Large Scale Gold Refining By the Aqua Regia Acid Method
The gold refining technique described here is the rather ancient wet chemical method whereby the goldbearing scrap is dissolved in aquaregia. m is gold solution is then filtered and the jewelers bench dirt, sandpaper grit, grinding wheel grains and similar material remains on the filter as a solid sludge, together with any silver present which will be in the form of silver chloride.