GEOFF BEARNE, BSc, CEng, FIMechE, is General Manager, Technology Delivery Systems, at Rio Tinto Technology & Innovation. He has more than thirty years of experience in the aluminum industry.
MARC DUPUIS, PhD, has been a consultant since 1994, when he founded GeniSim, Inc., his own consulting firm. He specializes in the application of mathematical modeling for the aluminum industry.
GARY TARCY, MS, is Manager of Smelting R&D at the Alcoa Technical Center in New Kensington, Pennsylvania. He holds twenty-six patents and has published thirty-one papers. He has been twice awarded TMS's Light Metals Award for Best Paper and also won the Australasian Smelting Technology Conference Best Paper Award.
Preface xvii
Lead Editors xxi
Editorial Team xxiii
Part 1: Fundamentals
Section Introduction 1
Overview
Principles of Aluminum Electrolysis 3
W. Haupin
Bath Properties
The Solubility of Aluminum in Cryolite Melts 12
K. Yoshida and E. Dewing
Viscosity of Molten NaF-AlF3-Al203-CaF2 Mixtures: Selecting and Fitting Models in a Complex System 19
T. Hertzberg, K. Torklep, and H. 0ye
On the Solubility of Aluminium Carbide in Cryolitic Melts —Influence on Cell Performance 25
R. 0degard, A. Sterten, and J. Thonstad
Liquidus Curves for the Cryolite - A1F3 - CaF2 - A1203 System in Aluminum Cell Electrolytes 33
R. Peterson and A. Tabereaux
The Solubility of Aluminium in Cryolitic Melts 39
R. 0degard, A. Sterten, and J. Thonstad
Dissolved Metals in Cryolitic Melts 49
X. Wang, R. Peterson, and N. Richards
Electrical Conductivity of Cryolitic Melts 57
X. Wang, R. Peterson, and A. Tabereaux
Electrical Conductivity of Molten Cryolite-Based Mixtures Obtained with a Tube-type Cell Made of Pyrolytic Boron Nitride 65
J. Hives, J. Thonstad, A. Sterten, and P. Fellner
Liquidus Temperature and Alumina Solubility in the System Na3-AlF6-AlF3-LiF-CaF2-MgF2 73
A.Solheim, S. Rolseth, E. Skybakmoen, L. Stoen, A. Sterten, and T. Store
Unconventional Bath
Lithium-Modified Low Ratio Electrolyte Chemistry for Improved Performance in Modern Reduction Cells 83
A. Tabereaux, T.Alcorn, and L. Trembley
Production of Aluminum with Low Temperature Fluoride Melts 89
T. Beck
Alumina Dissolution
The Structure of Alumina Dissolved in Cryolite Melts 96
H. Kvande
The Dissolution of Alumina in Cryolite Melts 105
J. Thonstad, A. Solheim, S. Rolseth, and O. Skar
Further Studies of Alumina Dissolution Under Conditions Similar to Cell Operation 112
G. Kuschel and B. Welch
Anode Effect Mechanism
Studies on Anode Effect in Aluminium Electrolysis 119
Q. Zhu-Xian, W. Ching-Bin, and C. Ming-Ji
Direct Observation of the Anode Effect by Radiography 127
T. Utigard, J. Toguri, and S. Ip
On the Anode Effect in Aluminum Electrolysis 131
J. Thonstad, T. Utigard, and H. Vogt
Energy and Voltage Breakdown
Anodic Overpotentials in the Electrolysis of Alumina 139
B. Welch and N. Richards
Cathode Voltage Loss in Aluminum Smelting Cells 147
W. Haupin
Interpreting the Components of Cell Voltage 153
W. Haupin
Thermodynamics of Electrochemical Reduction of Alumina 160
W. Haupin andH. Kvande
Field Study of the Anodic Overvoltage inPrebaked Anode Cells 166
H. Gudbrandsen, N. Richards, S. Rolseth, andJ. Thonstad
Current Efficiency
Current Efficiency and Alumina Concentration 172
B. Lillebuen and T. Mellerud
Continuous Measurement of Current Efficiency, by Mass Spectrometry, on a 280 KA Prototype Cell 177
M. Leroy, T. Pelekis, andJ. Jolas
The Influence of Dissolved Metals in Cryohtic Melts on Hall Cell Current Inefficiency 181
R. Peterson andX. Wang
The Interaction Between Current Efficiency and Energy Balance in Aluminium Reduction Cells 188
F. Stevens, W. Zhang, M. Taylor, and J. Chen
