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Solvent extraction: Principles and applications to process metallurgy. Part II
Fluid Phase Equilibria, 4 (1980) 309-320 0 Elsevier Scientific Publishing Company,
309 Amsterdam
- Printed in The Netherlands
Book Reviews ____ Solvent Extraction: Principles and Applications to Process Metallurgy. Part II, by G.M. Ritcey and A.W. Ashbrook, Elsevier Scientific Publishing Co, 1979, 737 pp, price US $ 86.75, ISBN O-444-41751-6. This book is the second part of a two-part treatise on solvent extraction in extractive metallurgy. The first volume, which has not been seen by the reviewer, is concerned with basic theory, chemistry and practice of the process. The second volume which is the subject of the present review, aims to provide a guide to process flowsheet development, selection of materials of construction and plant design. However Volume II does not stand on its own and references to Volume I are found throughout the text. Therefore, for the purposes of this review, it is assumed that readers will have a basic understanding of solvent extraction chemistry and extractive metallurgy. The book consist of eight chapters covering the development of the solvent extraction process, equipment, materials of construction, a discussion of many processes both commercial and speculative, and concludes with a lengthy discussion of the economic considerations of solvent extraction of metals. Chapter 1 provides a comprehensive discussion of the solvent extraction process itself. The number of variables involved in any solvent extraction process is quite rightly stressed, but it is perhaps a pity that the use of statistical design of experiments for process optimisation is not mentioned. Also, while the AKUFVE apparatus is undoubtedly a most useful tool in fundamental studies of solvent extraction systems, it is less useful for process development studies, as it will not handle the disparate phase ratios required by the phase ratio variation method of isotherm development. Constant pH isotherms can be produced but these need mathematical treatment to produce actual isotherms when systems operate in a hydrogen ion cycle. It would also have been useful if a simple guide to the various extractants available, their chemical formulae and structure, had been given. This would have made the book less dependent on Volume 1. In the reviewer’s experience, the need to refer back to another publication is always a minor annoyance to readers. Chapter 2 gives a very useful and comprehensive account of the equipment available and in commercial use for solvent extraction processes. In this chapter some mention is made of statistical design of experiment for kinetic studies. The chapter includes a unique comparison of performance of six contactors, including column contactors, mixer settlers, static mixers and centrifugal contactors using the extraction of copper with Kelex 100 from a copper, nickel, and zinc containing aqueous phase as the basis for comparison. It is curious that in Figure 1, the Kenics static mixer is classified as a stagewise contactor, but that on page 72 it is included in the description of
310
non-agitated columns under the heading of differential contactors. As this is a co-current contactor, it is by definition not of the differential type. The discussion of safety factors included in the chapter devoted to plant design and materials of construction is timely and important. The information given on materials of construction is most useful from the practical point of view. However the information given is curiously lacking in one respect, as highlighted by Table 3, in that while the aqueous phase is defined and the extractant specified, no information on the diluent or modifier used is given. As far as selection of materials of construction is concerned, information on diluent compatibility is often vital. It is interesting to note that the most comprehensive information is available for the copper, LIX plants. Chapter 4 gives a very long account of a variety of processes, some of which are in commercial operation and others that are still just laboratory developments. Considerable detail is given in some cases. This chapter is now somewhat out of date as no mention is made of the hydrogen peroxide process for MO/W separation developed in Russia in 1977; the Sumitomo plant at Niihama in Japan for Ni/Co separation is not mentioned and it is now believed that Nippon Mining no longer use DEHPA for this process. It is also surprising that no mention is made of the METSEP process for zinc recovery from spent galvanising liquors, either in this chapter or in Chapter 7, although its development predates the development of the Espindesa process (now called the Zincex process). The copper section is also somewhat out of date but readers can find useful updating in the Proceedings of ISEC 77, for example. An interesting discussion on solvent-in-pulp processes is given in Chapter 5, but the reader will be quick to notice that as yet no commercial application of this technique has taken place. Indeed, development of viable continuous ion exchange #equipment and use of a sand-slimes split technique, prior to in-pulp recovery processes, has added a new dimension to this area but this has come too late to be considered in this book. Chapter 6 gives a useful summary of plants and processes which, while not pretending to be comprehensive, provides a wide variety of applications and experiences. Chapter 7 gives a short account of the application of solvent extraction in effluent treatment, a potentially important area for development. The use of solvent extraction in the treatment of solid wastes and reclamation of metal from scrap is another important growth area and this is treated in Chapter 4 under the individual metal headings. It is arguable whether such applications merit treatment on their own rather than being lumped together with the primary processes. As is proper, the final chaper of the book is devoted to a discussion on the economic considerations of the application of solvent extraction in metal recovery. While a wealth of information and detail is provided, the somewhat rambling nature of this chapter detracts rather from its impact. It is also annoying to find frequently that no date is put against cost figures. This renders them useless for extrapolation purposes against capital cost, energy cost
