- Email: [email protected]
Use of microorganisms in the metals and minerals industry
Minerals Engineering, Vol. 14, No. 9, pp. 1123-1127, 2001
Pergamon
© 2001 Published by Elsevier Science Ltd All rights reserved 0892-6875/01/$ - see front matter
BOOK REVIEWS
Canadian Milling Practice Edited by B. Damjanovic and J.R. Goode xi + 292 pages 22x 28.7 cm, hard cover, published by Canadian Institute of Mining, Metallurgy, and Petroleum, Montreal 2000. Price $80 ($65 for members, $45 for students) + postage ($10 Canada, $15 USA, $25 other countries). ISBN 1-894475-10-0 This volume is an update of earlier books published in 1957 and 1978 treating the same topic. However, the earlier volumes were appreciably larger. Technology has certainly changed since the past two decades which warranted presenting the present work. The book is written by an impressive number of 200 authors who are operating the plants, hence it is an authoritative work. The book is divided into three parts: Milling of Metallic Ores, Milling of Nonmetallic Ores, and Testing facilities. Ores treated in the first part are: gold and silver, molybdenum and copper-molybdenum, nickelcopper, copper-zinc, lead-zinc, lead-zinc-copper, iron, uranium, and tantalum. Ores treated in the second part are: potash, tar sands, coal, lime and limestone, and diamonds. Testing facilities are those of commercial, government, and universities. The book is well prepared, illustrated by a number of photographs and flowsheets. However, it gives an incomplete picture of Canadian operations. For example, missing are operations related to asbestos, titanium, niobium, and a large number of industrial minerals. Contrary to previous volumes in the series, there is no general section introducing the Canadian mineral industry except a short half page. An index could also have been a desirable addition. In spite of all these drawbacks, the volume is a welcome addition to the library and will remain a reference work for those working in the field for at least another decade. Fathi Habashi, Laval University, Quebec, Canada. Fathi.Habashi @gmn. ulaval, ca S0892-6875(01)00120-0
Use of microorganisms in the metals and minerals industry C.F. Bonney MIRO, UK, 2001. Hard copy or CD-ROM £250. Hard-back 186 pps ISBN 1 872440 223 Although organised in to sections the work was in places disjointed, with references made to similar processes e.g. influence of mineral surface characteristics on the process of bioleaching/biooxidation, in different sections. When combined with the lack of an index and a good search engine (a search engine based on an interactive index would have been a useful feature) it was difficult to assimilate all the information on a subject area. The inclusion of a small section on 'Effluent and Waste Treatment' again highlighted the poor organisation of the review. A considerable number of the references used related to the ability of microorganisms to biosorb or bioremediate metals; the ability of micro-organisms to perform these process are presented as separate sections that contain similar references.
!123
1124
Book review
The review would have benefited from the inclusion of summaries at the start of each chapter/section to alert the reader to the breadth of material covered in that chapter/section. It would also have permitted the authors to highlight some of the more salient points they believed to be of importance e.g. key industrial developments and whether or not the process(es) being reviewed had reached commercial maturity or whether they were still at the laboratory and/or pilot scale. However, the text is up to date and contains a lot of extremely useful information that will both update and educate readers with differing knowledge and experience of the various technologies reviewed. This is the text's redeeming feature. Another useful feature was a list of all organisations, both academic and industrial, that were actively researching in this field when the review was compiled. Having now reviewed a publication on CD-Rom I would be wary of purchasing a similar item unless the ability to thoroughly test the merchandise was offered (a good search facility may compensate for poor organisation and is a powerful tool for the reader). A final comment is that CD-Roms are reliant upon the software availability and compatibility. If either of these cannot be guaranteed then perhaps the purchase of a traditional book is a better option? The following briefly outlines what the reader get for his/her £250.
Chapter lmExecutive Summary The first of seven chapters, the key point made is that biotechnological processes have been successfully integrated in to large-scale operations within the minerals and metals industries. The contribution of baseline research to the commercialisation and biotechnological processes is noted as is the continued need to develop a better understanding of heterotrophic micro-organisms and their potential applications.
