A systematic and comparative study of copper, nickel and cobalt-ammonia catalyzed thiosulfate processes for eco-friendly and efficient gold extraction from an oxide gold concentrate

A natural deep eutectic solvent-based aqueous biphasic system coupled with MoS2 photocatalytic reduction for green recovery of gold from thiosulfate solution

“…Generally, Cu(NH 3 ) 4 2+ , Ni(NH 3 ) 6 2+ , and Co(NH 3 ) 6 3+ are used to catalyze thiosulfate leaching of gold from ore. 40 Therefore, it is crucial to explore the selectivity of NADES–ATPSs for Au(S 2 O 3 ) 2 3− . Fig.…”

Eco-Friendly and Low-Energy Innovative Scheme for Green Gold Extraction: Thermodynamics, Kinetics, and Application of Self-Generating Thiosulfate at Atmospheric Pressure

“…Increasing the concentration of S 2 O 3 2− to 0.30 mol/L, a large amount of S 2 O 3 2− was oxidized to oxysulfide anions and combined with copper ions in the system to form a sulfurcontaining passivation film (eqs 11−15). 34,35 They are mainly ). 36,37 Therefore, the dissolution of gold was hindered, resulting in a continuous decrease in the extraction percentage of gold (56.90%) and a continuous increase in thiosulfate consumption (54.99 kg/tore).…”

“…Besides, the excessive adsorption time caused the thiosulfate being peroxidized to polythionates adsorbed on the resin surface, which competed with the copper anion (Cu(S 2 O 3 ) 3 5− ) causing a slight decrease in the adsorption percentage of copper. 34,41 For the adsorption of gold in actual pregnant solution, the adsorption percentage of gold in the pregnant solution increased significantly from 41.23 to 97.87% as the adsorption time is extended from 1 to 20 min. And the gold adsorption percentage also remained at a high level in the entire abscissa range (>99.20%) when the time exceeded ) occurs, resulting in a slight decrease in the percentage of gold adsorption.…”

Process Mechanism for Production of Green Lixiviant Thiosulfate at Atmospheric Pressure

“…Specifically, as green development has been widely advocated and promoted globally, thiosulfate was regarded as the most outstanding alternative green non-cyanide lixiviant. The reaction of gold leaching with single thiosulfate is slow in the absence of catalysts such as copper (II) (Cu 2+ as [Cu­(NH 3 ) 4 ] 2+ ). , However, the addition of Cu 2+ would invariably cause the metastable thiosulfate to be peroxidized into oxysulfide anions (S 4 O 6 2– , S 3 O 6 2– , SO 3 2– , and SO 4 2– ), resulting in the higher consumption of thiosulfate, which is also one of the primary reasons why this technology could not be fully commercialized. , …”

“…The reaction of gold leaching with single thiosulfate is slow in the absence of catalysts such as copper (II) (Cu 2+ as [Cu(NH 3 ) 4 ] 2+ ). 5,6 However, the addition of Cu 2+ would invariably cause the metastable thiosulfate to be peroxidized into oxysulfide anions (S 4 O 6 2− , S 3 O 6 2−…”