Hydrometallurgy, 10 (1983) 257--261 257 Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands

B I O H Y D R O M E T A L L U R G Y I N I N D I A 1 9 8 2 - - A B R I E F R O U N D - U P

M.J. SHAHANI

National Metallurgical Laboratory, Jamshedpur 831 O07 (India)

In continuation of the biohydrometallurgical activities in India reported in 1981, two major events took place in 1982.

1. THE INDIAN NATIONAL SCIENCE ACADEMY SEMINAR

A "Seminar on Research and Development for Planned Utilization of Mine- ral Resources" was held by the Academy in New Delhi from 4 to 6 October 1982 during which a whole session was devoted to "The Use of Microorganisms for Extract ion". Five papers included in the session were:

Use o f microorganisms in hydrometallurgy Kazutami Imai (Okayama University, Japan)

The development of improved facultative chemolithotrophic bacterial strains, which can also grow on organic substrates, for increased cell yield was described and the use of T. ferrooxidans to clarify acidic mine drainage con- taining high levels of ferrous iron was discussed.

Geomicrobiohydrometallurgy ... Emergent technology for the eighties M.J. Shahani (National Metallurgical Laboratory, Jamshedpur, India)

An overview of this composite discipline was presented and its potential as a highly value-engineered technology of high energy-effectiveness, conservation- effectiveness, ecology-effectiveness and even cost-effectiveness, was described. The possible linking with powder metallurgy as a bulk user of microbially pro- duced metal powders was also explored.

Microbial leaching o f low grade chalcopyrite: Difficulties arising due to jarosite and elemental sulfur deposition on ore surfaces D.N. Thakur, K.K. Saroj and A. Gupta (Central Mining Research Station, Dhanbad, India)

The enhanced recoveries obtainable by regrinding microbially leached resi- dues; by multiple washing of leached residues with carbon disulfide and ace- tone, the latter being more effective for removing the sulfur film from ore surfaces; and by using desulphovibro desulphuricans to pyritize precipated basic ferric sulfate on ore surfaces for renewed amenability to leaching by T. ferrooxidans, were some of the methods described.

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Nutrient requirements in the bacterial leaching studies on Keruadungri ore, Bihar S.C. Kulshrestha, K.K. Dwivedy and K.M. Jayaram (Department of Atomic Energy, Hyderabad, India)

The elimination of constituents such as ammonium sulfate, magnesium sulfate, calcium nitrate, potassium chloride and di-potassium hydrogen phos- phate from 9K nutrient formulations when soluble apatite and ferro-magnetic minerals are present in uraniferrous quartz-chlorite schists was described.

Use of Thiobacillus ferrooxidans in extraction of copper from chalcopyrite V.M. Kulkarni, K.M. Paknikar, A.B. Seal and A.D. Agat6 (MACS Research Institute, Pune, India)

Work on the isolation of over 60 cultures of T. ferrooxidans from various Indian ecosystems was described, using modified media to keep them active for over 4 years. Data-proving studies indicated that, since the initial time-lag in a chalcopyrite-adapted culture is much less than that of iron-grown cul- tures and continuous bioleaching gave higher yields, ecosystem-adapted cul- tures can be effectively supplied from a centralized centre to user mining centres on demand.

Other sessions at this seminar included hydrometallurgy-oriented papers such as:

Electrochemical technology in beneficiation hydrometallurgy of processing V.A. Chanturii (USSR) Separation of cadmium from solutions containing high concentrations of zinc ions K.D. Sharma, A.K. Bhutani and P. Parvathisem (Hindustan Zinc Ltd., India) Mine course of making of wasteless technology on the mines L.A. Baraskii (Academy of Sciences, USSR) The metal resources in manganese ore polymetallic nodules A.A. Archer (Royal Society, U.K.) Future technologies for metals and materials in India P.K. Rohatgi and B. Nagaraj (Indian Institute of Science, Bangalore, India)

2. THE MAHARASHTRA ASSOCIATION FOR THE CULTIVATION OF SCIENCE ( M A C S ) RESEARCH INSTITUTE - - ADVANCED WINTER INSTITU~fE (18 October--6 November, 1982)

A Regional Training Course-cum-Advanced Winter Institute on "Basic Principles of Geomicrobiology with Special Reference to Microbial Cultures used in Biohydrometallurgy" at the NACS Research Institute was sponsored by the United Nations Educational, Scientific and Cultural Organisation (UNESCO); the United Nations Environment Programme (UNEP); the Inter- national Cell Research Organisation (ICRO); the University Grants Commis- sion of India (UGC); the Indian National Science Academy (INSA).

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With the object of training teachers as well as scientists and technologists in the use and application of interdisciplinary biotechnology in the area of metals extraction, the three-week course consisted of a series of morning lectures on specialized topics and af ternoon practical demonstrat ions conducted for and by twenty participants drawn from several countries including Ceylon, Bangla- desh, Pakistan, Afghanistan and India.

Dr. K.R. Surang~, Direction of the MACS Research Insti tute welcomed all participants and the inaugural session, presided by Professor G.S. Mahajani, President of the Maharashtra Association for the Cultivation of Science, was addressed by Dr. V.V. Modi of M.S. University, Baroda (India) with a scene- setting keynote lecture on "Biotechnology and Tomor row" .

