Thiosulfate gold extraction technology has gained considerable interest owing to its environmental compatibility and broad applicability to diverse ore types. However, the lack of efficient methods to recover Au(S 2 O 3 )
3− 2
from leaching solutions has hindered its industrial implementation. To address this challenge, this study used a thiosulfate leaching solution from quartz-type gold ores to design an activated carbon-coated titanium electrode (Ti@AC) with a porous surface structure. This electrode facilitated the direct reduction of low-concentration Au(S 2 O 3 )
3− 2
to metallic gold (Au 0 ) in solution, achieving a gold recovery of 99.58%, surpassing other recovery methods from the leaching solution by 30%–80%. After ten consecutive 200 L pilot-scale tests, the Ti@AC electrode demonstrated remarkable stability, consistently maintaining a recovery >98% and yielding 20.23 g of gold. The porous architecture of the activated carbon (AC) promoted the adsorption of low-concentration Au(S 2 O 3 )
3− 2
, while its low charge transfer resistance facilitated the efficient conversion of Au(S 2 O 3 )
3− 2
to Au 0 . Moreover, the reduction reaction generated a concentration gradient near the cathode, promoting the diffusion of Au(S 2 O 3 )
3− 2
toward the electrode and ensuring an efficient recovery process. This study provides a feasible strategy for the direct reduction of low-concentration precious metal ions to monomers with high recovery and low costs, which is promising for industrial applications.
Thiosulfate has been considered as a more environmentally-friendly alternative to cyanide salts for the extraction of gold from gold ores and the development of affordable, green and efficient adsorbents for the isolation of gold-thiosulfate complex (Au(S 2 O 3 ) 2 3− ) from the leaching solution remains a significant challenge. To address this issue, chitosan, a natural macromolecule , was selected as a carrier and chemically modified with ionic liquids . The ionic liquids modified chitosan showed greater adsorption capacity towards Au(S 2 O 3 ) 2 3− compared with pristine chitosan. The adsorption of Au(S 2 O 3 ) 2 3− on ionic liquid modified chitosan followed Freundlich isotherm and pseudo-second order kinetic models, involving an anion-exchange mechanism with liquid film diffusion as the rate-limiting step. The chitosan modified with butylimidazolium-based ionic liquid had an adsorption capacity of 5.0 mg g −1 for gold (10 mg L −1 of gold, pH 6, 2 g L −1 of adsorbent dosage), outperforming other reported adsorbents. The ionic liquid modified chitosan showed a high adsorption efficiency of up to 96.7 % for Au(S 2 O 3 ) 2 3− in an actual thiosulfate leaching solution with a desorption efficiency of 98.4 %, suggesting that the ionic liquid modified chitosan has the potential to be a eco-friendly, biocompatible and effective adsorbent for the recovery of Au(S 2 O 3 ) 2 3− .
危险品化学品经营许可证（带存储）