# Excess smb in AR



## 7CHEESE8 (Mar 30, 2021)

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?


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## Lino1406 (Mar 30, 2021)

Try water addition + heat (if this is SMB)


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## 7CHEESE8 (Mar 31, 2021)

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.


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## dpgold (May 20, 2022)

7CHEESE8 said:


> 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


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## dpgold (May 20, 2022)

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.


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## Geo (May 20, 2022)

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.


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## 4metals (May 20, 2022)

_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. _


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## dpgold (May 20, 2022)

Geo said:


> 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.


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## Geo (May 20, 2022)

dpgold said:


> 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.


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## Geo (May 20, 2022)

dpgold said:


> 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.
> ...


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


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## Geo (May 20, 2022)

dpgold said:


> 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.
> ...


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.


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## dpgold (May 20, 2022)

Geo said:


> 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


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## dpgold (May 20, 2022)

Geo said:


> 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.


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## Geo (May 20, 2022)

dpgold said:


> 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.


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## Geo (May 20, 2022)

dpgold said:


> 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.


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## Geo (May 20, 2022)

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


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## Geo (May 20, 2022)

dpgold said:


> 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.


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## dpgold (May 20, 2022)

Geo said:


> 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.


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## Geo (May 20, 2022)

dpgold said:


> 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?


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## dpgold (May 20, 2022)

Geo said:


> 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


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## Geo (May 20, 2022)

Yes. I know these cables. It takes a huge amount in weight to make an appreciable amount. The gold you see in that filter can get lost in 1000ml's of solution. How much solution are you talking about? To give you a little perspective, if all the gold there was connected in a single sheet at that thickness, you would have no problem reading a printed page reading through it. It's not like foils you would find on finger cards. Fingers on slot cards may have gold up to 30 µin where the ribbon fingers may be as thin as 5 µin. There may be a tenth of a gram. 

But, we will assume I am totally wrong and proceed from there. 

It is possible that all of the gold that was there did precipitate. Leave it undisturbed over night and see what collects on the bottom of the container.


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## M Usmani (May 21, 2022)

Respected Members May I ask one question here that is it confirmed that the testing of AR solution with Stannous chloride shows 100% sure result of gold, Palladium, Platinum (in black, purple black etc) ?? or some other metals may also show the same colour with stannous chloride testing ??
Thanks and regards


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## Geo (May 21, 2022)

M Usmani said:


> Respected Members May I ask one question here that is it confirmed that the testing of AR solution with Stannous chloride shows 100% sure result of gold, Palladium, Platinum (in black, purple black etc) ?? or some other metals may also show the same colour with stannous chloride testing ??
> Thanks and regards


In my understanding, under normal testing conditions, stannous chloride is selective for precious metals, That is not to say that stannous chloride can not be forced to react to other metal. In the case of a false positive, the SO2 in solution can force a reaction to other metals such as copper. There are some more examples of stannous chloride causing a reaction or effect with other metal, so the chemistry is not fool proof. The benefits of using stannous chloride, even with these adverse effects, far outweighs any bad effects it may cause.


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## dpgold (May 21, 2022)

Geo said:


> Yes. I know these cables. It takes a huge amount in weight to make an appreciable amount. The gold you see in that filter can get lost in 1000ml's of solution. How much solution are you talking about? To give you a little perspective, if all the gold there was connected in a single sheet at that thickness, you would have no problem reading a printed page reading through it. It's not like foils you would find on finger cards. Fingers on slot cards may have gold up to 30 µin where the ribbon fingers may be as thin as 5 µin. There may be a tenth of a gram.
> 
> But, we will assume I am totally wrong and proceed from there.
> 
> It is possible that all of the gold that was there did precipitate. Leave it undisturbed over night and see what collects on the bottom of the container.


yes you are right, I did not loose much but is very little, I let you know how much there is. But in this case learning was more important to me.


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## dpgold (May 21, 2022)

Geo said:


> Yes. I know these cables. It takes a huge amount in weight to make an appreciable amount. The gold you see in that filter can get lost in 1000ml's of solution. How much solution are you talking about? To give you a little perspective, if all the gold there was connected in a single sheet at that thickness, you would have no problem reading a printed page reading through it. It's not like foils you would find on finger cards. Fingers on slot cards may have gold up to 30 µin where the ribbon fingers may be as thin as 5 µin. There may be a tenth of a gram.
> 
> But, we will assume I am totally wrong and proceed from there.
> 
> It is possible that all of the gold that was there did precipitate. Leave it undisturbed over night and see what collects on the bottom of the container.


