Agglomeration in Metallurgy (eBook)

Preface 7
Introduction 9
References 12
Contents 13
About the Authors 17
1 Sinter Production 19
1.1 General Information About the Sintering Process 19
1.2 Raw Materials of the Sintering Process 25
1.3 Preparation of Charge Components for Sintering (Crushing, Dosing, Mixing, Pelletizing) 31
1.3.1 Dosing of the Components of the Sinter Charge 32
1.3.2 Pelletizing of the Sinter Charge 34
1.4 Mass Exchange Processes in the Sintering Layer 60
1.4.1 Chemical Reactions with Participation of Solid Phases 61
1.4.2 Processes in the Formation of the Liquid Phase During Melting 74
1.4.3 Processes During Solidification (Crystallization) of the Melt 75
1.5 Heat Transfer in the Sintering Layer 76
1.5.1 General Information on the Sintering Heat Exchange 76
1.5.2 Zonal Heat Balances of Sintered Layer 79
1.5.3 Mathematical Model of Heat Exchange During Sintering 83
1.5.4 Three-Dimensional Mathematical Model of the Sintering Process 85
1.5.5 Calculation of the Specific Yield of the Sintering Gas 89
1.5.6 Vertical Sintering Speed 90
1.6 The Gas Dynamics of the Sintering Process 91
1.6.1 The Basic Equation of Dynamics of the Porous Layer 91
1.6.2 Gas-Dynamic Resistance Coefficients 92
1.6.3 Porosity of the Sintering Layer 94
1.6.4 Gas Dynamics of Sintering Technology 95
1.6.5 Sinter Machine Performance 98
1.6.6 Ways to Improve the Performance of Sintering Machines 99
1.6.6.1 Modernization to Increase Sintering Capacities 99
1.6.6.2 Increasing Sinter Yield 101
1.6.6.3 Intensification of the Sintering Process 103
1.7 Quality of the Sinter in Terms of Influence on the Performance of Blast Furnace Smelting 106
1.7.1 Sinter Quality Indicators 106
1.7.2 Influence of Sinter Quality on Gas-Dynamic Parameters of Blast Furnace Smelting 108
1.7.3 Requirements for Sinter Quality 111
1.7.4 Basic Solutions to Improve Quality of Sinter 117
1.7.4.1 Production of Low-Silicon Sinter 118
1.7.4.2 Control of the Porous Structure of the Sinter 122
1.7.4.3 Introduction of Low-Melting Additives 124
1.7.4.4 Return Mode 126
1.7.4.5 Regulation of the Thermal Level of the Sintering Process 128
1.7.5 Technology of Sintering Under Pressure 134
1.8 Energy Efficiency of the Sintering Technology 136
1.9 Environmental Aspects of Sinter Production (Best Available Technologies) 141
1.9.1 Thermodynamic Modeling of Emissions in the Sintering Process 142
1.9.2 Characteristics of Emissions from Sinter Production 144
1.9.3 Influence of Technological Factors on the Emission of Pollutants During Sintering 146
1.9.4 Environmental Requirements as the Main Priority of Production Modernization 151
1.9.5 Waste Gas Recirculation Concept 166
1.9.6 Recommendations on the Best Available Technologies (BAT) in Sintering 177
1.9.7 Sinter Plant Without Chimney 179
References 183
2 Pellet Production 189
2.1 General Information About Pellet Production 189
2.1.1 Technological Scheme of the Production of Pellets 189
2.1.2 Formation of Raw Pellets 192
2.1.3 Strengthening of Raw Pellets 194
2.1.3.1 Pellet Drying 194
2.1.3.2 Roasting of Pellets 196
2.2 Charge Components for the Production of Pellets 197
2.3 Formation of Raw Pellets 202
2.3.1 Interaction Between Wetted Particles During the Formation of a Raw Pellet 202
2.3.2 The Nature of the Action of Binding Additives in the Strengthening of Raw Pellets 205
2.3.3 The Effectiveness of Various Strengthening Additives in Pelletizing 207
2.4 Cold-Bonded Pellet Production 218
2.4.1 General Information About Cold Agglomeration 218
2.4.2 Strengthening Mechanism of Portland Cement Binders 219
2.4.3 Cold Strengthening Under Normal Conditions 221
2.4.4 Cold Agglomeration at Moderate Temperatures 223
2.4.5 Cold Agglomeration with Accelerated Strengthening 224
2.4.6 Advantages of Cold Agglomeration Method 226
2.5 Strengthening Pellets with Thermal Methods 226
2.5.1 Phenomenology of Mass Transfer Processes During Heat Treatment of Pellets 228
2.5.2 Simulation of Mass Transfer Processes During Heat Treatment of Pellets 230
2.5.3 Pellet Roasting as a Complicated Case of Sintering 244
2.5.3.1 The Main Laws of Sintering Kinetics 244
2.5.3.2 Sintering Mechanism of Iron Oxides 246
2.5.3.3 Characteristics of Iron Oxide Structure Defects 249
2.5.3.4 Dependence of the Defectiveness of the Hematite Structure on the Genesis of Oxide 256
