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High temperature bacterial leaching - continuous large scale testwork


This industrial research project is directed at the use
of therrnophilic bacteria for the bioleaching of sulphide
minerals and has been designated the "HIOX" process.
Although a considerable amount of research work has been
carried out on mesophiles and several plants have been
installed for Au bearing materials, there has to date
been no significant commercial breakthroughs in the use
of thermophilic bacteria. In addition, the technology of
bacterial leaching is dominated by South Africa and
Australia and it is the intention of this project to
establish the EU as a major technology base for
bioleaching, by using the expertise in the field of
thermophilic bacterial leaching which presently exists
within Europe.

Two types of thermophiles will be considered: the
moderate/high temperature thermophiles which operate at
55 75 C and the extreme thermophiles which operate above
75 C. The work will be arranged so that all aspects of
the process flowsheet are covered i.e. the bioleaching
and downstream process steps will be tested so that an
integrated industrial application can be finally
evaluated For all of the process steps the focus will be
on the practical parameters required for the optimisation
of an industrial application based on the "HIOX" process.
The industrial objectives will be to develop a new
bioleaching process:
for the treatment of chalcopyrite, which at present
is only treatable by pyrometallurgical methods or by
high pressure leaching, both with environmental
for metal production from complex sulphide
concentrates which are presently untreatable by
conventional means;
which is more economic and environmentally friendly,
for metal production from a range of other base metal
and Au bearing sulphide minerals and which can operate on
a small scale;
for metal production from low grade concentrates
(e.g. rougher flotation concentrates) and therefore
obtain higher metal recoveries from the mine;
that is environmentally friendly and leaves a low
grade inert residue and which does not produce SO2,
H2SO4 or As2O3;
that is an integrated hydrometallurgical process
based on thermophilic bacterial leaching that can be
economically used to produce Cu, Ni and Zn of 99.99%
purity and Au suitable for further refining;
with process flowsheets and plant designs to meet
the above targets;
which will make the European mining industry world
leaders in the field of bioleaching, based on
thermophilic bacterial mineral oxidation.

The work will involve:
Collection and Characterisation of Samples Sample
Selection and Preparation
Bacteriological Testwork
Laboratory testwork with thermophiles
Large scale Contiinuous Testwork Down
Stream Processing
Reactor Scale-up
Environmental Studies
Process Design Study
Economic Study and Exploitation Plan

The mining companies involved have each indicated one ore
deposit in which they have an immediate interest and
which cannot presently be exploited with existing
technology. Most of these are located within the EU,
namely Ireland, Spain, Sweden and Greece. If the "HIOX"
process can be successfully demonstrated and is
exploited commercially then these projects alone could
generate over ECU 1.5 billion per annum of income from
metal sales. The mining companies have combined annual
sales of over ECU 8 billion so if this is extrapolated
throughout the EU and worldwide then it is evident that
the high temperature bioleaching of sulphide minerals has
an enormous commercial potential.

Funding Scheme

CSC - Cost-sharing contracts


6,City Square 1
LS1 2ES Leeds
United Kingdom

Participants (6)

Boliden Mineral AB
936 00 Boliden
Bureau de Recherches Géologiques et Minières
Avenue Du Concyr
45060 Orléans
Greenwich Resources plc
United Kingdom
Mathon Place 1
WR13 SNZ Mathon - Malvern
Henkelstrasse 67
40589 Düsseldorf
University Campus, Porsean
971 87 Lulea
LaSource Compagnie Minière SAS
31,Avenue De Paris
45000 Orleans