Chapter 2---Literature Review Comprising of 14 different sections of varying length this chapter is the focal point for the publication. Brief comment is made on the content of each section in an attempt to provide the reader with a broad overview of its content. Section 1--Bioleaching/Biooxidation This section starts by subtly defining the difference between bioleaching and biooxidation and then proceeds to discuss the broad types of application of these processes.
Section 2-- Micro-organisms This section highlights the increasing reliance of the minerals industry on the expertise of microbiologists to carry out the fundamental biological research required to further develop the biotechnological processes to a stage where process engineers can drive them through to commercial reality. This is emphasised by the use of existing genetic techniques, as well as the development of systems more specific to micro-organisms found in mineral leaching environments; these techniques have greatly assisted in developing an understanding of the roles of the different micro-organisms allowing researchers to challenge opinions on which organisms catalyse acid mine drainage. The ability to investigate the role of micro-organisms present within a mixed culture within a series of bioreactors/bioheaps has provided an insight in to leaching/oxidation processes. Development of new metal-tolerant strains of bacteria through the study of chromosal DNA of Thiobacillus ferrooxidans is perhaps a future development. The isolation of microorganisms from extreme environments such as hydrothermal vents on the seabed is actively being pursued - could we eventually see the application of barotolerant and/or chloride tolerant bacteria in a new pressure bioleaching technique?
Section 3--Leaching and Bacterial Mechanisms A brief review of the presented. The studies mesophiles, modertate bacterial populations in
main processes responsible for the leaching and oxidation of mineral sulphides is highlighted focused predominantly on the range of bacteria already identified e.g. thermophiles and extreme thermophiles, and re-affirmed the importance of mixed bioreactors and bioheaps.
The interaction/importance of exopolymers/biolfilms on bioleaching processes is also noted. Studies citing the presence of ferric ions in exopolymers potentially suggest a mechanism for leaching via attachment of cells to the substrate and then catalysis of the electrochemical mechanism. Reference is also made to other
Bookreview
1125
studies demonstrating the importance of cell attachment via specific sections of cells e.g. one end of rodshaped bacterium. Techniques are cited that permit the proportion of bacteria attached to mineral sulphides based on the rate of Fe 2÷ oxidation to be evaluated. The attachment and detachment of cells from mineral surfaces (specifically Thiobacillusferroxidans) is also noted. The influence of both natural and synthetic crystal structure on rates of mineral oxidation and the chemical nature of a mineral in controlling the type of bacteria involved within its oxidation are discussed. New techniques to the minerals biotechnology field such as Pulsed Field Electrophoresis (PFEE) are becoming more widely used to add to the knowledge database by identifying proteins within the respiratory oxidation of Fe 2÷ in Thiobacillusferrooxidans. The further development of kinetics models to study and predict mineral bacterial interactions is noted.
Section 4 Process Development This section focuses upon individual and/or specific groups of metals in sub-sections. Within each subsection the application of biological processes in the production of these metals was reviewed to a lesser or greater extent depending upon the activity of researchers within that area. It was evident that considerable work was still being undertaken for the leaching/oxidation of ores-types containing copper, gold (and other precious metals), cobalt and nickel, with researchers utilising bacterial cultures from across the temperature spectrum in an attempt to optimise kinetics. Bioaccumulation is also considered, particularly with respect to the more exotic metals or those that are particularly undesirable to release to the environment e.g. uranium and the radio-nucleides. It was noticeable that many of the works referenced appeared to deal specifically with one or two elements, when in reality the success of a biological process will be based-upon its ability to adapt to a changing environment, specifically mineralogical changes within an ore body. It was unclear whether or not the source references demonstrated a more broad approach. The performance of different types of biomass (both living and dead) are referenced. The application of heterotrophic bacteric for the solubilisation of oxides ores containing aluminium, plus their ability to modify surface characteristics thus enhancing downstream process is noted in a number of the sub-sections.
