Add me to the list of idiots who ruin their solutions

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Tammyjefferywilliam

Member
Joined
Feb 23, 2015
Messages
16
Let me start by saying I hate doing this, and you can say "I told you so" all you want but I'm going to ask anyway, because this forum is the closest thing there is to a school for this stuff, and just maybe one of you will have the sympathy to help me yet again. So rest assured this is a last resort, as I have tried everything I know, which isn't much. I processed a bunch of gold with what they call poor man's aqua-regia and all I had for nitrate salt was ammonium nitrate. Now, I figured I could kill the nitrate with urea, and I wanted ALL the gold to dissolve, so I used a LOT of it (about 3 to 4 spoon full to a coffee pot). Now I guess you all know the outcome but I didn't. The solution tests positive for gold, I added urea until it will barely dissolve, but when I add metabisulphite, it just fizzes and there is the strong smell of ammonia. I have already added more than enough metabisulphite, but the gold still won't drop completely. The solution will get slightly cloudy and only drop a tiny amount of powder. And it still tests positive for gold with stannous chloride. Is there any way to save my solution?
 
Though it may also be possible to salvage, I agree that cementing on copper is probably your easiest way out.

But let's go back a step and see if we can find your root problem.
How much HCl, to the 3-4 spoons of ammonium nitrate powder? What sized spoons? Estimate an approximate weight?
How much gold do you expect you have placed in solution?
 
I put the liquid back into a large container and put in a clean copper pipe. It seems to be working. There is a black residue forming on the copper that I assume is gold. It isn't the brown powder that's normally precipitated, so when I recover it after the solution is depleted, will it melt in a crucible as-is or does it need to be treated again with aqua regia?
 
Neither.

It will need refining, assuming you want clean gold, but you need to know what you did wrong or you'll just do it again.
I would also suggest a lot more studying before you even think you're ready for melting gold.
 
Also don't forget the gold is forming inside your pipe too. Which is why we usually recommend a solid bar, though some hammer a pipe flat. As long as you are aware, you can do what you need to mitigate loss of gold.
 
I didn't just pick this up yesterday. I have been at this 8 months now. And I have absolutely nothing to show for it. I got the idea from watching youtube and thought "hey, I can do that!" I tried to read Hoke's book. It didn't seem to apply to me. I had no idea what threads to read on this forum because I had no idea what problems I would face. I thought I had a grasp on how to get started, but I guess I was wrong. But in this case, I assume that my problem was too much nitric for too little gold and using ammonium nitrate instead of the nitric acid I was saving for silver. From now on, I will try to use the LEAST amount possible. And I will scrape the black powder from the inside of the pipe, since that was all I had to use (I was saving that for silver as well). I do realize that I am lacking on knowledge. The videos on youtube made it look easier that it really is. I am not planning on doing this for a living or even as a hobby. I may never try it again. I had already decided to try it once 8 months ago. I am just trying to finish what I started. Am I supposed to weigh the recovered and dried black powder and calculate how much hydrochloric and nitric to add? If I am processing scrap there is no way to know the weight of the gold. How do I calculate the ratio then?
 
The black powder should be your gold or any other values that may be there.
You can wash your black powder and use HCl and chlorox to dissolve it which makes removing the oxidiser easier, just a little heat and or time, which means easier precipitation.
If you don't intend to do any further recoveries or refining please ensure you dispose of any wastes and chemicals responsibly!
 
Using copper pipe is a poor choice of copper because, as you said, you have black powder build up inside the pipe. If you ever have to use copper pipe to cement values, use a hammer and flatten the pipe as much as possible to help alleviate the problem of trapped values. There are a couple of techniques you can use to remove excess nitric acid from solutions before you try and precipitate values. Even cementing on copper can be done with less problems if you raise the PH to around 2-2.5 before starting.

Everyone has problems starting out. Just remember that you can't destroy gold. Unless you throw it away, it's still there. Dissolving gold and then bringing it back to solid metal is the trick that all refiners must master.
 
While your gold cements away, give us some rough numbers to work with and we can help you learn from a mistake. But you need to read too. Hoke's book is chock-full of valuable information. I find it hard to believe none of it applies to you.

What did you start with? How much of what material? Is this the ounce of plated pins you were working on a month ago? And if so, did you complete the AP process?

If you can tell roughly how much HCl acid you used, and how much ammonium nitrate you added, we can give you a rough idea of how far out you were.
There's no fixed unit of "spoons". Teaspoons? Ladles? Measure out about the same amount again and weigh it. We'll set you straight.

You do not have to use nitric acid, in fact I recommend you don't. It's even less forgiving.
As you have experienced, a nitrate salt is more than capable of dissolving gold. Nitric acid may be cleaner, and professional refiners will prefer it over nitrate salts. But if you read this forum you will consistently find that nitric (or nitrate) - should be added slowly, in increments, until your gold is digested.

Keep the urea. Your tomatoes will love it.
 
You said Hoke's book didn't apply to your "experiment"...
You didn't read enough of it to find out.

You also did not watch enough Youtubewillhurtyou. videos to get a better ideal of how much solution to use, how to "neutralize" nitric acid, which is wrong anyhow.

As far as reading the forum here... I have to call B.S. there as well.
Sorry to say it like it is.

Assembling a kids toy looks easy and quick at first glance. Then comes the "where is this supposed to go" or " how does that go there"?
What comes next....the instructions...and lots of banned words...

Good luck in your future en devours.

B.S.
 

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