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Desulphurization of Ferronickel Alloy Using a Waste Material from Alumina Production

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Desulphurization of Ferronickel Alloy Using a Waste Material from Alumina Production Desulphurization of Ferronickel Alloy Using a Waste Material from Alumina Production by Xinqiang Men A thesis submitted in conformity with the requirements for the degree of Master of Applied Science Graduate Department of Materials Science and Engineering University of Toronto © Copyright by Xinqiang Men, 2012 Desulphurization of Ferronickel Alloy Using a Waste Material from Alumina Production By Xinqiang Men Master of Applied Science Department of Materials Science and Engineering University of Toronto 2012 ABSTRACT Red mud is a waste product of alumina production and has an adverse effect on environment. About 90 million tonnes of red mud are produced annually throughout the world and little is recycled for useful applications. The world nickel reserves consist of approximately 30% sulphide ores and 70% oxide ores. Despite the relative abundance of oxide ores, 55% of nickel and nickel alloys produced today are derived from sulphide ores. However, with the production of nickel and its alloys from low-grade oxide ores becoming increasingly important, a major concern is high sulphur level in the resultant alloy. For this reason, desulphurization of the ferronickel becomes an important consideration. In the present study, experiments were conducted to determine if red mud could be used as a major ingredient of custom designed fluxes for the desulphurization of ferronickel alloy. Factors investigated included desulphurization rates, contact angle measurements and flux-refractory interactions. ii ACKNOWLEDGEMENTS I would like to express my sincerest appreciation to my supervisor Prof. A.McLean, Dr. Y.D. Yang, Dr. Soda, Prof. M. Barati for their continual guidance, support and encouragement. I would like to thank for the help from Paul, Karim, Yuki and other members of our research group. Appreciation is also expressed to Allan from Ryerson University for his help in preparing materials for me. I express my thanks to Process Research Ortech (PRO) for in-kind support and the Centre for Chemical Process Metallurgy (CCPM) together with NSERC for financial support through a CRD Grant. In addition, I would like to thank the Department of Materials Science and Engineering, and University of Toronto for support. Finally, I would like to thank my family and friends in China for their unending support and encouragement throughout my study. iii TABLE OF CONTENTS ABSTRACT ............................................................................................................................. ii ACKNOWLEDGEMENTS ..................................................................................................... iii TABLE OF CONTENTS ......................................................................................................... iv LIST OF TABLES ................................................................................................................. viii LIST OF FIGURES ................................................................................................................. ix LIST OF SYMBOLS ............................................................................................................... xi LIST OF APPENDICES ........................................................................................................ xiv CHAPTER ONE: INTRODUCTION....................................................................................... 1 1.1 Background ..................................................................................................................... 1 1.2 References ....................................................................................................................... 4 CHAPTER TWO：LITERATURE REVIEW ......................................................................... 5 2.1 The Production of Alumina and Red Mud ...................................................................... 5 2.1.1 Bayer Process............................................................................................................ 5 2.1.2 Sintering Process ...................................................................................................... 9 2.1.3 Combined Process .................................................................................................. 12 2.2 Physical and Chemical Properties of Red Mud ............................................................. 16 2.2.1 Physical Properties of Red Mud ............................................................................. 16 2.2.2 Chemical Properties of Red Mud ........................................................................... 16 2.3 Negative Influence Caused by Red Mud ...................................................................... 17 2.4 Means to Recycle Red Mud .......................................................................................... 18 2.4.1 Utilization of Red Mud as Building Materials ....................................................... 18 2.4.1.1 Producing cement ............................................................................................. 18 2.4.1.2 Producing glass-ceramic .................................................................................. 19 2.4.1.3 Producing bricks............................................................................................... 19 2.4.1.4 Producing pigment ........................................................................................... 20 2.4.2 Recovery of Valuable Elements from Red Mud ..................................................... 20 2.4.2.1 Recovery of Al2O3 and Na2O ........................................................................... 21 2.4.2.2 Recovery of Fe2O3 ............................................................................................ 22 2.4.2.3 Recovery of TiO2.............................................................................................. 23 iv 2.4.3 Utilization of Red Mud as Environmental Materials .............................................. 24 2.4.3.1 Water treatment ................................................................................................ 24 2.4.3.2 Gas cleaning ..................................................................................................... 28 2.4.3.3 Soil amelioration .............................................................................................. 28 2.5 Problems in Recycling Red Mud .................................................................................. 29 2.6 References ..................................................................................................................... 30 CHAPTER THREE: EXPERIMENTAL ASPECTS .............................................................. 36 3.1 Materials ........................................................................................................................ 36 3.1.1 Solid Materials ........................................................................................................ 36 3.1.2 Gas Material............................................................................................................ 38 3.1.3 Liquid Material ....................................................................................................... 38 3.2 Scanning Electron Microscopy (SEM) ......................................................................... 38 3.2.1 Basic Principles of SEM ......................................................................................... 38 3.2.2 Sample Preparation ................................................................................................. 39 3.3 X-ray Diffraction (XRD) ............................................................................................... 39 3.3.1 Basic Principles of XRD ......................................................................................... 39 3.3.2 Sample Preparation ................................................................................................. 41 3.4 X-ray Fluorescence (XRF) ............................................................................................ 41 3.4.1 Basic Principles of XRF ......................................................................................... 41 3.4.2 Sample Preparation ................................................................................................. 42 3.5 Thermogravimetric Analysis (TGA or TG) ................................................................... 42 3.5.1 Basic Principles of TGA ......................................................................................... 42 3.5.2 Sample Preparation ................................................................................................. 43 3.6 Desulphurization Experiments ...................................................................................... 43 3.6.1 Experimental Equipment ........................................................................................ 43 3.6.2 Sample Preparation ................................................................................................. 44 3.6.3 Experimental Procedure.......................................................................................... 45 3.6.4 Sulphur Analysis of Samples .................................................................................. 45 3.7 Contact Angle Experiments........................................................................................... 45 3.7.1 Experimental Equipment .......................................................................................
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