Principles of Mineral Processing Edited by Maurice C. Fuerstenau and Kenneth N. Han Published by the Exploration, Inc. Society for Mining, Metallurgy, and Exploration, Inc. (SME) 8307 Shaffer Parkway Littleton, Colorado, USA 80127 (303) 973-9550 / (800) 763-3132 www.smenet.org SME advances the worldwide mining and minerals community through information exchange and professional development. SME is the largest association of minerals professionals. Copyright ¤ 2003 Society for Mining, Metallurgy, and Exploration, Inc. All Rights Reserved. Printed in the United States of America. Information contained in this work has been obtained by SME, Inc. from sources believed to be reliable. However, neither SME nor its authors guarantee the accuracy or completeness of any information published herein, and neither SME nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. 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TN500.P66 2003 622'.7--dc21 2002042938 . Preface The world is faced with opportunities and challenges that require ever-increasing amounts of raw materials to fuel various industrial sectors, and, at the same time, meet environmental constraints asso- ciated with excavating and processing these raw materials. In addition, gradual depletion of mineral resources and the necessity of handling more complex forms of resources, primary and secondary, have led to challenges in the development of state-of-the-art technologies that are metallurgically efficient and environmentally friendly. Unquestionably, technology advances are the key to sustaining a suffi- cient supply of necessary raw materials. To advance the technology in the production of material resources, nations look to practicing and future engineers. Current and future mineral processing engineers must obtain sound and rigorous training in the sciences and technologies that are essential for effective resource development. Many industrial and academic leaders have recognized the need for more textbooks and references in this important area. This was the driving force for writing a comprehensive reference book that covers mineral processing and hydrometallurgical extraction. This book was written first to serve students who are studying mineral processing and hydro- metallurgy under various titles. We also hope that the book will serve as a valuable reference to many industrial practitioners in the mineral processing field. In the chapters that follow, you will find first principles that govern various unit operations in mineral processing and hydrometallurgy, along with examples to illustrate how fundamental principles can be used in real-world applications. In general, the volume covers topics in the order of the usual processing sequence. Comminution, the breakage of rocks and other materials, is covered in such a way that the fundamental principles can be used not only in mineral processing but also in other relevant areas such as chemical engineering and pharmaceutical fields. Understanding the characteristics of particles and the separation of particulate materials from one another is of ultimate importance. Separation technologies based on properties such as magne- tism, electrical properties, and surface properties of various minerals are present along with industrial examples. Because most mineral processing unit operations take place in water as a medium, understand- ing how solids can best be separated from water is of industrial importance. Efficiently using water during effective solid–liquid separation is often vital to the success of the overall mineral beneficiation operation. With computer application technologies continuing to emerge rapidly, the mineral industry has made tremendous advances in its industrial production. Plant automation and control often play a vital role in the overall success of the plant operation. The chapter on comminution covers some of these innovations in automation. ix Once desired minerals are recovered from the undesired portion of an ore deposit, chemical treat- ment to unlock the desired metal elements from various minerals is necessary. Hydrometallurgical treatment for the chemical release of metal elements from various minerals is presented along with fundamental water chemistry and kinetic principles. We are