scholarly journals Anodic Bubble Behavior in a Laboratory Scale Transparent Electrolytic Cell for Aluminum Electrolysis

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 806 ◽  
Author(s):  
Yipeng Huang ◽  
Zhaowen Wang ◽  
Youjian Yang ◽  
Bingliang Gao ◽  
Zhongning Shi ◽  
...  
Keyword(s):  
Bubble Dynamics ◽  
Aluminum Electrolysis ◽  
Electrolytic Cell ◽  
Laboratory Scale ◽  
Carbon Anode ◽  
Electrolysis Cell ◽  
Bubble Behavior ◽  
Electrolysis Process ◽  
Graphite Anodes ◽  
Carbon Anodes

In the Hall-Héroult process for extracting aluminum, the evolution and dynamics of anodic bubbles have a significant influence on the efficiency of the overall electrolysis process. In this study, the behavior of the bubbles beneath the carbon anode in cryolite-alumina molten salt was studied for the first time using a laboratory-scale transparent electrolysis cell to view the anode from the bottom. The bubble dynamics and the relevant characteristic parameters of bubbles were obtained using video cameras and image processing. It was found that the bubbles were observed to preferentially generate at several areas on the underside of the anode and the morphologies of coalesced bubbles show excellent similarity. Moreover, the behavior of gas on carbon and graphite anodes was significantly different, where the carbon anode favored the forming of larger bubbles. These observations confirmed different types of carbon anodes cause different bubble behavior. These findings are expected to be useful in optimizing the aluminum electrolysis process on an industrial scale.

ON THE ANODIC OVERVOLTAGE IN ALUMINUM ELECTROLYSIS

1964 ◽  
Vol 42 (7) ◽  
pp. 1542-1550 ◽  
Author(s):  
Jomar Thonstad ◽  
Eirik Hove
Keyword(s):  
Chemical Reactivity ◽  
Reference Electrode ◽  
Aluminum Electrolysis ◽  
Carbon Anode ◽  
Cell Reaction ◽  
Chemisorbed Oxygen ◽  
Reversible Potential ◽  
Graphite Anodes ◽  
Slow Transport ◽  
Carbon Anodes

The overvoltage on the carbon anode in aluminum electrolysis has been measured against a CO2/C reference electrode placed in the cryolite melt. The behavior of the reference electrode was first investigated against the aluminum cathode. This galvanic cell showed a stable potential of 1.15 V, which was close to the reversible potential for the cell reaction in aluminum electrolysis. Similar measurements were made with CO/C and CO2,CO/C electrodes. The potential of the CO/C electrode was in fair agreement with the reversible potential for the most probable cell reaction. The potentials obtained with CO2–CO mixtures were intermediate between those for the pure gases, increasing with increasing CO2 content. An explanation for the behavior of the CO2,CO/C electrode is suggested.The anodic overvoltage depended only to a limited extent on the chemical reactivity of carbon with respect to oxygen. Graphite anodes showed higher overvoltage than all other types of carbon anodes. Catalyzing and inhibiting additives to the carbon had small but significant influences on the overvoltage. Straight Tafel plots were obtained with slopes varying between 0.26 and 0.27. On this basis it is shown that the overvoltage may be due either to slow transport of oxygen ions through the double layer or to slow reaction between chemisorbed oxygen and carbon.

scholarly journals Comparing Anodic Bubble Behavior of Anodes from Anisotropic and Isotropic Cokes in Laboratory Scale Aluminum Electrolysis Cells

2019 ◽  
Vol 166 (13) ◽  
pp. E438-E452
Author(s):  
Camilla Sommerseth ◽  
Rebecca J. Thorne ◽  
Arne Petter Ratvik ◽  
Stein Rørvik ◽  
Hogne Linga ◽  
...  
Keyword(s):  
Aluminum Electrolysis ◽  
Laboratory Scale ◽  
Bubble Behavior ◽  
Electrolysis Cells

Thiophenic Sulfur Transformation in a Carbon Anode during the Aluminum Electrolysis Process

2017 ◽  
Vol 31 (4) ◽  
pp. 4539-4547 ◽  
Author(s):  
Qifan Zhong ◽  
Jin Xiao ◽  
Haojin Du ◽  
Zhen Yao
Keyword(s):  
Aluminum Electrolysis ◽  
Carbon Anode ◽  
Electrolysis Process ◽  
Sulfur Transformation

scholarly journals Analyze the effect of phosphorus on the mechanical properties and microstructure on cast iron

2018 ◽  
Vol 204 ◽  
pp. 05008
Author(s):  
Achmad Sambas ◽  
Ananto Gamawan ◽  
Sophiadi Gunara
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cast Iron ◽  
Mechanical Testing ◽  
Aluminum Electrolysis ◽  
Point Of View ◽  
Carbon Anode ◽  
Electrolysis Process ◽  
Microstructure Observation ◽  
Phosphorus Alloy

Cast Iron FC250 with phosphorus alloy is used as electrode connector in the aluminum electrolysis process at PT. Indonesia Asahan Aluminium (Inalum), that is used to connect the rod with carbon anode. It will be crushed after the carbon anode dimension is reduced, that takes approximately 30 days. In order to make crushing process easier, phosphorus alloy then added into such FC250. The objective of the study is determining phosphorus effect on FC 250. The methodology consists of determine the test specimens, initiate such specimen of casting by varying the amount of phosphorus percentage of 0.3%, 0.5%, 0.7% and 0.9%, then perform mechanical testing and microstructure observation on each specimen. The result is, as the percentage of phosphorus in FC 250 increased, so its hardness value whereas the value of the tensile strength even decreased. Form the microstructure point of view, the “steadit” increased as well in line with the rise of phosphorus.

