Application of Microwave Heating in the Comprehensive Utilization of Titanium Resources

Chen Jin, Gao Lei, Chen Guo

Description

The titanium industry is developing at a fantastic speed in China, which is promoted by the increasing demand for high-quality titanium resources. Thus, our research group led by Prof. Guo CHEN in Yunnan Minzu University is devoted to developing microwave heating applications in the production chain of titanium, and the corresponding results are summarized in this book.This book is divided into six chapters which initially look at the response and amenability of titanium-based elements tomicrowave power. Upon establishing its potential usefulness in titanium processing, the book assesses and introduces the various effects of microwave for different titanium related processes, including preweakening, drying, carbothermic reduction, leaching and roasting. A wide variety of analysis tools to determine the effects of microwave on these processes were utilized to support and explain the results. These include DSC, Raman, FTIR, SEM, EDAX. Finally, life cycle analysis was used to evaluate and to optimize microwave heating devices to provide information for further development of this process in the titanium industry. We hope this compilation can provide researchers and professionals working in the general minerals processing field the benefits of the microwave technique.

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III

CHAPTER 1

Microwave Absorbing Properties and Temperature Behaviour . . . . . . . . . . . . 1

1.1 Dielectric Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Measuring Instrumentation and Principle . . . . . . . . . . . . . . . . . . . . . . 2

1.3 Microwave Heating Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.4 Microwave-Absorbing Characteristics of Oxidised Ilmenite . . . . . . . . . 5

1.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.4.2 Microwave-Absorbing Characteristics of Carbothermic Reduction Products of Ilmenite and Oxidised Ilmenite . . . . . . . 6

1.4.3 Effect of Carbonaceous Reducing Agents on Microwave Absorbing Properties of Ilmenite . . . . . . . . . . . . . . . . . . . . . . . 13

1.4.4 Effect of Catalyst on Microwave Absorbing Properties of Ilmenite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.5 Microwave Absorbing Properties of Mechanically Activated Ilmenite . . 21

1.5.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

1.5.2 Effect of Mechanical Activated on Microwave Absorbing Properties of Ilmenite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1.6 Microwave Absorbing Characteristics of Mechanical Activated High Titanium Slag . . . . . . . . . . . .. . . . . . . . . . . . . . . . 26

1.6.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

1.6.2 Dielectric Loss Factor of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.6.3 Dielectric Constant of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.6.4 Loss Tangent Coefficient of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1.7 Microwave Absorbing Properties of High Titanium Slag . . . . . . . . . . . 30

1.7.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

1.7.2 Effect of Particle Size of High Titanium Slag on Microwave Absorbing Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.7.3 Effect of Mass Fraction of V2O5 on Microwave Absorbing Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1.8 Temperature Behaviour of Titanium Slag Under Microwave Heating . . 34

1.8.1 Materials and Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.8.2 Temperature Rise Characteristics of the Titanium-Rich Slag Using Microwave Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.9 Microwave Absorption Properties and Thermal Behaviour of Vanadium Titano-Magnetite (VTM) . . . . . . . . . . . . . . . . . . . . . . . . 38

1.9.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

1.9.2 Thermal Behaviour of VTM During Microwave Heating . . . . . . 41

1.9.3 Thermochemical Characteristics of VTM . . . . . . . . . . . . . . . . . 42

1.9.4 Dielectric Properties of VTM . . . . . . . . . . . . . . . . . . . . . . . . . . 45

1.9.5 Microwave Heating Characteristics of VTM . . . . . . . . . . . . . . . 47

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

CHAPTER 2

Microwave Pretreatment and Microwave Drying . . . . . . . . . . . . . . . . . . . . . . 53