A Laboratory Study of Current Efficiency in Cryolitic Melts 195
P. Solli, T. Haarberg, T. Eggen, E. Skybakmoen, and A. Sterten
Current Efficiency Studies in a Laboratory Aluminium Cell Using the Oxygen Balance Method 204
M. Dorreen, M. Hyland, and B. Welch
Current Efficiency inPrebake and Soderberg Cells 211
G. Tarcy and K. Torklep
Physical Properties
Bath/Freeze Heat Transfer Coefficients: Experimental Determination and Industrial Application 217
M. Taylor and B. Welch
Sludge in Operating Aluminium Smelting Cells 222
P. Geay, B. Welch, and P. Homsi
The Behaviour of Phosphorus Impurities in Aluminium Electrolysis Cells 229
E. Haugland, G. Haarberg, E. Thisted, andJ. Thonstad
Cell Studies
See-through Hall-Heroult Cell 234
W. Haupin and W. McGrew
Metal Pad Velocity Measurements in Prebake and Soderberg Reduction Cells 240
A. Tabereaux and R. Hester
Metal Pad Velocity Measurements by the Iron Rod Method 251
B. Bradley, E. Dewing, andJ. Rogers
On the Bath Flow, Alumina Distribution and Anode Gas Release in Aluminium Cells 257
O. Kobbeltvedt and B. Moxnes
Bubble Noise from Soderberg Pots 265
M. Jensen, T. Pedersen, and K. Kalgraf
Recommended Reading 269
Part 2: Modeling
Section Introduction 273
Thermal Balance
Simulation of Thermal, Electric and Chemical Behaviour of an Aluminum Cell on a Digital Computer 275
A. Ek and G. Fladmark
Estimation of Frozen Bath Shape in an Aluminum Reduction Cell by Computer Simulation 279
Y. Arita, N. Urata, and H. Ikeuchi
A Water-Model Study of the Ledge Heat Transfer in an Aluminium Cell 286
J. Chen, C. Wei, and A. Ackland
Computation of Aluminum Reduction Cell Energy Balance Using ANSYS® Finite Element Models 294
M. Dupuis
Thermo-Electric Design of a 400 kA Cell Using Mathematical Models: A Tutorial 303
M. Dupuis
A Modelling Approach to Estimate Bath and Metal Heat Transfer Coefficients 309
D. Severn and V. Gusberti
MHD and Stability
Computer Model for Magnetic Fields in Electrolytic Cells Including the Effect of Steel Parts 315
T. Sele
The Effect of Some Operating Variables on Flow in Aluminum Reduction Cells 322
E. Tarapore
Magnetics and Metal Pad Instability 330
N. Urata
Stability of Aluminum Cells - A New Approach 336
R. Moreau and D. Ziegler
Analysis of Magnetohydrodynamic Instabilities in Aluminum Reduction Cells 342
M. Segatz and C. Droste
Magnetohydrodynamic Effect of Anode Set Pattern on Cell Performance 352
M. Segatz, C. Droste, and D. Vogelsang
Stability of Interfacial Waves in Aluminium Reduction Cells 359
P. Davidson andR. Lindsay
Using a Magnetohydrodynamic Model to Analyze Pot Stability in Order to Identify an Abnormal Operating Condition 367
J. Antille andR. von Kaenel
Wave Mode Coupling and Instability in the Internal Wave in Aluminum Reduction Cells 373
N. Urata
Comparison of Various Methods for Modeling the Metal-Bath Interface 379
D. Severo, V. Gusberti, A. Schneider, E. Pinto, and V. Potocnik
Bubbles and Bath Flow
Physical Modelling of Bubble Behaviour and Gas Release from Aluminum Reduction Cell Anodes 385
S. Fortin, M. Gerhardt, and A. Gesing
Coupled Current Distribution and Convection Simulator for Electrolysis Cells 396
K. Bech, S. Johansen, A. Solheim, and T. Haarberg
Effect of the Bubble Growth Mechanism on the Spectrum of Voltage Fluctuations in the Reduction Cell 402
L. Kiss and S. Poncsak
Modeling the Bubble Driven Flow in the Electrolyte as a Tool for Slotted Anode Design Improvement 409
D. Severo, V. Gusberti, E. Pinto, andR. Moura
Other
Planning Smelter Logistics: A Process Modeling Approach 415
I. Eick, D. Vogelsang, and A. Behrens
CFD Modeling of the Fjardaal Smelter Potroom Ventilation 421
J. Berkoe, P. Diwakar, L. Martin, B. Baxter, C. Read, P. Grover, and D. Ziegler
