Sparc announces results of tailings treatment technology

Functionalised graphene composite-based adsorbents for the removal of precious metals, oils and PFAS contaminants have been explored and developed by the Sparc team 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. This new class of composite material has many potential 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, commented: “We are excited to see results from initial testing that demonstrate our Sparc graphene enhanced adsorbents significantly improves the recovery of gold and silver in solution, which gives us the encouragement to progress to the next stage of testing 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.”

Given the high demand for precious metals globally, the development of new recovery and recycling technologies is in high demand worldwide and has the potential for 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.

Adsorption study

The preliminary study was undertaken in conjunction with Sparc’s strategic partners and cornerstone shareholder, The University of Adelaide. For this initial screening study, eight available adsorbents were selected based on graphene-based composites designed and developed for adsorption of heavy metals and their applicability for precious metals Au, Ag and rare metals. Two different types of industry standard commercial adsorbents (activated carbon and biochar) were used as control adsorbents to compare efficiency and enhancements.

The adsorption study for removal of precious metals was performed using model water solutions with known concentration of Au (III) 1.2 mg L-1 (1.2 ppm) and Ag (I) 4.4 mg L-1 (4.4 pm) using common adsorption conditions for these metals and room temperature. Ag (I) and Au (III) ions were prepared from their stock solutions, silver (I) nitrate and chloroauric acid, respectively.

Among the in-house developed adsorbents, proprietary testing samples S8 and S9 outperformed all the tested adsorbents including the commercial adsorbents with 96.98% and 91.89% removal efficiency attained for Au (III) ions adsorption respectively.

In terms of Ag (I) ion adsorption, sample S5 outperformed all the adsorbents with 97.82 % adsorption efficiency attained.

Next stages

The next stages of the test work include testing Sparc graphene adsorbents against a wider range of commercially available adsorbents, progressing to live field trials targeting the extraction of actual gold and silver metals in tailings from mine sites.

Read the article online at: https://www.globalminingreview.com/environment-sustainability/22022021/sparc-announces-results-of-tailings-treatment-technology/