2.1 Microwave Pretreatment of Ilmenite Ore . . . . . . . . . . . . . . . . . . . . . . . 54

2.1.1 Materials and procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

2.1.2 Effects of Microwave Energy. . . . . . . . . . . . . . . . . . . . . . . . . . . 58

2.1.3 Microwave Pretreatment Optimisation . . . . . . . . . . . . . . . . . . . 64

2.2 Microwave Pretreatment of Titanium Slag . . . . . . . . . . . . . . . . . . . . . 72

2.2.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

2.2.2 Effects of Microwave Energy. . . . . . . . . . . . . . . . . . . . . . . . . . . 73

2.3 High Effective Microwave-Assisted Drying of a Small Portion of Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

2.3.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

2.3.2 Microwave Drying Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . 78

2.3.3 Effects of Microwave Energy. . . . . . . . . . . . . . . . . . . . . . . . . . . 80

2.3.4 Drying Kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

2.4 High Effective Microwave-Assisted Drying of a Large Portion of Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

2.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

2.4.2 Microwave Drying Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . 83

2.4.3 Effects of Microwave Energy. . . . . . . . . . . . . . . . . . . . . . . . . . . 86

2.4.4 Drying Kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

CHAPTER 3

Microwave Carbothermic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

3.1 Microwave Carbothermic Reduction of Ilmenite Ores . . . . . . . . . . . . . 96

3.1.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

3.1.2 Effects of Microwave on Carbothermic Reduction . . . . . . . . . . . 97

3.1.3 Phase Diagram for the FeO–TiO2–TiO1.5 System . . . . . . . . . . . 101

3.2 Microwave Carbothermic Reduction of Ilmenite Ores with Sodium Silicate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

3.2.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

3.2.2 Calibrations of Weight-Loss Fraction During Microwave Carbothermic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

3.2.3 Effects of Sodium Silicate on Microwave Carbothermic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

3.3 Microwave Carbothermic Reduction of Ilmenite Ores with NaCl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

3.3.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

3.3.2 Calibrations of Weight-Loss Fraction During Microwave Carbothermic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

3.3.3 Effects of NaCl on Microwave Carbothermic Reduction . . . . . . 113

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

CHAPTER 4

Microwave-Assisted Leaching and Intensification. . . . . . . . . . . . . . . . . . . . . . 119

4.1 Microwave-Assisted Leaching of Primary Titanium-Rich Materials . . . 120

4.1.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

4.1.2 Non-Isothermal Microwave Leaching Kinetics . . . . . . . . . . . . . . 121

4.1.3 Microwave Absorption Characteristics During Leaching . . . . . . 126

4.2 Microwave-Assisted Leaching of Titanium Slag Using Dilute Sulfuric Acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

4.2.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

4.2.2 Principle for the Simultaneous Removal of Cr(III) and V(V) . . 132

4.2.3 Effects of Microwave Energy During the Process. . . . . . . . . . . . 133

4.2.4 Effects of the Na2CO3/Slag Mass Ratio . . . . . . . . . . . . . . . . . . 133

4.3 Microwave-Assisted Leaching of Titanium Slag Using Hydrochloric Acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

4.3.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

4.3.2 Characterisation by XRD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

4.3.3 Characterisation by Raman Spectroscopy . . . . . . . . . . . . . . . . . 151

4.3.4 Characterisation by FI-IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

4.3.5 Characterisation by SEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

4.4 Microwave-Assisted Leaching of High Titanium Slag Using Phosphoric Acid . . . . . . . . . . .  . . . . . . . . . . . . 155

4.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

4.4.2 Characterisation by XRD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

4.4.3 Characterisation by SEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

4.4.4 Characterisation by FT-IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

4.4.5 Characterisation by Raman . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

4.5 Microwave Intensification for the Preparation of Rutile TiO2 from Panzhihua Sulphate Titanium Slag . . . . . . .  . . . . . . . 161

4.5.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

4.5.2 Characterisation by XRD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

4.5.3 Characterisation by SEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

4.5.4 Characterisation by Raman Spectroscopy . . . . . . . . . . . . . . . . . 165

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

CHAPTER 5

Microwave Roasting Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

5.1 Preparation of Synthetic Rutile from Titanium Slag . . . . . . . . . . . . . . 172

5.1.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

5.1.2 Roasting Process with Conventional Heating . . . . . . . . . . . . . . 175

5.1.3 Process Optimisation with Response Surface Methodology . . . . 180

5.2 The Effect of Na2CO3/Slag Ratio and a Comparison Between Conventional and Microwave Heating for the Preparation of Rutile TiO2 . . . . . . . . . . . . . .  . . 186

5.2.1 The Effect of Na2CO3/Slag Ratio . . . . . . . . . . . . . . . . . . . . . . . 186

5.2.2 The Comparison Between Different Heating Methods . . . . . . . . 189

5.3 Optimisation of Microwave Roasting Process Using Response Surface Methodology (RSM) . . . . . . . . .. . . . . . . . . . . . . . . 194

