Microfluidic study of sustainable gold leaching using glycine solution

The purpose of this paper is to investigate the in-situ leaching of gold using a microfluidic system with controlled flow, temperature and fluid composition. The microfluidic system is a microchannel embedding a nano-scale layer of gold over which the fluid can flow and etch (erode) gold at various temperatures and concentrations of lixiviant. The lixiviant in this case is an alkaline glycine system that has been identified as an environmentally friendly substance to dissolve precious metals, it is used to extract gold within the engineered micro-cavity. As the fluid flows in the microchannel, the thickness of the gold layer is monitored to control its reduction with respect to time and space. The experimental conditions were varied to evaluate their effects on the recovery rate. The results show that compared to traditional methods being used in laboratory testing, this technique can provide real time measurements with low consumption of chemicals and the results can be obtained in shorter periods of time.