Excess smb in AR

[7CHEESE8]

Hello everyone!

I'm a rookie. My first time putting gold into solution, I used too much nitric acid. I tried to denoxing the nitric with smb. I learned that is the wrong way to go. My problem is I have a lot of undisolved smb in the beaker.i learned the smb reacts with the hcl . How do I get rid of the excess smb?

 

[Lino1406]

Try water addition + heat (if this is SMB)

 

[7CHEESE8]

Hey Lino. Thanks for the reply. I kept adding smb to the solution to denox nitric. Everyone I added, the solution would foam up. So I figured the nitric was getting spent. Problem is, after a few teaspoons I noticed it was pulling up on the bottom. The pile of smb gets to the 400ml mark. This is in a 1000ml breaker. Solution is now at 650. I'll transfer to a larger beaker and add water to dissolve and I assume heat to help it dissolve, but also to evaporate. Maybe it will all dissolve and I can retrieve the gold without having to evaporate. Just thinking out loud. Thanks for the advice.

 

[dpgold]

Hey Lino. Thanks for the reply. I kept adding smb to the solution to denox nitric. Everyone I added, the solution would foam up. So I figured the nitric was getting spent. Problem is, after a few teaspoons I noticed it was pulling up on the bottom. The pile of smb gets to the 400ml mark. This is in a 1000ml breaker. Solution is now at 650. I'll transfer to a larger beaker and add water to dissolve and I assume heat to help it dissolve, but also to evaporate. Maybe it will all dissolve and I can retrieve the gold without having to evaporate. Just thinking out loud. Thanks for the advice.

as far as I know as a beginner smb is used for precipitation, for denoxing is used urea or other chemicals

 

[dpgold]

I have a question, I just denoxed AR by adding a bit urea at a time until there was no more reaction. Then I started adding a bit of SMB at a time and stir, I was not sure if I had to keep adding until there was no more reaction or until I see sign of precipitation. ?

2. My solution was greenish indicating I think there was some copper in it. It is my first time experimenting with this.

 

[Geo]

SMB is added at a 1 to 1 ratio as expected gold by weight. If you expect 100 grams of gold, add 100 grams of SMB. SMB will foam when added to HCl regardless of anything else. The SMB is destroyed when added to the acidic solution. It decomposes into SO2 gas and sulfuric acid in solution. The SO2 is the gas that reduces the gold to metal. A very small amount of free nitric acid can be removed from solution but it is a very poor choice of chemical for the job. The action by which SMB will remove free nitric acid is the SO2 precipitates a little gold and the free nitric acid dissolves this small amount of gold back into solution and releasing NO2. It is not a very efficient method to use for the purpose.

First, you did not mention a stannous chloride test. How do you know gold was in solution? If your not testing, how would you know you precipitated all the gold that might have been there?

Heating the solution beyond the decomposition temperature will destroy the remaining SMB in solution driving out the excess SO2 gas. The HCl and decomposing SMB will make sodium chloride crystals form ( table salt, but don't eat it. ) Luckily, it is water soluble. By now, if you still have it, there should be a large amount of salt crystals in solution. Filter the crystals from solution and lightly rinse with a spray bottle. The salt will dissolve back into solution so use the water sparingly. Place the container with the crystals aside and test the solution with stannous chloride. A positive means you got lucky. A negative means you have to dissolve all the salt in warm water to find any of the lost gold. Add water, tap water will work. Warm and let all the salt dissolve that will dissolve. If there is still salt left behind, decant the solution into another beaker and test it with stannous chloride. It should be negative. Add fresh water and dissolve the rest of the salt. If there are solids that will not dissolve in water, add a little fresh HCl and nitric acid BY THE DROP AFTER THE SOLUTION IS WARMED. It should be too hot to touch comfortably with a bare finger. If there is metallic gold that drop from the original solution, it should react almost instantly. Add a drop and let the reaction happen until it stops and then add another. When you add a drop with no reaction, remove from heat and let it cool completely. Test the solution with stannous chloride. A positive means you have found the lost gold and it is safely in solution. Add ice to both chill the solution and dilute the solution. Wait for the ice to melt mostly and try the drop again. Only add SMB by the gram and stir until no more gold drops. Trying to test with stannous chloride right after adding SMB will give you a false positive so keep that in mind.

