Accidentally made Gold hydroxide??

[HobbyChemist69]

I’ve been having trouble getting gold to precipitate from from chloroauric acid, and I was wondering if I could get some help. I started by dissolving a small amount of gold powder using HCl and bleach, which I then filtered and attempted to precipitate gold from using SMB. After adding the SMB and letting it sit overnight nothing precipitated. I thought it might be an issue with the pH so I added NaOH to balance it, which resulted in a black precipitate. I thought that this was my gold so I filtered it off, but when I did an HCl wash of the powder, it redissolved. I now believe that this black filtrate was gold hydroxide, but now it’s all redissolved and in solution. I’m not sure where to go from here, but I was thinking of maybe converting it back into gold hydroxide, filtering and washing it, then reacting it with HCl again to make a solution of only chloroauric acid (it would have no sodium or bisulfite ions in it) and trying to precipitate it again. Unfortunately, I have no standouts chloride so I can not be certain that there is gold in solution, but I’m pretty sure there is due to the color and the fact that I saw the original gold powder dissolve. Do you think my plan would work? Or would it just be wasted effort?

 

[eaglekeeper]

Since you have hydrochloric acid, all you need is some solder from the hardware/Walmart store. With those two items you can make stannous chloride easily.

Where did you get the SMB from?...also, The solution needs to be acidic for the SMB to work correctly.

 

[HobbyChemist69]

Since you have hydrochloric acid, all you need is some solder from the hardware/Walmart store. With those two items you can make stannous chloride easily.

Where did you get the SMB from?...also, The solution needs to be acidic for the SMB to work correctly.

I got the SMB from Amazon, the label claimed to be 99% pure and I found several reviews claiming they had used it to precipitate gold from AR. All I have right now is tin/lead solder but next time I’m out I’ll look around for some solder with a higher tin content.

 

[Yggdrasil]

I got the SMB from Amazon, the label claimed to be 99% pure and I found several reviews claiming they had used it to precipitate gold from AR. All I have right now is tin/lead solder but next time I’m out I’ll look around for some solder with a higher tin content.

Any Tin solder will do just fine.
And as Eaglekeeper said, for SMB to work the solution have to be acidic.
When you use HCl/Bleach there is a risk of pushing the pH too high.
Add some HCl to your solution and measure the pH, it should be between 2-4.

 

[nickvc]

You also need to drive off any remaining bleach from your solution as this will stop your gold from precipitating, to do that simply put your beaker on a low heat to drive off the chlorine.

 

[Lino1406]

I’ve been having trouble getting gold to precipitate from from chloroauric acid, and I was wondering if I could get some help. I started by dissolving a small amount of gold powder using HCl and bleach, which I then filtered and attempted to precipitate gold from using SMB. After adding the SMB and letting it sit overnight nothing precipitated. I thought it might be an issue with the pH so I added NaOH to balance it, which resulted in a black precipitate. I thought that this was my gold so I filtered it off, but when I did an HCl wash of the powder, it redissolved. I now believe that this black filtrate was gold hydroxide, but now it’s all redissolved and in solution. I’m not sure where to go from here, but I was thinking of maybe converting it back into gold hydroxide, filtering and washing it, then reacting it with HCl again to make a solution of only chloroauric acid (it would have no sodium or bisulfite ions in it) and trying to precipitate it again. Unfortunately, I have no standouts chloride so I can not be certain that there is gold in solution, but I’m pretty sure there is due to the color and the fact that I saw the original gold powder dissolve. Do you think my plan would work? Or would it just be wasted effort?

What was the amount of powder?
Was it pure gold?
What resulted from 1st filtration?
Gold hydroxide transforms to gold by heating to 160 - 200C

 

[D-dog]

Not sure if this will help anyone or not.
Modern small lead free fishing weights are made out of Tin. These can be bought anywhere that sells tackle.

 

[HobbyChemist69]

What was the amount of powder?
Was it pure gold?
What resulted from 1st filtration?
Gold hydroxide transforms to gold by heating to 160 - 200C

It was a very small amount of powder, just some small particles that were made as a byproduct of boiling some gold inquarted with copper in dilute nitric acid. I removed the gold powder from the solution by filtering it, then I washed it with some more dilute nitric acid to try to remove any excess copper that was in the powder. I can’t imagine there was more than a gram of the powder.
After the first filtration, I had some small black particles get caught in the filter, but most of the powder was dissolved into the HCl and bleach to make a yellow solution.
I checked the pH before adding SMB with litmus strips and it showed a pH of 1, so I don’t think the issue was lack of HCl.

 

[Yggdrasil]

It was a very small amount of powder, just some small particles that were made as a byproduct of boiling some gold inquarted with copper in dilute nitric acid. I removed the gold powder from the solution by filtering it, then I washed it with some more dilute nitric acid to try to remove any excess copper that was in the powder. I can’t imagine there was more than a gram of the powder.
After the first filtration, I had some small black particles get caught in the filter, but most of the powder was dissolved into the HCl and bleach to make a yellow solution.
I checked the pH before adding SMB with litmus strips and it showed a pH of 1, so I don’t think the issue was lack of HCl.

Gold Hydroxide has more or less the same color as Gold powder.
So I guess it is some kind of slag/oxide from the inquarting.

