basic concepts of iron and steel making

Basic Concepts of Iron and Steel Making

Sujay Kumar Dutta • Yakshil B. Chokshi

Basic Concepts of Ironand Steel Making

123

Sujay Kumar DuttaMetallurgical and MaterialsEngineering DepartmentFaculty of Technology and EngineeringThe Maharaja Sayajirao Universityof BarodaVadodara, Gujarat, India

Yakshil B. ChokshiMetallurgical Engineering DepartmentGovernment Polytechnic RajkotRajkot, Gujarat, India

ISBN 978-981-15-2436-3 ISBN 978-981-15-2437-0 (eBook)https://doi.org/10.1007/978-981-15-2437-0

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Preface

The steel is the most widely used metallic (i.e. iron) alloy, and its production(in world) is more than fifty times total production of combined all othermetals. That is why iron and steel form one group (i.e. ferrous metals), andother metal combinations (except iron) form other group (i.e. non-ferrousmetals). India occupies third position in world steel’s production and willbecome second in coming decade. All Metallurgical and Materials Engi-neering Departments in technical colleges/institutes, particularly in India,have teaching programmes in ironmaking and steelmaking. During the pastthree and half decades, many advances have been made in the implemen-tation of new technologies in the ironmaking and steelmaking. These tech-nical advances have been reflected also on the curriculum given at thetechnical colleges/institutes. This textbook covers almost all the importantbasic concepts, derivations and numerical for undergraduate and graduateengineering students in simple and easy to understand formats. Even plant’sengineers or operators and research scientists can brush up their under-standing of ironmaking and steelmaking and use as a source of reference.

This textbook is divided into six parts: Part I (Ironmaking) of the bookcovers Raw Materials and Blast Furnace Ironmaking, Part II coversAlternate Methods of Ironmaking including sponge iron, smelting reduc-tion processes, etc., Part III covers Physical Chemistry of Ironmakingincluding thermodynamics and kinetics, Part IV covers all SteelmakingProcesses, Part V covers Thermodynamics and Physical Chemistry ofSteelmaking, and Part VI discusses Pollution in iron and steel plants.

Sujay Kumar Dutta taught process metallurgy, in general, and ironmakingand steelmaking in particular, at M. S. University of Baroda, India, forthirty-six years. He visited several iron and steel plants; interactions withprofessionals have considerably enhanced his knowledge of the subject. Hewishes to gratefully acknowledge all of them. He expresses his gratitude tohis teachers Prof. A. K. Chakrabarti (earlier Bengal Engineering College,Shibpur; presently Indian Institute of Engineering Science and Technology,Shibpur, India) for introducing him to the metallurgy of ironmaking andsteelmaking and Prof. A. Ghosh (Indian Institute of Technology Kanpur,India) for advance ironmaking and steelmaking, which have inspired himthroughout his career.

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Despite taking all the possible care, there may be some errors or mistakesleft out unnoticed. If so, please feel free to interact with us. In moulding andcasting this textbook, we poured our long experience in it and also collectedthe information from several sources. We are indebted to one and all, fromwhose valuable knowledge we have been benefited. We thank our familymembers for their cooperation during the preparation of the book.

Vadodara, India Sujay Kumar DuttaRajkot, India Yakshil B. Chokshi

vi Preface

Contents

Part I Ironmaking

1 Raw Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.1 Introduction of Ferrous Extractive Metallurgy. . . . . . . . . . 31.2 Raw Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.2.1 Iron Ore. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.2.2 Metallurgical Coke . . . . . . . . . . . . . . . . . . . . . . 71.2.3 Fluxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181.2.4 Air Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181.2.5 Problem of Indian’s Raw Materials . . . . . . . . . . 19

1.3 Agglomeration Processes . . . . . . . . . . . . . . . . . . . . . . . . . 191.3.1 Sintering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201.3.2 Pelletization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241.3.3 Briquetting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301.3.4 Nodulizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311.3.5 New Feed Material (Iron Ore–Coal

Composite Pellet). . . . . . . . . . . . . . . . . . . . . . . . 321.3.6 Testing of Agglomerates . . . . . . . . . . . . . . . . . . 34

Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

2 Blast Furnace Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512.1 Outline of Blast Furnace Process . . . . . . . . . . . . . . . . . . . 512.2 Constructional Features of BF. . . . . . . . . . . . . . . . . . . . . . 522.3 Temperature Profile of BF . . . . . . . . . . . . . . . . . . . . . . . . 562.4 Function of Charged Materials in BF . . . . . . . . . . . . . . . . 572.5 Charging System of BF . . . . . . . . . . . . . . . . . . . . . . . . . . 58

2.5.1 Two-Bell Charging System . . . . . . . . . . . . . . . . 582.5.2 Bell-Less Top (BLT) System. . . . . . . . . . . . . . . 62

2.6 Size of Charge Particles . . . . . . . . . . . . . . . . . . . . . . . . . . 67Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

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3 Blast Furnace Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693.1 Blast Furnace Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . 69

3.1.1 Tuyere Reactions or Combustion ZoneReactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

3.1.2 Reactions in the Stack . . . . . . . . . . . . . . . . . . . . 713.1.3 Bosh Reactions . . . . . . . . . . . . . . . . . . . . . . . . . 733.1.4 Hearth Reactions . . . . . . . . . . . . . . . . . . . . . . . . 75

3.2 Slag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763.2.1 BF Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

3.3 Modern Concept of BF Process . . . . . . . . . . . . . . . . . . . . 783.3.1 Lumpy or Granular Zone . . . . . . . . . . . . . . . . . . 793.3.2 Softening and Melting Zone . . . . . . . . . . . . . . . 803.3.3 Dripping (or Dropping) Zone. . . . . . . . . . . . . . . 803.3.4 Raceway Zone . . . . . . . . . . . . . . . . . . . . . . . . . . 813.3.5 Hearth Zone. . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

3.4 Direct and Indirect Reduction . . . . . . . . . . . . . . . . . . . . . . 813.5 Tuyere Flame Temperature (TFT). . . . . . . . . . . . . . . . . . . 823.6 Raceway Adiabatic Flame Temperature (RAFT). . . . . . . . 823.7 Modern Trends of BF Practice . . . . . . . . . . . . . . . . . . . . . 84

3.7.1 Large Capacity of Furnaces . . . . . . . . . . . . . . . . 853.7.2 Burden Preparation . . . . . . . . . . . . . . . . . . . . . . 853.7.3 Better Distribution of Burden . . . . . . . . . . . . . . 863.7.4 Blast Temperature . . . . . . . . . . . . . . . . . . . . . . . 863.7.5 Oxygen Enrichment of Blast . . . . . . . . . . . . . . . 863.7.6 Humidification of Blast . . . . . . . . . . . . . . . . . . . 873.7.7 Auxiliary Fuel Injection . . . . . . . . . . . . . . . . . . . 883.7.8 Pulverized Coal Injection (PCI) . . . . . . . . . . . . . 893.7.9 Lime Injection . . . . . . . . . . . . . . . . . . . . . . . . . . 933.7.10 High Top Pressure . . . . . . . . . . . . . . . . . . . . . . . 93

3.8 Transfer of Silicon and Sulphur . . . . . . . . . . . . . . . . . . . . 943.9 Aerodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 953.10 BF Productivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

4 Furnace Auxiliaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1134.1 Cleaning of BF Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

4.1.1 Dust Catcher . . . . . . . . . . . . . . . . . . . . . . . . . . . 1134.1.2 Primary Cleaning or Wet-Cleaning . . . . . . . . . . 1144.1.3 Secondary Cleaning . . . . . . . . . . . . . . . . . . . . . . 1164.1.4 Dry-Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . 1184.1.5 Comparing of Dry- and Wet-Cleaning . . . . . . . . 118

4.2 Hot Blast Stoves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1194.3 Blast Furnace Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

4.3.1 Control of Temperature . . . . . . . . . . . . . . . . . . . 1214.3.2 Control of Composition . . . . . . . . . . . . . . . . . . . 122

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4.4 BF Cooling Arrangements . . . . . . . . . . . . . . . . . . . . . . . . 122Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

5 Operation of Blast Furnace. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1255.1 Operation of the Furnace . . . . . . . . . . . . . . . . . . . . . . . . . 125

5.1.1 Blowing In. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1255.1.2 Banking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1265.1.3 Blowing Out . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

