Processing Fingers with CuCl2 etching solution
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jason_recliner
Well-known member
Stainless steel is perfect. Make sure the foils are heated up to a dull red.purgatory said:
The standard process is to boil in HCl, then water. Repeat these two until it comes off perfectly clean.
Your question of washing in water first: I can't see water would wash much off before the HCl has done its thing, but it will not hurt.
MarcoP
Well-known member
MarcoP
Well-known member
Warning: the above picture represents the last incineration where all chlorides were already burned away.
When chlorides are present it must be done under a fume hood or, such as my case, outside while wearing protective gears.
Torch will be used when all water is boiled away, still outside.
When chlorides are present it must be done under a fume hood or, such as my case, outside while wearing protective gears.
Torch will be used when all water is boiled away, still outside.
Copper metal powder can oxidize more easily than a chunk of solid copper, a solid copper pipe may oxidize on its surface, with exposure to air, in an acidic or caustic and damp location the corrosion is hastened in the more corrosive environment. The solid copper oxidizes on its surface. Where the finer powders have much more surface area, and with the thin powders the corrosion will take more of the coppers percentage up as corrosion, leaving you with less of the copper metal un-corroded, or in a state of elemental copper.
With copper powders from your cementing process you can have salts of acids, these can increase the rate of oxidation of the copper when dried or exposed to air, oxygen and other gases in the air. It is hard to wash off all of these salts, storing this copper under water or even under some of the slightly acidic solution of the acid solution there were cemented from, can help to keep the copper metal powders bright and shining and keep them from exposure to air.
Copper exposed to air, will form several different types of oxidation of the copper metal. Cupric oxide, cuprous oxide, copper carbonate, copper hydroxide...
Some of this oxidation of copper is not dissolved that easily back into an acid, for that reason I store my copper powders under the solution they were cemented from, or use them to form other forms of copper salts, crystals, that I may have a use for, and even these are best stored in a state where air does not have a chance to oxidize them (some types of copper salts (crystals) will oxidize easier than others).
For example it is hard to take the green copper carbonate (copper powder exposed to air) and make it back into copper II chloride, the copper carbonate does not like to dissolve into the acid easily.
You can also roast the copper to black copper oxide, driving off the salts of the previous acid, and store them in an air tight container.
With copper powders from your cementing process you can have salts of acids, these can increase the rate of oxidation of the copper when dried or exposed to air, oxygen and other gases in the air. It is hard to wash off all of these salts, storing this copper under water or even under some of the slightly acidic solution of the acid solution there were cemented from, can help to keep the copper metal powders bright and shining and keep them from exposure to air.
Copper exposed to air, will form several different types of oxidation of the copper metal. Cupric oxide, cuprous oxide, copper carbonate, copper hydroxide...
Some of this oxidation of copper is not dissolved that easily back into an acid, for that reason I store my copper powders under the solution they were cemented from, or use them to form other forms of copper salts, crystals, that I may have a use for, and even these are best stored in a state where air does not have a chance to oxidize them (some types of copper salts (crystals) will oxidize easier than others).
For example it is hard to take the green copper carbonate (copper powder exposed to air) and make it back into copper II chloride, the copper carbonate does not like to dissolve into the acid easily.
You can also roast the copper to black copper oxide, driving off the salts of the previous acid, and store them in an air tight container.
You can use a program like irfanview (it's free!) to rotate the image, then save it. Then you can go to your post and click the edit button. Once you're in editing mode, you can delete the first image and upload the new one.purgatory said:
Anytime you edit a post, you should add a note at the bottom of your post explaining why you edited it and what you changed. Editing a post with the intention of changing the tone or intent of the post is against forum rules, but editing to fix errors is OK as long as you explain what you did.
Dave
Jason Recliner..... Thank you for you suggestion, I appreciate it.
Can I know please like how long the incineration process should be run for?
Dave, I have got it, thank you, actually using this Ipad is quite difficult for me, I will surely check the itunes store for the program you mentioned.
Alvi
Can I know please like how long the incineration process should be run for?
Dave, I have got it, thank you, actually using this Ipad is quite difficult for me, I will surely check the itunes store for the program you mentioned.
Alvi
Hi Everyone,
How are you all doing?
I did incinetation for about one and half hours in a stainless steel pan after recovering gold plating using nitric acid which is shown in the picture above.
