blueprintjonny
Member
Hi, you seem like a great community and I've already seen lots of great advice on here. I'm new to this community and to the gold extraction process but have always been fascinated by it and thought I'd like to give it a try. My knowledge of chemistry is very little to none but ive read C.M Hokes's book.
I know people frown upon it, but I'm the type of person who learns from doing not reading so I decoded to give the extraction a try on a very small scale of course. I got 150 or so gold plated sim cards, placed them in a beaker with 50% water and 50% nitric acid. The gold flakes came off the cards within ten or so minutes. I left the solution for about an hour so the stubborn flakes all came off then I filtered the flakes out of the solution on filter paper. Once I had collected the flakes I made a small quantity of aqua regia at 3 parts hcl to 1 part nitric acid. I put the flakes into a beaker and poured on just enough aqua regia to cover them and dissolve them. Next I cotton filtered that solution into another beaker.
This is the part I'm struggling with. I understand that in order to precipitate the gold out of the aqua regia I need to add sodium metabisulfite. So I got a small beaker with some water, dissolved a teaspoon of metabisulfite into it then slowly poured it into my filtered solution whilst stirring. Almost immediately I could see the reaction take place and saw the black gold flakes starting to precipitate. This is where I think I made the mistake. I continued pouring the metabisulfite solution into the mix and suddenly it changed back to a yellowish liquid and I could no longer see any gold flakes.
Is there a fine line when pouring in the metabisulfite where as soon as you see the reaction you must stop and ultimately did I end up pouring in too much? If so how do i now precipitate the flakes out of my now yellowish solution? Any help or advice would be greatly appreciated
I know people frown upon it, but I'm the type of person who learns from doing not reading so I decoded to give the extraction a try on a very small scale of course. I got 150 or so gold plated sim cards, placed them in a beaker with 50% water and 50% nitric acid. The gold flakes came off the cards within ten or so minutes. I left the solution for about an hour so the stubborn flakes all came off then I filtered the flakes out of the solution on filter paper. Once I had collected the flakes I made a small quantity of aqua regia at 3 parts hcl to 1 part nitric acid. I put the flakes into a beaker and poured on just enough aqua regia to cover them and dissolve them. Next I cotton filtered that solution into another beaker.
This is the part I'm struggling with. I understand that in order to precipitate the gold out of the aqua regia I need to add sodium metabisulfite. So I got a small beaker with some water, dissolved a teaspoon of metabisulfite into it then slowly poured it into my filtered solution whilst stirring. Almost immediately I could see the reaction take place and saw the black gold flakes starting to precipitate. This is where I think I made the mistake. I continued pouring the metabisulfite solution into the mix and suddenly it changed back to a yellowish liquid and I could no longer see any gold flakes.
Is there a fine line when pouring in the metabisulfite where as soon as you see the reaction you must stop and ultimately did I end up pouring in too much? If so how do i now precipitate the flakes out of my now yellowish solution? Any help or advice would be greatly appreciated