Sciencemadness Discussion Board

PCB in acid

DalisAndy - 26-10-2015 at 17:36

Is it plausible to dissolve a PCB in battery acid (35% sulfric acid)? I have some advanced PCBs from an old and BROKEN iPad. I have not use for them until I discovered that connectors are gold. Large pads and small connects.

Upsilon - 26-10-2015 at 18:06

If you're after pure gold, sulfuric acid will fail to dissolve any copper and silver that is also most certainly present on the board (unless hot and concentrated, but I don't think 35% will cut it). It will, however, dissolve any common metals like steel and zinc, so it would at least be a start. To further purify the gold, you would need to use nitric acid to dissolve away silver and copper. This will leave you impure but useable gold. Further purification would require dissolution in aqua regia and reducing the resulting chloroauric acid.

JJay - 26-10-2015 at 21:02

I think adding hydrogen peroxide to the acid would allow it to dissolve copper.

diddi - 27-10-2015 at 01:37

I have recovered gold from PCBs. to be honest you will spend more on acid than you will recover in gold. you need nitric for the Cu, then hot nitric for the Ag, then AR to get the gold, then have to recover Au again.