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Advances in molten salt chemistry
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theoretician and experimentalist. The quality of papers and discussion clearly justified wider circulation to those unfortunate not to be present at the meeting. This need has been satisfied by rapid publication in Colloids and Surfaces and the Editor and publishers are to be congratulated for their efforts. One may then question the need for further publication in this form. W.D. COOPER Chester
Advances in Molten Salt Chemistry, Volume 6. G. Mamantov, C.B. Mamantov and J. Braunstein (Editors). Elsevier, Amsterdam, Oxford, New York, Tokyo, 1987, xii + 362 pp., Dfl. 295.00. This series was begun in 1971. New volumes have appeared at irregular intervals, and have contained from four to six comprehensive review articles on specified topics within the molten salts field. It remains under the control of the original senior Editors, and has survivied a change of publisher between Vols. 4 and 5. It is highly regarded by workers in the field, and is the only vehicle in which such reviews can be found in this specialism. The articles are reproduced from camera ready copy prepared by the authors. Some variability of quality is therefore evident in the text, and more particularly the diagrams, though the quality of output now available on word processors makes this problem less serious than heretofore. Volume 6 contains four articles. The first is by Professor Klemm of the Max Planck Insitut, Maim, and is on “Ionic Mobilities”. This is a masterly review. Professor Klemm has worked on this topic for over 4 decades, and is an acknowledged authority on it. Of the 173 references cited, 23 are to his own publications. Even allowing for the tendency common to most authors for self-citation, this indicates the magnitude of his own contribution! Professor Klemm begins by reviewing the formalism used to describe mobilities (internal and external) in pure salts and mixtures. He goes on to describe experimental methods for measurement of mobilities, and presents a comprehensive survey of published data. The chapter concludes with a concise statement of the reasons why mobilites change with composition, temperature and pressure. This is a most valuable review, to which many workers will refer for some years to come. The second and third chapters are on related topics, namely the commercial production of aluminium and magnesium. Research on aluminium smelting has long been almost a monopoly of the Norwegians, and the author of Chapter 2, Dr. J. Thonstad of NTH Trondheim, has made many contributions himself. The Hall-Herault process now yields some 18 Mtonne per annum, and consumes 3% of the electrical energy produced in the industrialised countries worldwide. This process is described in great detail. Its chemistry has been studied exhaustively, and work is now concentrated on making
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marginal improvements in the efficiency of the process. New electrode materials seem to offer the best chance of further progress. A final section is devoted to the ALCOA process for production of aluminium from aluminium chloride, which offers some potential advantages but is not yet competitive with the Hall-Herault process. Though Thonstad’s chapter is very thorough, the authors of Chapter 3 (Drs. G.J. Kipouros and D.R. Sadoway) have adopted a more didactic style which makes their chapter somewhat easier to read. Magnesium smelting is currently on a much smaller scale than aluminium smelting (less than 1 Mtonne/year), but involves a greater variety of sources and methods, some electrochemical and some chemical. These are described in detail, and the discussion includes a satisfying thermodynamic analysis. It is evident that non-equilibrium processes frequently play an important role. Possibilities for improvement of the efficiency of the various processes are discussed. At present, only 20% of the magnesium produced is used as a structural material, and more extended use is forecast. (However, this reviewer remembers reading similar predictions in his “Boys’ Wonder Book of Science”, received as a Christmas present in 1945!). For any break-through to occur, not only must production methods be made more efficient, but new magnesium-based alloys or composites must be produced which have better corrosion resistance than those currently available. In this way the lightness, stiffness and strength which magnesium offers can be fully exploited, and some incursion into the markets held by aluminium alloys and plastics can be anticipated. The final chapter in the volume is by R.M. Pagni of the University of Tennessee, on organic and organometallic reactions in molten salts and related melts. This is the longest chapter, and has 200 references. This review is very comprehensive, and the specific role of the molten salt (when understood) is fully explained. As a physical chemist, I found the chapter interesting and easy to understand. The systems considered are: those based on aluminium chloride; pyridine hydrohalides; ammonium and phosphonium salts; nitrates and nitrites; chlorides of zinc, copper, iron and tin; antimony trichloride. Dr. Pagni points out that organic chemists do not make as full a use of molten salt media as they might, and that most specialists in the molten salts field are not organic chemists. Education of both groups, such as is provided by this article, should lead to increased activity. This volume continues the fine tradition established by the earlier ones, and provides valuable, state-of-the-art reviews of current topics which are indispensible to those in the field and should also be attractive to those on the periphery. The Editors and Authors are to be congratulated. It is a pity that the price of Volume 6 is so high as to put it possibly beyond the reach of the individual who might otherwise purchase it for his private library.
