Leaching of gold and silver from printed circuit .
The chemical leaching of whole PCB's extracted 86.23 g of Au/ton and 123.25 g of Ag/ton using aqua regia. The leaching with the commercial cyanide-based reagent obtained mean values of 112.02 g of Au/ton and 26.13 g of Ag/ton from whole PCB's. The results for leaching gold with alternative reagents, sodium thiosulfate and ammonium hydroxide, show that the best extraction was achieved at 0.1M ...