Gold extraction from oxide gold ores through glycine leaching

The use of glycine, a non-toxic and simple amino acid, has gained attention for gold extraction because of its selective dissolution of precious metals. This study explores gold extraction from oxide gold ore using non-analytical grade glycine at concentrations of 1-3 M and reaction times ranging from 4 to 60 hours. The pH was maintained at 11-12, with the reactor temperature set at 60 °C, a stirring speed of 350 rpm, and an air flow rate of 1 L·min-1. The ore's particle size averaged 70.7 μm. The highest gold extraction (81.41%) occurred at 3 M glycine after 48 hours. Silver extraction was moderate, reaching 44.50%, while iron solubility was low at 7.71%. The results show that increased reaction time and glycine concentration enhance gold dissolution from oxide ore. This glycine-based process offers a more environmentally friendly and sustainable approach for selective extraction of gold and silver from oxide ores or oxidized waste containing precious metals.