 

[4metals]

Gaseous Sulfur Dioxide is often used to denox solutions because it precipitates the gold as metallic gold which reacts with the free nitric to keep the aqua regia dissolving the gold. In reality the Sulfur Dioxide is dropping the gold and the metallic gold is reacting more nitric as it dissolves. Not unlike Harold’s trick of using pure gold to eliminate excess nitric.

But the gaseous Sulfur Dioxide does not accumulate in the solution so it is quite different than adding SMB. But it is probably why it is thought that SMB will burn off the excess nitric. As Geo pointed out, a small amount of nitric can be removed this way, but there are better options.

 

[dpgold]

SMB is added at a 1 to 1 ratio as expected gold by weight. If you expect 100 grams of gold, add 100 grams of SMB. SMB will foam when added to HCl regardless of anything else. The SMB is destroyed when added to the acidic solution. It decomposes into SO2 gas and sulfuric acid in solution. The SO2 is the gas that reduces the gold to metal. A very small amount of free nitric acid can be removed from solution but it is a very poor choice of chemical for the job. The action by which SMB will remove free nitric acid is the SO2 precipitates a little gold and the free nitric acid dissolves this small amount of gold back into solution and releasing NO2. It is not a very efficient method to use for the purpose.

First, you did not mention a stannous chloride test. How do you know gold was in solution? If your not testing, how would you know you precipitated all the gold that might have been there?

Heating the solution beyond the decomposition temperature will destroy the remaining SMB in solution driving out the excess SO2 gas. The HCl and decomposing SMB will make sodium chloride crystals form ( table salt, but don't eat it. ) Luckily, it is water soluble. By now, if you still have it, there should be a large amount of salt crystals in solution. Filter the crystals from solution and lightly rinse with a spray bottle. The salt will dissolve back into solution so use the water sparingly. Place the container with the crystals aside and test the solution with stannous chloride. A positive means you got lucky. A negative means you have to dissolve all the salt in warm water to find any of the lost gold. Add water, tap water will work. Warm and let all the salt dissolve that will dissolve. If there is still salt left behind, decant the solution into another beaker and test it with stannous chloride. It should be negative. Add fresh water and dissolve the rest of the salt. If there are solids that will not dissolve in water, add a little fresh HCl and nitric acid BY THE DROP AFTER THE SOLUTION IS WARMED. It should be too hot to touch comfortably with a bare finger. If there is metallic gold that drop from the original solution, it should react almost instantly. Add a drop and let the reaction happen until it stops and then add another. When you add a drop with no reaction, remove from heat and let it cool completely. Test the solution with stannous chloride. A positive means you have found the lost gold and it is safely in solution. Add ice to both chill the solution and dilute the solution. Wait for the ice to melt mostly and try the drop again. Only add SMB by the gram and stir until no more gold drops. Trying to test with stannous chloride right after adding SMB will give you a false positive so keep that in mind.

I decanted the solution and there was some gold at the bottom of the beaker, I will weigh it after another wash and decant. I used the spray bottle to get everything of the walls which for some reason was a extremely fine gold dark brown in colour.
As for the processing that is what I did:

(I did the stannous test with a drop of solution which looked yellowish in the drop form and I got some dark colours happening, not too much.
1. I added urea little by little until the granules did not dissolved and there was no reaction.
2. I added SMB little by little and stirred and after a while I could see the precipitation starting. I was worried because the solution was greenish.
3 I let it settle for about 6 hours and it looked settle, I decanted partially into another beaker until I could see I was getting close to the particles, I washed the walls and everything and let it settle again.

 

[Geo]

I have a question, I just denoxed AR by adding a bit urea at a time until there was no more reaction. Then I started adding a bit of SMB at a time and stir, I was not sure if I had to keep adding until there was no more reaction or until I see sign of precipitation. ?

2. My solution was greenish indicating I think there was some copper in it. It is my first time experimenting with this.

Test with stannous chloride. How do you know you have gold in solution. It's like refining in the dark and stannous chloride is a flashlight that shows you where the gold is hiding. Stop experimenting until you have made some stannous chloride or acquired it elsehow. Test when you add something, test when you remove something. Test when you move solution from one beaker to another or through a filter. I've had gold solution go through a filter and come out barren on the other side. It helps to catch something like that right away instead of assuming that something is a particular way for a half a dozen steps just to have to back track and find the lost gold. It's only a tiny drop each time. Test often.