1- After incinetation I boiled in hcl for about half an hour, did stannius chloride test for gold and there was no sign of gold in the solution.
2- After hcl bath I boiled the foils in de-ionized water for half an hour.
3- After decanting the water, I dissolved these foils in Aqua Regia made with Nitric Acid and Hydrochloric Acid.
4- performed stannous chloride test which I made today and you can see the result in a pictured attached.
5- Neutralized with Sulfamic Acid 99% pure, but there was no reaction upon it's addition. Then I moved further to..,,
6- Precipitae gold using Sodium Metabisulfite.
7- The beaker was getting chilled/cooled upon SMB's addition, is this normal?
There was a bubbling reaction, I was expecting 2 grams of gold, thats why I added 2 grams of SMB, there was a colour change in the solution but no precipitation occur, I thought I should be adding more SMB, I added 2 grams more but again there was no precipitation.
Can you please suggest me what to do now?
If the test shown the presence of gold in the solution then why it did not precipitate upon SMB's addition?
If there was no reaction/brown fumes upon addition of Sulfamic Acid, does it means the nitirc acid was completely utilized?
When I last added one gram of SMB, it reacted, it might still react if I put some more SMB, I do not understand what's going on.
Please help me in this regard.
Please note: I forgot to mention one bit (which is pint number 7) of reaction thats why edditing.
Alvi
How are you all doing?
I did incinetation for about one and half hours in a stainless steel pan after recovering gold plating using nitric acid which is shown in the picture above.
1- After incinetation I boiled in hcl for about half an hour, did stannius chloride test for gold and there was no sign of gold in the solution.
2- After hcl bath I boiled the foils in de-ionized water for half an hour.
3- After decanting the water, I dissolved these foils in Aqua Regia made with Nitric Acid and Hydrochloric Acid.
4- performed stannous chloride test which I made today and you can see the result in a pictured attached.
5- Neutralized with Sulfamic Acid 99% pure, but there was no reaction upon it's addition. Then I moved further to..,,
6- Precipitae gold using Sodium Metabisulfite.
7- The beaker was getting chilled/cooled upon SMB's addition, is this normal?
There was a bubbling reaction, I was expecting 2 grams of gold, thats why I added 2 grams of SMB, there was a colour change in the solution but no precipitation occur, I thought I should be adding more SMB, I added 2 grams more but again there was no precipitation.
Can you please suggest me what to do now?
If the test shown the presence of gold in the solution then why it did not precipitate upon SMB's addition?
If there was no reaction/brown fumes upon addition of Sulfamic Acid, does it means the nitirc acid was completely utilized?
When I last added one gram of SMB, it reacted, it might still react if I put some more SMB, I do not understand what's going on.
Please help me in this regard.
Please note: I forgot to mention one bit (which is pint number 7) of reaction thats why edditing.
Alvi
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jason_recliner
Well-known member
Your first photo here is not incineration. Or it that just your HCl boiling?
See MarcoP's photo of foils in a stainless steel pan on a hotplate with additional torching. The foils need to get red hot. A few minutes is enough.
What were the amounts and strengths of HCl and nitric acids that you used to make your aqua regia?
I'm thinking that if you're having trouble precipitating gold with SMB, you might still have free nitric. That will redissolve the gold before it gets a chance to fully drop.
See MarcoP's photo of foils in a stainless steel pan on a hotplate with additional torching. The foils need to get red hot. A few minutes is enough.
What were the amounts and strengths of HCl and nitric acids that you used to make your aqua regia?
I'm thinking that if you're having trouble precipitating gold with SMB, you might still have free nitric. That will redissolve the gold before it gets a chance to fully drop.
You have a large volume of gold chloride for only 2 grams of gold, how much HCl and HNO3 did you add?
Göran
Göran
Geo
Well-known member
purgatory, what you are describing is a classic mistake made by many. Stannous chloride test is positive but no gold will precipitate. Two grams of gold is a small amount in such a volume of solution. Evaporate the solution as you have it now without doing anything else to one third of what you have now. This will do a couple of things. As you have already added sulfamic acid, it will cause the reaction to drive off the excess nitric acid. I did not see where you heated the solution. The only time you will get a reaction with sulfamic acid is when the nitric acid content is very high. Even a couple of ml's of nitric acid will prevent the gold from precipitating. A heated solution will be more reactive. And too, gold is easier to drop from a more concentrated solution. Easier because it takes less reagents for a smaller amount of liquid and the drop is quicker.