5.2 Operational Problems of BF . . . . . . . . . . . . . . . . . . . . . . . 1275.2.1 Hot Spots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1275.2.2 Scaffolding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1285.2.3 Slipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1285.2.4 Breakouts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

5.3 BF Refractory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Part II Alternate Methods of Ironmaking

6 Raw Materials for DR Processes . . . . . . . . . . . . . . . . . . . . . . . 1356.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1356.2 Iron Ore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

6.2.1 Characteristics of Iron Ore. . . . . . . . . . . . . . . . . 1356.3 Coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

6.3.1 Reactivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1406.3.2 Ash Content. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1406.3.3 Volatile Matter and Sulphur Content . . . . . . . . . 1416.3.4 Coking and Swelling Indices . . . . . . . . . . . . . . . 142

6.4 Natural Gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1426.4.1 Reforming Reaction . . . . . . . . . . . . . . . . . . . . . . 142

6.5 Other Raw Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1456.6 Sizes of Raw Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . 1456.7 Composite Pellets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

7 Sponge Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1497.1 Introduction of Sponge Iron . . . . . . . . . . . . . . . . . . . . . . . 1497.2 Definition of Sponge Iron . . . . . . . . . . . . . . . . . . . . . . . . . 1497.3 Sponge Iron Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

7.3.1 Coal-Based Processes . . . . . . . . . . . . . . . . . . . . 1507.3.2 Gas-Based Processes . . . . . . . . . . . . . . . . . . . . . 152

7.4 Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1537.4.1 Coal-Based . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1537.4.2 Gas-Based . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

7.5 Coal-Based Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557.5.1 Rotary Kiln Process . . . . . . . . . . . . . . . . . . . . . . 1557.5.2 Rotary Hearth Process . . . . . . . . . . . . . . . . . . . . 162

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7.6 Gas-Based Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1667.6.1 Midrex Process . . . . . . . . . . . . . . . . . . . . . . . . . 1667.6.2 HyL Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 1697.6.3 Purofer Process . . . . . . . . . . . . . . . . . . . . . . . . . 1747.6.4 FINMET Process . . . . . . . . . . . . . . . . . . . . . . . . 1747.6.5 HIB Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

7.7 Forms of Sponge Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1757.7.1 Cold Sponge Iron/DRI (CDRI) . . . . . . . . . . . . . 1777.7.2 Hot Sponge Iron/DRI (HDRI) . . . . . . . . . . . . . . 1777.7.3 Hot Briquetted Iron (HBI) . . . . . . . . . . . . . . . . . 177

7.8 Characteristics of Sponge Iron . . . . . . . . . . . . . . . . . . . . . 1787.8.1 Metallization . . . . . . . . . . . . . . . . . . . . . . . . . . . 1797.8.2 Carbon Content . . . . . . . . . . . . . . . . . . . . . . . . . 1797.8.3 Gangue Content . . . . . . . . . . . . . . . . . . . . . . . . . 1797.8.4 Impurities and Residual Elements . . . . . . . . . . . 180

7.9 Quality of Sponge Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . 1807.10 Re-oxidation of Sponge Iron. . . . . . . . . . . . . . . . . . . . . . . 180

7.10.1 Preventive Measures . . . . . . . . . . . . . . . . . . . . . 1827.11 Use of Sponge Iron. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

7.11.1 Use of Sponge Iron/DRI in BF . . . . . . . . . . . . . 1847.11.2 Use of Sponge Iron/DRI in LD/BOF . . . . . . . . . 1857.11.3 Use of Sponge Iron/DRI in EAF . . . . . . . . . . . . 1867.11.4 Use of Sponge Iron/DRI in IMF . . . . . . . . . . . . 187

7.12 Environmental Benefits of Sponge Iron/DRI . . . . . . . . . . . 1887.13 Iron Carbide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

8 Smelting Reduction Processes . . . . . . . . . . . . . . . . . . . . . . . . . . 1998.1 Need of Smelting Reduction . . . . . . . . . . . . . . . . . . . . . . . 199

8.1.1 Why Are Smelting Reduction ProcessesRequired?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

8.2 Significance of Smelting Reduction . . . . . . . . . . . . . . . . . 2028.3 Principle of SR Processes . . . . . . . . . . . . . . . . . . . . . . . . . 2028.4 Classification of SR Processes . . . . . . . . . . . . . . . . . . . . . 203

