Surface Products on Gold leached in Ammoniacal Copper(II) Thiosulfate Solution

摘要

Surface-enhanced Raman scattering (SERS) spectroscopy has been applied in situ to identify species formed during gold leaching in copper(II) ammoniacal thiosulfate media. Species containing copper and sulfur develop on the gold surface and the coverage of these species was determined electrochemically. Vibrational modes due to sulfur-sulfur stretching at 382cm{sup}(-1) and symmetric sulfur-oxygen stretching at 1017cm{sup}(-1) develop during leaching. These modes diminish and are replaced by a single band at 255cm{sup}(-1), assigned to a M-S stretch, when rinsed and examined in water. In typical leach solutions, sulfur and copper coverages showed a 2:1 atomic ratio after leaching for 16h. Ex situ ATR-FTIR and XPS studies show that ammonia is adsorbed to a surface copper sulfide.