 

[Geo]

I decanted the solution and there was some gold at the bottom of the beaker, I will weigh it after another wash and decant. I used the spray bottle to get everything of the walls which for some reason was a extremely fine gold dark brown in colour.
As for the processing that is what I did:

(I did the stannous test with a drop of solution which looked yellowish in the drop form and I got some dark colours happening, not too much.
1. I added urea little by little until the granules did not dissolved and there was no reaction.
2. I added SMB little by little and stirred and after a while I could see the precipitation starting. I was worried because the solution was greenish.
3 I let it settle for about 6 hours and it looked settle, I decanted partially into another beaker until I could see I was getting close to the particles, I washed the walls and everything and let it settle again.

I had that typed and waiting. I posted it before I seen your reply.

 

[Geo]

I decanted the solution and there was some gold at the bottom of the beaker, I will weigh it after another wash and decant. I used the spray bottle to get everything of the walls which for some reason was a extremely fine gold dark brown in colour.
As for the processing that is what I did:

(I did the stannous test with a drop of solution which looked yellowish in the drop form and I got some dark colours happening, not too much.
1. I added urea little by little until the granules did not dissolved and there was no reaction.
2. I added SMB little by little and stirred and after a while I could see the precipitation starting. I was worried because the solution was greenish.
3 I let it settle for about 6 hours and it looked settle, I decanted partially into another beaker until I could see I was getting close to the particles, I washed the walls and everything and let it settle again.

There are several metals that looks green in a chloride solution. Copper and nickel would be what I suspect. This is what I would call a recovery and not so much as a refine, even though it is technically a refining process. If your solution is green but clear enough that you can see through it, you can drop the gold normally with SMB and the copper contamination wouldn't be that much more than if the solution was just slightly green. Just keep in mind that saturating the solution with SO2 is going to precipitate some copper no matter how much is in solution. Be frugal with the SMB and and the gold should drop nice and clean for your purposes. I always double refine regardless of how the recovered gold looked. Refining is purifying the recovered gold to the most pure state you can achieve.

 

[dpgold]

I had that typed and waiting. I posted it before I seen your reply.

Yes, this was the first thing I wanted to do before trying anything, I had to make or buy stannous solution, find urea, find SMB, it is hard to get all this over here but just yesterday I got my final ingredient urea. I have a small amount of stannous solution and I keep looking to see if it has still undissolved tin in it. By the way if I add SMB bit by bit and slowly stir and wait and add a bit again until i do not see a reaction anymore is it bad?

2. I also keep all the solutions for further testing and stockpot

 

[dpgold]

There are several metals that looks green in a chloride solution. Copper and nickel would be what I suspect. This is what I would call a recovery and not so much as a refine, even though it is technically a refining process. If your solution is green but clear enough that you can see through it, you can drop the gold normally with SMB and the copper contamination wouldn't be that much more than if the solution was just slightly green. Just keep in mind that saturating the solution with SO2 is going to precipitate some copper no matter how much is in solution. Be frugal with the SMB and and the gold should drop nice and clean for your purposes. I always double refine regardless of how the recovered gold looked. Refining is purifying the recovered gold to the most pure state you can achieve.

I hope it is mostly gold, it is so super fine it clings to everything and it leaves a very fine ring around the top of the liquid is hard to wash off with the bottle. I wiped it away with the tip of my glove and rinsed it off into the beaker. I will eventually do a refine when I gather more material I assume is mostly gold? What do you think. The solution was looking very clear green yellowish after filtration and with the pipete a drop would be more yellowish but the stannous test did not turn everything black, I will do further tests.
My thinking now is that I should have used AR because the ribbons were so many and small and hard to wash after AP, there are so many ways to skin a cat.

 

[Geo]

Yes, this was the first thing I wanted to do before trying anything, I had to make or buy stannous solution, find urea, find SMB, it is hard to get all this over here but just yesterday I got my final ingredient urea. I have a small amount of stannous solution and I keep looking to see if it has still undissolved tin in it. By the way if I add SMB bit by bit and slowly stir and wait and add a bit again until i do not see a reaction anymore is it bad?

