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  • DISSERTATIONES BIOLOGICAE UNIVERSITATIS TARTUENSIS

    39

    BIOLOGICAL LEACHING OF SHALES: BLACK SHALE AND OIL SHALE

    ANDRUS TASA

    TARTU 1998

  • DISSERTATIONES BIOLOGICAE UNIVERSITATIS TARTUENSIS

    39

  • DISSERTATIONES BIOLOGICAE UNIVERSITATIS TARTUENSIS

    39

    BIOLOGICAL LEACHING OF SHALES: BLACK SHALE AND OIL SHALE

    ANDRUS TASA

    TAETU UNIVERSITY

    P R E S S

  • Dissertation is accepted for the commencement o f the Doctor o f Philosophy (in Genetics) on June 22th, 1998 by the Council o f the Institute of Molecular and Cell Biology, University o f Tartu

    Opponent: Dr. Stoyan Nikolov Groudev (Bulgaria, Higher Institute of Mining and Geology)

    Commencement: October 23th, 1998

    The publication o f this dissertation is granted by the University of Tartu

    Andrus Tasa, 1998 Tartu likooli Kirjastuse trkikoda Tiigi 78, EE2400 Tartu Tellimus nr. 235

  • CONTENTS

    List o f original publications ................................................................................ 6List of abbreviations.............................................................................................. 71. Introduction........................................................................................................ 82. Review of literature ......................................................................................... 9

    2.1. Estonian sh a les .......................................................................................... 92.1.1. Black sh a le ...................................................................................... 92.1.2. Oil s h a le .......................................................................................... 10

    2.2. Biological leaching of ores ..................................................................... 112.3. Bioleaching studies of shale m aterials................................................... 15

    3. Materials and m ethods..................................................................................... 173.1. Shale sam ples............................................................................................. 173.2. Bacteria and culture m edia ...................................................................... 173.3. Leaching experiments .............................................................................. 183.4. Analytical methodology ........................................................................... 19

    4. Biological leaching of Estonian sh a les ......................................................... 214.1. Comparison of bacterial strains for following experiments............... 214.2. Leaching studies o f black shale .............................................................. 244.3. Leaching studies of oil sh a le ................................................................... 264.4. Mineral alterations during the biological leaching o f shales ............. 27

    5. Conclusions and further development .......................................................... 296. References.......................................................................................................... 31Kokkuvte (Summary in Estonian) .................................................................... 35Acknowledgements ............................................................................................... 37Publications ............................................................................................................ 39

    2

  • LIST OF ORIGINAL PUBLICATIONS

    The presented thesis is based on the following original papers which will be referred to by their Roman numerals:

    I. Tasa, A., Garcia, O. Jr., Bigham, J. M., Vuorinen, A. and Tuovi- nen, . H. (1995) Acid and biological leaching o f a black shale from Toolse, Estonia. In: Biohydrometallurgical Processing, Vol. I (Vargas, ., Jerez, C. A., Wiertz, J. V., Toledo, H. eds.), University o f Chile, Santiago, Chile, 229-238.

    II. Tasa, A. and Lindstrm, E. B. (1996) Biological desulphurization of Estonian oil shale. Oil Shale 13: 133-143.

    III. Tasa, A., Vuorinen, A., Garcia, O. Jr. and Tuovinen, . H. (1997) Biologically enhanced dissolution of a pyrite-rich black shale concentrate. J. Environ. Sei. Health A32 (9&10): 2683-2695.

    IV. Tasa, A. and Tuovinen, . H: Biological leaching of shales a review. Oil Shale 15: in press.

    6

  • LIST OF ABBREVIATIONS

    AAS atomic absorption spectroscopyAGP acid generation potentialANP acid neutralisation potentialEa activation energyL.O.I. loss o f ignitationNAG net acid generationQio temperature quotientS-compounds sulphurous compoundsSTR stirred tank reactorXRD X-ray diffraction9K growth medium for Thiobacillus ferrooxidans and other

