Gold is dissolved rapidly in alcohols via halogenation using inexpensive acetyl halides and the green oxidant hydrogen peroxide, potentially replacing more traditional and hazardous leaching procedures for the growing e-waste recycling industry.

Abstract

The dissolution of elemental gold is a fundamental step in its recycling by hydrometallurgy but has a significant environmental impact due to the use of strong acids or highly toxic reagents. Herein, it is shown that mixtures of acetyl halides and hydrogen peroxide in alcohols promote the rapid room-temperature dissolution of gold by halogenation to form Au(III) metalates. After leaching, distillation of the alcohol and re-dissolution in dilute HCl, the gold was refined through its precipitation by a simple diamide ligand; this method was also applied to separate gold from a mixture of metals. The leaching process is rapid, avoids the use of highly toxic materials and corrosive acids, and can be integrated into selective separation processes, so has the potential to be used in the purification of gold from ores, spent catalysts, and electronic and nano-waste.