8.4.1 Processes Utilizing Coal and Electricity. . . . . . . 2038.4.2 Processes Utilizing Oxygen and Coal . . . . . . . . 204

8.5 Advantages of Smelting Reduction Processes . . . . . . . . . . 2058.6 Limitations of Smelting Reduction Processes . . . . . . . . . . 2078.7 Major Smelting Reduction (SR) Processes. . . . . . . . . . . . . 207

8.7.1 Corex Process . . . . . . . . . . . . . . . . . . . . . . . . . . 2088.7.2 Romelt Process . . . . . . . . . . . . . . . . . . . . . . . . . 2128.7.3 DIOS Process . . . . . . . . . . . . . . . . . . . . . . . . . . 2158.7.4 HIsmelt Process . . . . . . . . . . . . . . . . . . . . . . . . . 215

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8.7.5 AusIron Process . . . . . . . . . . . . . . . . . . . . . . . . . 2198.7.6 FINEX Process . . . . . . . . . . . . . . . . . . . . . . . . . 2208.7.7 FASTMELT Process . . . . . . . . . . . . . . . . . . . . . 223

Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

9 Alternate Ironmaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2279.1 Low Shaft Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2279.2 Mini-blast Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2299.3 Charcoal Blast Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . 2309.4 Electrothermal Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 2329.5 ELRED Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2349.6 KR Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Part III Physical Chemistry of Ironmaking

10 Thermodynamics of Reduction . . . . . . . . . . . . . . . . . . . . . . . . . 24110.1 Reduction of Metal Oxide. . . . . . . . . . . . . . . . . . . . . . . . . 24110.2 Phase Stability Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . 243

10.2.1 Fe–C–O System. . . . . . . . . . . . . . . . . . . . . . . . . 24310.2.2 Fe–H–O System. . . . . . . . . . . . . . . . . . . . . . . . . 245

10.3 Reduction of Iron Oxides . . . . . . . . . . . . . . . . . . . . . . . . . 24710.3.1 Reduction by Carbon Monoxide . . . . . . . . . . . . 24910.3.2 Reduction by CO and H2 Mixtures . . . . . . . . . . 252

10.4 Reaction in BF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25310.4.1 Gas Concentration Within Stack of BF . . . . . . . 25310.4.2 Raceway Zone . . . . . . . . . . . . . . . . . . . . . . . . . . 25410.4.3 Bosh and Hearth . . . . . . . . . . . . . . . . . . . . . . . . 255

10.5 Carbon Deposition on Sponge Iron. . . . . . . . . . . . . . . . . . 26010.6 Mechanism of Smelting Reduction of Iron Oxides . . . . . . 261Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

11 Kinetics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27111.1 Reduction by Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

11.1.1 Interfacial Reaction Control . . . . . . . . . . . . . . . . 27111.1.2 Kinetics of Solid–Solid Reaction . . . . . . . . . . . . 27411.1.3 Reduction of Iron Oxides by CO and H2. . . . . . 278

11.2 Gasification of Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . 279Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

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Part IV Steelmaking

12 Historical Steelmaking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29312.1 Introduction of Steelmaking . . . . . . . . . . . . . . . . . . . . . . . 29312.2 Earlier Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

12.2.1 Wrought Ironmaking . . . . . . . . . . . . . . . . . . . . . 29412.2.2 Cementation Process . . . . . . . . . . . . . . . . . . . . . 29512.2.3 Crucible Process . . . . . . . . . . . . . . . . . . . . . . . . 295

12.3 Modern Steelmaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29612.4 Various Steelmaking Routes . . . . . . . . . . . . . . . . . . . . . . . 29712.5 Sources of Heat in Steelmaking . . . . . . . . . . . . . . . . . . . . 29912.6 Slag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30012.7 Ternary Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30212.8 Basic Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

12.8.1 Difference Between Cast Iron and Steel. . . . . . . 30412.8.2 Difference Between Plain Carbon Steel

and Alloy Steel . . . . . . . . . . . . . . . . . . . . . . . . . 30412.8.3 Difference Between Alloy Steel

and Ferro-Alloy . . . . . . . . . . . . . . . . . . . . . . . . . 304Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

