Determination of the potential gold electrowinning from an ammoniacal thiosulphate solution applied to recycling of printed circuit board scraps

Abstract

The use of electrochemical techniques in the selective recovery of gold from a solution containing thiosulphate, ammonia, and copper, obtained from the leaching of printed circuit boards from mobile phones using ammoniacal thiosulphate, are shown in this work. First, cyclic voltammetry tests were performed to determine the potential of electrodeposition of gold and copper, and then, electrowinning tests at different potentials for checking the rates of recovery of these metals were performed. The results of the cyclic voltammetry show that copper deposition occurs at potentials more negative than -600 mV (Ag/AgCl), whereas the gold deposition can be performed at potentials more positives than -600 mV (Ag/AgCl). The results of electrowinning show that 99% of the gold present in solutions containing thiosulphate and copper can be selectively recovered in a potential range between -400 mV (vs Ag/AgCl) and -500 mV (vs Ag/AgCl). Furthermore, 99% of copper can be recovered in potentials more negative than -700 mV (vs Ag/AgCl).

Electrochemical study of gold recovery from ammoniacal thiosulfate, simulating the PCBs leaching of mobile phones

“…As seen in our previous study [63], this low efficiency can be explained by the presence of copper in the solution. Even at potential values where there is no copper deposition, this species could contribute to the increase the current density.…”

Increased Recovery of Gold Thiosulfate Alkaline Solutions by Adding Thiol Groups in the Porous Structure of Activated Carbon

“…The voltammogram of supporting electrolyte is also presented in Figure 6 . No peaks were observed during the forward and reverse exploration of the supporting electrolyte, and, therefore, the presence of two different gold complexes was confirmed [ 31 , 32 ]. Finally, the voltammogram corresponding to the Au/(Thiosulfate 0.10 mol·L −1 + thioglycolate 0.05 mol·L −1 ) system is also presented, it is shown as a combination of voltammograms of the Au/thiosulfate and Au/Thioglycolate systems.…”

Recovery of gold and base metals from waste printed circuits boards

“…Undoubtedly, leaching and electro-wining/electro-refining process have always been attached and both became part of the first basis to establish hydrometallurgy as a formal study (Dutta et al, 2018), (Reyes-Valderrama et al, 2017), (Yang et al, 2018), (Liu et al, (2017), (Kasper et al, 2016), (Memon et al, 2017), (Zhang et al, 2018), (Mooiman et al, 2005). In order to reinforce this relationship more, if it is possible the aim of this paper which is to obtain precious metals using an environmental friendly treatment of electronic waste.…”