Heat Transfer Considerations for DC Busbars Sizing 427
A. Schneider, T. Plikas, D. Richard, and L. Gunnewiek
The Impact of Cell Ventilation on the Top Heat Losses and Fugitive Emissions in an Aluminium Smelting Cell 433
H. Abbas, M. Taylor, M. Farid, andJ. Chen
Mathematical Modelling of Aluminum Reduction Cell Potshell Deformation 439
M. Dupuis
Recommended Reading 445
Part 3: Design
Section Introduction 449
New Cell Design
Development of Large Prebaked Anode Cells by Alcoa 451
G. Holmes, D. Fisher, J. Clark, and W. Ludwig
Aluminium Pechiney 280 kA Pots 457
B. Langon and P. Varin
AP 50: The Pechiney 500 kA Cell 462
C. Vanvoren, P. Homsi, J. Basquin, and T. Beheregaray
The Pot Technology Development in China 468
X. Yang, J. Zhu, and K. Sun
Cell Retrofit
VAW Experience in Smelter Modernization 474
V. Sparwald, G. Wendt, and G. Winkhaus
From HOto 175 kA: Retrofit of VAW Rheinwerk Part I: Modernization Concept 479
D. Vogelsang, I. Eick, M. Segatz, and C. Droste
From 110 to 175 kA: Retrofit of VAW Rheinwerk Part II: Construction & Operation 485
J. Ghosh, A. Steube, and B. Levenig
Productivity Increase at Soral Smelter 489
T. Johansen, H. Lange, andR. von Kaenel
Reduction Cell Technology Development at Dubai Through 20 Years 494
A. Kalban, Y. AlFarsi, and A. Binbrek
Potline Amperage Increase from 160 kA to 175 kA during One Month 500
B. Moxnes, E. Furu, O. Jakob sen, A. Solbu, and H. Kvancle
AP35: The Latest High Performance Industrially Available New Cell Technology 506
C. Vanvoren, P. Homsi, B. Feve, B. Molinier, and Y. di Giovanni
Tomago Aluminium AP22 Project 512
L. Fiot, C. Jamey, N. Backhouse, and C. Vanvoren
Development of D18 Cell Technology at Dubai 518
D. Whitfield, A. Said, M. Al-Jallaf, and A. Mohammed
New Cathodes in Aluminum Reduction Cells 523
N. Feng, Y. Tian, J. Peng, Y. Wang, X. Qi, and G. Tu
Other
Dimensioning of Cooling Fins for High-Amperage Reduction Cells 527
I. Eick and D. Vogelsang
Satisfying Financial Institutions for Major Capital Projects 534
J. Heintzen andR. Harrison
Development and Deployment of Slotted Anode Technology at Alcoa 539
X. Wang, G. Tarcy, S. Whelan, S. Porto, C. Ritter, B. Ouellet, G. Homley, A. Morphett, G. Proulx,
S. Lindsay, andJ. Bruggeman
Innovative Solutions to Sustainability in Hydro 545
H Lange, N. Holt, H Linga, and L. Solli
Recommended Reading 551
Part 4: Operations
Section Introduction 553
Anode Change
Current Pickup and Temperature Distribution in Newly Set Prebaked Hall-Heroult Anodes 555
R. 0degard, A. Solheim, and K. Thovsen
Thermal Effects by Anode Changing in Prebake Reduction Cells 562
F. Aune, M. Bugge, H. Kvande, T. Ringstad, and S. Rolseth
Material Issues
Considerations in the Selection of Alumina for Smelter Operation 569
A. Archer
Alumina Transportation to Cells 574
I. Stankovich
Study of Alumina Behavior in Smelting Plant Storage Tanks 581
H Hsieh
New Aerated Distribution (ADS) and Anti Segregation (ASS) Systems for Alumina 590
M. Karlsen, A. Dyr0y, B. Nagell, G. Enstad, and P. Hilgraf
Beryllium in Pot Room Bath 596
S. Lindsay and C. Dobbs
Hard Gray Scale 602
N. Dando and S. Lindsay
Aluminum Fluoride — A Users Guide 608
S. Lindsay
Anode Cover and Crust
Crusting Behavior of Smelter Aluminas 613
D. Townsend and L. Boxall
On Alumina Phase Transformation and Crust Formation in Aluminum Cells 622
R. Oedegard, S. Roenning, S. Rolseth, andJ. Thonstad
Heat Transfer, Thermal Conductivity, and Emissivity of Hall-Heroult Top Crust 630
K. Rye, J. Thonstad, andX. Liu
Improving Anode Cover Material Quality at Nordural— Quality Tools and Measures 639
H. Gudmundsson
Operational Improvement
Appraisal of the Operation of Horizontal-Stud Cells with the Addition of Lithium Flouride 645
K. Mizoguchi and K. Yuhki
