Table Of ContentRate Processes
of Extractive
Metallurgy
Rate Processes
of Extractive
Metallurgy
Edited by
Hong Yong Sohn
and
Milton E. Wadsworth
University of Utah
Salt Lake City, Utah
Plenum Press • New HJrk and London
Library of Congress Cataloging in Publication Data
Main entry under title:
Rate processes of extractive metallurgy.
Includes bibliographical references and index.
1. Metallurgy. I. Sohn, Hong Yong. II. Wadsworth, Milton E.
TN665.R27 669 78-15941
ISBN 978-1-4684-9119-7 ISBN 978-1-4684-9117-3 (eBook)
DOl 10.1007/978-1-4684-9117-3
© 1979 Plenum Press, New York
A Divison of Plenum Publishing Corporation
227 West 17th Street, New York, N.Y. 10011
Softcover reprint of the hardcover 1st edition 1979
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted,
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
Contributors
Robert W. Bartlett, Stanford Research Institute, Menlo Park,
California; formerly Kennecott Research Center, Salt Lake City,
Utah
Ivan B. Cutler, Department of Materials Science and Engineering,
University of Utah, Salt Lake City, Utah
James W. Evans, Department of Materials Science and Mineral
Engineering, University of California, Berkeley, California
John A. Herbst, Department of Metallurgy and Metallurgical
Engineering, University of Utah, Salt Lake City, Utah
C.-H. Koo, Department of Materials Science and Mineral Engineering,
University of California, Berkeley, California
Sanaa E. Khalafalla, Twin Cities Metallurgy Research Center, U.S.
Bureau of Mines, Twin Cities, Minnesota
Jan D. Miller, Department of Metallurgy and Metallurgical
Engineering, University of Utah, Salt Lake City, Utah
Charles H. Pitt, Department of Metallurgy and Metallurgical
Engineering, University of Utah, Salt Lake City, Utah
Hong Yong Sohn, Department of Metallurgy and Metallurgical
Engineering, University of Utah, Salt Lake City, Utah
Julian Szekel" Department of Materials Science and Engineering,
Massachusetts Institute of Technology, Cambridge, Massachusetts
E. T. Turkdogan, Research Laboratory, U.S. Steel Corporation,
Monroeville, Pennsylvania
Milton E. Wadsworth, Department of Metallurgy and Metallurgical
Engineering, University of Utah, Salt Lake City, Utah
v
Preface
Computer technology in the past fifteen years has essentially rev
olutionized engineering education. Complex systems involving coupled
mass transport and flow have yielded to numerical analysis even for
relatively complex geometries. The application of such technology
together with advances in applied physical chemistry have justified a
general updating of the field of heterogeneous kinetics in extractive
metallurgy. This book is an attempt to cover significant areas of extrac
tive metallurgy from the viewpoint of heterogeneous kinetics.
Kinetic studies serve to elucidate fundamental mechanisms of reac
tions and to provide data for engineering applications, including
improved ability to scale processes up from bench to pilot plant. The
general theme of this book is the latter-the scale-up. The practicing
engineer is faced with problems of changes of order of magnitude in
reactor size. We hope that the fundamentals of heterogeneous kinetics
will provide increasing ability for such scale-up efforts. Although ther
modynamics is important in defining potential reaction paths and the end
products, kinetic limitations involving molecular reactions, mass trans
port, or heat flow normally influence ultimate rates of production. For
this reason, rate processes in the general field of extractive metallurgy
have been emphasized in this book.
This book is an edited version of the notes for an intensive short
course of the same title held at the University of Utah in 1975. The
section on oxide reduction was added subsequently. Although various
chapters and sections are contributions by different authors, we selected
and organized the topics so that coherence and continuity were pre
served as far as possible. There are some slight differences in the notation
in the various sections, but in such cases the symbols are defined where
they first appear in a given section.
We wish to thank all those who have helped in making the short
course possible and in the preparation of this book. While we cannot
vii
lliii Preftu:e
possibly name all of them, we would like to mention the following: We
gratefully acknowledge the support of the Kennecott Copper Corpora
tion, the U.S. Steel Corporation, and the U.S. Bureau of Mines, and the
encouragement and assistance of Dr. K. J. Richards of Kennecott
Research Center. Professor Henry Eyring of the University of Utah, a
pioneer in the field of chemical kinetics, delivered a keynote lecture on
the subject of "Reaction-Rate Theory and Some Applications." Professor
Julian Szekely of the Massachusetts Institute of Technology deserves
thanks for introducing one of us (HYS) to extractive and process metal
lurgy and for instilling in him an "erroneous" idea, through his many
short courses and conferences, that a short course of this type is an easy
venture. Professors R. D. Pehlke (University of Michigan) and T. J.
O'Keefe (University of Missouri-Rolla) offered encouragement and
support of our effort and made valuable suggestions regarding the
contents of the book.
The inception of the short course was a result of the combined
efforts by our colleagues in the Department of Metallurgy and Metal
lurgical Engineering, University of Utah. We also thank the participants
of the short course for providing lively discussions during the sessions
and helpful comments afterward. Our warmest thanks go to our
secretarial staff for typing much of the manuscript and assisting us in
many ways with its preparation.