13 Raw Materials for Steelmaking . . . . . . . . . . . . . . . . . . . . . . . . 30713.1 Raw Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30713.2 Sources of Metallic Iron . . . . . . . . . . . . . . . . . . . . . . . . . . 307

13.2.1 Primary Sources of Metallic Iron . . . . . . . . . . . . 30713.2.2 Secondary Sources of Metallic Iron . . . . . . . . . . 308

13.3 Oxidizing Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31213.3.1 Deoxidizers and Alloy Additions . . . . . . . . . . . . 312

13.4 Fluxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31313.5 Furnace Refractory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31313.6 Sources of Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314

13.6.1 Heat Balance of Steelmaking Process . . . . . . . . 31413.7 Pre-treatment of Hot Metal . . . . . . . . . . . . . . . . . . . . . . . . 315

13.7.1 De-siliconization . . . . . . . . . . . . . . . . . . . . . . . . 31513.7.2 De-sulphurization. . . . . . . . . . . . . . . . . . . . . . . . 31613.7.3 De-phosphorization . . . . . . . . . . . . . . . . . . . . . . 31713.7.4 Advantages of Pre-treatment to Hot Metal. . . . . 319


14 Steelmaking Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32114.1 Acid Bessemer Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

14.1.1 Refining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32214.1.2 Air Blowing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 32414.1.3 Heat Balance . . . . . . . . . . . . . . . . . . . . . . . . . . . 324

14.2 Basic Bessemer Process . . . . . . . . . . . . . . . . . . . . . . . . . . 32514.2.1 Refining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32514.2.2 Air Blowing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

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14.2.3 Heat Balance . . . . . . . . . . . . . . . . . . . . . . . . . . . 32614.2.4 Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

14.3 Open-Hearth Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32714.3.1 Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32814.3.2 Melting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32814.3.3 Refining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33014.3.4 Finishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33014.3.5 Modification of Open-Hearth Furnace . . . . . . . . 332


15 Oxygen Steelmaking Processes . . . . . . . . . . . . . . . . . . . . . . . . . 34315.1 LD Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

15.1.1 Design of Converter. . . . . . . . . . . . . . . . . . . . . . 34415.1.2 Lance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34615.1.3 Oxygen Lancing . . . . . . . . . . . . . . . . . . . . . . . . 34615.1.4 Mechanism of Refining . . . . . . . . . . . . . . . . . . . 35215.1.5 Characteristic of Slag. . . . . . . . . . . . . . . . . . . . . 35415.1.6 Mechanism of Carbon Reaction. . . . . . . . . . . . . 35415.1.7 Manganese Reaction . . . . . . . . . . . . . . . . . . . . . 35615.1.8 Phosphorous Reaction . . . . . . . . . . . . . . . . . . . . 35815.1.9 Sulphur Reaction . . . . . . . . . . . . . . . . . . . . . . . . 35915.1.10 Control of Carbon and Phosphorus

Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36015.1.11 Process Controlling Factors . . . . . . . . . . . . . . . . 36015.1.12 Economics of Process . . . . . . . . . . . . . . . . . . . . 36215.1.13 Operating Results/Performance . . . . . . . . . . . . . 36215.1.14 Lining of Converter . . . . . . . . . . . . . . . . . . . . . . 36315.1.15 Pollution Control . . . . . . . . . . . . . . . . . . . . . . . . 365

15.2 Oxygen Bottom Blowing Processes . . . . . . . . . . . . . . . . . 36615.2.1 OBM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36715.2.2 LWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370

15.3 LD-AC/OLP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37115.4 Rotary Oxygen Processes . . . . . . . . . . . . . . . . . . . . . . . . . 373

15.4.1 Kaldo Process . . . . . . . . . . . . . . . . . . . . . . . . . . 37415.4.2 Rotor Process. . . . . . . . . . . . . . . . . . . . . . . . . . . 375

15.5 New Developments in Oxygen SteelmakingProcesses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37515.5.1 Mixing by Inert Gas Through Porous

Bricks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37715.5.2 Mixing by Inert Gas Through Tuyeres . . . . . . . 38015.5.3 Combined Blowing Processes . . . . . . . . . . . . . . 382