B. CLEAVER Southampton
theoretician and experimentalist. The quality of papers and discussion clearly justified wider circulation to those unfortunate not to be present at the meeting. This need has been satisfied by rapid publication in Colloids and Surfaces and the Editor and publishers are to be congratulated for their efforts. One may then question the need for further publication in this form. W.D. COOPER Chester
Advances in Molten Salt Chemistry, Volume 6. G. Mamantov, C.B. Mamantov and J. Braunstein (Editors). Elsevier, Amsterdam, Oxford, New York, Tokyo, 1987, xii + 362 pp., Dfl. 295.00. This series was begun in 1971. New volumes have appeared at irregular intervals, and have contained from four to six comprehensive review articles on specified topics within the molten salts field. It remains under the control of the original senior Editors, and has survivied a change of publisher between Vols. 4 and 5. It is highly regarded by workers in the field, and is the only vehicle in which such reviews can be found in this specialism. The articles are reproduced from camera ready copy prepared by the authors. Some variability of quality is therefore evident in the text, and more particularly the diagrams, though the quality of output now available on word processors makes this problem less serious than heretofore. Volume 6 contains four articles. The first is by Professor Klemm of the Max Planck Insitut, Maim, and is on “Ionic Mobilities”. This is a masterly review. Professor Klemm has worked on this topic for over 4 decades, and is an acknowledged authority on it. Of the 173 references cited, 23 are to his own publications. Even allowing for the tendency common to most authors for self-citation, this indicates the magnitude of his own contribution! Professor Klemm begins by reviewing the formalism used to describe mobilities (internal and external) in pure salts and mixtures. He goes on to describe experimental methods for measurement of mobilities, and presents a comprehensive survey of published data. The chapter concludes with a concise statement of the reasons why mobilites change with composition, temperature and pressure. This is a most valuable review, to which many workers will refer for some years to come. The second and third chapters are on related topics, namely the commercial production of aluminium and magnesium. Research on aluminium smelting has long been almost a monopoly of the Norwegians, and the author of Chapter 2, Dr. J. Thonstad of NTH Trondheim, has made many contributions himself. The Hall-Herault process now yields some 18 Mtonne per annum, and consumes 3% of the electrical energy produced in the industrialised countries worldwide. This process is described in great detail. Its chemistry has been studied exhaustively, and work is now concentrated on making
183
marginal improvements in the efficiency of the process. New electrode materials seem to offer the best chance of further progress. A final section is devoted to the ALCOA process for production of aluminium from aluminium chloride, which offers some potential advantages but is not yet competitive with the Hall-Herault process. Though Thonstad’s chapter is very thorough, the authors of Chapter 3 (Drs. G.J. Kipouros and D.R. Sadoway) have adopted a more didactic style which makes their chapter somewhat easier to read. Magnesium smelting is currently on a much smaller scale than aluminium smelting (less than 1 Mtonne/year), but involves a greater variety of sources and methods, some electrochemical and some chemical. These are described in detail, and the discussion includes a satisfying thermodynamic analysis. It is evident that non-equilibrium processes frequently play an important role. Possibilities for improvement of the efficiency of the various processes are discussed. At present, only 20% of the magnesium produced is used as a structural material, and more extended use is forecast. (However, this reviewer remembers reading similar predictions in his “Boys’ Wonder Book of Science”, received as a Christmas present in 1945!). For any break-through to occur, not only must production methods be made more efficient, but new magnesium-based alloys or composites must be produced which have better corrosion resistance than those currently available. In this way the lightness, stiffness and strength which magnesium offers can be fully exploited, and some incursion into the markets held by aluminium alloys and plastics can be anticipated. The final chapter in the volume is by R.M. Pagni of the University of Tennessee, on organic and organometallic reactions in molten salts and related melts. This is the longest chapter, and has 200 references. This review is very comprehensive, and the specific role of the molten salt (when understood) is fully explained. As a physical chemist, I found the chapter interesting and easy to understand. The systems considered are: those based on aluminium chloride; pyridine hydrohalides; ammonium and phosphonium salts; nitrates and nitrites; chlorides of zinc, copper, iron and tin; antimony trichloride. Dr. Pagni points out that organic chemists do not make as full a use of molten salt media as they might, and that most specialists in the molten salts field are not organic chemists. Education of both groups, such as is provided by this article, should lead to increased activity. This volume continues the fine tradition established by the earlier ones, and provides valuable, state-of-the-art reviews of current topics which are indispensible to those in the field and should also be attractive to those on the periphery. The Editors and Authors are to be congratulated. It is a pity that the price of Volume 6 is so high as to put it possibly beyond the reach of the individual who might otherwise purchase it for his private library.
B. CLEAVER Southampton