 

[Barstool miner]

I’ve been having trouble getting gold to precipitate from from chloroauric acid, and I was wondering if I could get some help. I started by dissolving a small amount of gold powder using HCl and bleach, which I then filtered and attempted to precipitate gold from using SMB. After adding the SMB and letting it sit overnight nothing precipitated. I thought it might be an issue with the pH so I added NaOH to balance it, which resulted in a black precipitate. I thought that this was my gold so I filtered it off, but when I did an HCl wash of the powder, it redissolved. I now believe that this black filtrate was gold hydroxide, but now it’s all redissolved and in solution. I’m not sure where to go from here, but I was thinking of maybe converting it back into gold hydroxide, filtering and washing it, then reacting it with HCl again to make a solution of only chloroauric acid (it would have no sodium or bisulfite ions in it) and trying to precipitate it again. Unfortunately, I have no standouts chloride so I can not be certain that there is gold in solution, but I’m pretty sure there is due to the color and the fact that I saw the original gold powder dissolve. Do you think my plan would work? Or would it just be wasted effort?

I am doing the some Mistake I have lost 200 grams of gold when I dissolved My anode Bag Sludge With HCl and Clorox. My stannous Chloride showed High concentrates of Gold. Then I fell into the trap of neutralizing the acid. I filtered this sludge , dried it and Fired it in Flux , Pow I ended up with Nothing. I am concerned Because I have another 5 kilos of anode bag sludge to process. Am I lost in the wilderness?

 

[Barstool miner]

I am doing the some Mistake I have lost 200 grams of gold when I dissolved My anode Bag Sludge With HCl and Clorox. My stannous Chloride showed High concentrates of Gold. Then I fell into the trap of neutralizing the acid. I filtered this sludge , dried it and Fired it in Flux , Pow I ended up with Nothing. I am concerned Because I have another 5 kilos of anode bag sludge to process. Am I lost in the wilderness?

I no longer use SMB as a precipitant because the sulfur dioxide that it contains dissipates form it , when the ambient temperature around the SMB powder Here in the Deset where I live. I believe that it is the excess free Sodium in the HCl-Cl leach keeps the gold in solution and not Precipitating with weak SMB

 

[Yggdrasil]

I no longer use SMB as a precipitant because the sulfur dioxide that it contains dissipates form it , when the ambient temperature around the SMB powder Here in the Deset where I live. I believe that it is the excess free Sodium in the HCl-Cl leach keeps the gold in solution and not Precipitating with weak SMB

Well that is your perogative.
If it is a wise one is a different question.
Most drop SMB due to the smell.
The one thing important with SMB is acidity.
And getting it below the surface.

 

[Barstool miner]

Well that is your prerogative.
If it is a wise one is a different question.
Most drop SMB due to the smell.
The one thing important with SMB is acidity.
And getting it below the surface.

Yes you are Right with SMB , That is when there is a strongly Sulfur Dioxide Smell. But When SMB no longer smells of SO2 then it does not work as it should.
For interest's sake Look up how SMB is manufactured.

 

[eaglekeeper]

Yes you are Right with SMB , That is when there is a strongly Sulfur Dioxide Smell. But When SMB no longer smells of SO2 then it does not work as it should.
For interest's sake Look up how SMB is manufactured.

You can use ferrous sulfate (copperas) instead of SMB. You can get at your local Ace hardware. Once you dissolve the ferrous sulfate it will need to be filtered before use.

 

[Barstool miner]

You can use ferrous sulfate (copperas) instead of SMB. You can get at your local Ace hardware. Once you dissolve the ferrous sulfate it will need to be filtered before use.

View attachment 60855

Thank you for your information. I used to make Copperas for myself dissolving Steel wool in Battery acid. But the Chinese pot scourers have excessive
none soluble ingredients, so that one got shot down in flames. I wish you all a Happy Prosperous New Year.

 

[Golddigger76]

Thank you for your information. I used to make Copperas for myself dissolving Steel wool in Battery acid. But the Chinese pot scourers have excessive
none soluble ingredients, so that one got shot down in flames. I wish you all a Happy Prosperous New Year.

I have used plain steel wool that you buy at the hardware store for polishing chrome or for woodworking with dilute sulfuric acid to make copperas and it works great.

I don't think making iron sulfate would work so well if you use the scouring pads with detergents made for scrubbing cooking pans because it will add junk that will pollute your gold bearing solution...

 

[Yggdrasil]

I have used plain steel wool that you buy at the hardware store for polishing chrome or for woodworking with dilute sulfuric acid to make copperas and it works great.

I don't think making iron sulfate would work so well if you use the scouring pads with detergents made for scrubbing cooking pans because it will add junk that will pollute your gold bearing solution...

And it is probably not Iron but Stainless Steel.

 

[Golddigger76]

And it is probably not Iron but Stainless Steel.

You are probably right about the stainless steel.
It's just the wrong kind of steel wool period.
You can make it out to steel nails, nolts, even rebar but it needs to be just plain steel or iron but not stainless steel, if it is covered with rust that is what you want to use.

 

[eaglekeeper]

I think Butcher mentioned awhile back about making copperas from the iron laminates out of small transformers....I've never had the need to try it though.

 

[Yggdrasil]

I think Butcher mentioned awhile back about making copperas from the iron laminates out of small transformers....I've never had the need to try it though.

I have done that and it is easy.

Edit to add:
It is important that it is properly roasted to burn off fat and oil.
And proper filtration after.