Hi I'm new to this but I'm learning, I dissolved my gold findings, cpu and goldplated pins in Aqua Regia, the solution turned a deep emerald green color, I then neutralized the acid with Urea, after that I use cooper to make the gold drop, nothing happen, no mud at the bottom of the solution, I tested and it still have gold in it, where did I go wrong act and what do I need to do to get the gold out. Please help! Thanks in Advance.
No precipitated out of solution
- Thread starter sandy218
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Copper is generally used to drop the gold in waste solutions after the majority has been precipitated by more efficient methods.
I think you need to do some more reading.
I think you need to do some more reading.
stannous test good you tested, it can be a very sensitive test, was it a violet color? if so then nitric must be low enough in solution, as too much nitric will redissolve the tin chloride and gold reaction, will not show up in your test or dissapear.
the gold can cement and/or plate to copper.
If High nitric content copper will just dissolve adding copper to your dissolved gold solution and gold may not cement.
if solution too basic gold again may not cement from solution.
the gold can cement and/or plate to copper.
If High nitric content copper will just dissolve adding copper to your dissolved gold solution and gold may not cement.
if solution too basic gold again may not cement from solution.
I agree I need to read a lot more but I need to know what should I do to get my gold out. I don't want to lose it. The cooper did dissovle in the solution I also filter out the waste before I put the cooper in the solution. I thank you guy for your help.
First read up on HOKE’S BOOK, then you would not have question as how do I get my gold back.
Use this as a learning experience, learn to use stannous chloride test.
You may or may not have gold in solution, without testing you will never know only be guessing, and may just be guessing wrong most of the time, it could be with any metals you did not dissolve or in the fitered materials you had?????
Aqua regia is made with nitric acid, this oxidizes the gold and allows the gold to form a chloride with HCl, new members tend to use way too much acid, and usually have very little gold, and dissolve base metals in aqua regia with their gold, all of these are problems and just the beginning of them, it is a wonder we can recover from doing so many things wrong.
Nitric in solution will not let gold precipitate nitric will just keep the gold dissolved, also nitric in solution will not let the stannous chloride test work either as it will keep gold dissolved not letting the purple of cassius form with tin chloride reaction.
You already added copper was this metal or powder form, this added much base metal to your solution that may form colloids that gold plates to and will not fall to bottom.
This can be a real mess.
Heat can help to dissolve the colloids in an acidic solution, heat can also drive off excess nitric acid if that is the problem, I suspect these and more like tin or lead in solution.
I would add a large piece of copper bar (buss bar) or clean copper pipe(long enough so some of it is out of solution to use as a handle), in a Pyrex vessel (I use Pyrex coffee pot, on a hot plate, on low to (medium) heat slowly evaporate, if you have a lot of excess acid much of the copper will dissolve.
do not attempt to rush this by getting it too hot boiling over when it concentrates is another mistake, lowering temperature as it concentrates helps.
Take caution here: if a lot of nitric acid in solution the solution will concentrate, the nitric in solution slowly evolves mostly water at first, but will concentrate the nitric and when it gets to an azeotropic solution the concentrated nitric will start to bubble almost pure nitric, these can foam over easily boiling out any metals you expect to get from this learning experience, so once the solution concentrates lower temp to low and watch it, when you get to a syrup (do not let it go to salt or crystals do not let it cook dry), add a little HCL and continue on low heat evaporating this to syrup, a little more Hcl remove what is left of copper bar (with old tooth brush clean off any powder on bar into solution), evaporate to syrup again, pour this syrup into a jar of water about four times as much as syrup, white powder and brown solution may form let it set, overnight the powder may be white copper salts, if you have gold it will also be in these copper I chloride salts, after solution clears test with your stannous chloride, if barren of gold put in a container to deal with it later, add very hot HCL to the copper I chloride powder, this may make a dark brown solution and powder takes time to settle, if too thick add just a little water, again let sit till clear and test the solution for gold, if barren add to your copper solution for later, repeat until the brown or white powder will not form a dark reaction with hot HCL and is only a blue solution, most of the copper will be gone and mostly gold will remain with some copper,
If you have gold here I would study Harold’s technique for washing the gold powder, (seems to me in the post getting gold pure and shining or something like that), Hokes book is very easy to find, and in my opinion no one should even attempt aqua regia with out it or studying more, I am not ragging on you but once you do this for a while I think you will feel the same.
