So I have some braze paste that is au/ni. I did my first batch which yielded the solid gold in the picture. I know I had too much metals and not enough chemicals. I filters the leftover chemicals which is the gold colored material in the jar in the picture. The material in this jar, is that mostly gold? Does Ni dissolved faster or would it change color? I did this first batch with hcl and increments of nitric over low heat and I yielded the piece of gold in the picture. My second batch I did the same thing over medium heat and even let it work longer but I ended up not yielding anything except some minute brown particles after dropping it with SMB. So my question is, does too much heat make the AR not dissolve enough. I will say, as a beginner and my first couple times I did rush the job and only had 4oz of nitric which I split into 2oz for each batch. I know I didn't have enough. When I do this again I'm going to make sure that I order everything I need along with making a fume hood. So with all that said, how much heat should I use? And the leftover material, is that mostly gold or is the nickel still present and just changed color? Will and pure nitric bath dissolve the nickel leaving the gold? The grey powder in the picture is the braze paste before putting it into AR. Also, is there anything better to use to precipitate the gold other than SMB or is that the best to use? And where can I buy the stuff to make strenuous chloride test? I found tin shot on Amazon but dont know where to get the Crystals.
Au and Ni questions
- Thread starter bpcp7208
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If the only metals involved are nickel and gold in powder form, I would probably first attempt to recover the gold before refining it.
To recover the gold, leaching or dissolving the nickel into solution, we could use nitric alone, or where the nitric acid price is not cost-effective, using a cupric chloride leach, or a ferric chloride leach, or something similar to put the nickel into solution while leaving gold as a powder.
Gold in fine powder it would be easier to use HCl and sodium hypochlorite bleach to dissolve the gold, without the trouble of removing the oxidizer before precipitating the gold.
Precipitated gold can look like black powder contaminated with base metal drag-down, from brown to a light tan fairly pure, precipitated gold under some rare conditions, can look like gold being yellow and shiny like gold, although the condition of this type of precipitation is rarer, I am unsure of why this happens, my belief is that the atoms have more time to build the bulk of the cluster before precipitating and they clump tighter to the point of almost forming a crystal structure more like gold than clumps of atoms forming powders loosely combined.
you can make the stannous chloride out of tin shot, 95% tin solder, even some types of pewter.
To recover the gold, leaching or dissolving the nickel into solution, we could use nitric alone, or where the nitric acid price is not cost-effective, using a cupric chloride leach, or a ferric chloride leach, or something similar to put the nickel into solution while leaving gold as a powder.
Gold in fine powder it would be easier to use HCl and sodium hypochlorite bleach to dissolve the gold, without the trouble of removing the oxidizer before precipitating the gold.
Precipitated gold can look like black powder contaminated with base metal drag-down, from brown to a light tan fairly pure, precipitated gold under some rare conditions, can look like gold being yellow and shiny like gold, although the condition of this type of precipitation is rarer, I am unsure of why this happens, my belief is that the atoms have more time to build the bulk of the cluster before precipitating and they clump tighter to the point of almost forming a crystal structure more like gold than clumps of atoms forming powders loosely combined.
you can make the stannous chloride out of tin shot, 95% tin solder, even some types of pewter.
Geo
Well-known member
Roughly one gram of sodium hypochlorite has enough chlorine to dissolve one gram of gold in solution. It's actually much more gas than that but that's about what you can expect to dissolve before the gas escapes the solution. If your bleach is 10% sodium hypochlorite, it is measured by weight. 10 grams of bleach would have 1 gram of sodium hypochlorite. Be mindful that the bleach is basic and will neutralize some of the acid. Add an excess of HCl for the reaction. The volume of solution will need to be evaporated anyway to ensure the destruction of excess hypochlorite so it serves two purposes.
