A new process has been uncovered that allows for the recovery of a mineral from uranium previously thought unrecoverable.
Scientists at Murdoch University have discovered the dissolution mechanism for brannerite, which was previously ignored and discarded as waste material due to its difficulty in recovery, according to Science WA.
Dr. Aleks Nikoloski and PhD candidate Rorie Gilligan uncovered the counterintuitive approach for the mineral, which currently accounts for 15 per cent of uranium unrecovered, after nearly a decade of research.
“The traditional wisdom in extractive metallurgy is that if you use more aggressive corrosive conditions, say by increasing the acid concentration, minerals will dissolve allowing the metal to come out, but it’s not the case with brannerite because of its chemical properties,” Nikoloski explained.
“While it can be extracted with high temperatures, high free acid concentrations and long leaching times, the process isn’t efficient or economical.
“By gaining an understanding of the chemical processes of brannerite, we have found a dissolution mechanism that supports effective extraction under relatively mild conditions.”
The scientists used a number of early studies from the 50s and 60s as a foundation for the extraction process.
“We took these as a starting point and applied more current knowledge,” Gilligan stated.
“We started by considering how brannerite behaves in the standard sulphuric acid/iron sulfate media and then looked at how it behaved when we introduced other substances, such as phosphates and fluoride, which are known to occur in natural deposits.
“There was no research into how these interacted with brannerite, so by taking a step-by-step approach we were able to better understand the mineral’s chemical processes.”
The researchers said early results exceeded expectations.
“At first I couldn’t believe the results. We were getting an extraction rate of 80 to 90 per cent for a mineral that was supposed to be refractory,” Nikoloski said.
While these initial recoveries are high, it is not yet known how high the cost outcomes will be on the uranium industry.