311
and labour cost indices, unless the original articles are referred to and it also creates problems with currency exchange rate variation. Labour costs also refer specifically to the country within which the plant is operated. It is interesting that seldom, if ever, are the actual labour requirements given in terms of men per shift. When providing cost comparisons it is also important to make sure that one compares like with like, i.e. treatment of the same feed material by a variety of processes through the same product or one that commands a similar market value. For example, the comparison of a solvent extraction-electrowinning process producing cathode copper with a process producing cement copper, as in Table 9, is not a fair comparison as cement copper must be refined to bring it up to a value comparable to electrowon copper. This comparison is shown later in Tables 20 and 21. The reader should also exercise caution over the discussion and conclusions on the comparative performance of LIX65N, LIX70 and Kelex 100 for copper extraction, given in Table 12. No consideration appears to have been given to the need to provide scrub stages to remove acid extracted into the organic phase by Kelex 100 on acid stripping, to the need for acid makeup in the tankhouse electrolyte or to the general water balance in the circuit. It is noteworthy in this respect that no copper solvent extraction plants, to date, operate with Kelex 100 as the extractant. It is also worth noting that quantitative data on solvent loss is not given here and for such data the reader must refer to Volume 1. In general the book is a very useful compendium of practical information on the application of solvent extraction in hydrometallurgy. The pragmatic approach of the authors makes for easy reading. Unfortunately, given the timescale within which such a book can be written and the rate of progress in research and development of the subject matter, it is inevitable that the book is virtually out of date when finally printed. It is noticeable that it is assumed that the readers will be familiar with the nomenclature of solvent extraction and presumably this is dealt with in Volume 1. When comparison is made with alternative processes, it is a pity that recent developments in continuous ion exchange came too late for inclusion, as the CIX developments would undoubtedly modify some of the conclusions reached in such comparisons. The book, which has been produced directly from cameraready typescript, contains relatively few errors although Chapter 2 contains two Figure 9’s. The authors are to be commended for their dedication in producing what is a statement of their philosophy of the use of solvent extraction in hydrometallurgy. The book will be of use to hydrometallurgists generally and is worth the cost. D.S. FLETT
309 Amsterdam
- Printed in The Netherlands
Book Reviews ____ Solvent Extraction: Principles and Applications to Process Metallurgy. Part II, by G.M. Ritcey and A.W. Ashbrook, Elsevier Scientific Publishing Co, 1979, 737 pp, price US $ 86.75, ISBN O-444-41751-6. This book is the second part of a two-part treatise on solvent extraction in extractive metallurgy. The first volume, which has not been seen by the reviewer, is concerned with basic theory, chemistry and practice of the process. The second volume which is the subject of the present review, aims to provide a guide to process flowsheet development, selection of materials of construction and plant design. However Volume II does not stand on its own and references to Volume I are found throughout the text. Therefore, for the purposes of this review, it is assumed that readers will have a basic understanding of solvent extraction chemistry and extractive metallurgy. The book consist of eight chapters covering the development of the solvent extraction process, equipment, materials of construction, a discussion of many processes both commercial and speculative, and concludes with a lengthy discussion of the economic considerations of solvent extraction of metals. Chapter 1 provides a comprehensive discussion of the solvent extraction process itself. The number of variables involved in any solvent extraction process is quite rightly stressed, but it is perhaps a pity that the use of statistical design of experiments for process optimisation is not mentioned. Also, while the AKUFVE apparatus is undoubtedly a most useful tool in fundamental studies of solvent extraction systems, it is less useful for process development studies, as it will not handle the disparate phase ratios required by the phase ratio variation method of isotherm development. Constant pH isotherms can be produced but these need mathematical treatment to produce actual isotherms when systems operate in a hydrogen ion cycle. It would also have been useful if a simple guide to the various extractants available, their chemical formulae and structure, had been given. This would have made the book less dependent on Volume 1. In the reviewer’s experience, the need to refer back to another publication is always a minor annoyance to readers. Chapter 2 gives a very useful and comprehensive account of the equipment available and in commercial use for solvent extraction processes. In this chapter some mention is made of statistical design of experiment for kinetic studies. The chapter includes a unique comparison of performance of six contactors, including column contactors, mixer settlers, static mixers and centrifugal contactors using the extraction of copper with Kelex 100 from a copper, nickel, and zinc containing aqueous phase as the basis for comparison. It is curious that in Figure 1, the Kenics static mixer is classified as a stagewise contactor, but that on page 72 it is included in the description of
