@lithicmetals: Chemically refining pure gold. After removing the base metals with nitric acid, I'm left with a gold sponge. I then dissolve the gold into solution using Aqua Regia. After filtering, the gold is dropped back out of solution with sodium-metabisulfite. Leaving any left over traces of base metals in the solution. Next we decant the waste solution and rinse the gold with hydrochloric acid, ammonia, and distilled water. Once it's dry, it goes into the melt dish. As you can see in the video, while molten and exposed to oxygen, no oxides form. A clear indicator of very pure gold! If you have karat gold or sterling silver that you'd like refined, go to lithicmetals.com and email me more the details. I'd be happy to refine your scrap metal for you! #Science #lithicmetals #gold