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16 Electric Furnace Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40116.1 Introduction of Electric Furnaces . . . . . . . . . . . . . . . . . . . 40116.2 Electric Arc Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

16.2.1 Main Parts of EAF . . . . . . . . . . . . . . . . . . . . . . 40516.2.2 Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41216.2.3 Design of Furnace . . . . . . . . . . . . . . . . . . . . . . . 419

16.3 Further Developments in EAF . . . . . . . . . . . . . . . . . . . . . 42516.3.1 Design Aspect . . . . . . . . . . . . . . . . . . . . . . . . . . 42616.3.2 Process Modifications . . . . . . . . . . . . . . . . . . . . 42916.3.3 Charge Modifications. . . . . . . . . . . . . . . . . . . . . 430

16.4 DC Arc Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43516.4.1 Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43616.4.2 Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43716.4.3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43716.4.4 Difference Between AC and DC . . . . . . . . . . . . 438

16.5 Induction Melting Furnace (IMF) . . . . . . . . . . . . . . . . . . . 43916.5.1 Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44016.5.2 Raw Materials . . . . . . . . . . . . . . . . . . . . . . . . . . 44016.5.3 Electromotive Force. . . . . . . . . . . . . . . . . . . . . . 44116.5.4 Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . 44216.5.5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44316.5.6 Merit and Limitation . . . . . . . . . . . . . . . . . . . . . 44316.5.7 Difference Between EAF Versus IMF . . . . . . . . 44516.5.8 Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . 446

16.6 Quality Steel Production by Using Sponge Iron . . . . . . . . 44616.6.1 Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44716.6.2 Melting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44816.6.3 Mechanism of Nitrogen Removal . . . . . . . . . . . 45016.6.4 Product Characteristics. . . . . . . . . . . . . . . . . . . . 45116.6.5 Advantages of Using Sponge Iron in EAF. . . . . 451

16.7 Use of Hot Metal in EAF . . . . . . . . . . . . . . . . . . . . . . . . . 45216.7.1 CONARC Process . . . . . . . . . . . . . . . . . . . . . . . 45416.7.2 EOF Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 45616.7.3 ECOARC Process . . . . . . . . . . . . . . . . . . . . . . . 45916.7.4 CONSTEEL Process . . . . . . . . . . . . . . . . . . . . . 46116.7.5 FASTEEL Process . . . . . . . . . . . . . . . . . . . . . . . 46116.7.6 Shaft Furnace Technology . . . . . . . . . . . . . . . . . 462

16.8 Stainless Steel Production . . . . . . . . . . . . . . . . . . . . . . . . . 46416.8.1 Earlier Method. . . . . . . . . . . . . . . . . . . . . . . . . . 46416.8.2 Rustless Process. . . . . . . . . . . . . . . . . . . . . . . . . 46516.8.3 Rapid Process . . . . . . . . . . . . . . . . . . . . . . . . . . 46616.8.4 New De-carburization Techniques . . . . . . . . . . . 46816.8.5 Stainless Steel Production by IMF. . . . . . . . . . . 474


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17 Secondary Steelmaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49717.1 Introduction of Secondary Steelmaking. . . . . . . . . . . . . . . 49717.2 Ladle Furnace (LF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498

17.2.1 ASEA-SKF Furnace. . . . . . . . . . . . . . . . . . . . . . 49917.3 De-gassing Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500

17.3.1 Gases in Liquid Steel. . . . . . . . . . . . . . . . . . . . . 50017.3.2 Vacuum De-gassing . . . . . . . . . . . . . . . . . . . . . . 502

17.4 Injection Ladle Metallurgy . . . . . . . . . . . . . . . . . . . . . . . . 51617.4.1 Submerge Injection Through Lance . . . . . . . . . . 51717.4.2 Cored Wire Injection . . . . . . . . . . . . . . . . . . . . . 51717.4.3 Efficiency of Calcium . . . . . . . . . . . . . . . . . . . . 520

17.5 De-oxidation of Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52117.5.1 Precipitation De-oxidation . . . . . . . . . . . . . . . . . 52117.5.2 Diffusion De-oxidation. . . . . . . . . . . . . . . . . . . . 524