That is the gold which settled at the bottom, it seems like I did not loose very much, although I could not decant all the way down and there was some very little gold which went to the stockpot by decanting, now I have wash it again and thinking to use a small paper filter to filter and wash the beaker in. I could weigh the filter first and then weigh again with the gold after I have dried it. I am not sure how well this is visible


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## M Usmani (May 21, 2022)

Geo said:


> In my understanding, under normal testing conditions, stannous chloride is selective for precious metals, That is not to say that stannous chloride can not be forced to react to other metal. In the case of a false positive, the SO2 in solution can force a reaction to other metals such as copper. There are some more examples of stannous chloride causing a reaction or effect with other metal, so the chemistry is not fool proof. The benefits of using stannous chloride, even with these adverse effects, far outweighs any bad effects it may cause.


Thanks for clarification


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## Geo (May 21, 2022)

M Usmani said:


> Respected Members May I ask one question here that is it confirmed that the testing of AR solution with Stannous chloride shows 100% sure result of gold, Palladium, Platinum (in black, purple black etc) ?? or some other metals may also show the same colour with stannous chloride testing ??
> Thanks and regards


I apologize about the short answer, it was late and I was sleepy. The color of the stannous chloride test on the common metals a refiner might find varies. Gold, of course, is purple to black. Palladium starts out yellow to slightly orange, I call it rainbow because you can see two or three different colors, but over a period of minutes, the test will change in color to green. Light green is minor content while olive green is much more palladium metal in solution. Platinum will turn orange and stay orange to orange/red. Rhodium will turn red and stay red. If there is enough rhodium in solution, the stannous test will look like a drop of blood.


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## Geo (May 21, 2022)

dpgold said:


> That is the gold which settled at the bottom, it seems like I did not loose very much, although I could not decant all the way down and there was some very little gold which went to the stockpot by decanting, now I have wash it again and thinking to use a small paper filter to filter and wash the beaker in. I could weigh the filter first and then weigh again with the gold after I have dried it. I am not sure how well this is visible


The gold is heavy compared to water. 19 times heavier in fact. Decant as much water off as you can. Then rinse the gold powder into a smaller glass container. As small as possible. Let all the powder settle completely and decant again. If you can, transfer to a smaller container. Every time you move to a smaller container, it allows you to decant more water without the gold moving. What you are trying to do is get the gold powder dry without transferring the powder to a filter paper. Filter papers will trap the gold powder. Depending on what you are planning to melt the gold powder with, if you do put the gold powder in a filter, you need to melt the gold still in the filter. Place the filter and all in a melting dish. The filter paper will make the borax black momentarily until the torch burns the carbon away. I try not to add anything to my melt dish except for the metal I am melting.


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## M Usmani (May 21, 2022)

Geo said:


> I apologize about the short answer, it was late and I was sleepy. The color of the stannous chloride test on the common metals a refiner might find varies. Gold, of course, is purple to black. Palladium starts out yellow to slightly orange, I call it rainbow because you can see two or three different colors, but over a period of minutes, the test will change in color to green. Light green is minor content while olive green is much more palladium metal in solution. Platinum will turn orange and stay orange to orange/red. Rhodium will turn red and stay red. If there is enough rhodium in solution, the stannous test will look like a drop of blood.


I am really very thankful to you and highly obliged of detailed description and appreciate your efforts on the forum


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## dpgold (May 21, 2022)

Geo said:


> The gold is heavy compared to water. 19 times heavier in fact. Decant as much water off as you can. Then rinse the gold powder into a smaller glass container. As small as possible. Let all the powder settle completely and decant again. If you can, transfer to a smaller container. Every time you move to a smaller container, it allows you to decant more water without the gold moving. What you are trying to do is get the gold powder dry without transferring the powder to a filter paper. Filter papers will trap the gold powder. Depending on what you are planning to melt the gold powder with, if you do put the gold powder in a filter, you need to melt the gold still in the filter. Place the filter and all in a melting dish. The filter paper will make the borax black momentarily until the torch burns the carbon away. I try not to add anything to my melt dish except for the metal I am melting.


I have weighed the two pieces of filter I have used and partially dried so far it looks like there are 5 grams from a bit over 2kg of ribbons but when it dries completely it could be less. I don't know what is about this gold but is extremely fine that there is clinging to the beaker walls when I decant even if I spray with the water there is some left and a tiny bit floats even when sprayed with water. I will not melt, I will save them. There might still be some left in the solutions I decanted and filtered and on the walls of a bucket. However the biggest gain is the learning. When you melt it how do you direct the fire. I am trying to use a propane burner torch and a cylindrical small graphite crucible when I decide to melt. Still so much to learn
Also I had a big problem with another type of coffee filter because very fine gold got through.


