Ian Wark Research Institute
ARC Special Research Centre
ARC Special Research Centre
Mechanisms in the Selective Oxidation and Separation of Copper
Sulphide Minerals and Pyrite in Copper Concentrates
Research Area: Colloid science, physical chemistry, chemical
engineering, minerals engineering, physical chemistry, and physics
Supervisors: Dr
Sarah Harmer, Dr Igor
Ametov and Prof Stephen
Grano
Description
Significance of the Proposed Research: Separation of copper minerals and
pyrite is important for copper producers for a number of reasons, i.e.
improving the final concentrate grade, removing penalty minerals and,
also for downstream processing in smelting. It has been shown that
separation of copper minerals and pyrite in the final flotation
concentrate can be achieved by selective oxidation of copper minerals
and pyrite with hydrogen peroxide or oxygen at elevated temperatures.
However, the mechanism of selective oxidation and separation is not
clear.
This PhD project will be focussed on the mechanisms involved in copper
mineral separation by selective oxidation, and will identify key process
parameters to control the extent of surface oxidation.
Research Methodology
It is well established that, in the case of hydrogen peroxide, its
interaction with xanthate in solution forms perxanthate intermediate
which subsequently decomposes. In this project, known amounts of
xanthate will be pre-adsorbed onto the copper sulphide minerals.
Surfaces will then be conditioned with oxygen and hydrogen peroxide and
the amount of xanthate and perxanthate desorbed with time determined. In
parallel, in-situ ATR FTIR studies will be conducted to determine the
types of adsorbed collector species being removed as a function of Eh
and time. Surface analysis techniques such as X-ray photoelectron
spectrometer (XPS) and time of flight secondary ions mass spectrometry (ToF-SIMS)
will be used for understanding reaction mechanisms of sulphide minerals.
The Wark is equipped with the Kratos axis ultra, a state of the art
X-ray photoelectron spectrometer (XPS) with imaging capabilities.
Imaging XPS provides quantitative chemical imaging allowing individual
sulphide mineral particles to be analysed. A new PHI nanoTOF-SIMS, with
spatial resolution less than 1 μm, will be due at The Wark by the end of
2008. ToF-SIMS will be used for determining the distribution of chemical
species across the minerals surface at the sub micron level The
successful candidate may also be involved in synchrotron studies funded
through the Australian Synchrotron Research Programme (ASRP), at a
synchrotron where the lateral resolution of imaging XPS and XAS
techniques is between 10 and 100 nm.
Funding
All applicants should apply for an IWRI fully-funded scholarship.
International students should also apply for an International
Postgraduate Research Scholarship (IPRS) and a UniSA President’s
Scholarship (UPS). Australian students should also apply for an
Australian Postgraduate Award (APA) and a UniSA Australian Postgraduate
Research Award (USAPRA). Project maintenance costs will be met from
internal funding.
