Table Of ContentFlash Ironmaking
This book addresses the two major issues faced by the modern steel industry: CO
2
emissions and energy consumption. The steel industry accounts for 6.7% of the
anthropogenic CO emissions and consumes 6% of the total energy consumed in
2
manufacturing. In response to these critical issues, a new technology called flash
ironmaking has been developed, aimed at producing iron directly from iron ore
concentrate using gaseous reductants/fuels such as natural gas or hydrogen. This
ironmaking technology takes advantage of the rapid reaction rate of fine particles
and bypasses the palletization process. This book discusses the principles of flash
ironmaking, laboratory experiments, and design and operation of a prototype flash
reactor.
• Provides theories and principles of ironmaking and a novel ironmaking
technology.
• Includes laboratory experiments to establish the kinetic feasibility of flash
ironmaking.
• Covers the design and operation of a prototype flash reactor as well as the
design of industrial-size flash ironmaking reactors.
• Describes various cases of flow sheet development, which forms the basis
for process analysis and simulation.
• Presents economic analysis case studies.
Presenting a novel technology that addresses contemporary issues facing one of the
largest manufacturing industries, this book is aimed at professionals and research-
ers in metallurgy, materials engineering, manufacturing engineering, and related
disciplines.
Flash Ironmaking
H. Y. Sohn
MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks
does not warrant the accuracy of the text or exercises in this book. This book’s use or discussion
of MATLAB® software or related products does not constitute endorsement or sponsorship by The
MathWorks of a particular pedagogical approach or particular use of the MATLAB® software.
First edition published 2023
by CRC Press
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© 2023 H. Y. Sohn
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ISBN: 978-1-032-37775-9 (hbk)
ISBN: 978-1-032-37838-1 (pbk)
ISBN: 978-1-003-34219-9 (ebk)
DOI: 10.1201/9781003342199
Typeset in Times
by codeMantra
To Victoria Bee-Tuan, Berkeley Jihoon, and Edward Jihyun
for their Sacrifices, Triumphs, and Love
Contents
Abbreviations ...........................................................................................................xv
Nomenclature .........................................................................................................xvii
Preface.....................................................................................................................xxi
Acknowledgments ................................................................................................xxiii
Author ....................................................................................................................xxv
Chapter 1 Introduction ..........................................................................................1
Chapter 2 Current Technologies for Ironmaking ..................................................3
2.1 Blast Furnace Process ................................................................3
2.2 Direct Reduction Processes .......................................................7
2.3 Smelting Reduction Processes ...................................................9
2.3.1 Advantages .................................................................10
2.3.2 Disadvantages .............................................................11
Chapter 3 Issues Facing the Steel Industry .........................................................13
3.1 Raw Materials ..........................................................................13
3.2 Greenhouse Gas Emissions .....................................................13
3.3 Energy Consumption ...............................................................15
Chapter 4 Flash Ironmaking Technology – Concept Development ....................17
Chapter 5 Basic Properties and Sources of Magnetite Concentrate ...................21
Chapter 6 Principles Related to Iron Oxide Reduction .......................................23
6.1 Thermochemistry ....................................................................23
6.1.1 The First Law of Thermodynamics – Heat and
Heat Capacity .............................................................23
6.1.2 Physical Changes and Heat Content ...........................24
6.1.3 Chemical Changes and Standard State ......................26
6.1.4 Standard Heat of Formation or Standard
Enthalpy of Formation ...............................................27
6.1.5 Standard Heat of Combustion ....................................27
6.1.6 Hess’ Law ...................................................................27
6.1.7 Heat of Chemical Reaction ........................................28
6.1.8 Heat of Reaction at Different Temperatures ..............29
6.1.9 Adiabatic Reaction Temperature ................................31
6.1.10 Heat of Mixing ...........................................................31
vii
viii Contents
6.1.11 The Second Law of Thermodynamics .......................32
6.1.12 Activity and Activity Coefficient ...............................34
6.1.13 Chemical Equilibrium ................................................37
6.1.14 Calculation of Equilibrium Composition ...................41