H. Y. Sohn
M. E. Wadsworth
Contents
1. Fundamentals of the Kinetics of Heterogeneous Reaction Systems in
Extractive Metallurgy
H. Y. Sohn
1.1. Elementary Steps ................... 1
1.1.1. Mass Transfer between a Solid Surface and a Fluid 3
1.1.2. Diffusion of Fluid Species through the Pores of a Solid 4
1.1.3. Intrinsic Kinetics of Heterogeneous Reactions on Solid
Surfaces . . . . . . . . . . . . . . . . . . . . . 5
1.1.4. Heat Transfer between a Solid Surface and a Moving Fluid
Stream ............. 6
1.1.5. Conduction of Heat in Porous Solids 7
1.1.6. Summary ............ 7
1.2. Reaction of a Single Nonporous Particle 8
1.2.1. Reactions in Which No Solid Product Layer Is Formed 8
1.2.2. Reactions in Which a Product Layer Is Formed 11
1.2.3. Nonisothermal Reactions in Shrinking-Unreacted-Core
Systems . . . . . . . . . . 17
1.2.4. Summary and Comments . . . . . . . . . . 22
1.3. Reaction of a Single Porous Particle ... . . . . . 23
1.3.1. Reactions in Which No Solid Product Is Formed 24
1.3.2. Reactions in Which a Product Layer Is Formed 30
1.3.3. Concluding Remarks . . . . . . . . . . . . 37
1.4. Reactions between Two Solids Proceeding through Gaseous
Intermediates ...... 38
1.4.1. Formulation of Model 40
1.4.2. Results 43
1.4.3. Discussion 47
1.5. Notation 47
References 49
j"
Contents
"
2. Rate Processes in Multiparticle Metallurgical Systems
J. A. Herbst
2.1. General Approach to Describing Rate Processes in Multiparticle
Systems . . . . . 53
2.1.1. Introduction . . . . . . 53
2.1.2. Motivation ...... 54
2.1. 3. Particle Characterization 61
2.1.4. Representation of Property Distributions 63
2.1.5. Population-Balance Framework 74
2.1.6. Application of Population Balance to Extractive Metallurgical
Systems . . . . . . . . . 81
2.1.7. Summary and Conclusions 110
References ........ 111
2A. Chemical Process Analysis and Design for Multiparticle
Systems
Robert W. Bartlett
2A.1. Introduction ................ . 113
2A.2. The Concept of General Reactor Scale-up Criteria 114
2A.2.1. Particle Phenomenological Kinetics 115
2A.2.2. Rate-Controlling Steps in Particle Reactions 116
2A.2.3. Particle Size Distribution ........ . 118
2A.2.4. Residence Time Distribution in the Reactor 119
2A.3. Computed Dimensionless Design Curves 119
2A.4. Application of F Curves in Process Design 127
2A.4.1. Determining the Kinetic Data 127
2A.4.2. Scale-up 128
2A.4.3. Discussion 128
2A.5. Application Examples 129
References ..... 131
S. Hydrometallurgical Processes
Sec. 3.1. Milton E. Wadsworth
Sec. 3.2. Milton E. Wadsworth
Sec. 3.3. J. D. Miller
3.1. Principles of Leaching (MEW) ................ 133
3.1.1. Introduction . . . .. ................ 133
3.1.2. Heterogeneous Kinetics of Importance in Hydrometallurgy 136
3.1.3. Leaching of Metals . 172
3.1.4. Leaching of Sulfides ........ 179
3.1.5. Leaching. of Oxides ........ 182
3.2. Dump and In Situ Leaching Practices (MEW) 186
3.2.1. Introduction . . . . . . . . . . . . 186
Contents xi
3.2.2. Leaching Systems 187
3.2.3. Rate Processes 189
3.3. Cementation (JDM) 197
3.3.1. Electrochemical Reactions 198
3.3.2. Mass Transfer-Hydrodynamics 210
3.3.3. Surface Deposit Effects 226
References 241
4. Pyrometallurgical Processes
Sec. 4.1. S. E. Khaiafalla
Sec. 4.2. J. W. Evans and C.-H. Koo
Sec. 4.3. H. Y. Sohn and E. T. Turkdogan
Sec. 4.4. I. B. Cutler
Sec. 4.5. E. T. Turkdogan
Sec. 4.6. C. H. Pitt
4.1. Roasting as a Unit Process (SEK) 245
4.1.1. Introduction . . . 245
4.1.2. Roasting Operations and Furnaces 247
4.1.3. Thermodynamics of Roasting Reactions 250
4.1.4. Gas-Solid Reactions in Roasting . . . . 253
4.1.5. Kinetics of Roasting Reactions . . . . . 254
4.1.6. Selected Cases in Metallurgical Roasting 262
4.2. The Reduction of Metal Oxides (JWE and CHK) 285
4.2.1. Introduction . . . . . 285
4.2.2. Iron Ore Reduction 286
4.2.3. Nickel Oxide Reduction 303
4.2.4. Lead Oxide Reduction 3 13
4.2.5. Reduction of Other Oxides by Gases 314
4.2.6. Reduction of Oxides by Solid Carbonaceous Materials 314
4.2.7. Di rect Red uction Processes 3 15
4.3. Calcination (HYS and ETT) 321
4.4. Sintering (!Be) ..... 329
4.4.1. Introduction . . . . 329
4.4.2. The Driving Force for Sintering 329
4.4.3. Stages of Sintering . . . . . . 330
4.4.4. Variables That Change Sintering Characteristics of Materials 335
4.4.5. Interaction between Grain Growth and Densification 338
4.4.6. Relationship of Strength to Densification by Sintering 338
4.4.7. Application of Principles of Sintering to Extractive
Metallurgical Operations 339
4.5. Smelting and Refining (ETT) . . . . . . . . . . . . . 340
4.5.1. Introduction . . . . . . . . . . . . . . . . . . 340
4.5.2. Selected Properties of Gases, Liquid Metals, Mattes, and
Slags ....................... 341
