|
Bacterial oxidation of sulphide ores
BATEMAN offers a range of services for the bacterial oxidation of
refractory gold ores, copper-gold concentrates and base metal ores and
concentrates.
BATEMAN is currently the engineering, procurement, construction and
management (EPCM) contractor for the Kasese cobalt project, Uganda,
and has conducted the engineering design based on a Mintek / BacTech
process design for the LSTK (lump sum turnkey) Beaconsfield gold treatment
plant in Australia. BATEMAN’s track record in bacterial oxidation
technology also includes many studies on continuous stirred tank reactors
and heap leach systems.
A broad ranging alliance has been formed with Mintek to commercialise
the bioleaching technology developed by Mintek. Mintek has a global
alliance agreement with BacTech. The technology is marketed as a package
in which Mintek / BacTech provide the process design and BATEMAN the
project engineering.
Bacterial oxidation is a process in which sulphide minerals are broken
down and associated metals made amenable for recovery. Naturally occurring
soil bacteria operating in acidic sulphate solutions at pH 1 to 2 and
35° to 50° C attack the sulphides in the minerals. After oxidation of
the concentrate gold, silver and lead remain in the oxidised residue
and are leached in a second treatment process. Base metals such as copper,
cobalt, nickel and zinc are dissolved in the bacterial oxidation solution
and can be recovered by a second process such as solvent extraction.
A bacterial process route is often indicated when arsenic is present
in the mineral, as this avoids the adverse impact on the environment
resulting from the pyrometallurgical processing needed to recover the
metal values.
The bioleach technology marketed by BATEMAN and MINTEK has several advantages
compared to other systems on the market. It offers the highest rate
and extent of oxidation of sulphide. The mass reduction of the sulphide
minerals by as much as 50 % during bacterial action upgrades the concentration
of the metal in the residue, thus reducing the size of the plant needed
for downstream processing. There is no need for pH adjustment during
the process which could result in the precipitation of iron or arsenic.
Such precipitation increases slurry viscosity, frothing and foaming,
and in the case of gold ores, may result in re-encapsulation of the
gold particles and reduced recovery. Where gold is concerned the process
also offers the lowest cyanide consumption rate by the oxidised residue.
This alliance between BATEMAN and MINTEK provides optimised process
design and coordinated plant commissioning. In addition, BATEMAN offers
the full spectrum of project services, from the establishment of plant
specifications through design, cost estimates and arranging finance,
feasibility studies, procurement, construction management and commissioning.
Please contact Dr Peter Spencer, General Manager, Gold,
on +61-9316-6905 or e-mail gold@batemanengineering.com
for more information.
VIEW PDF
|
