Dirty gold bearing solution scenario...

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Xydoman

Active member
Joined
May 10, 2021
Messages
39
Hi there. I'm wanting to ask a hypothetical question aboug a not so hypothetical situation..

A while back I searched the forum for answers regarding a solution I had made out of hcl and bleach to disolve my gold. It did disolve the gold of course, but apparently I carelessly left other metals in the mix as well that were also dissolved, giving me a solution that was a funky blue/green color. So I found a thread on a similar problem, where the guy was told to precipitate the gold with copper. So i did this and it worked beautifully . I of course had to start over once it was precipitated, but it was a second chance to be more careful. I ended up with a modest, yet decent yield on that run.

Fast forward to now.. I'm looking at a batch of 200g of ic chips that I soaked in hcl for a week or so to remove the legs. I've incinerated them and pulverized them. And I've noticed, after dragging the resulting powder with a magnet thourughly to remove any wierd stuff, that It appears I still have some wierd non magnetic stuff in it. So I went ahead and utilized the AP method, since that's all I knew to do, and after a week or so of that, I finally see my gold bond wires without all the junk.. So it seems. There are still a few stragglers that appear to not be gold. They're just entirely too robust and thick to be gold. So I'm wondering about the method mentioned earlier. Woukd it be feasible to go ahead and purposely disolve the gold into a dirty solution, tgen use tge copper to seperate it that way, then continue the process? I'm definitely not the smartest person here, so I can't help but assume that there's a real good reason that this isn't ideal, because by this logic, one should be able to take a heap of scrap once processed to a certain point, and then just dissolve everything, seperate the gold with copper, put the gold precipitate back into solution. By its self, then drop with smb and b done with it. Seeking guidance from someone who knows better. Thanks.
 
You can precipitate gold out of a "dirty" mix metal solution with SMB although the preferred precipitant is ferrous sulfate. The trick will be to get the gold to dissolve in the first place. HCl and chlorine will dissolve gold but it is not very powerful. It loses it's oxidizing ability to dissolve gold quickly compared to nitric acid. If there is the least bit of other metal that is not gold, the gold in solution will simply cement back out of solution on what ever is there. It will not have the power to redissolve the gold and the offending base metal. The electromotive series of metals tells us that all other metal that is more reactive than copper (including copper) has to dissolve completely before the gold will dissolve and stay in solution. Until then, the gold will dissolve and cement in a cycle over and over until the oxidizer is depleted or the base metal dissolves.
 
Ah. I see. I knew tgere had to be a reason tgat it wasn't done this way. Apparently I just didn't contemplated
this.. Curiosity, hard enough. If I had, I'd have realized that the answer basically lies in the body of the post. I used copper to precipitate the gold from a previous dirty solution.. Alot of what we're dissolving during the ap process is copper base, if I put it all together I'd have seen that tge gold would merely precipitate right back out. Although since I'm no chemist, and can really only follow steps and procedures, there are so many how's and why's that I just don't know yet, so I wouldn't have understood that it would just keep happening over and over without your input. I actually AM studying chemistry in my spare time now to become more productive with this new hobby. It's actually really interesting, thinking about what happens on a molecular level when you create certain conditions. I appreciate your response and the lesson learned on maybe thinking about things a bit more thorough.
 
I have a question about precipitation..that I desperately need help with!! I am in possession of a pound or so of what can only be described as lumps of molten.metals that were recovered from a fire in a house quite a bit of which was gold (I'm going to try to include photos) I tried to just use a poor man's a/r what I ended up with was a really dirty solution and the truth is that I am reluctant to do anything else until I have a better idea how not to lose gold as there is quite a bit of it
 

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I have a question about precipitation..that I desperately need help with!! I am in possession of a pound or so of what can only be described as lumps of molten.metals that were recovered from a fire in a house quite a bit of which was gold (I'm going to try to include photos) I tried to just use a poor man's a/r what I ended up with was a really dirty solution and the truth is that I am reluctant to do anything else until I have a better idea how not to lose gold as there is quite a bit of it
Sorry for your loss.
Welcome to us though.
Can you please use a different format for the pictures, they don’t show in the forum.

Next set your lumps and liquids safely aside until you have studied a bit and we have come to a plan together.
Here is some info for safety and study.

1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

Suggested reading: The Library
 
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Beside tge reading and following Yggdrasil advice, I have some questions for you:
Did everything dissolve or is there metal left in the dirty solution?
One thread that help you understand precipitation of pm's:
When In Doubt, Cement It Out
If there are base metals left undissolved, there will not be pm's in solution.
If all metals dissolved, filter solution and cement it out.
 
How do I download photos the right way on here?
If you can get the photos into JPG format, that's readable everywhere (the HEIC format is proprietary to Apple). I was able to download and convert a few of your photos, attached below, so folks can see what you have.

I take it this is the lumps of metal after some time in acid? The crystalline pattern on the surface looks like acid-etched metal to me.

One challenge with a mix of metals is gold will only dissolve in aqua regia, but silver will only dissolve in nitric acid, so a mix of gold and silver may need to be inquarted to dissolve in anything. Hoke's free book covers this.

As long as you don't throw anything away, the metal is still there, so you can take your time and figure out how to do it right!
 

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Terry, on your phone, go to camera / settings / advance options of taking photos / turn off "highly efficient video". This should be for video, but maybe is applied to photos as well because I see that yours are in HEVC format.
 
If you can get the photos into JPG format, that's readable everywhere (the HEIC format is proprietary to Apple). I was able to download and convert a few of your photos, attached below, so folks can see what you have.

I take it this is the lumps of metal after some time in acid? The crystalline pattern on the surface looks like acid-etched metal to me.

One challenge with a mix of metals is gold will only dissolve in aqua regia, but silver will only dissolve in nitric acid, so a mix of gold and silver may need to be inquarted to dissolve in anything. Hoke's free book covers this.

As long as you don't throw anything away, the metal is still there, so you can take your time and figure out how to do it right!
Yes I saw that, but some Apple folks don't like to be remembered that there are more generic and suitable formats out there ;)
I think it is possible to set up the phone to store the pictures in jpg. It did on my iPhone.
 
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