Section 5--Biosorption This section reviews briefly the historical development of the technique, and notes how the process of immobilisation dramatically developed the technology. The fundamental parameters governing such processes were noted to have received considerable attention during the early 1980's and 1990's but the technology is still consideredas not proven commercially. The literature cited provides examples of various studies involving the biosorption of metals.
Section 6--Bioremediation This section focuses upon microbial processes that have been extensively pilot plant tested or are commercially available. Such processes fall in to two categories 1. Extracelluler precipitation such as the use of sulphate-reducing bacteria to produce hydrogen sulphide which then promote precipiation of metals as sulphides. 2. Extra-cellular binding or complexation where the metals are concentrated upon external surfaces of cells. Various examples of where the aforementioned techniques have been applied are cited, including techniques for decreasing metal mobility (acidophilic sulphate reducing bacteria) as well as those applied for the treatment of soils, water and various rock materials.
Section 7 Biodegradation A relatively short section that cites examples of where the process of biodegradation has been applied. Included are cyanide degradation by plants and micro-organisms, degradation of thiocyanate/cyanide in BIOX effluents and processes for metal detoxification and immobilisation. The degradation of some organic reagents is mentioned.
1126
Bookreview
Section 8--Bioprecipitation A number of the examples cited, for example the use of sulphate-reducing bacteria for metal precipitation, suggest that this section could be combined with section 6. Section 9--Biosensor Comments provided for a cursory note on the development of a biosensor for the detection of copper. Section lO---Reactor Design and Engineering This section starts by outlining the key engineering requirements and design features of equipment used for the processes of the biooxidation and bioleaching. Of particular note are comments by the authors that during this current review <5% of all the papers reviewed discussed aspects of bioreactors (design, operation etc.). This is interesting as the performance of a bacterial system may be greatly influence by the operating conditions of a reactor/series of reactors. It was also noted that the design of reactors larger than those currently in operation may be not feasible due to engineering constraints; air sparging system can create vibratory forces. It will no doubt be interesting to see if industry responds to this challenge by either redesigning current reactors, or by providing us with innovative solutions. Section 11--Effluent and Waste Treatment The ability of bacteria to biodegrade, oxidise, accumulate and adsorb metals from liquid effluents is noted. The majority of examples cited in this short section of under 3 pages could have been included in previous section(s). Section 12--Genetic Improvements This section reviews how the application of genetic processes has contributed to the understanding of how certain bacteria perform specific functions, and the relationship of 'biomining' bacteria to rest of the microbiological world. It demonstrates the need to further develop links between both the biological/microbiological and process engineering fraternities, especially since the latter is becoming increasingly dependent upon the ability of the former to identify and develop (engineer) more 'efficient' bacterial systems.
Section 13--ModeUing Brief notes are made of the application of models assisting in the design, operation and optimisation of bioleaching plants. Reference is also made to a model used for biosorption. Section 14--Ancillary Processes Brief notes are made on the influence of selected solvents on bacterial activity as well as sterilisation techniques.
Chapter 3---Commercial Developments This section reviews the application of bioooxidation and bioleaching throughout the minerals industry. The section contains a useful mix of text, figures and photographs but in the opinion of the reviewer would have benefited greatly from being better organised. The examples provided are in no specific order and with comment made on an gold operation in Australia immediately followed by an example of a cobaltiferous pyrite operation (to provide an example). I suggest the reader would have benefited from a more structured approached whereby these processes could have been segregated in to regional/continental areas e.g. Australasia, Africa, or by ore type e.g. precious metals, base metals. The information is there but not in the most useful format.
Chapter 4 Patents Note is made a couple of processes that were being patented, or had just been patented, during the preparation of this review.
Chapter 5--Researchers Provides a list of organisations/researchers active during the period covered by this review and is potentially very useful.
Book review
1127
Chapter 6--References Comprehensive list of all references cited with the odd reference repeated twice. Chapter 7----Glossary Limited in the definition of certain biological terms and lacking for a reader whose knowledge of the area is limited.
