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SOLVOMET/SIM² KU Leuven researchers developed a solvometallurgical process to regenerate and reuse the anionic collector SDS and to strip copper from foam phases produced after the ion flotation of Cu-Zn dilute ammoniacal leachates. The work was performed in the framework of the H2020 MSCA-ETN SULTAN project for the remediation and reprocessing of sulphidic mining waste sites. The work is published in the special issue in the Journal of Sustainable Metallurgy, entitled “Mine Tailings: Problem or Opportunity? Towards a Combined Remediation and Resource Recovery Approach”.


Ion flotation

Ion flotation is an efficient separation technique for the recovery of metal ions from dilute aqueous solutions. Provided that both the collected metal and the surfactant are recovered from the foam phase, it could be considered as an alternative to ion exchange, adsorption or solvent extraction in hydrometallurgy.

However, most studies are focusing only on the metal recovery by ion flotation and neglect the development of a closed-loop ion flotation flow sheet with regeneration of the collector. As a consequence, the industrial implementation of this technique to hydrometallurgical operations is limited.

New solvometallugical process for copper recovery

The objective of this paper was to develop a simple solvometallurgical process for the decomposition of copper(II) tetraamine dodecyl sulfate sublates from foams generated after the ion flotation of dilute copper–zinc ammoniacal solutions with sodium dodecyl sulfate (SDS).

It was possible to recover copper almost quantitatively as a copper-bearing precipitate, after mixing the foam phase with a 8 g L−1 NaOH in methanol solution. The collector was regenerated from the solution by removal of methanol by distillation and its reusability was tested in five subsequent ion flotation cycles.

The efficiency of the regenerated SDS for the recovery of copper from dilute copper–zinc ammoniacal solutions was similar (ca. 80%) to that of fresh SDS solution without make-up. Based on the experimental results, a conceptual closed-loop flow sheet is proposed for the recovery of copper from dilute ammoniacal leachates by ion flotation.

Full reference of paper

Xanthopoulos, P., Binnemans, K. Closing the Loop in Ion Flotation: Recovery of Copper, Regeneration and Reuse of Collector from the Foam Phase by a Solvometallurgical Process. J. Sustain. Metall. (2021). https://doi.org/10.1007/s40831-021-00463-y

Acknowledgements

The research leading to these results has received funding from the European Community’s Horizon 2020 Programme under Grant Agreement No. 812580 SULTAN) (MSCA- ETN SULTAN). This publication reflects only the authors’ view, exempting the Community from any liability.