Gold (Au) is arguably the most important metal which is recovered during an industrialscale waste printed circuit board (WPCB) recycling operation. This is because Au is a highly economically valuable metal which is present in WPCBs in appreciable concentrations, often tens to hundreds of times greater than in naturally occurring ore deposits. In terms of economic value per kg of WPCB, Au accounts for 60-80 % of the total economic value of WPCBs . Hence, the profitability of most industrial-scale WPCB recycling operations is intrinsically linked to successful Au recovery. Unfortunately, significant value loss and resource wastage occurs when conventional processes utilising expensive pyrometallurgical techniques are used for Au recovery from WPCBs. In response to these drawbacks, there has been increased research into the development of efficient, environmentally sustainable, and economically feasible hydrometallurgical processes for Au recovery from WPCBs . Most hydrometallurgical processes for Au recovery from WPCBs commence with the leaching of a size-reduced WPCB particulate in a strongly oxidising and complexing aqueous lixiviant. A strongly oxidising lixiviant is required for Au leaching since Au possesses a large positive reduction potential, owing to the relativistic contraction of its 6s orbitals, while a strongly complexing lixiviant is required since leached Au (as Au and/or Au + ions) is thermodynamically unstable unless it is complexed by a suitable ligand . During the aforementioned leaching process, Au, and other metals (namely Ag, Pd, Fe, Ni, Zn, Sn, Sb, Mn, and Al) present in the WPCBs encounter the lixiviant and are subsequently leached. This leaching step produces a leachate from which Au is recovered after a refining process utilising techniques such as solvent extraction and electrowinning , .