M.A. Whitbread-Jordan, Keeco UK Ltd, Truro, UK. Email: mark-wiordan @keeco-uk.demon.co.uk S0892-6875(01)00121-2
Comprehensive information on books in mineral processing and extractive metallurgy can be found on the 'Books News' pages of www.min-eng.com
Pergamon
© 2001 Published by Elsevier Science Ltd All rights reserved 0892-6875/01/$ - see front matter
BOOK REVIEWS
Canadian Milling Practice Edited by B. Damjanovic and J.R. Goode xi + 292 pages 22x 28.7 cm, hard cover, published by Canadian Institute of Mining, Metallurgy, and Petroleum, Montreal 2000. Price $80 ($65 for members, $45 for students) + postage ($10 Canada, $15 USA, $25 other countries). ISBN 1-894475-10-0 This volume is an update of earlier books published in 1957 and 1978 treating the same topic. However, the earlier volumes were appreciably larger. Technology has certainly changed since the past two decades which warranted presenting the present work. The book is written by an impressive number of 200 authors who are operating the plants, hence it is an authoritative work. The book is divided into three parts: Milling of Metallic Ores, Milling of Nonmetallic Ores, and Testing facilities. Ores treated in the first part are: gold and silver, molybdenum and copper-molybdenum, nickelcopper, copper-zinc, lead-zinc, lead-zinc-copper, iron, uranium, and tantalum. Ores treated in the second part are: potash, tar sands, coal, lime and limestone, and diamonds. Testing facilities are those of commercial, government, and universities. The book is well prepared, illustrated by a number of photographs and flowsheets. However, it gives an incomplete picture of Canadian operations. For example, missing are operations related to asbestos, titanium, niobium, and a large number of industrial minerals. Contrary to previous volumes in the series, there is no general section introducing the Canadian mineral industry except a short half page. An index could also have been a desirable addition. In spite of all these drawbacks, the volume is a welcome addition to the library and will remain a reference work for those working in the field for at least another decade. Fathi Habashi, Laval University, Quebec, Canada. Fathi.Habashi @gmn. ulaval, ca S0892-6875(01)00120-0
Use of microorganisms in the metals and minerals industry C.F. Bonney MIRO, UK, 2001. Hard copy or CD-ROM £250. Hard-back 186 pps ISBN 1 872440 223 Although organised in to sections the work was in places disjointed, with references made to similar processes e.g. influence of mineral surface characteristics on the process of bioleaching/biooxidation, in different sections. When combined with the lack of an index and a good search engine (a search engine based on an interactive index would have been a useful feature) it was difficult to assimilate all the information on a subject area. The inclusion of a small section on 'Effluent and Waste Treatment' again highlighted the poor organisation of the review. A considerable number of the references used related to the ability of microorganisms to biosorb or bioremediate metals; the ability of micro-organisms to perform these process are presented as separate sections that contain similar references.
!123
1124
Book review
The review would have benefited from the inclusion of summaries at the start of each chapter/section to alert the reader to the breadth of material covered in that chapter/section. It would also have permitted the authors to highlight some of the more salient points they believed to be of importance e.g. key industrial developments and whether or not the process(es) being reviewed had reached commercial maturity or whether they were still at the laboratory and/or pilot scale. However, the text is up to date and contains a lot of extremely useful information that will both update and educate readers with differing knowledge and experience of the various technologies reviewed. This is the text's redeeming feature. Another useful feature was a list of all organisations, both academic and industrial, that were actively researching in this field when the review was compiled. Having now reviewed a publication on CD-Rom I would be wary of purchasing a similar item unless the ability to thoroughly test the merchandise was offered (a good search facility may compensate for poor organisation and is a powerful tool for the reader). A final comment is that CD-Roms are reliant upon the software availability and compatibility. If either of these cannot be guaranteed then perhaps the purchase of a traditional book is a better option? The following briefly outlines what the reader get for his/her £250.
Chapter lmExecutive Summary The first of seven chapters, the key point made is that biotechnological processes have been successfully integrated in to large-scale operations within the minerals and metals industries. The contribution of baseline research to the commercialisation and biotechnological processes is noted as is the continued need to develop a better understanding of heterotrophic micro-organisms and their potential applications.