The first series of resource lectures were int roductory to the microbiologi- cal world and included:

Introduction to the microbial world: Scope and applications J.V. Bhat (Retd. Professor, Indian Insti tute of Science, Bangalore, India)

The existence of microorganisms ranging in size from a few microns to al- most full-fledged entities and as simple as DNA to the more complex cells was highlighted and their role in synthesis was described.

Isolation, identification and preservation of microorganisms Yvonne M. Freitas (St. Xavier's College, Bombay, India)

The various methods of isolating pure cultures from mixed cultures, nurtur- ing these cultures and identifying them were described in detail.

Routine microbiological techniques S.H. Godbol~ (MACS Research Institute, Pune, India)

Aerobic and anaerobic microorganisms with methods for their isolation and identification were discussed.

Special microbiological techniques and Autotrophs and heterotrophs Arvind D. Agat~ (MACS Research Institute, Pune, India)

Specific microorganisms, pertinent to biohydrometallurgy, present in se- lected ecosystems were described with particular reference to iron, sulfur and manganese reacting cultures, and related methods were discussed.

The second series of lectures by Professor Donald G. Lundgren of Syra- cuse University, U.S.A., dealt with iron and sulfur oxidizing bacteria, and covered the following: Overview of geomicrobiology; Physiological principles of concerned microbes; Microorganisms in hydrometallurgy; Sulfur-oxidizing bacteria; Iron-oxidizing bacteria. Basic principles were described and discussed in all their fundamental and applicational aspects.

The third series of lectures, by Dr. Graham W. Skyring of Baas Becking Geobiological Laboratory, Canberra, Australia, dealt with sulfate reducing

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bacteria. Aspects covered were: Introduction to sulfate reducing bacteria; Their growth, cultivation and preservation; The biochemistry and physiology o f sulfate reduction; Sulfate reduction in marine and fresh water environment; The ecological and industrial importance o f sulfate reducers.

Other talks on the microbiological aspects of geomicrobiohydrometal lurgy were:

Role o f budding bacteria in iron transformation C. Postmaster (SIES College, Bombay, India)

Hypomicrobial isolates were discussed and the potential of these cultures for enrichment of low-grade iron and manganese ores was described.

Iron reduction by microorganisms J. DeSouza (CPIR, Panaji, India)

The ecology of the microflora involved in iron metabolism was discussed with particular reference to the role of microorganisms useful for reducing iron and manganese ores from Goa, India.

Manganese oxidizing organisms and their role Arvind D. Agat~ (MACS Research Institute, Pune, India)

The ability of Arthrobacter bacillus to oxidize manganese in pyrolusite to obtain gamma manganese dioxide suitable for dry cell applications was described and related studies of parameters such as ionic concentration and pH were reported.

In the final series of presentations, the mining and biohydrometallurgical aspects were highlighted:

In situ leaching techniques --Prospects and applications in India D.N. Thakur (Central Mining Research Station, Dhanbad, India)

In situ practices world-wide were reviewed and possibilities of application in India to recover metallic values from over-burden rock from open-cast mines were discussed.

Statistical design, analysis and optimization o f bacterial leaching processes S.R. Dav~ (Gujarat University, Ahmedabad, India)

The analysis and design of experiments in bio-leaching using statistical methodology were dealt with and examples of mathematical models applic- able to bacterial leaching experiments were described in detail.

Copper microbiohydrometallurgy and Microbiohydro metal powders Moti J. Shahani (National Metallurgical Laboratory, Jamshedpur, India)

The technological applications of geomicrobiohydrometallurgical tech- niques to the extraction of copper from low-grade deposits as well as from

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complex ores and wastes such as tailings, slags, flue dust, cinders and the like were reviewed. Hydrometallurgical operations for the extraction of copper by cementation, electrolysis, solvent extraction and other processes were discussed in detail.

The significance of deriving metals from bioleachates in powder form for use in powder metallurgy and other applications was highlighted and the im- plications of a composite technology for producing and using metal powders via these routes were visualized.

Microbial leaching of uranium K.M. Jayaram, K.K. Dwiwedi, G.R. Udas (BARC, Hyderabad,India) Uranium recovery from ores and Scope for bacterial leaching T.K.S. Murthy (BARC, Bombay, India)

Of the two papers on microbial uranium, one was on the microbiological aspects describing the use of Aspergillus fumigatus for the precipitation of uranium from leach liquors and the other discussed the technological as- pects of extracting uranium in different modes of application.

Valedictory Session

The concluding session, apart from the formal award of certificates to the participants, included panel discussions which emphasized the necessity of co-ordinating activities in microbial leaching R&D in the region to minimize duplication of work. The suggestion for setting up a constantly-updated com- puterized data bank to serve the region was also well received. Dr. Graham Skyring summed up the Winter Institute with an assessment of the course which he felt would help accelerate the growth of activity in geomicrobiology, while Dr. Don Lundgren delivered the valedictory address and consoled the participants that "Rome was not built in a day" and that there was every possibility of wider commercial acceptance of microbial leaching especially in developing countries in the coming years.