5.3.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

5.3.2 Process Optimisation with Response Surface Methodology . . . . 196

5.3.3 Characterization of the Synthetic Rutile . . . . . . . . . . . . . . . . . . 201

5.3.4 Another Optimisation Case . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

5.4 Phase Transformation of Titanium Slag Using Microwave Irradiation . 209

5.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

5.4.2 Systematical Study on the Influence of Microwave on the Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

5.5 Preparation of Synthetic Rutile from Sulphate Titanium Slag with the Assistance of Microwave . . . . . . . . .  . . . . . . . . . . . 214

5.5.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

5.5.2 Characterization of the Synthetic Rutile . . . . . . . . . . . . . . . . . . 216

5.6 Preparation of Synthetic Rutile from High Titanium Slag with the Assistance of Microwave . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

5.6.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

5.6.2 Roasting Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

5.6.3 Weight Increase Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

5.6.4 Sulfur and Carbon Content Analysis . . . . . . . . . . . . . . . . . . . . 226

5.6.5 TiO2 Content Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

CHAPTER 6

Microwave Heating Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

6.1 Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation of Microwave Tube and Shaft Furnace . . . . . . . . . . . . . . 232

6.1.1 Hierarchical Structure of Assessment . . . . . . . . . . . . . . . . . . . . 232

6.1.2 Details for the Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

6.1.3 Features of the Microwave Tube Furnace . . . . . . . . . . . . . . . . . 237

6.1.4 Features of Microwave Shaft Furnaces . . . . . . . . . . . . . . . . . . . 238

6.2 Life Cycle Assessment on Microwave Leaching Process . . . . . . . . . . . . 240

6.2.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

6.2.2 Analytic Hierarchy Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

6.2.3 Pairwise Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

6.2.4 Life Cycle of Assessment of the Microwave-Assisted Leaching . . 243

6.3 Life Cycle Assessment on Microwave Hot Air Systems . . . . . . . . . . . . . 243

6.3.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

6.3.2 Features of Microwave Hot Air Systems . . . . . . . . . . . . . . . . . . 249

6.3.3 Life Cycle of Assessment of the Microwave Hot Air Systems . . . 250

6.4 Numerical Modeling of the Microwave Heating Device. . . . . . . . . . . . . 250

6.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

6.4.2 Details for Numerical Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

6.4.3 Temperature Rise Curve of High Titanium Slag by Microwave Irradiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

6.4.4 Characterisation of High Titanium Slag . . . . . . . . . . . . . . . . . . 256

6.4.5 Distribution of the Microwave Fields . . . . . . . . . . . . . . . . . . . . 257

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

Sujets

• Contrôle des processus
• Automatisation
• Automate
• Materials Science
• Sciences et techniques
• Titanium
• Technology
• Engineering
• Ingénierie
• Titane
• Sciences appliquées
• Sciences appliquées
• Ingénierie
• Sciences appliquées

Informations

• Publié par: EDP Sciences
• Date de parution: 12 mai 2022
• Nombre de lectures: 1
• EAN13: 9782759826971
• Langue: English
• Poids de l'ouvrage: 30 Mo

Extrait

Current Natural Sciences

TECHNOLOGY & ENGINEERING

Guo CHEN, Lei GAO and Jin CHEN

ApplicationofMicrowaveHeating in the Comprehensive Utilization of Titanium Resources

TECHNOLOGY & ENGINEERING

ISBN : 978-2-7598-2696-4

9 782759 826964

Current Natural Sciences

ApplicationofMicrowaveHeating in the Comprehensive Utilization of Titanium Resources

Guo CHEN, Lei GAO and Jin CHEN

The titanium industry is developing at a fantastic speed in China, which is promoted by the increasing demand for highquality titanium resources. Thus, our research group led by Prof. Guo CHEN in Yunnan Minzu University is devoted to developing microwave heating applications in the production chain of titanium, and the corresponding results are summarized in this book.