The copper chloride you saved can be used in other processes, but study up on them before trying or it will just be another mess and I am not good at explaining thing and their are more than one ways to make a mess good thing is there is at least one way sometimes more to get out of it, but it is a very hard way to learn and very time consuming and you will do better studying and processing gold than trying to get something from a messy goop.
Use this as a learning experience, learn to use stannous chloride test.
You may or may not have gold in solution, without testing you will never know only be guessing, and may just be guessing wrong most of the time, it could be with any metals you did not dissolve or in the fitered materials you had?????
Aqua regia is made with nitric acid, this oxidizes the gold and allows the gold to form a chloride with HCl, new members tend to use way too much acid, and usually have very little gold, and dissolve base metals in aqua regia with their gold, all of these are problems and just the beginning of them, it is a wonder we can recover from doing so many things wrong.
Nitric in solution will not let gold precipitate nitric will just keep the gold dissolved, also nitric in solution will not let the stannous chloride test work either as it will keep gold dissolved not letting the purple of cassius form with tin chloride reaction.
You already added copper was this metal or powder form, this added much base metal to your solution that may form colloids that gold plates to and will not fall to bottom.
This can be a real mess.
Heat can help to dissolve the colloids in an acidic solution, heat can also drive off excess nitric acid if that is the problem, I suspect these and more like tin or lead in solution.
I would add a large piece of copper bar (buss bar) or clean copper pipe(long enough so some of it is out of solution to use as a handle), in a Pyrex vessel (I use Pyrex coffee pot, on a hot plate, on low to (medium) heat slowly evaporate, if you have a lot of excess acid much of the copper will dissolve.
do not attempt to rush this by getting it too hot boiling over when it concentrates is another mistake, lowering temperature as it concentrates helps.
Take caution here: if a lot of nitric acid in solution the solution will concentrate, the nitric in solution slowly evolves mostly water at first, but will concentrate the nitric and when it gets to an azeotropic solution the concentrated nitric will start to bubble almost pure nitric, these can foam over easily boiling out any metals you expect to get from this learning experience, so once the solution concentrates lower temp to low and watch it, when you get to a syrup (do not let it go to salt or crystals do not let it cook dry), add a little HCL and continue on low heat evaporating this to syrup, a little more Hcl remove what is left of copper bar (with old tooth brush clean off any powder on bar into solution), evaporate to syrup again, pour this syrup into a jar of water about four times as much as syrup, white powder and brown solution may form let it set, overnight the powder may be white copper salts, if you have gold it will also be in these copper I chloride salts, after solution clears test with your stannous chloride, if barren of gold put in a container to deal with it later, add very hot HCL to the copper I chloride powder, this may make a dark brown solution and powder takes time to settle, if too thick add just a little water, again let sit till clear and test the solution for gold, if barren add to your copper solution for later, repeat until the brown or white powder will not form a dark reaction with hot HCL and is only a blue solution, most of the copper will be gone and mostly gold will remain with some copper,
If you have gold here I would study Harold’s technique for washing the gold powder, (seems to me in the post getting gold pure and shining or something like that), Hokes book is very easy to find, and in my opinion no one should even attempt aqua regia with out it or studying more, I am not ragging on you but once you do this for a while I think you will feel the same.
The copper chloride you saved can be used in other processes, but study up on them before trying or it will just be another mess and I am not good at explaining thing and their are more than one ways to make a mess good thing is there is at least one way sometimes more to get out of it, but it is a very hard way to learn and very time consuming and you will do better studying and processing gold than trying to get something from a messy goop.
patnor1011
Well-known member
Do not try another batch in same way as you did this one. You said that you dissolved gold plated pins and CPU`s in AR. This is not good approach. Your material contained probably less than 1% of gold and more than 99% of basic metals. When processing such material it is advised to dissolve as much basic metals as you can either in nitric or HCl. Whatever is left can be treated with AR or different method.