2. I also keep all the solutions for further testing and stockpot

No, not seeing a reaction, other than the gold dropping, is to be expected. See if you can find a chemical with the formula (H3NSO3) Sulfamic Acid. It is sold commercially here as a grout cleaner for tile grout. I can't think of any explosive precursor that can be formed with it so it should be legal. If you look for "sulfamic acid", there are formulas that are not the same if you order online. Be sure it is H3NSO3.
Sulfamic acid will destroy nitric acid in solution. It converts NO2 to N2O on a 1 to 1 ratio by weight. It converts nitrogen dioxide to nitrous oxide. NO2 is noxious and corrosive. N2O has a sweet smell and is used as anesthesia. That's not to say that the gasses you produce is safe to consume, but just the opposite. We do not create pure gasses. Usually it is a mixture of gasses and they all are deadly. Urea on the other hand is a precursor to high explosives in and of itself.

 

[Geo]

I hope it is mostly gold, it is so super fine it clings to everything and it leaves a very fine ring around the top of the liquid is hard to wash off with the bottle. I wiped it away with the tip of my glove and rinsed it off into the beaker. I will eventually do a refine when I gather more material I assume is mostly gold? What do you think. The solution was looking very clear green yellowish after filtration and with the pipete a drop would be more yellowish but the stannous test did not turn everything black, I will do further tests.
My thinking now is that I should have used AR because the ribbons were so many and small and hard to wash after AP, there are so many ways to skin a cat.

When you are finished, add a small splash (metaphorically speaking) of HCl and a few drops of chlorine bleach and swish it around in the jar. It will dissolve little little dusting stuck to the glass.

 

[Geo]

When you dissolved the gold, did all the metals dissolve? Totally, any left over solids?

 

[Geo]

Yes, this was the first thing I wanted to do before trying anything, I had to make or buy stannous solution, find urea, find SMB, it is hard to get all this over here but just yesterday I got my final ingredient urea. I have a small amount of stannous solution and I keep looking to see if it has still undissolved tin in it. By the way if I add SMB bit by bit and slowly stir and wait and add a bit again until i do not see a reaction anymore is it bad?

2. I also keep all the solutions for further testing and stockpot

Always keep solutions that contained gold. When I refine gold, I keep the solutions on hand until the end. Then I put all the spent solutions in one large beaker, adjust pH up to around 2 and add copper metal buss and heat. There is always a reaction near the boiling point of the solution. After the reaction the solution is normally too dark to see through. I leave everything undisturbed until it is cool. I gently pull the copper and rinse it in a clean beaker. I let the solution settle over night and decant it in to a plastic five gallon bucket. I have scrap rebar that I add to the buckets to cement the copper from solution.

 

[dpgold]

When you dissolved the gold, did all the metals dissolve? Totally, any left over solids?

I did not see anything like solid metals it only look like a bit of paper mush left.:
After I filtered the AP solution (did also stannous test negative) and filtered twice because I had washed a second time the ribbons and I have put the two filters in HCL (both filters had golden fine dust in them. Then I have added bit by bit Nitric and the second day I had filtered the mush and washed it into the beaker through the filter. Did a stannous test twice and the solution had changed but not too impressive. Then I denoxed and put smb cautiously and waited and after a while it started to look like it was precipitating getting darker.

 

[Geo]

I did not see anything like solid metals it only look like a bit of paper mush left.:
After I filtered the AP solution (did also stannous test negative) and filtered twice because I had washed a second time the ribbons and I have put the two filters in HCL (both filters had golden fine dust in them. Then I have added bit by bit Nitric and the second day I had filtered the mush and washed it into the beaker through the filter. Did a stannous test twice and the solution had changed but not too impressive. Then I denoxed and put smb cautiously and waited and after a while it started to look like it was precipitating getting darker.

When you say ribbon cables, are you talking about ribbon cables with the little gold fingers? Mylar ribbon cables?

 

[dpgold]

When you say ribbon cables, are you talking about ribbon cables with the little gold fingers? Mylar ribbon cables?

yes , small like 12mm x 10