    chemolithotrophic acidophiles

    7

  • 1. INTRODUCTION

    Micro-organisms possibility to extract metals from the ores, a process known as bioleaching, has gained increasing attention in recent years. Beginning from 40-ties, when Colmer and Hinkle (1947) isolated and described bacteria with the capacity o f acceleration the oxidation o f ferrous iron, both the fundamental and applied aspects o f mineral biodegradation phenomena have been studied. The recovery o f metals (copper, uranium, etc.) by biologically assisted leaching methods (dump and heap mining techniques) are currently practised in a number o f countries. Reactor- and high temperature leaching have been applied for the release o f high-value components from the ores (gold, silver). It is estimated that 10 to 50 million USD worth of gold was recovered by biooxidation in 1988 and that this value would increase to 2 to 3 billion USD by 1998 (Blake et al., 1994). Micro-organisms play beneficial role in the mineral processing o f metals, but on the other hand, the same bacteria may cause environmental problems. Acid rock drainage and leaching of heavy metals from waste rock heaps have to be mentioned. Most of the bioleaching studies have been carried out with sulphide ores or high-sulphur coal samples. There are only few reports on the bacterial leaching of shale materials available.

    Oil shale is the most important mineral resource in Estonia. The other shale, black shale, has been mentioned as potential mineral resource in Estonia (Mareme, 1988). The extensive deposits of oil shale around the world are considered important fuel reserves for the future (Russel, 1990). The shale studies have strong output to practice. Using the results of the studies new alternative and environmentally sound methods might be tested for industry as well as environmental protection.

    The aim of the present work was to assess the bacterial leaching o f Estonian shale samples and to broaden the understanding of basic processes of shale bioleaching. This interdisciplinary study might be of interest for microbiologists, geologists, environmentalists and technologists. In the first part o f the present paper, the present state o f studies of leaching of Estonian shales and the subject of bioleaching will be reviewed by literature. In the second part of the paper, experimental results of the studies o f Estonian shales bioleaching are presented.

    8

  • 2. REVIEW OF LITERATURE

    2.1. Estonian shales

    Shales are fine-grained sedimentary rocks that are formed by the consolidation of beds o f mud, clay or silt. These beds were deposited slowly over geological time. Shales consist mainly of clay minerals such as illite and montmorillonite, mixed with fine particles of quartz and mica. Two type of shales have been represented in Estonia, black shale and oil shale, both of them belong to the group o f oil shale.

    2.1.1. Black shale

    Black shale (also called as dictyonema argillite, graptolite argillite, Dictyonema shale) layers with the thickness up to 7 m are distributed in Northern-Estonia. The black shale includes organic material (kerogen), illite, quartz, K-feldspar, pyrite and some other minerals in small quantities (muscovite, biotite, etc.) (Kleesment, Kurvits, 1987). Estonian black shale contains up to 20% of organic matter and 4 to 6% of pyrite. Most o f the pyrite presents in the shale with a fine-dispersed form (Kallaste and Pukkonen, 1992). Common feature for Estonian black shales as all others Baltoscandian black shales of lower paleozoic age is relatively high concentration o f metals (Andersson, et al., 1985). For example Estonian black shale consists molybdenum up to 1990 ppm, uranium up to 1038 ppm and vanadium up to 1910 ppm (Pukkonen, 1989, Pukkonen and Rammo, 1992). According to Palvadre and Kleemeier (1982) about 30% of uranium in the black shale is bind with organic matter, about 30% with clay minerals, about 30% with phosphates and about 6% with pyrite.

    Black shale has been titled as a potential mineral resource in Estonia. According to Mareme (1988) the possible ways o f utilisation of black shale might be following: (i) the raw material for building materials; (ii) the component for cement production in the mixture with limestone; (iii) fertiliser and plant growth stimulant and (iiii) raw material for extraction of metals. The last way has been considered the most advantageous. After the World War II Soviet government, looking for raw material for nuclear industry, selected the black shale as one o f the potential source o f uranium. Investigations were started at the Institute o f Mineral Resources, at the Institute of Chemical Technology (both in Moscow) and at the Institute o f Chemistry, Estonian Academy of Sciences (in Tallinn). Three different leaching technologies were tested: auto- clavical, biochemical and chemical (Althausen, 1992). Autoclavical and biochemical leaching studies were carried out by Russian scientists. These results were treated as st

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