This book is divided into six chapters which initially looks at the response and amenability of titaniumbased elements to microwave power. Upon establishing its potential usefulness in titanium processing, the book assesses and introduces the various effects of microwave for different titanium related processes, including preweakening, drying, carbothermic reduction, leaching and roasting. A wide variety of analysis tools to determine the effects of microwave on these processes were utilised to support and explain the results. These include DSC, Raman, FTIR, SEM, EDAX. Finally, life cycle analysis was used to evaluate and to optimize microwave heating devices to provide information for further development of this process in the titanium industry. We hope this compilation of the work can provide researchers and professionals working in the general minerals processing field with the benefits of the microwave technique.

www.edpsciences.org

Current Natural Sciences

Guo CHEN, Lei GAO and Jin CHEN

Application of Microwave Heating in the Comprehensive Utilization of Titanium Resources

Printed in France

EDP Sciences–ISBN(print): 9782759826964–ISBN(ebook): 9782759826971 DOI: 10.1051/9782759826964

All rights relative to translation, adaptation and reproduction by any means whatsoever are reserved, worldwide. In accordance with the terms of paragraphs 2 and 3 of Article 41 of the French Act dated March 11, 1957,“copies or reproductions reserved strictly for private use and not intended for collective use”and, on the other hand, analyses and short quotations for example or illustrative purposes, are allowed. Otherwise,“any representation or reproduction–whether in full or in part–without the consent of the author or of his successors or assigns, is unlawful”(Article 40, paragraph 1). Any representation or reproduction, by any means whatsoever, will therefore be deemed an infringement of copyright punishable under Articles 425 and following of the French Penal Code.

The printed edition is not for sale in Chinese mainland.

Science Press, EDP Sciences, 2022

Preface

Titanium (Ti) is abundant in the crust, ranks fourth among metal elements, and is mainly concentrated in the form of ores such as ilmenite and rutile in nature. Thus, ilmenite and rutile are the origin of the modern titanium industry for the production of TiCl 4 , the intermediate products used for the manipulation of titanium sponge or titanium dioxide. In this industrial chain, the routes for the production of TiCl 4 are flexible as shown in the following figure, where ilmenite is transferred to titanium slag or synthetic rutile. Meanwhile, ilmenite can also directly transfer to titanium dioxide with the assistance of acid leaching. Clearly, the demands for titanium and its related products will be continuously boosted in the future. Nevertheless, the traditional titanium production chain is facing challenges with the gradual depletion of high grade titanium resources and environmental concerns.

DOI: 10.1051/9782759826964.c901 Science Press, EDP Sciences, 2022

IV

Preface

Thus, our research group in Yunnan Minzu University assisted by Kunming University of Science and Technology is working on the application of microwave heating in multiple production processes including drying, sintering and leaching, which are important for the production of titanium dioxide and related titanium products. Microwave heating, a multiphysics phenomenon that involves electro magnetic waves and heat transfer, is an important and powerful tool found in laboratories across the world, applied beyond reheating leftovers and across varying chemical applications. With the ability to heat efficiently, precisely, and safely, laboratory microwaves benefit chemicalsynthesis, materialdigestion, and now has semiindustrialization applications. In this book, the principles of microwave heating as applied to industrial pro cessing are outlined and the basic design of the microwave enhancing processes is introduced and the book is divided into six chapters. Prof. Guo Chen has con tributed on the design of the whole frame and the outline of the book, and also contributed chapter1. Dr. Lei Gao has contributed chapters2,3, and4. Prof. Jin Chen has contributed chapters5and6. Prof. Wei Li has provided valuable assis tance in the formation of chapters1and3. Prof. Jinhui Peng has also contributed on the design of the whole frame of the book and provided significant guidance. In chapter1, the microwave absorbing properties of various titanium resources including ilmenite, vanadium titanomagnetite and titanium slag are introduced. The corresponding temperature behaviours of these titanium resources under the radiation of microwave are systematically reported. In chapter2, microwave pretreatment technology and microwave drying technology in fascinating and attractive advanced interdisciplinary fields of research are introduced as well. In chapter3, the improvement on the carbothermic reduction in ilmenite and titaniumrich materials with microwave heating is reported, the purpose is to explore the possibility of further reduction in the energy consumption and envi ronment issues. In chapter4, research data related to microwave assisted leaching and intensification are introduced for process optimisation. In chapter5, the preparation of rutile from different kinds of titanium slag by microwave roasting process is reported in addition to the optimised parameters suggested by response surface methodology. In chapter6, life cycle assessment resulting from analytic hierarchy process and fuzzy comprehensive evaluation used for the optimisation of microwave heating devices is made. We hope these experimental data and the cor responding analysis can be helpful for the industrial application of microwave heating and thus further promote the development of titanium industry. We would like to acknowledge the National Natural Science Foundation of China (Grant No. U1802255, 51764052, 52104351), National Key R&D Program of China (2018YFC1900500), Yunnan Fundamental Research Projects (202101AU00088), Scientific Research Fund Project of Yunnan Education Department (No. 2021J0652), and the Kunming Key Laboratory of Energy Materials Chemistry, the Key Laboratory of GreenChemistry Materials in University of Yunnan Province, the Innovative Research Team (in Science and Technology) in the University of Yunnan province for the financial support. Meanwhile, we also appreciate the financial support from School of Chemistry and the Environment, Yunnan Minzu University for the publication of this book.