2.5.3.5 Defects in the Crystal Structure of Iron Oxides and Sintering Processes 262
2.5.4 The Pellet Macrostructure and Strength 265
2.6 Metallurgical Properties of Iron Ore Pellets 269
2.6.1 Pellet Quality Test Methods 269
2.6.2 Quality Requirements for Pellets 272
2.6.3 Basic Solutions for Improving the Quality of Pellets 276
2.6.3.1 Optimization of the Ratio of Fine and Coarse Fractions of the Concentrate 277
2.6.3.2 Minimization of the Zonal Structure of the Pellet 278
2.6.3.3 Introduction of Modifying Additives 279
2.6.3.4 Oxide Structure Defect Management 281
2.6.3.5 Regulation of Liquid-Phase Sintering 282
2.7 Resource Saving in the Production of Pellets 286
2.7.1 Resource Consumption in the Production of Pellets 286
2.7.2 Energy Efficiency of Conveyor Machines as Units for Pellets Roasting 287
2.7.3 Best Available Technologies (BAT) in the Production of Pellets Aimed at Improving Energy Efficiency 290
2.7.3.1 General BAT Solutions 290
2.7.3.2 Improving Thermal Schemes of Roasting Conveyor Machines 290
2.8 Environmental Aspects of Pellet Production 292
2.8.1 General Characteristics of Emissions to the Environment in the Production of Pellets 292
2.8.2 Sources of Emissions from Technological Operations in the Production of Pellets 294
2.8.3 The Best Available Technology in the Production of Pellets 298
References 300
3 Briquetting 305
3.1 General Information on Briquetting of Natural and Anthropogenic Raw Materials 305
3.2 History of the Industrial Briquetting in Ferrous Metallurgy 309
3.2.1 Beginning of the Twentieth Century—The 20s of the Twentieth Century 315
3.2.2 30–50s of the Twentieth Century 322
3.2.3 60–70s of the Twentieth Century 325
3.2.4 The 80s—The End of the Twentieth Century 332
3.2.5 Twenty-First Century 339
3.3 Basic Materials for Briquetting 346
3.3.1 Mining and Beneficiation of Ores 346
3.3.2 Sinter and Pellet Production 348
3.3.3 Coke Production 348
3.3.4 Blast Furnace Production 349
3.3.5 Steelmaking 349
3.3.6 Rolling Production 350
3.3.7 Ferroalloy Production 351
3.3.8 Direct Iron Production 352
3.4 Basic Industrial Technologies of Briquetting in Ferrous Metallurgy 352
3.4.1 Briquetting Using Roller Presses 352
3.4.2 Vibropressing for Briquetting 360
3.4.2.1 The Physical Essence of Vibropressing and the Structure of the Briquette 360
3.4.2.2 Technology of Vibropressing, Transportation, Heat Treatment, and Storage of Briquettes 365
3.4.3 Stiff Vacuum Extrusion Briquetting Technology 369
3.4.3.1 Preparation of Burden Materials for SVE Briquetting 370
3.4.3.2 Technological Process of Briquetting by Method of Stiff Vacuum Extrusion 372
3.4.3.3 The Movement of the Briquetted Mass in the Extruder 376
3.5 Requirements to Metallurgical Properties of Briquettes 388
3.5.1 Briquetting of Natural and Anthropogenic Materials in Blast Furnace (BF) Production 388
3.5.1.1 Metallurgical Properties of Vibropressed Blast Furnace Briquettes 391
3.5.1.2 Metallurgical Properties and Optimization of Extrusion Briquette (Brex) Compositions for Blast Furnace Production (Experimental Work) 396
3.5.1.3 Metallurgical Properties of Industrial Brex Used as the Main Component of a Blast Furnace Charge 403
3.5.1.4 Blast Furnace Operation with 100% Brex in Charge 411
3.5.1.5 Assessment of Prospects for the Use of Carbon-Containing Briquettes from Iron Ore Concentrate 413
3.5.2 Briquetting of Natural and Anthropogenic Raw Materials for Ferroalloy Production 415
3.5.2.1 Metallurgical Properties of Brex on the Basis of Manganese Ore Concentrate 420
3.5.2.2 Metallurgical Properties of Brex on the Basis of Manganese Ore Concentrate and Baghouse Dusts of Silicomanganese Production 421
3.5.2.3 Full-Scale Testing of Silicomanganese Smelting with Brex in the Charge of Submerged EAF 430
3.5.2.4 Metallurgical Properties of Briquettes on the Basis of Chromium-Containing Materials 437
3.5.3 Briquetting in Direct Reduced Iron (DRI) Production 446
References 459
4 Best Available Technologies for Agglomeration of the Raw Materials for Blast Furnaces 466
4.1 Production of Sinter as a BAT 466
4.2 Production of Pellets as a BAT 468
4.3 Stiff Extrusion Briquetting as a BAT 469
4.4 Comparative Analysis of Technologies for Agglomeration of the Raw Materials for Blast Furnace 470
References 471