Guys I screwed up...
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I may have been the cause for this discussion going from a base like sodium bicarbonate being discussed instead of a base like sodium hydroxide being discussed, I do not know if my old age will hold up as an excuse or not. Or if I just misread the base goldman94 used originally...
Most everything still holds relevant in this discussion, and most of all the reactions are similar except maybe for some CO2 gas evolution along the way that using the caustic NaOH would not have formed...
Sodium hydroxide and hydrochloric acid form a salt, we often call table salts NaCl and water.
HCL + NaOH --> NaCl + H2O
Sodium bicarbonate and hydrochloric acid form a salt, we often call table salts NaCl and water with the evolution of CO2 gas.
HCl + NaHCO3 --> NaCl + H2O + CO2
Sodium hydroxide and nitric acid form a salt of sodium nitrate and water.
HNO3 + NaOH --> NaNO3 + H2O
Sodium bicarbonate and nitric acid form a salt of sodium nitrate in water with the evolution of CO2 gas.
HNO3 + NaHCO3 --> NaNO3 +H2O + CO2
About the only difference besides CO2 gas emission, the only other point I can see different is that with the bicarbonate not being as basic as sodium hydroxide is. you are not likely to get the amphoteric gold to dissolve as a base with an excess of sodium bicarbonate...
Most everything still holds relevant in this discussion, and most of all the reactions are similar except maybe for some CO2 gas evolution along the way that using the caustic NaOH would not have formed...
Sodium hydroxide and hydrochloric acid form a salt, we often call table salts NaCl and water.
HCL + NaOH --> NaCl + H2O
Sodium bicarbonate and hydrochloric acid form a salt, we often call table salts NaCl and water with the evolution of CO2 gas.
HCl + NaHCO3 --> NaCl + H2O + CO2
Sodium hydroxide and nitric acid form a salt of sodium nitrate and water.
HNO3 + NaOH --> NaNO3 + H2O
Sodium bicarbonate and nitric acid form a salt of sodium nitrate in water with the evolution of CO2 gas.
HNO3 + NaHCO3 --> NaNO3 +H2O + CO2
About the only difference besides CO2 gas emission, the only other point I can see different is that with the bicarbonate not being as basic as sodium hydroxide is. you are not likely to get the amphoteric gold to dissolve as a base with an excess of sodium bicarbonate...
butcher said:
First of all, I just want to immensely thank you for everything that you've done for this thread and the forum in general, you really know your stuff.
As to what to do next, what you're suggesting to me is that I should evaporate my solution/salts mixture until syrupy and then add in HCL and repeat a few times? Then after that should all the salts be gone by then? And then I can just precipitate the gold out then? Do I need to use anymore nitric in this?
Goldman94,
Sorry if I am complicating things for you, it is not my intention.
You could do this in a few different ways and still come up with the same results.
you can just evaporate the liquid and as suggested, or just test the solution for gold if it test shows violet in the reaction with stannous chloride you have gold in solution, if it is brown it is likely a false positive (if you previously used SMB or some other sulfite)...
If tin was involved you could even have invisible to the eye gold floating in solution as colloids that will not show up in a stannous chloride test...
You can decide for yourself if you wish to trust the test and treat the solution for waste or evaporate it to concentrate it and treat it along with the salts you have now.
If evaporating the solution, I would separate the salts you have now from the liquid while evaporating the liquid to concentrate it, you can add it back to the salts you have now after the water is removed before reconstituting in HCl...
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Now you should be left with salts (and possibly a very concentrated liquid).
Here we can add some heat and just a tiny bit of HCl.
Just as it describes in Hoke's book.
Any nitrates in solution (or salts) once acidified by adding HCl. will reform nitric acid, in the heat of this concentrated solution, they will also convert to gases, evolving a red-brown cloud of deadly gaseous NOx.
Here we again evaporate to remove water, to concentrate and to help decompose nitrates and remove nitric as gases(evaporate water which came from the added HCl we added, which is 20% acid and 80%water, and any water created in the reaction, along with any nitric created in the reaction).
Repeating with another small addition of HCl to the concentrate (watching for the deadly gas to evolve indicating nitric or nitrates remaining)...
Repeat the third time to insure decomposition of any nitric or nitrates...
Now we still have a concentrated saturated chloride solution of salts free of nitrates or nitric.
if you did not have a tin in solution with the gold originally I would proceed.
Bringing the salts back into solution with HCl...
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a test to check for possibly problems with tin would be to see how well the solution filters before you concentrating it, if it will not pass the filter easily I would suspect tin is involved and go ahead and dry the salts, fuse them, and roast them)...
if tin was originally involved with the gold in solution, I would consider a possibly fusion of the salts to oxidize and tin salts that may be involved) in this case dry everything to salt at low heat and then heat the salts (keeping them stirred while they evolve gases, heating the dried salts until they melt into a thick syrup, then keep heating until this syrup dries to a crust, crushing the crust to powder and roasting the powder to a red hot glow, cool crush again and reconstitute in HCl...
