Highly Efficient Recovery of Au(I) from Gold Leaching Solution Using Sodium Dimethyldithiocarbamate

Peng Yang; Xinrong Li; Shuliang Chen; Futing Zi; Xianzhi Hu

doi:10.1021/acsomega.4c01941

Highly Efficient Recovery of Au(I) from Gold Leaching Solution Using Sodium Dimethyldithiocarbamate

ACS Omega. 2024 Apr 26;9(18):20547-20556. doi: 10.1021/acsomega.4c01941. eCollection 2024 May 7.

Authors

Peng Yang^{1

2}, Xinrong Li¹, Shuliang Chen¹, Futing Zi², Xianzhi Hu²

Affiliations

¹ Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China.
² Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China.

Abstract

As a sustainable, nontoxic and environmentally friendly cyanide-free gold leaching agent, thiosulfate has been applied to some extent in the field of hydrometallurgy. However, the difficult recovery of gold ions in gold leaching solutions limits further application of thiosulfate gold leaching technology. This study demonstrated the feasibility of gold recovery by sodium dimethyldithiocarbamate (SDD) precipitation and recycling of ammonia and a lixiviant in solution. SDD achieved the purpose of recovering gold by forming granular precipitates with gold ions in solution. It can almost completely recover gold ions in 2.5-17.34 mg/L of gold leaching solution within 1 min at 25 °C, in which a gold recovery capacity of 7.99 kg/t is achieved. The leaching rate of gold ore did not change significantly after recycling the residual ammonia and thiosulfate in the leaching solution after gold recovery by SDD, and its leaching rate basically remained at 81%. The mechanism of SDD recovering Au was determined to involve the ligand exchange of SDD^- and Au[(S₂O₃)₂]^3-. Moreover, the interaction mechanism between SDD and Au(I) was further validated by density functional theory calculations. Considering its low cost, simple technology, and environmental friendliness, the SDD precipitation process has the potential for large-scale application in gold recovery from thiosulfate gold leaching solutions.