Sparc Technologies (ASX: SPN) has reported results of test work on the recovery of gold and silver that shows its graphene-enhanced adsorption material “substantially outperforms” commercially available adsorbents, a key part of the tailings treatment process.
As part of its drive to develop technologies that can enhance large-scale industrial markets and provide a solution for previously uneconomic or environmentally hazardous scenarios, the company has been exploring and developing the use of functionalised graphene composite-based adsorbents for the removal of precious metals, oils and per- and polyfluoroalkyl substances (PFAS) contaminants.
According to Sparc, this new class of composite material has many benefits over currently available adsorbents, which are primarily based on activated carbon, by providing higher adsorption capacity and recovery rates.
Sparc managing director Tom Spurling said these results from initial testing gives the company encouragement to progress to the next stage of evaluation at both operating and residual mine sites.
“Furthermore, the results are consistent with the significant improvement in performance that we are seeing in other projects being undertaken by Sparc with materials that are enhanced with graphene,” he added.
Adsorption study results
The preliminary study was conducted at The University of Adelaide in South Australia and involved comparing eight graphene-based composite adsorbents, along with two industry standard commercial adsorbents (activated carbon and biochar based) as the control material.
According to Sparc, the best results from the test work highlighted 96.98% and 97.82% adsorption of gold and silver from solution into graphene-based adsorbents.
Enhanced precious metals recovery
The development of new recovery and recycling technologies is in high demand around the world due to the corresponding high uptake of precious metals globally. Sparc believes new technological development in this field could have potentially significant implications for sustainability and enhanced recoveries in the mining industry.
“Australia is a considerable global exporter of precious metals and Sparc is hopeful that this technology will improve the economics of existing mineral extraction practices, whilst improving mine life and reducing environmental and carbon footprints relative to the amount of metal produced,” the company stated in an announcement.
The company said it is targeting an estimated US$1 trillion (A$1.27 trillion) worth of precious metals already extracted from the ground, sitting at historical mining sites globally.
The next stage of test work includes comparing the company’s graphene adsorbents against a wider range of commercially available adsorbents.
In addition, plans are already underway to progress to live field trials targeting the extraction of actual gold and silver metals in tailings from mine sites.