Non-cyanide Extraction of Gold from Carlin-Type Gold Concentrate by Pressure Oxidation Pretreatment–Jarosite Decomposition–Fine Grinding: An Eco-Friendly Process and Its Mechanism

Of late, given the difficulties in gold extraction and severe environmental pollution emanating from cyanide extraction of Carlin-type gold concentrate (CTGC), a novel pressure oxidation pretreatment followed by sodium jarosite decomposition and fine grinding was first proposed to extract gold from...

Full description

Saved in:
Bibliographic Details
Published in:Journal of sustainable metallurgy 2022, Vol.8 (3), p.1299-1317
Main Authors: Zhang, Lei, Guo, Xue-yi, Tian, Qing-hua, Zhong, Shui-ping, Li, Dong, Qin, Hong, Xu, Xiao-yang, Makuza, Brian
Format: Article
Language:English
Subjects:
Decomposition
Earth and Environmental Science
Environment
Fine grinding
Gibbs free energy
Gold
Gold ores
Grinding
Jarosite
Leaching
Metallic Materials
Oxidation
Partial pressure
Polysulfides
Pretreatment
Reaction mechanisms
Research Article
Sodium
Sustainable Development
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Of late, given the difficulties in gold extraction and severe environmental pollution emanating from cyanide extraction of Carlin-type gold concentrate (CTGC), a novel pressure oxidation pretreatment followed by sodium jarosite decomposition and fine grinding was first proposed to extract gold from the CTGC in a non-cyanide system. Thermodynamic computations of the Gibbs free energy and the Eh–pH diagram of different reaction systems were calculated to reveal the reaction mechanism during the treatment process. The optimal pressure oxidation pretreatment conditions were determined as follows: stirring speed 600 r/min, liquid-to-solid ratio of 4, pH 1.2–1.3, partial pressure of oxygen 1200 kPa, temperature 225 °C, and time 1.5 h. The extraction of gold increased from 9.7 to 82.1%. The sulfur conversion mechanism and the distribution of the gold phase as a function of leaching temperature during the pressure oxidation leaching process were investigated. The precise regulation and control mechanism of sodium jarosite decomposition and fine grinding were clarified. Furthermore, the polysulfide leaching results show that pressure oxidation leaching of the CTGC followed by sodium jarosite decomposition and fine grinding can efficiently liberate gold from the mineral envelope and provide favorable conditions for gold extraction in a non-cyanide leaching system. The leaching efficiency of gold in the polysulfide system reached 96.8%. This process has proved to be a promising alternative for efficient and environmentally friendly extraction of gold from the refractory gold ore. Graphical Abstract
ISSN:2199-3823
2199-3831
DOI:10.1007/s40831-022-00567-z