Heat the solution when you are using sulfamic acid to rid a solution of free nitric acid. Be careful as a heated solution will give a more vigorous reaction.
Heat the solution when you are using sulfamic acid to rid a solution of free nitric acid. Be careful as a heated solution will give a more vigorous reaction.
A
Anonymous
Guest
Why would there still be free Nitric in a solution if enough Sulfamic has been added ? It's more likely that not enough has been used to take the free Nitric out of the equation.
I agree with warming the solution Geo however I'm not sure of the benefit of reducing the volume by 2/3.
edit: This is a reason why I always use crystalline sulfamic without dissolving it in water first and adding the liquid.
Jon
I agree with warming the solution Geo however I'm not sure of the benefit of reducing the volume by 2/3.
edit: This is a reason why I always use crystalline sulfamic without dissolving it in water first and adding the liquid.
Jon
Geo
Well-known member
It.s just good practice to precipitate from a concentrated solution. You could precipitate two grams from a gallon of solution and there's no requirement to precipitate from a concentrated solution, but it is easier for the person dealing with it. I'm not repeating this from others. When I first started dissolving gold and precipitating, I was precipitating from what now seems enormous amounts of solution. I have since come to understand better. Waiting days for a couple of grams of finely divided gold powder to settle from so much liquid is unnecessary.
Hi Everyone,
How are you all doing?
Well, I have been a bit impatient, as I was expecting the instant precipitaion but the solution was not concentrated enough to get the gold precipitated upon the addition of SMB, I found the gold powder at the bottom of the beaker when I saw it now after almost 12 hours,
Jason Recliner, it is not the photo of incineration, the comment section of that photo states hcl bath. There was no reaction upon addition of Sulfamic Acid, please tell me that is that not a sign of a completely neutralized nitirc acid?
Goran, I added 35 ml of hcl 30% and 4 ml of nitric acid 60%. Additional water was added upon rinsing the filter and the beaker, I have consumed a lot of water in rinsing them I presume. Or what else I did wrong to increase the solution?
Geo, thank you for your kind suggestions, I really appreciate your suggestions at it's elite level, you are right Geo, I did not heat the solution when I was adding Sulfamic Acid, thank you for clarifying it, I have learnt one more step that I should heat the solution while addition of Sulfamic Acid, but why there was no reaction when I added Sulfamic Acid? Was that a sign of a completely neutralized nitric?
Jon, It was my false assumption to assume that may be the nitric was not been neutralized upon Sulfamic Acid's addition, Imdid not add more as there was no reaction, I'm learning the details of te whole process, all of the senior members of this forum have been so kind to give their suggestions in order to get me on the right tract of this chemical process. I'm thankfull to all of them. I did not dissolve the Sulfamic Acid in water either. But my mistake was to use more than enough water to rinse the filter and the beaker when I was filtering gold chloride solution, that was why the solution exceeded the required amount of it.
I checked the remaining solution with stannous chloride after when I saw the gold was precipitated, I am going to take a picture and post it here to show you guys, the colour is sligtly yellow tinted but transparent and the gold powder (which I'm boiling in hcl after water rinse) is of dark infact very dark colour after precipitation. Let's see which colour it would come up in after this wash which Harold suggested us to wash the gold powder.
Thank you everyone for your very much informative suggestions, I appreciate them all, so nice of you all.
Alvi
How are you all doing?
Well, I have been a bit impatient, as I was expecting the instant precipitaion but the solution was not concentrated enough to get the gold precipitated upon the addition of SMB, I found the gold powder at the bottom of the beaker when I saw it now after almost 12 hours,
Jason Recliner, it is not the photo of incineration, the comment section of that photo states hcl bath. There was no reaction upon addition of Sulfamic Acid, please tell me that is that not a sign of a completely neutralized nitirc acid?
Goran, I added 35 ml of hcl 30% and 4 ml of nitric acid 60%. Additional water was added upon rinsing the filter and the beaker, I have consumed a lot of water in rinsing them I presume. Or what else I did wrong to increase the solution?
Geo, thank you for your kind suggestions, I really appreciate your suggestions at it's elite level, you are right Geo, I did not heat the solution when I was adding Sulfamic Acid, thank you for clarifying it, I have learnt one more step that I should heat the solution while addition of Sulfamic Acid, but why there was no reaction when I added Sulfamic Acid? Was that a sign of a completely neutralized nitric?
