-139 ◽  
Author(s):  
A.A. Jalali ◽  
F. Mohammadi ◽  
S.N. Ashrafizadeh
2019 ◽  
Vol 25 (33) ◽  
pp. 43-56 ◽  
Author(s):  
Narjes Shojaikaveh ◽  
Seyed Nezamedin Ashrafizadeh ◽  
Fereydoon Mohammadi ◽  
Amin Amerighasrodashti

2013 ◽  
Vol 828 ◽  
pp. 45-54 ◽  
Author(s):  
Anupam Agnihotri ◽  
Shail Umakant Pathak ◽  
Jyoti Mukhopadhyay

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.


1979 ◽  
Vol 18 (1) ◽  
pp. 13-18 ◽  
Author(s):  
C. Castellano ◽  
D. Bratland ◽  
K. Grjotheim ◽  
T. Müftüoglu ◽  
J. Thonstad

2020 ◽  
Vol 299 ◽  
pp. 798-804
Author(s):  
Oksana N. Gruba ◽  
Dmitrii V. Ardashev ◽  
Victor P. Chernobrovin

One of the main problems common to all areas of technology is to increase the reliability and durability of machines, devices, and mechanisms. This problem can be solved by applying wear-resistant coatings and chromium-based alloys. The method of electrochemical chrome plating has a number of significant drawbacks: low current efficiency of chromium; the lowest dispersing capacity among galvanic processes; high energy intensity; the presence of high internal stress chrome plating; hydrogenation of chromium sediments and base alloy. Therefore, at present, a large number of works are being carried out aimed at intensifying the processes of chromium plating. This work is aimed at exploring the possibilities of optimizing the process of chrome plating by changing the composition of the electrolyte. Classification of currently used electrolytes of chromium plating was carried out according to the following parameters: electrolyte composition, process conditions, cathode output by current and quality of the coatings obtained. On the basis of experimental studies conducted by the authors, the possibility of intensifying the process of electrolytic chromium plating from aqueous solutions, due to a change in the composition of the electrolyte, is shown. The effect of a number of anions (SO2-4, SiF2-6,Cl-,F-, NH2SO-3, PO3-4, IO3-3, I2O4-7) on the quality of sediments and current efficiency is studied. The ways to improve the most popular universal electrolytes are proposed.


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