Chapter 2---Literature Review Comprising of 14 different sections of varying length this chapter is the focal point for the publication. Brief comment is made on the content of each section in an attempt to provide the reader with a broad overview of its content. Section 1--Bioleaching/Biooxidation This section starts by subtly defining the difference between bioleaching and biooxidation and then proceeds to discuss the broad types of application of these processes.
Section 2-- Micro-organisms This section highlights the increasing reliance of the minerals industry on the expertise of microbiologists to carry out the fundamental biological research required to further develop the biotechnological processes to a stage where process engineers can drive them through to commercial reality. This is emphasised by the use of existing genetic techniques, as well as the development of systems more specific to micro-organisms found in mineral leaching environments; these techniques have greatly assisted in developing an understanding of the roles of the different micro-organisms allowing researchers to challenge opinions on which organisms catalyse acid mine drainage. The ability to investigate the role of micro-organisms present within a mixed culture within a series of bioreactors/bioheaps has provided an insight in to leaching/oxidation processes. Development of new metal-tolerant strains of bacteria through the study of chromosal DNA of Thiobacillus ferrooxidans is perhaps a future development. The isolation of microorganisms from extreme environments such as hydrothermal vents on the seabed is actively being pursued - could we eventually see the application of barotolerant and/or chloride tolerant bacteria in a new pressure bioleaching technique?
Section 3--Leaching and Bacterial Mechanisms A brief review of the presented. The studies mesophiles, modertate bacterial populations in
main processes responsible for the leaching and oxidation of mineral sulphides is highlighted focused predominantly on the range of bacteria already identified e.g. thermophiles and extreme thermophiles, and re-affirmed the importance of mixed bioreactors and bioheaps.
The interaction/importance of exopolymers/biolfilms on bioleaching processes is also noted. Studies citing the presence of ferric ions in exopolymers potentially suggest a mechanism for leaching via attachment of cells to the substrate and then catalysis of the electrochemical mechanism. Reference is also made to other
Bookreview
1125
studies demonstrating the importance of cell attachment via specific sections of cells e.g. one end of rodshaped bacterium. Techniques are cited that permit the proportion of bacteria attached to mineral sulphides based on the rate of Fe 2÷ oxidation to be evaluated. The attachment and detachment of cells from mineral surfaces (specifically Thiobacillusferroxidans) is also noted. The influence of both natural and synthetic crystal structure on rates of mineral oxidation and the chemical nature of a mineral in controlling the type of bacteria involved within its oxidation are discussed. New techniques to the minerals biotechnology field such as Pulsed Field Electrophoresis (PFEE) are becoming more widely used to add to the knowledge database by identifying proteins within the respiratory oxidation of Fe 2÷ in Thiobacillusferrooxidans. The further development of kinetics models to study and predict mineral bacterial interactions is noted.
Section 4 Process Development This section focuses upon individual and/or specific groups of metals in sub-sections. Within each subsection the application of biological processes in the production of these metals was reviewed to a lesser or greater extent depending upon the activity of researchers within that area. It was evident that considerable work was still being undertaken for the leaching/oxidation of ores-types containing copper, gold (and other precious metals), cobalt and nickel, with researchers utilising bacterial cultures from across the temperature spectrum in an attempt to optimise kinetics. Bioaccumulation is also considered, particularly with respect to the more exotic metals or those that are particularly undesirable to release to the environment e.g. uranium and the radio-nucleides. It was noticeable that many of the works referenced appeared to deal specifically with one or two elements, when in reality the success of a biological process will be based-upon its ability to adapt to a changing environment, specifically mineralogical changes within an ore body. It was unclear whether or not the source references demonstrated a more broad approach. The performance of different types of biomass (both living and dead) are referenced. The application of heterotrophic bacteric for the solubilisation of oxides ores containing aluminium, plus their ability to modify surface characteristics thus enhancing downstream process is noted in a number of the sub-sections.
Section 5--Biosorption This section reviews briefly the historical development of the technique, and notes how the process of immobilisation dramatically developed the technology. The fundamental parameters governing such processes were noted to have received considerable attention during the early 1980's and 1990's but the technology is still consideredas not proven commercially. The literature cited provides examples of various studies involving the biosorption of metals.
