g_axelsson said:
Your melt looks more like a piece of copper oxide slag. Hit it with a hammer, slag crushes while gold flattens out. Just don't loose any pieces, though it looks like a glass it could have fine grained gold powder in it.
Are you able to melt a silver coin of similar size? It might be that you don't reach high enough temperature to melt the gold so it only mixes with your borax and creates a glass with powder suspended in it.
You should do some tests on smaller amounts of material before going on to a bigger lot like this. I suggest that you stop experimenting with the big lot and concentrate on smaller lots. Last week I refined the gold from one gold finger (4 gram of circuit boards). I worked in test tubes and with drops of acid and it worked just fine. The only thing I have left is to melt the gold into a microscopic button, then I will make a post about it.
What I recommend you to do is to stop all experimenting. Then read up on making stannous and a small amount of gold standard solution. The gold from a single finger is enough for the standard solution, pale yellow gold chloride is easily detected. And then test the solution with stannous so you learn how a positive gold test looks like. Then star testing all your solutions to see where the gold is.
It may take some time, but your gold is still there somewhere as long as you don't throw anything away.
Solids can be tested by taking a small sample, then dissolve all metal and test the resulting solution.
This is not a complete instruction on how to recover your gold, you should keep on studying a lot before going back to the large lot.
I'm quite sure that the gold is not where you think it is.
Göran
I would love to read that post about making a microscopic button from one gold finger. I'm not sure if you mean one finger contact or one strip of finger contacts. Either way, I think that information and experiment would help a lot of people (myself included) learn the process without ending up with gallons of waste.
Most of my own experiments with this were very small scale refining. I did end up with a couple tiny pieces of impure gold extracted from various sources. I think they are in a little cardboard coin holder as a keepsake somewhere. The tiny scale experiments were enough to convince me that I need an actual lab with fume hood and scrubbers before doing any larger scale experiments.
Actually, the main reason I have been inactive in this hobby for years now, is that my small scale experiments showed me that I would need a lot more gold containing scrap than what I have.
As I said, I'm very interested in small or even micro scale versions of the processes needed to separate and refine the precious metals from the other scrap materials. It would be great if it you could continue on after the gold is captured and purified, and show the steps needed (still on a small scale) to get the other metals out of solution either in a usable or saleable form or as waste.
Geo's post and video about Removing copper from spent AP solution
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=52&t=23645 made me a lot more interested in this hobby. I was a little disappointed to learn that "It is chunky when wet but crumbles to dust when it dries." but it still looked nice. I still only have limited gold containing scrap so a small scale tutorial sounds great. I'm tempted to try to make that tutorial myself but your version would likely need fewer corrections than mine. I assume you would include the stannous chloride testing. I'd be tempted to try making my own stannous test solution using a mL or two of HCl and some solder salvaged off of the scrap circuit board.
Of course, I'm also tempted to make my own HCl from scrap PCV pipe and my own bleach from salt water and electricity so you might not want to listen to me. I know the cost would likely end up being many times more than the value of any metals recovered and the needed chemicals are still fairly easy to obtain (muriatic acid, household bleach, etc.) so this would be mainly an educational process. I do think it would be fun, especially if you ended up with even a tiny speck of gold in the end. Making as many of the needed chemicals as possible would just add to the fun. I have spent many hours and days panning, sluicing, drywashing, and dredging around looking for a tiny speck of gold before so I know a visible (even with a magnifying glass) piece of gold would put a smile on my face.
Sharing my own experiments (if I really do them) might not be the best idea. A little knowledge could be a bad thing. Let's see ... If I put some plastic pipe shavings into a test tube and heat it up ... Cough, cough ....
Please do share your experiments.