Technical Results of Improved Soederberg Cells 652
H. Hosoi, M. Sugaya, and S. Tosaka
Strategies for Decreasing the Unit Energy and Environmental Impact of Hall-Heroult Cells 659
N. Richards
Operational and Control Improvements in Reduction Lines at Aluminium Delfzijl 669
M. Stam, M. Taylor, J. Chen, and S. van Dellen
Power Modulation and Supply Issues
Modeling Power Modulation 674
M. Dupuis
Smelters in the EU and the Challenge of the Emission Trading Scheme 679
H. Kruse
Challenges in Power Modulation 683
D. Eisma and P. Pate I
Cell Start-up and Restart
Hibernating Large Soderberg Cells 689
N. Sundaram
Thermal Bake-Out of Reduction Cell Cathodes-Advantages and Problem Areas 694
W. Richards, P. Young, J. Keniry, and P. Shaw
The Economics of Shutting and Restarting Primary Aluminium Smelting Capacity 699
K. Driscoll
Brazil 2001 Energy Crisis -The Albras Approach 707
H. Dias
Potline Startup with Low Anode Effect Frequency 712
W. Kristensen, G. Hoskuldsson, and B. Welch
Cell Preheat/Start-up and Early Operation 718
K. Rye
Loss in Cathode Life Resulting from the Shutdown and Restart of Potlines at Aluminum Smelters 723
A. Tabereaux
Simultaneous Preheating and Fast Restart of 50 Aluminium Reduction Cells in an Idled Potline 729
A. Mulder, A. Folkers, M. Stam, andM. Taylor
Recommended Reading 735
Part 5: Control
Section Introduction 737
Overview
Overview of Process Control in Reduction Cells and Potlines 739
P. Homsi, J. Peyneau, andM. Reverdy
Alumina Control
A Demand Feed Strategy for Aluminium Electrolysis Cells 747
K. Robilliard and B. Rolofs
Design Considerations for Selecting the Number of Point Feeders in Modern Reduction Cells 752
M. Walker, J. Pur die, N. Wai-Poi, B. Welch, andJ. Chen
Pseudo Resistance Curves for Aluminium Cell Control - Alumina Dissolution and Cell Dynamics 760
H. Kvande, B. Moxnes, J. Skaar, and P. Solli
Aiming For Zero Anode Effects 767
W. Haupin and E. Seger
Reduction of CF4 Emissions from the Aluminum Smelter in Essen 774
M. Iffert, J. Opgen-Rhein, andR. Ganther
The Initiation, Propagation and Termination of Anode Effects in Hall-Heroult Cells 782
TMS, G. Tarcy, and A. Tabereaux
Heat Balance Control
Operation of 150 kAPrebaked Furnaces with Automatic Voltage Control 786
R. Bacchiega, A. Innocenti, M. Holzmann, and B. Panebianco
Bath Chemistry Control System 798
D. Salt
The Liquidus Enigma 804
W. Haupin
Control of Bath Temperature 808
P. Entner
Noise Classification in the Aluminum Reduction Process 812
L. Banta, C. Dai, and P. Biedler
Increased Current Efficiency and Reduced Energy Consumption at the TRIMET Smelter Essen Using 9 Box Matrix
Control 817
T. Rieck, M. Iffert, P. White, R. Rodrigo, andR. Kelchtermans
A Nonlinear Model Based Control Strategy for the Aluminium Electrolysis Process 825
S. Kolas and S. Wasbo
Probes and Sensors
Bath and Liquidus Temperature Sensor for Molten Salts 830
P. Verstreken and S. Benninghoff
Anode Signal Analysis — The Next Generation in Reduction Cell Control 838
J. Keniry and E. Shaidulin
Alcoa STARprobe™ 844
X. Wang, B. Hosier, and G. Tarcy
Recommended Reading 851
Part 6: Environmental
Section Introduction 855
HF and Other Gaseous Emission
A Study of Factors Affecting Fluoride Emission from 10,000 Ampere Experimental Aluminum Reduction Cells 857
J. Henry
The Characterisation of Aluminium Reduction Cell Fume 865
L. Less and J. Waddington
Factors Affecting Fluoride Evolution from Hall-Heroult Smelting Cells 870
W. Wahnsiedler, R. Danchik, W. Haupin, D. Backenstose, andJ. Colpitts
A Study of the Equilibrium Adsorption of Hydrogen Fluoride on Smelter Grade Aluminas 879
W. Lamb
The Role and Fate of S02inthe Aluminium Reduction Cell Dry Scrubbing Systems 889
W. Lamb
