Australian iron-ore mining and exploration company Centrex Metals is advancing its diversification strategy through a collaborative research funding partnership with the University of South Australia (UniSA) as part of efforts to use molten salt technology to significantly reduce energy and water use.

The research is based on the company’s Oxley potassium project, in Western Australia, and is being undertaken by UniSA’s School of Engineering and Future Industries Institute.

“It will allow us to look at competing in the bulk fertiliser space for our globally unique large-scale potassium feldspar deposit at Oxley, creating more long-term jobs in Australia’s currently struggling mining industry,” Centrex CEO Ben Hammond states.

The company listed on the ASX in July 2006, having exploration licences covering an area of over 2 000 km2 of known iron-ore deposits and prospects on the Eyre Peninsula of South Australia.

Prior to the deterioration of the iron-ore market, Centex expected an oversupply of iron-ore and began a process of diversification into other minerals and bulk commodities. This process has seen the acquisition of the Goulburn and Archer tenements (polymetallic) and Woolgarlo (gold) in New South Wales. More recently, in March 2015, the company acquired Oxley from mineral-sands-focused explorer and developer Sheffield Resources and is now conducting testwork with a view to completing a scoping study in the middle of 2016.

Between Centrex, the Minerals Research Institute of Western Australia and the Mining Industry Participation Office of South Australia, A$464 000 in external funding will support the university’s work on the first two stages of the proposed three-stage research programme.

Hammond states that the partnership will expand current research capacity with regard to molten salt for solar energy applications into minerals processing with a view to increasing successful technology development and commercialisation.

The research programme, led by UniSA associate research professor Frank Bruno, will develop a minerals processing circuit to leach, extract and purify metals from silicate minerals in a solely molten salt environment, without the need for subsequent aqueous processing.

If the research successfully enables all processing steps to be undertaken in a molten salt environment, it will significantly lower energy and water use, as well as the associated costs, Bruno emphasises.
Centrex Metals will use the technology at its Oxley potash project to become the first commercial and cost-competitive manufacturer of bulk potassium chloride fertiliser from potassium feldspar ore.

The Oxley project, located in the Midwest region of Western Australia, about 125 km south-east of the Port of Geraldton, encompasses a rare 32-km-long shallow dipping and outcropping potash feldspar-rich lava flow.

Hammond reports that the new technology will take advantage of the unique liquid properties of molten salt to not only convert metals within silicate ore to an extractable form, but also separate and purify them, saving energy and water and reducing the overall project footprint.

Molten salt technology was previously used in the solar and nuclear energy industries at temperatures of up to 600 ºC, including the 110 MW Crescent Dunes solar energy project, in Nevada, US. However, Bruno states that the UniSA project will use salts at temperatures of 850 ºC and above for the first time.

Bruno reports that the research could have broader implications for mineral refinement in the mining industry and provide valuable insights for its further development in the solar and nuclear industries. “Salts at the higher temperatures are generally more corrosive and . . . higher temperatures . . . create greater reactions,” he says.

The team at UniSA is a world leader in molten salt technology and has focused on its applications for thermal energy storage for the past four years, Bruno points out.

“At that point, we would never have thought we would be able to use it for this application.” However, Bruno adds that, now that people know that Centrex is working with higher-temperature molten salt, they are approaching the company to investigate all sorts of applications.