South Australia’s molten salt technology to reduce mineral processing costs

University of South Australia associate professor Frank Bruno. Image: theleadsouthaustralia.com.au

A research funding partnership between the University of South Australia and Centrex Metals is developing the use of molten salt technology in mineral processing to minimise energy and water costs.

It expands on research on molten salt for solar energy applications into mineral processing with the goal of developing and commercialising the technology.

Led by UniSA’s associate research professor Frank Bruno, the program will create a minerals processing circuit to leach, extract, and purify metals from silicate minerals entirely in a molten salt environment, without needing subsequent aqueous processing. This will both reduce water usage and lower energy costs, ultimately minimising the overall cost of molten salt processing.

The technology will be used at Centrex Metals’ Oxley Project in Western Australia which has a rare 32km long shallow dipping and outcropping lava flow, rich in potash feldspar. It will become the first bulk potassium chloride fertiliser from potassium feldspar ore commercial manufacturer.

Ben Hammond, Centrex Minerals CEO said, “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.”

While molten salt technology has been used at temperatures up to 600°C in the nuclear and solar energy industries, the project uses temperatures of 850°C for the first time.

Bruno said it could have wider implications for mineral refinement in the resources sector.

“Salts at the higher temperatures are generally more corrosive and also because you’re at higher temperatures that in itself creates greater reactions,” he added.

The research team has been focusing on molten salt technology’s thermal energy applications over the past four years, with Bruno saying at the time, they never considered using it for this application.

A total of $464,000 in external funding from the Minerals Research Institute of Western Australia, Centrex, and Mining Industry Participation Office of South Australia will be provided for two of the proposed three stages of the program.