subject: Do You Want To Learn How to Reclaim Gold from eWastes using Aqua Regia? [print this page] Gold refining protocol I Gold refining protocol I
1. Use a hammer to break the scrap and clean it using water. It is much better if you work with little pieces.
2. Place the scraps in a beaker or a plastic container and add nitric solution (A). Wait for the scraps of gold and pins to fall down at the bottom of the beaker.
Because this takes a day or two, you can speed it up by heating the solution even on a coffee pot and after 15-20 minutes repeat the process until the solution becomes clear; wash the scrap with clean water. Here, we are cleaning the scrap from those metals that react with nitric acid (copper for example). Remember neutralize the used solution before discharge. (Solution A: nitric acid: water 1:1 v/v)
3. Prepare the aqua regia solution (1 volume of nitric acid per 3 volumes of hydrochloride acid). It can be prepared in the same beaker that already contains the cleaned scrap. Put HCL into the beaker until it covers all the scraps. Slowly add nitric acid until the required volume is completely poured and wait for around 40 minutes. The more gold you have the more brown-yellow the solution becomes!
4. Add three water volumes to the solution to neutralize the acid (very important). After the acid has been neutralized, filtrate it using a dense cloth. The cloth should be dense enough so that all the organic dirt is filtered. Recover the solution in a clean new beaker.
5. Add zinc powder until the solution gives a black-grey color and appears like a dark dust. Wait for 15 minutes to let the dust fall down. Recover the deposition (gold and zinc) and do step one of this protocol again.
6. Wash the dust several times using water. Boil the solution. Slowly add sulfuric acid with precaution as it reacts violently with water. Discharge the solution and repeat the washing cycle again.
Finally, recover the final product that should be black red-dust in color. This is now your gold. I have to mention that this is a free protocol I usually use in my lab although there are better approaches to obtain a cleaner gold.
Do You Want To Learn How to Reclaim Gold from eWastes using Aqua Regia?