17.6 Inclusion and Its Control. . . . . . . . . . . . . . . . . . . . . . . . . . 52517.6.1 Classification of Non-metallic Inclusions . . . . . . 52517.6.2 Inclusion Control . . . . . . . . . . . . . . . . . . . . . . . . 529


18 Casting Pit Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53718.1 Introduction of Casting Pit Practice . . . . . . . . . . . . . . . . . 53718.2 Teeming Ladle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53718.3 Ingot Mould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53818.4 Hot Top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53918.5 Solidification of Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540

18.5.1 Killed Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . 54018.5.2 Semi-killed Steels . . . . . . . . . . . . . . . . . . . . . . . 54118.5.3 Rimming Steels . . . . . . . . . . . . . . . . . . . . . . . . . 54118.5.4 Capped Steels . . . . . . . . . . . . . . . . . . . . . . . . . . 54118.5.5 Mechanism of Solidification . . . . . . . . . . . . . . . 541

18.6 Ingot Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54218.6.1 Pipe Formation . . . . . . . . . . . . . . . . . . . . . . . . . 54218.6.2 Blow Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54318.6.3 Columnar Structure . . . . . . . . . . . . . . . . . . . . . . 54418.6.4 Segregation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54418.6.5 Non-metallic Inclusions . . . . . . . . . . . . . . . . . . . 54418.6.6 Internal Rupture and Hairline Cracking . . . . . . . 54518.6.7 Surface Defects . . . . . . . . . . . . . . . . . . . . . . . . . 546

18.7 Teeming Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 547Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549

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19 Continuous Casting (CONCAST) . . . . . . . . . . . . . . . . . . . . . . . 55119.1 Introduction of CONCAST . . . . . . . . . . . . . . . . . . . . . . . . 55119.2 Equipments for CONCAST . . . . . . . . . . . . . . . . . . . . . . . 552

19.2.1 Ladle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55219.2.2 Tundish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55219.2.3 Mould . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55319.2.4 False Bottom or Dummy Plug Bar . . . . . . . . . . 55319.2.5 Withdrawal Rolls . . . . . . . . . . . . . . . . . . . . . . . . 55319.2.6 Cooling Sprays . . . . . . . . . . . . . . . . . . . . . . . . . 554

19.3 Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55419.4 Types of Casters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55519.5 Mould Powder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556

19.5.1 Powder Consumption. . . . . . . . . . . . . . . . . . . . . 55919.5.2 Slag Films . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561

19.6 Merits of CONCAST . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56119.7 Improvements of CONCAST . . . . . . . . . . . . . . . . . . . . . . 562

19.7.1 Remotely Adjustable Moulds (RAM) . . . . . . . . 56219.7.2 Ladle Slag Detection System . . . . . . . . . . . . . . . 56219.7.3 Submerged Entry Nozzle (SEN) . . . . . . . . . . . . 56219.7.4 Electromagnetic Stirring (EMS) . . . . . . . . . . . . . 56419.7.5 Electromagnetic Brakers (EMBR) . . . . . . . . . . . 56419.7.6 Argon Purging Through Tundish Mono-Block

Stopper (MBS). . . . . . . . . . . . . . . . . . . . . . . . . . 56519.8 Quality Control in CONCAST . . . . . . . . . . . . . . . . . . . . . 566

19.8.1 Cleanliness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56619.8.2 Chemical Homogeneity . . . . . . . . . . . . . . . . . . . 56619.8.3 Porosity and Cracks . . . . . . . . . . . . . . . . . . . . . . 56619.8.4 Desired Shape . . . . . . . . . . . . . . . . . . . . . . . . . . 567

19.9 Further Developments of CONCAST Practices. . . . . . . . . 56819.9.1 Near-Net-Shape (NNS) Casting . . . . . . . . . . . . . 56919.9.2 Horizontal Continuous Casting (HCC). . . . . . . . 57019.9.3 Direct Rolling (ISP and CSP) . . . . . . . . . . . . . . 570


Part V Thermodynamics and Physical Chemistryof Steelmaking

20 Thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57520.1 Physical Chemistry of Steelmaking. . . . . . . . . . . . . . . . . . 575

20.1.1 Oxidizing Power of Slag . . . . . . . . . . . . . . . . . . 57620.1.2 Sulphide Capacity of Slag . . . . . . . . . . . . . . . . . 577