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## Shark (May 21, 2022)

Charmin plug for a filter will work to catch the fine stuff. Dropping from a dilute solution will often cause the precipitates to be very fine and slow settling. Combine with a dirty solution e.g. copper, can cause it as well. When I used coffee filters I had problems with contaminants in my melted gold. When I went to lab grade filters (thanks snowman) the quality of my gold buttons went up drastically. Geo taught me the charmin plug method which made a large improvement as well.


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## Geo (May 21, 2022)

dpgold said:


> I have weighed the two pieces of filter I have used and partially dried so far it looks like there are 5 grams from a bit over 2kg of ribbons but when it dries completely it could be less. I don't know what is about this gold but is extremely fine that there is clinging to the beaker walls when I decant even if I spray with the water there is some left and a tiny bit floats even when sprayed with water. I will not melt, I will save them. There might still be some left in the solutions I decanted and filtered and on the walls of a bucket. However the biggest gain is the learning. When you melt it how do you direct the fire. I am trying to use a propane burner torch and a cylindrical small graphite crucible when I decide to melt. Still so much to learn
> Also I had a big problem with another type of coffee filter because very fine gold got through.


It is a possibility that all of the precipitated solids is not gold but insoluble salts. There is several different types of gold plating. The plating that deposits the least amount of gold is used on the types of low grade connectors. Look up "honeydipped gold plating" and read up on it. It is an immersion type plating. The thickness is dependent on time immersed in the solution. Usually long enough for the plated part to look gold colored. No doubt these part were plated in real gold but there are plating solution that looks like gold but contains no gold. Usually copper based. Even though the gold was real, there's just not a lot of it.


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## Geo (May 21, 2022)

Shark said:


> Charmin plug for a filter will work to catch the fine stuff. Dropping from a dilute solution will often cause the precipitates to be very fine and slow settling. Combine with a dirty solution e.g. copper, can cause it as well. When I used coffee filters I had problems with contaminants in my melted gold. When I went to lab grade filters (thanks snowman) the quality of my gold buttons went up drastically. Geo taught me the charmin plug method which made a large improvement as well.


I would not use a graphite cylinder using a torch. Too much surface area to heat unless it is sitting in a furnace. When torch melting, use a fused silica melting dish. There are tutorials all over the forum on how to prep a dish and use it correctly. Prep the dish and glaze it with borax. Make sure the melt dish is hot and add the material. Depending on the torch you have (oxy/fuel is best) play the torch gently across the top edge of the melt dish allowing the flame to indirectly heat the top of the heap. Once the top is a red heat, you can move the flame over the heap a little more and a little more from the outside inward until you reach the middle. Then direct the heat on the middle until it starts to melt and then go in reverse back to the outside edge of the dish. Like anything else, it takes practice. Clean pure gold is much harder to blow out of a melting dish than most people thinks. Gold is very heavy when compared to most everything else.

Sorry Shark. I meant to reply to @dpgold


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## dpgold (May 21, 2022)

Geo said:


> I would not use a graphite cylinder using a torch. Too much surface area to heat unless it is sitting in a furnace. When torch melting, use a fused silica melting dish. There are tutorials all over the forum on how to prep a dish and use it correctly. Prep the dish and glaze it with borax. Make sure the melt dish is hot and add the material. Depending on the torch you have (oxy/fuel is best) play the torch gently across the top edge of the melt dish allowing the flame to indirectly heat the top of the heap. Once the top is a red heat, you can move the flame over the heap a little more and a little more from the outside inward until you reach the middle. Then direct the heat on the middle until it starts to melt and then go in reverse back to the outside edge of the dish. Like anything else, it takes practice. Clean pure gold is much harder to blow out of a melting dish than most people thinks. Gold is very heavy when compared to most everything else.
> 
> Sorry Shark. I meant to reply to @dpgold


Thanks, very good explanation.


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## Shark (May 21, 2022)

Also clean gold will melt faster than dirty gold. Clean gold will also make your melting dish last longer. Getting a very clean, pure button of gold is a real rush as well. It makes all the study and work worth while.


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## goldshark (May 22, 2022)

When you say Charmin plug, is that as in Chamin toilet paper? Wad or fold?


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## goldshark (May 22, 2022)

goldshark said:


> When you say Charmin plug, is that as in Chamin toilet paper? Wad or fold?


