Popov K.I., Djokic S.S., Grgur B.N. Fundamental Aspects of Electrometallurgy
Подождите немного. Документ загружается.
FUNDAMENTAL ASPECTS
OF ELECTROMETALLURGY
This page intentionally left blank
FUNDAMENTAL ASPECTS
OF ELECTROMETALLURGY
Konstantin I. Popov
University of Belgrade
Belgrade, Yugoslavia
Westaim Corporation
Fort Saskatchewan, Alberta, Canada
Branimir N. Grgur
University of Belgrade
Belgrade, Yugoslavia
KLUWER ACADEMIC PUBLISHERS
NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW
eBook ISBN: 0-306-47564-2
Print ISBN: 0-306-47269-4
©2002 Kluwer Academic Publishers
New York, Boston, Dordrecht, London, Moscow
Print ©2002 Kluwer Academic/Plenum Publishers
All rights reserved
No part of this eBook may be reproduced or transmitted in any form or by any means, electronic,
mechanical, recording, or otherwise, without written consent from the Publisher
Created in the United States of America
Visit Kluwer Online at: http://kluweronline.com
and Kluwer's eBookstore at: http://ebooks.kluweronline.com
New York
CONTRIBUTORS
Konstantin I. Popov
Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Yugoslavia
The Westaim Corporation, Fort Saskatchewan, Alberta, T8L 3W4, Canada
Branimir N. Grgur
Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Yugoslavia
v
This page intentionally left blank
FOREWORD
Electrometallurgy is a broad field but it is not a new one. It was the great Faraday
in the 1830s who discovered laws covering the electrodeposition of metals and its
relation to the current passed and equivalent weight of the metal undergoing deposi-
tion. Since that time, applications and developments of his discoveries have spread to
many areas of technology. Electrowinning is the most well known, partly because it
embraces the process by which aluminum is extracted from its ores. In electrorefining,
the impure metal is made into anode and the pure metal dissolved therefrom is
deposited on a cathode. Electroplating is exemplified by its use in the manufacture of
car bumpers. Finally, in electroreforming, objects may be metallized, often with a very
thin layer of the coating desired.
The numerous technologies vary greatly in the degree to which they are intellec-
tualized. Until the work of Popov et al., electrometallurgy has been regarded as largely
empirical, an activity in which there was much art and little science. This will all
change with the publication of this book. Several aspects of the background of its
senior author, Konstantin Popov, make him uniquely suited to the job of intellectualiz-
ing electrometallurgy. First, he had as his mentor the great surely
the leading electrochemist in Eastern Europe since the death of Frumkin. Second, he
has had ample experience with the leading electrochemical engineer in America,
Ralph White. And third, he has an admirable track record of a series of publications
aimed at showing the remarkable variety of forms which may be made to arise in
electrodeposition.
Dr. Popov’s contributions are characterized by a comprehensive mathematical
treatment of the phenomena he has discovered. Co-author too, has had
much relevant experience in applying the ideas so extensively developed in Belgrade
at Canadian companies.
The contents of the present volume illustrate how certain fields of science become
settled in certain countries. Industrial organic chemistry grew up in Germany, and
developed predominantly there until World War II. In electrometallurgy, the intellec-
tual development has been largely in Serbia, with the most fundamental studies in
nucleation being carried out in the neighboring country of Bulgaria (Kaischev, Busev-
ski). This is not to imply that there have been few American contributors (one recalls
Brenner, Kardos, Lowenheim), but that the contributions made here in this field have
vii
viii
Foreword
come from commercial laboratories and have been near the commercialization stage.
University or research institute work on electrometallurgical topics in the United States
has been nonexistent since the 1950s.
There are many figures in this splendid book of Popov et al. which impress me.
The first is the strong, broad contents of its arrangement. There is a fine first chapter on
the principles of application to electrochemical kinetics—the equations being written
in a form modified for use in electrometallurgical situations (e.g., deposition on the tips
of growing crystals of minimal radius of curvature and on corners and edges). Here, it
is encouraging to find authors applying the electrochemical version of Kelvin’s equa-
tion relating vapor pressure as a function of the radius of drops to the phenomena
during the electrogrowth of dendrites.