20.2 Fundamental Thermodynamic Relations . . . . . . . . . . . . . . 57720.2.1 Carbon in Iron–Carbon Alloys. . . . . . . . . . . . . . 57720.2.2 Oxygen in Iron . . . . . . . . . . . . . . . . . . . . . . . . . 578

20.3 Thermodynamics of Refining . . . . . . . . . . . . . . . . . . . . . . 58020.3.1 Carbon–Oxygen Equilibrium Reaction. . . . . . . . 58020.3.2 Silicon Reaction. . . . . . . . . . . . . . . . . . . . . . . . . 585

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20.3.3 Manganese Reaction . . . . . . . . . . . . . . . . . . . . . 58620.3.4 Phosphorous Reaction . . . . . . . . . . . . . . . . . . . . 59020.3.5 Sulphur Reaction . . . . . . . . . . . . . . . . . . . . . . . . 594

20.4 Thermodynamics of De-oxidation of Steel . . . . . . . . . . . . 59720.4.1 Thermodynamics for Oxygen in Molten

Steel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59720.4.2 De-oxidation Equilibrium. . . . . . . . . . . . . . . . . . 599

20.5 Thermodynamics of De-sulphurization . . . . . . . . . . . . . . . 60020.6 Thermodynamics of Chromium Reactions . . . . . . . . . . . . 60320.7 Thermodynamics of Vacuum Degassing . . . . . . . . . . . . . . 607

20.7.1 Hydrogen During Vacuum. . . . . . . . . . . . . . . . . 60720.7.2 Nitrogen During Vacuum . . . . . . . . . . . . . . . . . 60820.7.3 Oxygen During Vacuum . . . . . . . . . . . . . . . . . . 60920.7.4 De-sulphurization During Vacuum. . . . . . . . . . . 611


Part VI Pollution in Iron and Steel Industries

21 Carbon Foot Prints for Iron and Steel Production . . . . . . . . . 62521.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62521.2 Iron and Steel Sector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62621.3 Estimation of CO2 Emissions . . . . . . . . . . . . . . . . . . . . . . 628

21.3.1 One Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . 62821.3.2 Another Methods . . . . . . . . . . . . . . . . . . . . . . . . 632

21.4 Product and by-Product. . . . . . . . . . . . . . . . . . . . . . . . . . . 63321.5 Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633Probable Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634

Appendix A: Ellingham Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . 635

Appendix B: Physical Properties of Metals . . . . . . . . . . . . . . . . . . . 637

Appendix C: Standard Free Energy Change for SomeImportant Reactions DG�

T . . . . . . . . . . . . . . . . . . . . . . 639

Appendix D: Free Energy and Enthalpy Values for SomeImportant Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . 641

Appendix E: Free Energy Values for Some Reactions . . . . . . . . . . 643

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About the Authors

Sujay Kumar Dutta is a former Professor and Head of the Department ofMetallurgical & Materials Engineering at Maharaja Sayajirao University ofBaroda, India. He received his Bachelor of Engineering (Metallurgy) fromCalcutta University in 1975 and his Master of Engineering (IndustrialMetallurgy) from MS University of Baroda in 1980. He completed his PhD atthe Indian Institute of Technology, Kanpur, India, in 1992. He joined MSUniversity of Baroda as a Lecturer in 1981 and was promoted to Professor in2001. Prof. Dutta has received several awards, including an Essar GoldMedal (2006), a Fellowship (2014) and a Distinguished Educator Award(2015), all from the Indian Institute of Metals (IIM), Kolkata, in recognitionof his distinguished service to the field of Metallurgical Education and to theIIM. He has authored of five books, two chapters of “Encyclopedia of Iron,Steel, and Their Alloys”, and published more than 120 research papers innational/international journals and conference proceedings. Very recentlyProf. Dutta was awarded “SAIL Award 2019” by The Institution of Engineers(India).

Yakshil B. Chokshi is a Lecturer at the Department of Metallurgy,Government Polytechnic Rajkot, India. He received his BE in Metallurgical& Materials Engineering from Gujarat University in 2010 and his ME inIndustrial Metallurgy from MS University of Baroda in 2012.

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basic concepts of iron and steel making

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