Sorry if I am complicating things for you, it is not my intention.
You could do this in a few different ways and still come up with the same results.
you can just evaporate the liquid and as suggested, or just test the solution for gold if it test shows violet in the reaction with stannous chloride you have gold in solution, if it is brown it is likely a false positive (if you previously used SMB or some other sulfite)...
If tin was involved you could even have invisible to the eye gold floating in solution as colloids that will not show up in a stannous chloride test...
You can decide for yourself if you wish to trust the test and treat the solution for waste or evaporate it to concentrate it and treat it along with the salts you have now.
If evaporating the solution, I would separate the salts you have now from the liquid while evaporating the liquid to concentrate it, you can add it back to the salts you have now after the water is removed before reconstituting in HCl...
--------------------------------------------------
Now you should be left with salts (and possibly a very concentrated liquid).
Here we can add some heat and just a tiny bit of HCl.
Just as it describes in Hoke's book.
Any nitrates in solution (or salts) once acidified by adding HCl. will reform nitric acid, in the heat of this concentrated solution, they will also convert to gases, evolving a red-brown cloud of deadly gaseous NOx.
Here we again evaporate to remove water, to concentrate and to help decompose nitrates and remove nitric as gases(evaporate water which came from the added HCl we added, which is 20% acid and 80%water, and any water created in the reaction, along with any nitric created in the reaction).
Repeating with another small addition of HCl to the concentrate (watching for the deadly gas to evolve indicating nitric or nitrates remaining)...
Repeat the third time to insure decomposition of any nitric or nitrates...
Now we still have a concentrated saturated chloride solution of salts free of nitrates or nitric.
if you did not have a tin in solution with the gold originally I would proceed.
Bringing the salts back into solution with HCl...
-----------
a test to check for possibly problems with tin would be to see how well the solution filters before you concentrating it, if it will not pass the filter easily I would suspect tin is involved and go ahead and dry the salts, fuse them, and roast them)...
if tin was originally involved with the gold in solution, I would consider a possibly fusion of the salts to oxidize and tin salts that may be involved) in this case dry everything to salt at low heat and then heat the salts (keeping them stirred while they evolve gases, heating the dried salts until they melt into a thick syrup, then keep heating until this syrup dries to a crust, crushing the crust to powder and roasting the powder to a red hot glow, cool crush again and reconstitute in HCl...
butcher said:
Okay, so what I should plan to do is decant as much clear liquid off as I can from the beakers and evaporate that down and reconstitute with HCL then precipitate out with SMB?
As for the salts, I'm still kind of confused as to how to recover the gold from them. It is a very thick layer of gunk at the bottom along with some brown powder and what looks to be metallic gold.
As I mentioned before, there should be about 9g of gold in there and I cant afford to throw out any solution or salts that may contain the gold in them.
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Richard
A Chemistry question. If as you say the gold is in a hydrous form then shouldn't HCl alone then convert it back to the Gold Chloride?
A Chemistry question. If as you say the gold is in a hydrous form then shouldn't HCl alone then convert it back to the Gold Chloride?
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Goldman94 said:
Sorry if I missed something already mentioned but is the amount of solution shown in the two beakers all the solution you have? The yellow solution certainly looks like it could have some gold in it but not 9 grams. My experience, which is minimal, would suggest that 9g of gold in 200ml of solution would be more of an orange color. The other darker solution might have some gold in it but you said it's test came back negative. What, and how much of it, was the source material?
Dennis
denim said:
I had 18g of 10k and 4g of 14k which should equal 9.8g of 24k.
Yes that is all the solution I have. I was confused as to the color difference between both of them too. It started as a very dark orange color and then when I added the SMB nothing came out and then I decided to add baking soda to neutalize the nitric, but now I know that was a very bad idea. So after adding that it turned the color to a bright yellow and the other, darker, solution stayed the same.
As I mentioned before, i think some of the gold has already precipitated out due to a brown mud at the bottom, along with some metallic pieces that look like gold.
This is why I'm very confused since the first time I did it I had 0 issues with it but the next time I have no idea what I did wrong. I have a feeling that some gold is still in solution but the majority of it is trapped inside the sediment at the bottom and have no idea on how to retrieve it.
But I do have a feeling i lost a lot of gold and I have no idea where it could have gone...
This is what I'm left with now. I'm currently trying to evaporate the solution on the burner and the other one is just all the sediment I have that I believe has the majority of gold in it. Since the one I have on the burner tested negative for any gold in solution I'm confused since I combined all the solution in that one and all the sediment in the other one.
Attachments
I have a bad habit of posting then editing and reposting, or thinking of something to add to the post, and edit, normally it is not a problem as nobody has time to post or post before I finish.
Here you guys are reading and posting before I finish editing, and even quoting, making my bad habit obvious and a problem, no wonder editing posts is discouraged by the forum rules.
