Highly Efficient and Selective Extraction of Gold from Thiosulfate Leaching Solution Using Functionalized Dicationic...

Area of Science:

• Materials Science
• Hydrometallurgy
• Green Chemistry

Background:

• Thiosulfate leaching is a promising alternative to cyanidation for gold recovery.
• Current methods face challenges in recovering low gold concentrations from thiosulfate solutions.
• Liquid-liquid extraction is limited by volatile and toxic organic solvents.

Purpose of the Study:

• To synthesize functionalized dicationic ionic liquids (DILs) for gold recovery.
• To evaluate DILs as environmentally friendly extraction solvents for gold-thiosulfate complexes.
• To investigate the mechanism and influencing factors of gold extraction using DILs.

Main Methods:

• Synthesis of functionalized dicationic ionic liquids (DILs).
• Experimental extraction of gold-thiosulfate complex ([Au(S2O3)2]3-) using DILs.
• Analysis of extraction rates, mechanisms (anion exchange, endothermic process), and selectivity.

Main Results:

• DILs exhibited higher extraction rates for [Au(S2O3)2]3- compared to monocationic counterparts due to stronger electrostatic interactions.
• Extraction is an anion exchange and endothermic process, rate-limited by the interface.
• ILs with anions possessing strong hydrogen-bonding ability showed high extraction efficiency.

Conclusions:

• DILs are effective and selective solvents for recovering gold-thiosulfate complexes from leaching solutions.
• DILs present a viable, environmentally friendly alternative to conventional organic solvents in gold recovery.
• The study highlights the potential of tailored ionic liquids for sustainable hydrometallurgical processes.