Investigating Effects of Different Flue-Wall Deformation Modes on the Performance of Anode Baking Furnaces for Aluminum Electrolysis

2019 ◽  
Author(s):  
Abdul Raouf Tajik ◽  
Mouna Zaidani ◽  
Tariq Shamim ◽  
Rashid K. Abu Al-Rub
Keyword(s):  
Gas Flow ◽  
Aluminum Electrolysis ◽  
Deformation Mode ◽  
Carbon Anode ◽  
Operational Parameters ◽  
Aluminum Reduction ◽  
Wall Deformation ◽  
Anode Temperature ◽  
Carbon Anodes ◽  
Deformation Modes

Abstract In carbon anode baking furnaces, temperature and quality of carbon anodes are significantly affected by the deformation of the flue-walls, where the flue-gases flow and combustion occur. Flue-walls aging gives rise to non-homogeneous baking of the carbon anodes and results in deterioration of the anode quality, which eventually causes instabilities in aluminum reduction cells and overconsumption of anodes and energy. It is imperative to develop a fully coupled 3D multi-physics computational model which takes into account a large number of physical phenomena that play vital roles in the baking process and are affected by the flue-wall deformation mode. In the present study, the effects of flue-wall deformation modes on flue-wall cavity gas flow and anode temperature distribution are investigated. The pressure and flow distributions for different levels of flue-wall deformation are demonstrated. It is perceived that a 100 mm convex mode of flue-wall deformation leads to under-baking of anodes by almost 20 degC. For the concave mode of deformation, since the packing coke thickness reduces, overbaking of anode occurs. The methodology and results presented in the present research can be employed effectively by the aluminum industry in modifying the furnace geometrical and operational parameters to enhance baking uniformity after flue-wall is deformed.

Test of Corrosion Resistance of Heat Insulating Materials to Cryolite Vapor

2018 ◽  
Vol 768 ◽  
pp. 59-63
Author(s):  
Gang Wang ◽  
Qi Zhang ◽  
Jian Shen Han ◽  
Bo Yuan ◽  
Hong Xia Li
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Electrolysis ◽  
Electrolytic Cell ◽  
Test Methods ◽  
Electrolysis Cell ◽  
Test Device ◽  
Insulating Materials ◽  
Service Environment ◽  
Performance Decline ◽  
Aluminum Electrolytic Cell

Heating insulating materials were often eroded by cryolite vapor when they were used outside the wall of energy saving aluminum electrolysis cell. Insulating effect of aluminum electrolytic cell became worse with the time of extension. According to service environment of the aluminum electrolytic cell, a set of test methods was put forward. The physical properties, phase compositions and microstructures of the heating insulating materials under the different test conditions were studied by self-made test device. The results showed that test and characterization the corrosion resistance to cryolite vapor was of great significance for evaluating the performance decline and exploring the mechanism of corrosion resistance in the service process of materials. It provided a guidance to develop and choose the appropriate insulating materials.

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 Effect of carbon anode production parameters on anode cracking

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Salah Amrani ◽  
Duygu Kocaefe ◽  
Yasar Kocaefe ◽  
Dipankar Bhattacharyay ◽  
Mohamed Bouazara ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Crack Density ◽  
Raw Material ◽  
Carbon Anode ◽  
Know How ◽  
Production Parameters ◽  
Environmental Emissions ◽  
Carbon Anodes ◽  
Tomographic Analysis

AbstractCarbon anodes are used in the electrolytic production of aluminum. The quality of anodes is directly related to the production cost, carbon and energy consumption, and environmental emissions. It is desired that the anodes have high density, low porosity/cracks, low electrical resistivity as well as low air and CO2 reactivities. Low resistivity of anodes reduces energy required to produce aluminum during electrolysis. The presence of cracks and pores increases the anode electrical resistivity. Therefore, it is important to know how and when the pores and cracks form during the anode production so that the necessary actions could be taken to prevent their formation. A study was carried out to investigate the effect of different anode production parameters such as anode composition, type of raw material used, time and top-former bellow pressure of vibro-compactor, green anode cooling medium, and heating rate used during baking on the crack formation. The anodes are fabricated at the carbon laboratory of University of Quebec at Chicoutimi (UQAC) and characterized by measuring their properties (density, electrical resistivity, and surface crack density). The anode properties, hence the anode quality, were correlated with the anode production parameters. Also, their tomographic analysis was carried out to visualize and quantify the internal cracks. Graphical abstract

Sign in / Sign up

Export Citation Format

Share Document