310
non-agitated columns under the heading of differential contactors. As this is a co-current contactor, it is by definition not of the differential type. The discussion of safety factors included in the chapter devoted to plant design and materials of construction is timely and important. The information given on materials of construction is most useful from the practical point of view. However the information given is curiously lacking in one respect, as highlighted by Table 3, in that while the aqueous phase is defined and the extractant specified, no information on the diluent or modifier used is given. As far as selection of materials of construction is concerned, information on diluent compatibility is often vital. It is interesting to note that the most comprehensive information is available for the copper, LIX plants. Chapter 4 gives a very long account of a variety of processes, some of which are in commercial operation and others that are still just laboratory developments. Considerable detail is given in some cases. This chapter is now somewhat out of date as no mention is made of the hydrogen peroxide process for MO/W separation developed in Russia in 1977; the Sumitomo plant at Niihama in Japan for Ni/Co separation is not mentioned and it is now believed that Nippon Mining no longer use DEHPA for this process. It is also surprising that no mention is made of the METSEP process for zinc recovery from spent galvanising liquors, either in this chapter or in Chapter 7, although its development predates the development of the Espindesa process (now called the Zincex process). The copper section is also somewhat out of date but readers can find useful updating in the Proceedings of ISEC 77, for example. An interesting discussion on solvent-in-pulp processes is given in Chapter 5, but the reader will be quick to notice that as yet no commercial application of this technique has taken place. Indeed, development of viable continuous ion exchange #equipment and use of a sand-slimes split technique, prior to in-pulp recovery processes, has added a new dimension to this area but this has come too late to be considered in this book. Chapter 6 gives a useful summary of plants and processes which, while not pretending to be comprehensive, provides a wide variety of applications and experiences. Chapter 7 gives a short account of the application of solvent extraction in effluent treatment, a potentially important area for development. The use of solvent extraction in the treatment of solid wastes and reclamation of metal from scrap is another important growth area and this is treated in Chapter 4 under the individual metal headings. It is arguable whether such applications merit treatment on their own rather than being lumped together with the primary processes. As is proper, the final chaper of the book is devoted to a discussion on the economic considerations of the application of solvent extraction in metal recovery. While a wealth of information and detail is provided, the somewhat rambling nature of this chapter detracts rather from its impact. It is also annoying to find frequently that no date is put against cost figures. This renders them useless for extrapolation purposes against capital cost, energy cost
311
and labour cost indices, unless the original articles are referred to and it also creates problems with currency exchange rate variation. Labour costs also refer specifically to the country within which the plant is operated. It is interesting that seldom, if ever, are the actual labour requirements given in terms of men per shift. When providing cost comparisons it is also important to make sure that one compares like with like, i.e. treatment of the same feed material by a variety of processes through the same product or one that commands a similar market value. For example, the comparison of a solvent extraction-electrowinning process producing cathode copper with a process producing cement copper, as in Table 9, is not a fair comparison as cement copper must be refined to bring it up to a value comparable to electrowon copper. This comparison is shown later in Tables 20 and 21. The reader should also exercise caution over the discussion and conclusions on the comparative performance of LIX65N, LIX70 and Kelex 100 for copper extraction, given in Table 12. No consideration appears to have been given to the need to provide scrub stages to remove acid extracted into the organic phase by Kelex 100 on acid stripping, to the need for acid makeup in the tankhouse electrolyte or to the general water balance in the circuit. It is noteworthy in this respect that no copper solvent extraction plants, to date, operate with Kelex 100 as the extractant. It is also worth noting that quantitative data on solvent loss is not given here and for such data the reader must refer to Volume 1. In general the book is a very useful compendium of practical information on the application of solvent extraction in hydrometallurgy. The pragmatic approach of the authors makes for easy reading. Unfortunately, given the timescale within which such a book can be written and the rate of progress in research and development of the subject matter, it is inevitable that the book is virtually out of date when finally printed. It is noticeable that it is assumed that the readers will be familiar with the nomenclature of solvent extraction and presumably this is dealt with in Volume 1. When comparison is made with alternative processes, it is a pity that recent developments in continuous ion exchange came too late for inclusion, as the CIX developments would undoubtedly modify some of the conclusions reached in such comparisons. The book, which has been produced directly from cameraready typescript, contains relatively few errors although Chapter 2 contains two Figure 9’s. The authors are to be commended for their dedication in producing what is a statement of their philosophy of the use of solvent extraction in hydrometallurgy. The book will be of use to hydrometallurgists generally and is worth the cost. D.S. FLETT