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## Yggdrasil (May 22, 2022)

Search Charmin plug on google or here


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## Shark (May 22, 2022)

It can be any of those. It is more in how you plug the opening in the funnel. I have used cotton balls as well but my preferred material for AR was shredded fiberglass. The stuff used as home insulation. I would pack a small wad in the funnel opening and make it tight enough to trap more of the particles than a coffee filter could catch. There is quite a lot of posts about them on the forum. Many people have their own way of using them and it can be a very useful tool for those just getting started.


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## dpgold (May 22, 2022)

Shark said:


> Also clean gold will melt faster than dirty gold. Clean gold will also make your melting dish last longer. Getting a very clean, pure button of gold is a real rush as well. It makes all the study and work worth while.


yes, I enjoy all the experiments and learning as well, so much stuff to learn and remember!


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## goldshark (May 23, 2022)

Is there an optimal plug for maximum filtration rate, and fine mesh size? What is it?


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## goldshark (May 23, 2022)

Googled as per suggestion. Still not too specific as to what most solid sizes are, as far as mesh sizes. I would like to pre filter most solids before running it through the constricted Charmin filter so it doesn't clog as readily. Anybody know what size prefilter works best so my lazy cheap ass doesn't need to go buy a bunch of different mesh filter sizes?


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## Yggdrasil (May 23, 2022)

Charmin filter are for difficult solutions not for general filtering.
The fineness is decided by how hard you stuff your plug into the funnel.
And if it is fibre glass cotton, paper or what ever you choose to use.


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## Shark (May 23, 2022)

I use a #2 Whatman or an equivalent lab filter for most everything these days. It is rare that I need anything else. I do use a vacuum flask and Büchner funnel with them. Still on occasion I need something more and depending on what the problem is determines what I make the Charmin plug from and how tight I pack it. I like the fiberglass insulation as it can pack very light for fast coarse material or packed tight and will stop most anything from passing through. It takes some practice and experience to get a good feel for using them but can work really well, especially on smaller jobs. Cotton balls work well and can be packed tight enough to practically stop the flow all together. They can be a bit more finicky to pack loosely in my experience. The heavy paper type shop towels do a good job but are more problematic getting them just right as well.

I feel filtering is the biggest problem for most people trying to get a very clean and shiny gold button. I know it was my biggest problem and the hardest for me to overcome. I started testing various “filters” by running muddy, gritty water through different stuff and settled on my #1 choice of fiberglass and my #2 choice of cotton balls.

Don’t hold me to this but I think the #2 Whatman filter is a 5 micron filter. Been so long since I checked I can’t remember for sure.


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## dpgold (May 23, 2022)

I am making a correction, after weighing again the material after it has been dried completely the yield of processing over 2kg of some weird mylar cables is less than 1 gram 0.57g . It is also in the form of a very fine gold. With all the work involved and everything it is only the learning experience that is left of this. I wanted to start with this material because it was only one type of material.


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## Geo (May 23, 2022)

Find a used coffee maker at the thrift store. The kind the basket is detachable. Remove the basket. The basket should sit squarely and securely on top of a 1L beaker. Use the coffee filters made for the coffee maker. It is slow but it's premade and ready to use as soon as you get it. After the solution passes through the coffee filter once, you can pass it through a funnel plug. I use cotton balls as they incinerate with very little ash. The first pass, pack the cotton balls in so that water passes through in a thin stream. This will catch the next biggest solids after coffee filters. The next pass through the funnel plug will be with the cotton balls packed tightly enough that just water will only drip through. This will give you a crystal clear solution. It is time consuming. If it is your material and there are no time constraints, it is cheap and easy. Vacuum filtration with lab grade slow filters are relatively faster when you need it done as quickly as possible.


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## Shark (May 23, 2022)

Several years ago I found a plastic cup holder for use on the beach. I would cut the tip off making them into a funnel with an “x” in the middle. These were great as you could use a plug on them and vacuum them on a flask as well. I will see if I can find one or maybe a picture of one. I have not seen them for sale in several years but I haven’t looked for them either.


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## dpgold (May 23, 2022)

Shark said:


> Several years ago I found a plastic cup holder for use on the beach. I would cut the tip off making them into a funnel with an “x” in the middle. These were great as you could use a plug on them and vacuum them on a flask as well. I will see if I can find one or maybe a picture of one. I have not seen them for sale in several years but I haven’t looked for them either.


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## Shark (May 23, 2022)

Close. Think of a funnel with the drain hole closed. Best I recall these were made somewhere in Florida, or the logo was from Florida. It maybe that I am thinking that because that is where I bought them. I bought a dozen for $5.


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## goldshark (May 24, 2022)

Thanks all for the responses.


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