Jon, It was my false assumption to assume that may be the nitric was not been neutralized upon Sulfamic Acid's addition, Imdid not add more as there was no reaction, I'm learning the details of te whole process, all of the senior members of this forum have been so kind to give their suggestions in order to get me on the right tract of this chemical process. I'm thankfull to all of them. I did not dissolve the Sulfamic Acid in water either. But my mistake was to use more than enough water to rinse the filter and the beaker when I was filtering gold chloride solution, that was why the solution exceeded the required amount of it.
I checked the remaining solution with stannous chloride after when I saw the gold was precipitated, I am going to take a picture and post it here to show you guys, the colour is sligtly yellow tinted but transparent and the gold powder (which I'm boiling in hcl after water rinse) is of dark infact very dark colour after precipitation. Let's see which colour it would come up in after this wash which Harold suggested us to wash the gold powder.
Thank you everyone for your very much informative suggestions, I appreciate them all, so nice of you all.
Alvi
Geo, you're absolutely right, your last post justifies this late precipitation in my case, well said Geo. this is what the experience is all about which you have while dealing with scrap in countless numbers of processes, I have seen couple of your videos at youtube, I like your very straight forward instructions, unfortunately I cant see no more videos at youtube, because there is a dispute in between youtube and my service provider. I do not know how long it will take to resolve the issues, or I will have to change the service I think.
A
Anonymous
Guest
HI Alvi
Thanks for the replies, I'm glad the guys have been able to help.
Geo, there are differing schools of thought on the concentration of the solution before dropping the gold. I understand your way of doing it and the reasoning behind it- I prefer to do it the way that GSP does it which is diluted.
Thanks for the replies, I'm glad the guys have been able to help.
Geo, there are differing schools of thought on the concentration of the solution before dropping the gold. I understand your way of doing it and the reasoning behind it- I prefer to do it the way that GSP does it which is diluted.
Geo
Well-known member
This is something that I have learned on my own. You can neutralize free nitric acid to a point that you can precipitate gold at ambient temperatures, but upon heating, the precipitated gold will re-dissolve into solution. There are factors that govern chemical reactions, concentration, atmospheric pressure, heat (energy) just to name a few. A chemical reaction between reagents requires one, some or all of these factors and it changes with each factor introduced. Where the gold can precipitate from a solution at ambient temperatures, the same solution will dissolve gold if heated. The same is in effect for many of the reactions we want. When you dissolve sulfamic acid into liquid, it cools the liquid as energy is absorbed. When you heat the solution in the presence of other reagents, the energy is released in the form of heat which is why you should be careful adding sulfamic acid to a heated solution to avoid a boil over. If it does not work the first time you use it or even the second or third, it doesn't mean that the process doesn't work, it's just that you are either doing it incorrectly or there's nothing there to react with it. Since the test is positive and the addition of SMB fizzes and no gold drops, that's an indication of free nitric. Since we know that sulfamic acid converts nitric acid to nitrous oxide and sulfuric acid, there's no reason it wont work. This is one of the little things that you can play with (within reason) and not mess up the final product. By heating and additions of sulfamic acid and then a small quantity of SMB, you can repeat this over and over until you get it right.
Jon, you're wellcome, pleasure is all mine.
Well, there is very strange thing happened when I was boiling the precipitated gold in hcl and water according to Harold suggests, you guys will not beleive that all the gold was dissolved in it and I checked it with stannous chloride, it showed gold in the solution, I have taken pictures and going to post, aftaer stannous chloride test, I again repeated te whole process like adding Sulfamic Acid while heating the solution and there was no reaction then I added SMB and I cant explain what I felt after seeing the precipitation of gold in the form of solid gold in it's real colour, please have a look and explain what is going on here, I do not understand.
Well, there is very strange thing happened when I was boiling the precipitated gold in hcl and water according to Harold suggests, you guys will not beleive that all the gold was dissolved in it and I checked it with stannous chloride, it showed gold in the solution, I have taken pictures and going to post, aftaer stannous chloride test, I again repeated te whole process like adding Sulfamic Acid while heating the solution and there was no reaction then I added SMB and I cant explain what I felt after seeing the precipitation of gold in the form of solid gold in it's real colour, please have a look and explain what is going on here, I do not understand.