6.1.15 Ellingham Diagram – ∆G° – T Diagram ...................42
6.1.16 Gibbs’ Phase Rule ......................................................44
6.1.17 Stability Diagram ......................................................46
6.2 Reaction Kinetics of Fine Solid Particles with a Gas ..............47
6.2.1 Introduction ................................................................47
6.2.2 Chemically Controlled Shrinking-Core Kinetics ......49
6.2.3 Nucleation and Growth Kinetics – Avrami–
Erofeev Equation ........................................................50
6.2.4 Nucleation and Growth Kinetics – Prout–
Tompkins Model (Also Called the Autocatalytic
Model) ........................................................................53
6.2.5 Solid-State Diffusion Model ......................................53
6.2.6 Summary of Various Solid-State Reaction
Kinetics Models..........................................................55
6.2.7 Analysis of Rate Data .................................................55
6.2.7.1 The Isothermal Method ..............................57
6.2.7.2 The Direct Differential Method –
Linear T-t Program .....................................57
6.2.7.3 Coats–Redfern Integral Method –
Linear T-t Program .....................................57
6.2.7.4 Iso-Conversional Methods ..........................58
6.2.7.5 Sohn’s Non-Linear Temperature–Time
Program ......................................................59
Chapter 7 Development of Flash Ironmaking Technology – Reduction
Kinetics of Magnetite Concentrate Particles ......................................63
7.1 Materials ..................................................................................64
7.2 Experimental Apparatus ..........................................................65
7.3 Experimental Procedure ..........................................................67
7.4 Formulation of Reduction Kinetics Equation ..........................68
7.4.1 Definitions of Parameters ...........................................68
7.4.1.1 Reduction Degree .......................................68
7.4.1.2 The Amount of Excess Reducing Gas ........69
7.4.1.3 Excess Driving Force ..................................70
7.4.1.4 Particle Residence Time .............................70
7.4.2 Selection of Rate Equation .........................................72
7.4.3 Determination of the Reaction Order with
Respect to Gas Partial Pressures ................................75
7.4.4 Effect of Particle Size .................................................76
7.4.5 Determination of the Activation Energy ....................78
7.4.6 Verification of the Absence of the Effects of
Mass Transfer and Pore Diffusion ..............................79
Contents ix
7.5 Results of Rate Measurements and Rate Equations ................82
7.5.1 Reduction by Hydrogen: Temperature Range of
1,150°C–1,350°C ........................................................83
7.5.2 Reduction by Hydrogen: Temperature Range of
1,350°C–1,600°C .......................................................85
7.5.3 Reduction by Carbon Monoxide: Temperature
Range of 1,150°C–1,350°C ........................................86
7.5.4 Reduction by Carbon Monoxide: Temperature
Range of 1,350°C–1,600°C ........................................88
7.5.5 Reduction by H + CO Mixtures: Temperature
2
Range of 1,150°C–1,350°C ........................................88
7.5.6 Reduction by H + CO Mixtures: Temperature
2
Range of 1,350°C–1,600°C ........................................91
7.5.7 Summary on the Reduction Kinetics of
Magnetite Concentrate Particles ................................92
7.6 Refinements of the Rate Equations for the Reduction
of Concentrate Particles through Computational Fluid
Dynamics Modeling ................................................................93
7.6.1 Approach and Methodology .......................................93
7.6.2 Numerical Procedure .................................................98
7.6.3 Modeling Results ........................................................99
7.6.4 Kinetics Analysis Procedure ....................................103
7.6.5 Complete Rate Equations .........................................103
7.6.5.1 Reduction by Hydrogen: Temperature
Range of 1,150°C–1,350°C .......................103
7.6.5.2 Reduction by Hydrogen: Temperature
Range of 1,350°C–1,600°C ......................104
7.6.5.3 Reduction by Carbon Monoxide:
Temperature Range of 1,150°C–1,350°C ....106
7.6.5.4 Reduction by Carbon Monoxide:
Temperature Range of 1,350°C–1,600°C ....107
7.6.5.5 Reduction of Hematite Concentrate by
H or CO ...................................................107
2
7.6.5.6 Derivation for Comparison of X-vs-t of a
Compound with That of an Intermediate
Phase as a Separate Reactant ......................111
7.6.6 Reduction by H + CO Mixtures ...............................112
2
7.6.7 Summary and Concluding Remarks ........................120
Chapter 8 Development of Flash Ironmaking Technology – Tests in a
Laboratory Flash Reactor .................................................................121
8.1 Laboratory Flash Reactor ......................................................121
8.1.1 Importance of Testing in Laboratory Flash Reactor .....121
8.1.2 Apparatus .................................................................122
8.1.3 Experimental Procedure ...........................................124
