# Precipitation Difficulty



## Woodard711 (Mar 24, 2018)

Hello, I'm relatively new to gold recovery and after spending months collecting DATA I have been working on my process.
To deplate computer scrap I use 2 parts A/P (1L HCLO2 + 200ML h202) and 1 Part Acetic Acid I created from concentrated vinegar. This has been very successful, completely stripping circuit boards within 48 hours in most cases.
My Aqua Regia mixture is 200ML HCLO2 and 10-15ml Bleach. I then heat the mixture up to a light boil for about 30 minutes, than allow to sit for 2-3 hours. So far I've had few issues with dissolving.
Precipating has been touch and go for me, but I'm starting to get more and more dark brown/blackish powder which looks a lot like the product I'm supposed to have. I use 2-3 TBSP of SMB mixed in about 200ML of water and it seems to be working. I have yet to smelt any of the brown powders because I'm unsure of the smelting process.
Here is my problem, last night I extracted a black powder that turned into a blue glass-like substance with black chunks through it when I attempted to smelt it. What on earth did I create? 
My first smelt was a poor attempt with Map Gas. Any input would be greatly appreciated.


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## g_axelsson (Mar 24, 2018)

I have no idea of what you created but it doesn't sound like gold.

What you are calling aqua regia is not aqua regia.

With that set of chemicals I have no clue of what you have created. Do you have a problem getting HCl?

Göran


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## kernels (Mar 25, 2018)

I assume you tried to melt the powder ? Smelting being a high-heat chemical reaction. 

What was the computer scrap and how much of it was there ? When you finished with the AP part, what did you have? Did you have Gold foils ? How much ?

Boiling aqua regia is not necessary and not a good idea.


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## FrugalRefiner (Mar 25, 2018)

Woodard, welcome to the forum. Your post is one of those that many members probably read, and then don't respond because they don't know where to start. Since I see you returned today, I'll try to take a shot.



Woodard711 said:


> Hello, I'm relatively new to gold recovery and after spending months collecting DATA I have been working on my process.
> To deplate computer scrap I use 2 parts A/P (1L HCLO2 + 200ML h202) and 1 Part Acetic Acid I created from concentrated vinegar. This has been very successful, completely stripping circuit boards within 48 hours in most cases.


Here on the forum, many members use an "A/P" leach on ewaste, especially fingers, but it's not what you describe. What we use is mostly hydrochloric acid (HCl) with a small amount of hydrogen peroxide (H2O2). Did you actually use chlorous acid (HClO2) instead of hydrochloric acid (HCl)? Although many old posts talk about using a lot of hydrogen peroxide to start the leach, for many years now we have advised using only a tiny amount, like a capful. Using more can oxidize some of your gold and cause it to go into solution. Why did you add acetic acid? It will complicate things by adding more chemical to the solution. There are leaches that use acetic acid, but they just aren't as cost effective as using hydrochloric acid.



> My Aqua Regia mixture is 200ML HCLO2 and 10-15ml Bleach. I then heat the mixture up to a light boil for about 30 minutes, than allow to sit for 2-3 hours. So far I've had few issues with dissolving.


That's not aqua regia. Aqua regia is a combination of hydrochloric acid and nitric acid. Other acid combinations can dissolve gold, but they're not called aqua regia. Again you mention using HClO2. Is that really what you're using?



> Precipating has been touch and go for me, but I'm starting to get more and more dark brown/blackish powder which looks a lot like the product I'm supposed to have. I use 2-3 TBSP of SMB mixed in about 200ML of water and it seems to be working.


If you only needed 10-15 ml of bleach to oxidize your gold, you shouldn't need 2-3 tablespoons of SMB to precipitate it. Using excess SMB can cause other metals to precipitate with your gold if they are in solution. It also sounds like your solution was very dilute. That can cause gold to precipitate as very fine particles which don't agglomerate and settle well.



> I have yet to smelt any of the brown powders because I'm unsure of the smelting process.


As kernels mentioned, after you have refined gold, you simply melt it, not smelt it.



> Here is my problem, last night I extracted a black powder that turned into a blue glass-like substance with black chunks through it when I attempted to smelt it. What on earth did I create?


You haven't mentioned how you're melting. Are you using a melting dish? Have you seasoned it with borax or are you using borax when you're trying to melt? Borax becomes glassy after it's been melted and allowed to cool. Blue color in borax often comes from base metals like copper, as do black chunks as the base metals oxidize.



> My first smelt was a poor attempt with Map Gas. Any input would be greatly appreciated.


I don't really know if you're trying to melt or smelt, or what you're starting material is, or what processes you've actually used.

I hope you don't get your feathers ruffled by the answers you're getting. We're willing to help, but we're going to need a lot more information, and you're the only one who can provide it. If you answer the questions I've asked, we'll try to help. If you don't, this will just be another thread that dies on its own.

In addition to answering questions, I'll also recommend reading through the Tips for Navigating and Posting on the Forum thread. There is a link to the Glossary that will help you understand the terminology used here.

What was your starting material? Fingers, pins, processors, something else? How much?
Are you using chlorous acid or hydrochloric?
Where did you learn this process?
Are you insulating your dish/crucible when trying to melt?
Can you provide some pictures?

The ball is in your court.

Dave


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## Woodard711 (Mar 30, 2018)

I'm going to go back and double check all the questions you asked me. What I'm actually using to strip is A/P from Muriatic Acid and Peroxide, mixed with Acetic Acid that I've made myself. The stripping produces large gold flakes and always tests negative with the stannous, I'm pretty confident my process there is correct.
I went back and did a lot of research on AR and poor man's AR, to be honest I think my biggest mistake was patience. I didn't refine the gold enough, so the impurities ruined the batch.
I used a basic Crucible with Borax for a flux. I have consulted with a local blacksmith for guidance and he's agreed to help me out.
I appreciate the critisim, the mentality of chemistry is new to me and your questions made me think.


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## Woodard711 (Mar 30, 2018)

I honestly don't have all the answers to the questions you asked, so obtaining them will be my next priority. 
Thank you much for the input so far, it's made me realize I need more book time before I go cooking in the lab.


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## Woodard711 (Mar 30, 2018)

g_axelsson said:


> I have no idea of what you created but it doesn't sound like gold.
> 
> What you are calling aqua regia is not aqua regia.
> 
> ...



I can get Muriatic acid quite easily, my goal was to try to find a more environmentally friendly way of depleting without sacrificing effiency. To be honest, im onto something with it but I have to run more trials.

I now dissolve the gold using 250ML of Muriatic Acid with either 10-15 ml of bleach, or I'll use salt. Honestly im not sure which one works better as they both show great stannous results. When I precipitate I use 1 tbsp of SMB per 5 ml of bleach, mixed with 250 ml of distilled water.
I might add that one process I forgot when melting this first batch was to strain solids after dissolving. I'm learning patience, it's hard though as I find this incredibly exciting.


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## g_axelsson (Mar 30, 2018)

Just because you use more benign chemicals doesn't mean the end result is less toxic. The toxic part is the dissolved metals, not the acids used.

Before trying to invent a better wheel you should learn how an ordinary wheel work.

Göran


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## Palladium (Mar 30, 2018)

g_axelsson said:


> Just because you use more benign chemicals doesn't mean the end result is less toxic. The toxic part is the dissolved metals, not the acids used.
> 
> Before trying to invent a better wheel you should learn how an ordinary wheel work.
> 
> Göran



Very well put!


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## Woodard711 (Apr 3, 2018)

Update*
I am now extracting and successfully melting pure gold. Thank you all for the input! It was all very helpful and enlightening.


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