Download Preface 1 (pdf, 27 kB)

Preface
The idea of this book came during the organization of the seminars “Refractories
and Carbon Cathode Materials for Aluminium Industry” that were held in 2001,
2002, 2003, and 2004 in Samara, Sayanogorsk, Novokuznetsk, and Bratsk (Russia).
The hosts of these seminars were smelters and secondary aluminium plants, and
that enabled people directly involved in refractories and carbon cathode materials
and the service life of metallurgical devices to be invited.
We tried to plan the seminar programs so that the invited lectures from academic
science were followed by the applied science papers, which in turn were followed
by the papers and presentations of leading producers of materials used in the
aluminium industry. It seems to me it helped to speak one language among the
people involved in R&D of materials science, in reduction and casting of aluminium, in problems of service life, sometimes in connection with procurement issues.
At that time, in the course of preparatory work for these seminars and the
invitation of the key lectures, from one side, and in preparation for the proceedings,
from another, the understanding was growing that the theme “Refractories and
Carbon Cathode Materials for Aluminium Industry” is a multidisciplinary sphere,
where one meets people with different educations and different understandings of
the processes.
Probably the key issue there is that the reduction of aluminium (as a part of the
metallurgy of aluminium) is actually high-temperature electrochemistry, which is a
sufficiently more peculiar sphere than ferrous metallurgy. Peculiarity number one is
that the reduction of aluminium is an electrochemical reaction giving heat, and this
heat should dissipate, while the temperature range of the processing of this reaction
is very narrow — only 25–30 . Both freezing of electrolyte and overheating of
electrolyte will stop the reduction process. Peculiarity number two is that the main
constituent of electrolyte for the reduction of aluminium is cryolite, which is a
substance that dissolves alumina in the best possible way. Certainly, it will dissolve
all other oxides, and not only oxides. Peculiarity number three is that the producers
of carbon materials (and carbon cathode refractory materials as well) try to set
themselves a little bit apart from refractory society, speak a slightly different
v
vi
Preface
language, and use special terminology and testing methods. Probably peculiarity
number four is that in contrast with traditional metallurgy (where also something
may be improved anytime), the construction of reduction cells for the electrolysis of
aluminium is still under development, and at least for some 20 years this process
will continue.
Probably one more peculiarity is that “refractories for aluminium” is a rather
young branch, because initially aluminium producers used refractories that were
made for ferrous metallurgy. It was only in the 1980s and 1990s that special
research and development together with industrial trials outlined “refractories for
aluminium” as a special branch.
The main materials for the lining of the reduction cells:
– carbon cathode blocks and carbon ramming pastes;
– carbon and silicon carbide side lining materials and ramming pastes, concretes
and mortars for the installation of them;
– refractory barrier layer bricks and dry barrier mixtures;
– heat insulation materials
are described in the following sequence:
–
–
–
–
the purpose of the material and its basic properties, grades of materials;
raw materials for processing;
installation in the reduction cell;
elements of technology and processing, processing equipment, structure of the
materials;
– the typical defects of materials;
– testing and characterization.
– the behavior in reduction cell during the service in connection with physical
changes and chemical interactions.
Critical pore sizes for the penetration of corrosive liquids in refractory materials
are discussed for every specific material.
The casting of aluminium is a traditional process, but the interesting point in the
cast house is how the materials that cannot be considered optimal refractory
materials from the viewpoint of physical chemistry were worked out and adjusted
in the course of R&D in a way that can be considered quite satisfactory for service
life and economics of processing.
Currently, it is possible to say that for the existing Hall–Heroult process of
aluminium reduction, the service life of the metallurgical equipment has reached a
certain satisfactory level, and significant investments in R&D of refractory materials for aluminium are not likely. The exception is the materials science of carbon
cathode materials, where certain efforts could be made.
Yet to implement the technology of inert anode for the reduction of aluminium
(and most probably in combination with drained cathode design), profound materials science R&D will be required.
The book is addressed to the people working at aluminium smelters and at the
secondary aluminium plants and to the people producing refractories and heat
Preface
vii
insulation materials. The designers and specialists in construction of metallurgical
devices may also find something useful by looking through the material. I tried to
compose the book’s material in such a way that it may cover the interests of people
from R&D and to the persons in charge of service life. Even procurement people
might look through selected pages. I hope that both undergraduate and postgraduate
students will also find something interesting by reading this text in the course of
specialization.
The figures and illustrations for this book were made by Dr. Dmitry Ivanov, to
whom I’m very grateful. Special words of gratitude go to Prof. Vasily Kryukovsky
for his consultations in reduction technology and to Prof. Dick Bradt for his
permanent warm words of encouragement toward the project; the consultations of
Prof. Peter Polyakov and the team of “Light Metals” from Krasnoyarsk are also
appreciated. Special thanks to Vasily Borisov for his consultations on constructions
of reduction cells and dry autopsies and for his assistance in our joint investigations,
and special thanks to Dr. Sergey Hramenko, with whom we tried to find answers to
many questions that are in our joint publications. Thanks and words of gratitude to
all participants and co-organizers of the seminars of “Refractories for Aluminium”
in Samara, Novokuznetsk, Sayanogorsk, and Bratsk.
Moscow, Russia
Andrey Yurkov
http://www.springer.com/978-3-319-11441-5

Download Report