Sulphur Containing Compounds in the Anode Gas from Aluminium Cells, A Laboratory Investigation 898
R. Oedegard, S. Roenning, A. Sterten, andJ. Thonstad
Mathematical Model of Fluoride Evolution from Hall-Heroult Cells 903
W. Haupin andH. Kvande
Factors Influencing Cell Hooding and Gas Collection Efficiencies 910
M. Karlsen, V. Kielland, H Kvande, and S. Vestre
Sulfur and Fluorine Containing Anode Gases Produced during Normal Electrolysis and Approaching an Anode Effect 918
M. Dorreen, D. Chin, J. Lee, M. Hyland, and B. Welch
Understanding the Effects of the Hydrogen Content of Anodes on Hydrogen Fluoride Emissions from Aluminium Cells... 924
E. Patterson, M. Hyland, V. Kielland, and B. Welch
Effect of Open Holes in the Crust on Gaseous Fluoride Evolution from Pots 930
M. Slaugenhaupt, J. Bruggeman, G. Tarcy, and N. Dando
Alumina Structural Hydroxyl as a Continuous Source of HF 936
M. Hyland, E. Patterson, and B. Welch
Investigation of Solutions to Reduce Fluoride Emissions from Anode Butts and Crust Cover Material 942
G. Girault, M. Faure, J. Bertolo, S. Massambi, and G. Bertran
Gas Capture and Treatment
Global Considerations of Aluminium Electrolysis on Energy and the Environment 948
R. Huglen and H. Kvande
The Surface Chemistry of Secondary Alumina from the Dry Scrubbing Process 956
A. Gillespie, M. Hyland, andJ. Metson
S02 Emission Control in the Aluminium Industry 962
S. Strommen, E. Bjornstad, and G. Wedde
Reduction of HF Emissions from the TRIMET Aluminum Smelter (Optimizing Dry Scrubber Operations and Its Impact on Process Operations) 968
M. Lffert, M. Kuenkel, M. Skyllas-Kazacos, and B. Welch
Handling C02EQ from an Aluminum Electrolysis Cell 975
O. Lorentsen, A. Dyroy, andM. Karlsen
Dry Scrubbing for Modern Pre-Bake Cells 981
S. Lindsay and N. Dando
Pot Gas Heat Recovery and Emission Control 987
A. Sorhuus and G. Wedde
The Applicability of Carbon Capture and Sequestration in Primary Aluminium Smelters 993
S. Broek and S. Save
Material Issues
Dusting Properties of Industrial Aluminas 999
P. Ravn and A. Windfeldt
Perfluorocarbon (PFC) Emissions
Evaluation of Fluorocarbon Emissions from the Aluminum Smelting Process 1007
R. Roberts and P. Ramsey
Perfluorocarbon (PFC) Generation at Primary Aluminum Smelters 1015
B. LeberJr., A. Tabereaux, J. Marks, B. Lamb, T. Howard, R. Kantamaneni, M. Gibbs, V. Bakshi, andE. Dolin
Factors Affecting PFC Emissions from Commercial Aluminum Reduction Cells 1024
J. Marks, A. Tabereaux, D. Rape, V. Bakshi, and E. Dolin
Protocol for Measurement of Tetrafluoromethane and Hexafluoroethane fromPrimary Aluminum Production 1032
J. Marks, R. Kantamaneni, D. Rape, and S. Rand
On Continuous PFC Emission Unrelated to Anode Effects 1037
W. Li, Q. Zhao, J. Yang, S. Qiu, X. Chen, J. Marks, and C. Bayliss
Recommended Reading 1043
Part 7: Alternative Processes
Section Introduction 1047
Overview
Impact of Alternative Processes for Aluminium Production on Energy Requirements 1049
K Grjotheim and B. Welch
Alternate Smelting Processes for Aluminum 1056
C. Cochran
Carbothermic
Technoeconomic Assessment of the Carbothermic Reduction Process for Aluminum Production 1070
W. Choate andJ. Green
Solid State Carbothermal Reduction of Alumina 1076
D. Liu, G. Zhang, J. Li, and O. Ostrovski
Other
Production of Aluminum-Silicon Alloys from Sand and Clay in Hall Cells 1082
A. Tabereaux and C. McMinn
Bench Scale Electrolysis of Alumina in Sodium Fluoride-Aluminum Fluoride Melts Below 900°C 1089
W. Sleppy and C. Cochran
Electrolysis of Alumina in a Molten Salt at 760°C 1095
A. LaCamera
Aluminum Reduction via Near Room Temperature Electrolysis in Ionic Liquids 1100
B. Wu, R. Reddy, andR. Rogers
Recommended Reading 1107
Author Index 1109