fortunate that many world-class authorities in various areas of mineral processing have joined this endeavor, and we thank them for their participation. We would also like to take this oppor- tunity to thank the staff of the Society for Mining, Metallurgy, and Exploration, Inc., for their support in producing this book. x . Contents LIST OF AUTHORS vii PREFACE ix CHAPTER 1 INTRODUCTION 1 Maurice C. Fuerstenau and Kenneth N. Han Goals and Basics of Mineral Processing 1 Metallurgical Efficiency 1 Economic Concerns 3 Unit Operations 4 Examples of Mineral Processing Operations 5 Environmental Consequences of Mineral Processing 8 CHAPTER 2 PARTICLE CHARACTERIZATION 9 Richard Hogg Particle Characteristics 9 Mathematical Treatment of Particle Distributions 14 Measurement of Particle Characteristics 29 Comparison and Interconversion of Particle Size Data 53 Appendix 2.1: Moment Determination and Quantity Transformation from Experimental Data 54 Appendix 2.2: Combination of Sieve and Subsieve Size Data 54 CHAPTER 3 SIZE REDUCTION AND LIBERATION 61 John A. Herbst, Yi Chang Lo, and Brian Flintoff Introduction 61 Fundamentals of Particle Breakage 63 Comminution Equipment 79 Comminution Circuits 94 Process Control in Comminution 100 Financial Aspects of Comminution 113 Symbol Glossary 115 CHAPTER 4 SIZE SEPARATION 119 Andrew L. Mular Introduction 119 Laboratory Size Separation 121 Sedimentation Sizing Methods 127 iii Industrial Screening 129 Size Classification 148 CHAPTER 5 MOVEMENT OF SOLIDS IN LIQUIDS 173 Kenneth N. Han Introduction 173 Dynamic Similarity 173 Free Settling 174 Particle Acceleration 179 Particle Shape 181 Hindered Settling 183 CHAPTER 6 GRAVITY CONCENTRATION 185 Frank F. Aplan Introduction 185 The Basics of Gravity Separation 188 Float–Sink Separation 195 Jigs 202 Flowing Film Concentrators, Sluices, and Shaking Tables 206 Centrifugal Devices 212 Pneumatic Devices 212 Process Selection and Evaluation 214 CHAPTER 7 MAGNETIC AND ELECTROSTATIC SEPARATION 221 Partha Venkatraman, Frank S. Knoll, and James E. Lawver Introduction 221 Review of Magnetic Theory 221 Conventional Magnets 228 Permanent Magnets 232 Superconducting Magnets 236 Electrostatic Separation 239 CHAPTER 8 FLOTATION 245 Maurice C. Fuerstenau and Ponisseril Somasundaran Surface Phenomena 245 Flotation Reagents 252 Chemistry of Flotation 259 Flotation Machines 292 Column Flotation 296 Flotation Circuits 299 CHAPTER 9 LIQUID–SOLID SEPARATION 307 Donald A. Dahlstrom Introduction 307 Major Influences on Liquid–Solid Separation 309 Liquid–Solid Separation Equipment 317 Gravitational Sedimentation 317 Filtration 322 Basic Guidelines for Application 334 iv Gravity Sedimentation Applications 336 Continuous Vacuum Filtration 346 Batch Pressure Filters 357 CHAPTER 10 METALLURGICAL BALANCES AND EFFICIENCY 363 J. Mark Richardson and Robert D. Morrison Terminology 363 Applications 366 Types of Balances 368 Calculation Methods 376 Data 385 CHAPTER 11 BULK SOLIDS HANDLING 391 Hendrik Colijn Theory of Solids Flow 391 Design of Storage Silos and Hoppers 393 Feeders 397 Mechanical Conveying Systems 402 Pneumatic Conveying Systems 407 Instrumentation and Control 408 CHAPTER 12 HYDROMETALLURGY AND SOLUTION KINETICS 413 Kenneth N. Han and Maurice C. Fuerstenau Introduction 413 Solution Chemistry 414 Electrochemistry 434 Reaction Kinetics 442 Shrinking Core Models 454 Reactor Design 462 Recovery of Metal Ions from Leach Liquor 479 CHAPTER 13 MINERAL PROCESSING WASTES AND THEIR REMEDIATION 491 Ross W. Smith and Stoyan N. Groudev Liquid Wastes 491 Contaminated Soils 503 Solids Disposal and Long-term Management of Tailings Impoundments 509 CHAPTER 14 ECONOMICS OF THE MINERALS INDUSTRY 517 Matthew J. Hrebar and Donald W. Gentry Supply-Demand Relationships 517 Distinctive Features of the Minerals Industry 520 Mineral Project Evaluation 522 INDEX 561 v . CHAPTER 1 Introduction Maurice C. Fuerstenau and Kenneth N. Han The term mineral processing is used in a broad sense throughout this book to analyze and describe the unit operations involved in upgrading and recovering minerals or metals from ores. The field of mineral processing is based on many fields of science and engineering. Humanities and social science have also become an integral part of this technology because mineral processing,