I personally find the treatments of the effects of current varying regimes (e.g.,
pulse, reverse pulse, square wave, sinusoidal, etc.) the most exciting for I have long
thought that instead of the use of chemical additives to the solution, the type of surface
finally produced—even the crystal shape—could be achieved by electrical variations
only. This book contains much toward the realization of this approach.
In the second half of the book, one finds the mathematical treatments of practical
situations in electrowinning, electrorefining, electroplating, and electroreforming.
What is the difference all this will make? It should enable to engineer to set up regimes
to achieve what he wants with a minimum of prefatory experiments.
This book has no competitor. There are certainly books on electroplating, but
they are largely recipes for what to do which eschew the important question of why.
Getting the intellectual side over to the practical engineer, of course, requires
great lucidity, for he will not puzzle over material delivered over his head. I think the
required clarity has been attained herewith, particularly in the early chapters where
the concepts of exchange currents and overpotential are being added to the weary
thermodynamics which covers most of what engineers are likely to know about
electrochemistry.
A great strength is in the photographs of electrodeposited crystals in all their
variety. Such photographs can be found in the usual journals, but I have not previously
seen such a collection accompanied by textual rationalization.
Lastly, I was impressed by the application of the theory to areas which normally
receive little more than a definition. I would cite electropolishing, where theory is
seldom presented; electromachining; and electroless plating.
This book is a feast simply to read, but I believe its main importance is that it gives
for the first time an educational tool. It will surely lead to translations and its use will
feed back upon the economics of electrometallurgical processes—with a reduction in
cost many orders of magnitude greater than the total in purchases of the books.
John O’M. Bockris
Texas A&M University
PREFACE
In their preface to the book Fundamental Aspects of Electrocrystallization,
Bockris and Razumney in 1966 wrote: “Electroplating, the electrochemical extraction
of metals from ores and mixtures, and electrodeposition from nonaqueous solutions,
together make up a large area in technology. It is relevant to distinguish two classes of
technologies: those in which, the fundamentals and theory were understood first and
the applications followed, and those in which the applied side began as a kind of art and
the theory limped behind the art, sometimes dragged back by it and occasionally given
a little push. Of course, the atomic energy and electronic industry are ideal example of
the first two. The electrodeposition and electroextraction industry is a fair example of
the second. It is clear enough that the rate of development of the first type of industry
was much greater than that of the second, as the possibilities could be estimated or at
least the direction in which to push defined, whereas the second type relied in the past
on what might be called “inspired groping.” It is hoped that this small monograph may
provide a basis for the training of research workers who can then perform the conver-
sion of what remains an art in technological electrocrystallization into a technology
with a largely rational basis.” In the meantime, although the electrochemistry of metals
has significantly advanced, the message of Bockris and Razumney, especially in the
light of education professionals, is practically the same. The bridge between high level
theory and highly developed practice is still necessary, probably even more than
previously. The purpose of this book is to enable this. It is written in order to explain
the principles of electrometallurgical technologies, not to give their technical details. It
should be easy to follow by a reader with a graduate or an undergraduate degree in
either engineering or science. It assumes the knowledge of the basic facts required on
the level of Modern Electrochemistry by Bockris and Reddy.
The book comprises twelve chapters, which can tentatively be divided into three
parts: Chapters 1,2,6, and 7 are written by Grgur and Popov, Chapters 3–5 and 8 by
Popov and Grgur and Chapters 9–12 by
In the first part (Chapters 1 and 2) the significance of electrometallurgy in science
and technology is discussed. The fundamentals of electrochemistry necessary for an
understanding of electrometallurgical processes are also given. In the second part
(Chapters 3–6) the mechanisms of metal deposition are discussed at a high scientific
level although efforts were made to simplify them in an approachable way. For
ix