Potassium Balance and Its Distribution in Commercial Aluminum Reduction Cells—When Potassium-containing Alumina Is Used as the Raw Material for Aluminum Electrolysis

Alumina is an indispensable raw material for the modern aluminum electrolysis industry. The distribution and transmission of alumina within the bath is of great significance to maintain stable operation and reduce energy consumption. In this study, a computational fluid dynamics (CFD) model was developed to investigate the bath flow and its related alumina transmission in aluminum reduction cells. The bath flow driven by bubbles, electromagnetic force, and aluminum flow presented two different sized vortices in the horizontal plane of the anode–cathode distance (ACD). Both numerical results and industrial data show that the average alumina concentration in the half-cell at the duct end is slightly larger than that of the tap end. With the application of slotted anodes, the maximum velocity of the bath flow increased and the average velocity decreased slightly in the horizontal plane, resulting in a more uniform distribution of alumina than that in the use of unslotted anodes. The symmetrical nature of the bath flow vortices became more obvious with the upgrade of the busbar design and the alumina concentration gradient became smaller within the bath.

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Research of Aluminum Reduction Cell Thermal Balanced Intelligent Control System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.311-313.644 ◽

2011 ◽

Vol 311-313 ◽

pp. 644-647

Author(s):

Xiang Yang Xia ◽

Jie Li

Keyword(s):

Control System ◽

Heat Balance ◽

Concentration Field ◽

Flow Distribution ◽

Aluminum Electrolysis ◽

Primary Aluminum ◽

Aluminum Reduction Cell ◽

Control Technique ◽

Aluminum Reduction ◽

Reduction Cell

This paper proposes an intelligence control system of heat balance for aluminum reduction cell and reviews in each period the control technique of aluminum electrolysis at home and abroad. Mutual coupled relations of physical fields such as electric field, magnetic field, flow distribution, thermal field, stress field, concentration field in aluminum reduction cell are analyzed simply. In this system automatic control of furnace temperature and liquidus temperature in aluminum electrolyte are detected in real-time accurately. This control system can reduce the superheat of aluminum reduction cell in a certain range, and reduce production cost of per ton of primary aluminum on maximal degree. Thus, energy consumption and waste is decreased and heat balance in aluminum electrolysis is realized, efficient operations are certified in the product of aluminum electrolysis.

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Carbon Raw Material Effects on Aluminum Reduction Cell Anodes

Essential Readings in Light Metals ◽

10.1002/9781118647745.ch8 ◽

2013 ◽

pp. 53-58

Author(s):

P.J. Rhedey ◽

S.K. Nadkarni

Keyword(s):

Aluminum Reduction Cell ◽

Raw Material ◽

Aluminum Reduction ◽

Reduction Cell

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Carbon Raw Material Effects on Aluminum Reduction Cell Anodes

Essential Readings in Light Metals ◽

10.1007/978-3-319-48200-2_8 ◽

2016 ◽

pp. 53-58

Author(s):

P. J. Rhedey ◽

S. K. Nadkarni

Keyword(s):

Aluminum Reduction Cell ◽

Raw Material ◽

Aluminum Reduction ◽

Reduction Cell

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

Applied Sciences ◽

10.3390/app10072228 ◽

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.

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

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2019-10507 ◽

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.

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Application of genetic algorithms to an inverse field problem in magnetic fluid dynamics

Serbian Journal of Electrical Engineering ◽

10.2298/sjee0301001k ◽

2003 ◽

Vol 1 (1) ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Milko Kuilekov ◽

Marek Ziolkowski ◽

Hartmut Brauer

Keyword(s):

Fluid Dynamics ◽

Genetic Algorithms ◽

Magnetic Fluid ◽

Aluminum Electrolysis ◽

Field Measurements ◽

Electrolysis Cell ◽

Field Problem ◽

Aluminum Reduction ◽

Two Fluids ◽

Magnetic Field Measurements

The purpose of the present work is to study whether genetic algorithms can solve an inverse field problem in magnetic fluid dynamics (MFD) efficiently. We have investigated how the interface between two fluids of different conductivity in a highly simplified model of an aluminum electrolysis cell can be reconstructed by means of external magnetic field measurements. The knowledge of the interface deformation can be used to prevent undesired instabilities in aluminum reduction cells .

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Experimental Research and Numerical Simulation Analysis of Sodium Expansion in Tib2-Carbon Cathodes during Aluminum Electrolysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.266.93 ◽

2011 ◽

Vol 266 ◽

pp. 93-97

Author(s):

Qing Sheng Liu ◽

Hai Feng Tang ◽

Fang Hui ◽

Ji Lai Xue

Keyword(s):

Simulation Analysis ◽

Three Dimensional ◽

Aluminum Electrolysis ◽

Sodium Concentration ◽

Aluminum Reduction ◽

Reduction Cell ◽

Proposed Model ◽

Dimensional Distribution ◽

Sodium Expansion ◽

Sodium Penetration

Experimental investigation of sodium expansion in TiB2-carbon with different TiB2 content during aluminum electrolysis was carried out in a laboratory cell. The model based on the swelling due to the sodium penetration has been discussed, and relationship between the sodium expansion and time has been proposed that has been calculated by MATLAB. The proposed model was extended to the three-dimensional distribution of sodium concentration, stress and first principal stress that was implemented by ANSYS. Validation of this numerical tool was achieved through the Rapoport tests. The results show good agreement between analytical solution and numerical modeling as well as between experimental and numerical results. This means that the chosen numerical model is suitable to predict sodium expansion as well as induced stresses in TiB2-carbon cathodes and is great interest in the work to extend aluminum reduction cell lifetime.

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Mental representation of economic crisis in Italian and Swiss samples 1The authors would like to thank Maurizio Mistri for his help in the construction of items. This research was supported by a grant from the Italian Murst (ex 40%).

Swiss Journal of Psychology ◽

10.1024//1421-0185.60.1.11 ◽

2001 ◽

Vol 60 (1) ◽

pp. 11-14 ◽

Cited By ~ 10

Author(s):

Lucia Savadori ◽

Eraldo Nicotra ◽

Rino Rumiati ◽

Roberto Tamborini

Keyword(s):

Economic Crisis ◽

Mental Representation ◽

Mental Representations ◽

Social Contexts ◽

Raw Material ◽

National Context ◽

Cluster Procedure ◽

Total N ◽

Two Samples ◽

Important Symptom

The content and structure of mental representation of economic crises were studied and the flexibility of the structure in different social contexts was tested. Italian and Swiss samples (Total N = 98) were compared with respect to their judgments as to how a series of concrete examples of events representing abstract indicators were relevant symptoms of economic crisis. Mental representations were derived using a cluster procedure. Results showed that the relevance of the indicators varied as a function of national context. The growth of unemployment was judged to be by far the most important symptom of an economic crisis but the Swiss sample judged bankruptcies as more symptomatic than Italians who considered inflation, raw material prices and external accounts to be more relevant. A different clustering structure was found for the two samples: the locations of unemployment and gross domestic production indicators were the main differences in representations.

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