Jon, I cannot answer that, I do not know from experience if Au(OH)3 is soluble in HCl alone or not.
https://en.wikipedia.org/wiki/Gold(III)_hydroxide
https://chemequations.com/en/?s=Au%28OH%293+%2B+HCl+%3D+AuCl3+%2B+H2O
I would expect he does not have a gold hydroxide, but the base metals involved in solution has most likely reduced his gold as they formed oxides and hydroxides as metallic gold, I doubt the baking soda could even form a gold hydroxide like NaOH can
Here you guys are reading and posting before I finish editing, and even quoting, making my bad habit obvious and a problem, no wonder editing posts is discouraged by the forum rules.
Jon, I cannot answer that, I do not know from experience if Au(OH)3 is soluble in HCl alone or not.
https://en.wikipedia.org/wiki/Gold(III)_hydroxide
https://chemequations.com/en/?s=Au%28OH%293+%2B+HCl+%3D+AuCl3+%2B+H2O
I would expect he does not have a gold hydroxide, but the base metals involved in solution has most likely reduced his gold as they formed oxides and hydroxides as metallic gold, I doubt the baking soda could even form a gold hydroxide like NaOH can
That is an awful lot of salts.
I am just curious, have you tested the pH of the solution?
Either way acidic or basic it still holds metals in solution, I am doubtful it would hold any gold, it would most likely have precipitated as black powder long ago from the base metals in solution (and as salts now).
I am just curious, have you tested the pH of the solution?
Either way acidic or basic it still holds metals in solution, I am doubtful it would hold any gold, it would most likely have precipitated as black powder long ago from the base metals in solution (and as salts now).
butcher said:
I have not checked it, I dont have a ph kit but I would assume it is very acidic from when I was adding in baking soda last night it continued to fizz like crazy.
I think we may be getting somewhere though, I have no idea how but I've been seeing quite a lot of metallic gold being separated out somehow, as well as brown powder that is mixed in with the salts. I have a feeling much more is mixed in there but I just cannot see it.
I'm still trying to figure out a way as to how I can separate the gold from the salts, as well as if any of the salts contain gold that need to be chemically extracted, that part is where I will be stuck longest.
Most of the salts will be water-soluble and dissolve in water.
HCl is around 80% water 20%acid.
If tin is involved, the tin hydrolyzes in water to gooey gunky SnCl4, where HCl will dissolve it better as SNCl2.
Thus HCl is suggested it will dissolve the salts, it has plenty of water, and the acid will assist to dissolve some of the salts that may not be as water-soluble now, also using HCl may save somewhat on the volume of waste that will be generated trying to clean this mess up.
If tin is not involved, and you do not mind evaporating more water from your waste stream later then I would definitely use water at first to dissolve as much of the salts as possible, before using acids...
A clue if tin is involved now would be to take a small sample a few milliliters of concentrated solution dilute it with water and see how well it passes the filter.
If the filter clogs or runs slow I would suspect tin is involved, and avoid using water at first to dissolve the bulk of salts, using HCl at least at the beginning to put the tin in solution.
Karat gold normally does not have a problem with tin (as long as solder is not involved) that gold-filled junk jewelry or electronic scrap has.
I do not know if any junk jewelry or gold fill is involved here in this batch unless each piece was tested before dissolving to verify that the karat marking was correct and the ring was not a fake, or gold-filled...
HCl is around 80% water 20%acid.
If tin is involved, the tin hydrolyzes in water to gooey gunky SnCl4, where HCl will dissolve it better as SNCl2.
Thus HCl is suggested it will dissolve the salts, it has plenty of water, and the acid will assist to dissolve some of the salts that may not be as water-soluble now, also using HCl may save somewhat on the volume of waste that will be generated trying to clean this mess up.
If tin is not involved, and you do not mind evaporating more water from your waste stream later then I would definitely use water at first to dissolve as much of the salts as possible, before using acids...
A clue if tin is involved now would be to take a small sample a few milliliters of concentrated solution dilute it with water and see how well it passes the filter.
If the filter clogs or runs slow I would suspect tin is involved, and avoid using water at first to dissolve the bulk of salts, using HCl at least at the beginning to put the tin in solution.
Karat gold normally does not have a problem with tin (as long as solder is not involved) that gold-filled junk jewelry or electronic scrap has.
I do not know if any junk jewelry or gold fill is involved here in this batch unless each piece was tested before dissolving to verify that the karat marking was correct and the ring was not a fake, or gold-filled...
butcher said:
What if I still have gold in solution? I'm not going to evaporate that off, am I? Also, no tin should have been present as everything was tested to be at least 10k and real karat gold.
By dissolving the salts, will the gold be precipitated out of the solution by itself or will it be in solution?
I'm going to try and adding water to it and evaporating it today like you said. Probably going to take quite awhile but hey, what can ya do.
goldenchild
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STOP. You're digging yourself into a bigger and bigger hole. At this point I think you should filter your solutions and put the liquids and solids to the side. If you go this route I can help you. If not your just going to keep spinning your wheels.
