Home' Australian Resources and Investment : March 2010 Contents AUSTRALIAN RESOURCES & INVESTMENT • MARCH 2010 • 143
iron ore-exploration update
Western Australian (WA) Department of Mines and Petroleum, which was
then stored in a structured way, filters applied and content validated for
final delivery through Google Earth visualisation software.
"We are currently building a secure hosted site for the database so
external users can access it."
Among the findings from the database, for example, is that in
addition to our remaining one billion tonnes of high-grade ore,
Australia has at least eight billion tonnes of high-phosphorus iron ore
in WA alone, as well as large resources of lower-grade ore.
However, ores with more than 0.1 per cent phosphorus adversely
affect the strength of the steel produced from them -- unless the
phosphorus is reduced. "The database has given us a good grasp of the
phosphorus issue facing the iron ore industry and where the priority
areas are," Dr Holmes says. "It has increased our confidence in the
approaches we are taking to unlock the value of Australian high-
phosphorus iron ores."
Dr Holmes says the team has recently lodged a patent application
for a process that may halve the phosphorus content of an ore using
low concentration leaching agents and reduced heat inputs, in
preparation for a future when such reserves will emerge as significant
Working closely with iron ore companies large and small, the
Flagship team is using this mass of data about the scale and quality of
reserves to help design potential product blends and flowsheet options
for the beneficiation of lower grade ores.
"This will increase the understanding of available ore resources,
prolong the life of mines and maximise market acceptance of final
products at the same time," Dr Holmes says.
Another new technology developed by the Flagship is 'Recognition',
an optical image analyser for automated identification of minerals and
textures in iron ore and sinter samples. A user-defined expert system, it
can be trained to recognise minerals, associations and ore textures
based on their colour, reflectance, hardness, porosity and mineral
associations. Dr Holmes says it can greatly reduce the uncertainty
involved in manual classification.
Another key focus of the team's research is on fine-tuning the
sintering process, which produces approximately two-thirds of the
world's blast furnace feedstock. Researchers are using x-rays and other
analytical tools to define in unprecedented detail the cascade of
chemical events that occur when iron ore fines are heated with fuel and
fluxes to make sinter. The goal is to tailor sinter recipes to produce
stronger and higher-yielding sinter, save energy, and reduce waste and
The group recently completed a major industry-funded project on
the sintering of higher alumina content iron ores found in some new
Australian deposits. This will help industry to meet the challenge of
rising alumina content and maximise use of these ores in steel mills
Another significant impurity in Australian iron ores is kaolinite and
the group has recently published new findings on ways to remove it
using cationic flotation. The team has established that, unlike silica
impurities that float strongly with ether diamine, high doses of ether
monoamine are needed to induce strong flotation of kaolinite,
particularly in acidic solutions. In addition, they established that the
flotation recovery of kaolinite increases with ionic strength, which is
the opposite of what happens with oxides.
Researchers are also working with a number of smaller mining
houses to develop better methods of exploiting magnetite ores. The
bulk of Australian ore mined today is hematite and goethite, but the
continent also harbours tens of billions of tonnes of lower-grade (35 to
45 per cent iron) magnetite in which there is rising global interest due
to the strong demand for steel.
"Magnetite ores are more straightforward to upgrade than
hematite/goethite ores, although you need to watch the silica content
of the concentrate," Dr Holmes says. "We can help by characterising the
gangue minerals present in the ore, and identify the best processing
techniques for a particular ore. This can assist small companies gain
entrance to the market or increase their market share by exploiting
some of these lower-grade ores using the most cost-effective processes
and designing the process to suit the ore."
In a more futuristic venture, the team is working with indigenous
microbes found in Australian iron ores to develop bioflotation and
bioflocculation processes for separating mineral contaminants from iron
ore using the polysaccharides and enzymes excreted by the bugs. The
advantage of this approach, should promising laboratory trials bear fruit
at larger scales, is that it can be used to more selectively reject
impurities from iron ores. "It's a possible process for the future, not for
now," Dr Holmes adds.
In another important advance for the environmental sustainability
of iron-making, the team has tested new sampling and quenching
methods as a means of quantifying the emission of dioxins during
sintering. The team has successfully demonstrated the use of urea,
ammonium sulfate and anthracite as potential inhibitors for dioxin
formation, with the result that dioxin emissions were cut by as much as
60 to 80 per cent.
Industry partnership is also flourishing, with the recent
announcement that BHP Billiton and CSIRO have entered into an
agreement that has led to BHP Billiton relocating its Carbon Steel
Materials research group to CSIRO's Queensland Centre for Advanced
Technologies (QCAT) in Brisbane.
"This will significantly enhance R&D links between the two
organisations in the iron ore, manganese and coke-making areas," Dr
Holmes says. "As part of this co-location, BHP Billiton is relocating its
two pilot-scale coke ovens from Newcastle to QCAT and research will be
contracted out to CSIRO."
Together, all these developments will help build a more secure and
prosperous iron ore sector for Australia into the future in which,
potentially, more processing will occur onshore before export to add
further value to the nation's iron ore reserves.
This article originally appeared in the February 2010 issue of CSIRO's Process magazine.
Andre Poliakov using Recognition software- an optical image analyser for automated identifi-
cation of minerals and textures in iron ore and sinter samples. Credit-Jason Starr
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