Gold recovery from chloride leach solution of TCCA using D301 anion exchange resin and elution with thiourea

• Published in: Hydrometallurgy 2024-12, Vol.230, p.106384, Article 106384
• Main Authors: Niu, Huiqun, Yang, Hongying, Tong, Linlin
• Format: Article
• Language: English
• Subjects: Adsorption procedure; D301 resins; Desorption procedure; Kinetics and isotherms; TCCA leaching solution
• ISSN: 0304-386X
• DOI: 10.1016/j.hydromet.2024.106384

Trichloroisocyanuric acid (TCCA), which is used for gold leaching, is an alternative to cyanidation due to its lower toxicity and higher efficiency. This study investigated the gold recovery procedures from highly effective chloride leaching solution using the D301 resin. This approach prevented the inhibition of gold adsorption when using activated carbon. Herein, the optimal conditions for gold adsorption were discussed, including establishing adsorption kinetics and isotherms, and calculating adsorption activation energy. Additionally, SEM (Scanning Electron Microscope), FTIR (Fourier Transform Infrared Spectroscopy), and XPS (X-ray Photoelectron Spectroscopy) techniques were used to reveal the mechanism of gold adsorption using D301 resin. Under optimal conditions (pH 4.0, temperature 25 °C, time 120 min), an average adsorption percentage of 99.2% was achieved. Analysis of the adsorption data confirmed that gold adsorption followed the pseudo-second-order kinetic model and Freundlich adsorption isotherm. The calculated activation energy was 9.69 kJ mol−1, indicating a predominance of physical adsorption involving ion exchange reactions with protonated tertiary amine groups in the D301 resin beads. Furthermore, among various eluents tested in desorption experiments, a solution containing a mixture of thiourea and hydrochloric acid with 0.4 mol L−1 and 0.8 mol L−1, respectively, demonstrated superior efficiency, achieving a successful desorption percentage reaching 95.7 ± 0.3% within 80 min. After three cycles of resin regeneration, the regeneration efficiency reached 91.2% while maintaining an average adsorption percentage of 95.3%. •The adsorption process follows pseudo-second-order kinetic model.•The adsorption process follows Freundlich isotherm model.•The resin's functional groups act in the way of N:→H+ during adsorption.•The adsorption ratio between resin functional group and [AuCl4]− is approximately 1:1.•After three cycles of regeneration, the resin exhibits an adsorption percentage of 95.3%.