Section 6--Bioremediation This section focuses upon microbial processes that have been extensively pilot plant tested or are commercially available. Such processes fall in to two categories 1. Extracelluler precipitation such as the use of sulphate-reducing bacteria to produce hydrogen sulphide which then promote precipiation of metals as sulphides. 2. Extra-cellular binding or complexation where the metals are concentrated upon external surfaces of cells. Various examples of where the aforementioned techniques have been applied are cited, including techniques for decreasing metal mobility (acidophilic sulphate reducing bacteria) as well as those applied for the treatment of soils, water and various rock materials.
Section 7 Biodegradation A relatively short section that cites examples of where the process of biodegradation has been applied. Included are cyanide degradation by plants and micro-organisms, degradation of thiocyanate/cyanide in BIOX effluents and processes for metal detoxification and immobilisation. The degradation of some organic reagents is mentioned.
1126
Bookreview
Section 8--Bioprecipitation A number of the examples cited, for example the use of sulphate-reducing bacteria for metal precipitation, suggest that this section could be combined with section 6. Section 9--Biosensor Comments provided for a cursory note on the development of a biosensor for the detection of copper. Section lO---Reactor Design and Engineering This section starts by outlining the key engineering requirements and design features of equipment used for the processes of the biooxidation and bioleaching. Of particular note are comments by the authors that during this current review <5% of all the papers reviewed discussed aspects of bioreactors (design, operation etc.). This is interesting as the performance of a bacterial system may be greatly influence by the operating conditions of a reactor/series of reactors. It was also noted that the design of reactors larger than those currently in operation may be not feasible due to engineering constraints; air sparging system can create vibratory forces. It will no doubt be interesting to see if industry responds to this challenge by either redesigning current reactors, or by providing us with innovative solutions. Section 11--Effluent and Waste Treatment The ability of bacteria to biodegrade, oxidise, accumulate and adsorb metals from liquid effluents is noted. The majority of examples cited in this short section of under 3 pages could have been included in previous section(s). Section 12--Genetic Improvements This section reviews how the application of genetic processes has contributed to the understanding of how certain bacteria perform specific functions, and the relationship of 'biomining' bacteria to rest of the microbiological world. It demonstrates the need to further develop links between both the biological/microbiological and process engineering fraternities, especially since the latter is becoming increasingly dependent upon the ability of the former to identify and develop (engineer) more 'efficient' bacterial systems.
Section 13--ModeUing Brief notes are made of the application of models assisting in the design, operation and optimisation of bioleaching plants. Reference is also made to a model used for biosorption. Section 14--Ancillary Processes Brief notes are made on the influence of selected solvents on bacterial activity as well as sterilisation techniques.
Chapter 3---Commercial Developments This section reviews the application of bioooxidation and bioleaching throughout the minerals industry. The section contains a useful mix of text, figures and photographs but in the opinion of the reviewer would have benefited greatly from being better organised. The examples provided are in no specific order and with comment made on an gold operation in Australia immediately followed by an example of a cobaltiferous pyrite operation (to provide an example). I suggest the reader would have benefited from a more structured approached whereby these processes could have been segregated in to regional/continental areas e.g. Australasia, Africa, or by ore type e.g. precious metals, base metals. The information is there but not in the most useful format.
Chapter 4 Patents Note is made a couple of processes that were being patented, or had just been patented, during the preparation of this review.
Chapter 5--Researchers Provides a list of organisations/researchers active during the period covered by this review and is potentially very useful.
Book review
1127
Chapter 6--References Comprehensive list of all references cited with the odd reference repeated twice. Chapter 7----Glossary Limited in the definition of certain biological terms and lacking for a reader whose knowledge of the area is limited.
M.A. Whitbread-Jordan, Keeco UK Ltd, Truro, UK. Email: mark-wiordan @keeco-uk.demon.co.uk S0892-6875(01)00121-2
Comprehensive information on books in mineral processing and extractive metallurgy can be found on the 'Books News' pages of www.min-eng.com