Afternoon everyone….
I don’t remember exactly how long ago @trumpman did a post about refining some gold from scrap. I commented on his post that I had done a bunch of this over the years with scrap I had picked up, @summertooth had also commented to ask me as well.
This process uses chemicals that can be harmful if you do not use caution or use them as intended. While the product used is a very common acid used by plumbers and metal workers, and can be bought at any big box home center for around $10 in the United States.
The use of nitrile gloves or preferably heavier rubber gloves is mandatory. I would also suggest goggles, in case of splashing. Until you are familiar with working with these items you can NEVER be too cautious.
I did this as a hobby, not as a profession. I have tried many different ways, with items much more hazardous. I’ve also tried several ways with items that are totally safe. This process, got me the best results for the least amount of money out of pocket. I’ve recovered nearly ten ounces of pure gold using this exact process.
First you need the scrap to refine.
These are gold plated fingers from RAM sticks, and other various electronics. You want to trim as much of the green fiber board off as possible to minimize the acid used.
I use a large beaker to process mine. Because I was doing many loads of these it was much easier to calculate amounts of solution needed. But a large clean glass jar with work just fine.
This process needs to be done in a well ventilated area, not inside your home. I do all of my refining outside.
You will also need muriatic acid, which is a diluted hydrochloric acid, which is available at any home center. You need hydrogen peroxide from any drug store or dollar store. Coffee filters and a funnel to strain the mixture after it is complete. Distilled water, and a brand new spray bottle for the distilled water to rinse the jar/beaker and the green boards. Bonide Stump-removerto precipitate the gold, also available at any home center, and unscented bleach. The total investment is about $25 if you don’t buy a beaker.
Now let’s begin….
Take the gold plated fingers and place them in a beaker. I think this batch was 300 grams of fingers.
Cover the fingers half way with distilled water. It must be distilled water, regular water and even filtered water has chemicals in it and will ruin the process. Then carefully pour the muriatic acid in to cover the fingers. I used 250ml of each. (Never add water to acid, it must water first then acid) Now add four ounces of hydrogen peroxide and stir. It must be a glass rod or a plastic rod to stir nothing metal or the acids will react to it.
If you have a way to heat the solution it works much quicker. I use an old corningware dish, put the beaker in it on a hot plate.
Once you pour in the hydrogen peroxide and stir the solution should start to produce small bubbles.
This solution eats all of the base metals under the gold plating to release the gold plating. The solution will start turning green, this is mostly copper being added to the solution, which is a base metal.
How long this process takes has several variables. The amount of fingers being processed, the amount of base metals in your waste, whether you heated the solution, how thick the plating is.
You should see little flakes of gold accumulating at the bottom of the beaker. You can stir the mixture every once in a while. This will help release the gold flakes.
Everytime you stir the mixture with a glass or plastic rod, you MUST spray it off over the beaker with distilled water.
If your solution stops bubbling, and all the foils have not fallen off, you can add additional hydrogen peroxide to reactive the acid.
Once all of the gold has fallen from the green board. I take a clean beaker put a small plastic colander over it and slowly pour the solution into it. When the acid beaker is empty, spray the inside of it with distilled water to rinse it out and wash any gold foils into the colander.
I then rinse the green boards from the colander ensuring all the gold flakes have passed through the colander and into the solution.
Now you need the coffee filters and funnel. I use cone style coffee filters and double them up usually. The funnel I use is one I bought from an auto parts store with a wide spout not long but wide. Roughly the size of a quarter. I use one gallon plastic jugs for this next process.
Place the funnel with the doubled up coffee filter inside it into the mouth of the gallon jug. Lightly spray the filter with distilled water to form it to the funnel. Slowly pour the solution into the funnel not allowing the solution to go above the filter. This is the longest hands on part of the process and can take a while.
Once the beaker is empty, spray the inside of the beaker with distilled water while the lip of it is over the funnel and filter to catch any remaining gold foils.
Depending on the amount of foils you have is what determines whether you will move on to the next process or not. From this lot of 300 grams of fingers I ended up with this.
After zeroing out my scale. I ended up with 1.6 grams of gold.
This is not pure 24K gold, it’s roughly 20-22K. So it’s roughly $90 worth of gold. I usually won’t process it further unless I have over 2-3 grams. I will save it in the pill bottle till then.
But to be thorough on the process…
The next process is to dissolve and purify the gold.
This is where the bleach comes in.
AGAIN this process MUST BE done outside. I personally wear a mask while doing this part. It’s a 3M mask with a chemical/organic vapor filter on it.
In a much smaller beaker or glass jar. Place the gold foils inside. Pour just enough muriatic acid in to cover the gold foils completely. My foils would use about 3 ounces, that’s how little. Add about a tablespoon of bleach to the acid.
This reaction with be fairly quick, and your solution should turn a light yellow to a golden yellow/orange depending on the amount of gold.
Triple the volume of liquid in the beaker with distilled water.
Now we have to precipitate the gold out of the solution.
It’s called dropping the gold. The chemical that does this is sodium metabisulfite, which is the main ingredient in Bonide stump remover.
For this amount of gold I will only need about a heaping tablespoon to drop the gold.
I use plastic spoons for this part to put the Bonide in and stir the solution.
The solution will turn a dark grey/brown muddy color once you mix it. This is the reaction. Stir for about ten seconds to ensure it dissolves completely, then leave the solution alone till it turns clear.
Your gold will now be a brown clay like powder in the bottom of the beaker.
Without shaking or stirring. Pour off as much of the clear solution as you can without disrupting the gold powder. I then heat up the beaker in the Corningware on the hot plate till the powder is dry.
You can melt it in a crucible and pour a little button of gold.
Congratulations you now have pure gold.
It’s not .999 pure but it’s over 98% pure at this point. If you want to purify it further repeat the bleach process one more time.