Preface

V

The authors want to express their appreciation to their students Mr. Hewen Zheng, Miss. Qiannan Li, Miss. Yeqing Ling, Mr. Xiandong Hao, Mr. Yuxi Gui, Miss. Hongju Qiu, Miss. Yanqiong Zhang, Mr. Sirui Zhang, Miss. Jiajia Lu, and Miss. Weiwei Huang, for their contributions on the edition of this book. The authors pay deep respect and gratitude to those concerned for their suggestions and comments, and the authors are aware that the expertise is limited and there may be some errors in the book. If so, please do not hesitate to point them out.

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 1 Microwave Absorbing Properties and Temperature Behaviour . . . . . . . . . . . . 1.1 Dielectric Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Measuring Instrumentation and Principle . . . . . . . . . . . . . . . . . . . . . . 1.3 Microwave Heating Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 MicrowaveAbsorbing Characteristics of Oxidised Ilmenite . . . . . . . . . 1.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4.2 MicrowaveAbsorbing Characteristics of Carbothermic Reduction Products of Ilmenite and Oxidised Ilmenite . . . . . . . 1.4.3 Effect of Carbonaceous Reducing Agents on Microwave Absorbing Properties of Ilmenite . . . . . . . . . . . . . . . . . . . . . . . 1.4.4 Effect of Catalyst on Microwave Absorbing Properties of Ilmenite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Microwave Absorbing Properties of Mechanically Activated Ilmenite . . 1.5.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.2 Effect of Mechanical Activated on Microwave Absorbing Properties of Ilmenite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 Microwave Absorbing Characteristics of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6.2 Dielectric Loss Factor of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6.3 Dielectric Constant of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6.4 Loss Tangent Coefficient of Mechanical Activated High Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 Microwave Absorbing Properties of High Titanium Slag . . . . . . . . . . . 1.7.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.2 Effect of Particle Size of High Titanium Slag on Microwave Absorbing Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7.3 Effect of Mass Fraction of V 2 O 5 on Microwave Absorbing Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Contents

1.8 Temperature Behaviour of Titanium Slag Under Microwave Heating . . 1.8.1 Materials and Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . 1.8.2 Temperature Rise Characteristics of the TitaniumRich Slag Using Microwave Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 Microwave Absorption Properties and Thermal Behaviour of Vanadium TitanoMagnetite (VTM) . . . . . . . . . . . . . . . . . . . . . . . . 1.9.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9.2 Thermal Behaviour of VTM During Microwave Heating . . . . . . 1.9.3 Thermochemical Characteristics of VTM . . . . . . . . . . . . . . . . . 1.9.4 Dielectric Properties of VTM . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9.5 Microwave Heating Characteristics of VTM . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 2 Microwave Pretreatment and Microwave Drying . . . . . . . . . . . . . . . . . . . . . . 2.1 Microwave Pretreatment of Ilmenite Ore . . . . . . . . . . . . . . . . . . . . . . . 2.1.1 Materials and procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.2 Effects of Microwave Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.3 Microwave Pretreatment Optimisation . . . . . . . . . . . . . . . . . . . 2.2 Microwave Pretreatment of Titanium Slag . . . . . . . . . . . . . . . . . . . . . 2.2.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Effects of Microwave Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 High Effective MicrowaveAssisted Drying of a Small Portion of Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 Microwave Drying Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.3 Effects of Microwave Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.4 Drying Kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 High Effective MicrowaveAssisted Drying of a Large Portion of Titanium Slag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.2 Microwave Drying Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.3 Effects of Microwave Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.4 Drying Kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 3 Microwave Carbothermic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Microwave Carbothermic Reduction of Ilmenite Ores . . . . . . . . . . . . . 3.1.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.2 Effects of Microwave on Carbothermic Reduction . . . . . . . . . . . 3.1.3 Phase Diagram for the FeO–TiO–TiO System . . . . . . . . . . . 2 1.5 3.2 Microwave Carbothermic Reduction of Ilmenite Ores with Sodium Silicate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Materials and Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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82 83 83 86 90 91

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