Gold Foam

[Striker578]

My first try in recovery.I had 400g of assorted pins & cards. I did a Aqua Regia boil and got 4x of green foam & 500 ml of liquid. I passed thru a coarse filter. I got a settlement of greenish paste in filter. I still have to drop the gold from the liquid.

My question is. What was the foam and paste. Should I process the paste again to extract anything left?

 

[Martijn]

My first try in recovery.I had 400g of assorted pins & cards. I did a Aqua Regia boil and got 4x of green foam & 500 ml of liquid. I passed thru a coarse filter. I got a settlement of greenish paste in filter. I still have to drop the gold from the liquid.

My question is. What was the foam and paste. Should I process the paste again to extract anything left?

Welcome tot the forum. The foam and the paste will be from the junk you put in AR that not belongs there.
Sorry for the harsh words, but you applied a refining process to material that was not even prepared enough for a recovery process.

You will probably get some must read info from Yggdrasil, and here is one for now:
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
looking at the picture, i really want to ask you to take a step back and study safety first. that BBQ grid can not be used for food ever again! and that's just one observation of many.
You need a safe workspace with a cath basin if you do tip over unstable setups like yours.

stay alive and go study a bit first. Then ask us about the theory you're working on before putting it in practice.

why?
because:
https://goldrefiningforum.com/threa...imple-question-and-get-a-simple-answer.21412/
Martijn.

 

[Striker578]

The pic is to show contents & grill is garbage anyway.
I have safety equipment, a vent hood and ceramic pan. I've done Silver Scrap with no issues. A HCL boil was done first. I got Gold to drop but still need to know about the Greenish paste. I appreciate your criticism,concern & the input.

 

[Martijn]

Fair enough. I understand. But it looks like you heated a beaker on a hotplate on a grid that is sticking out on all sides making it easy to tip over? Will that toxic mess be safe on the rooftop?

So the PCB'S went into AR?

About answering the issue, no simple answer is possible until you provide more info on exactly what you did and what you added to what etc etc.
The HCl wash e.g.
Do not drop pieces of info at a time.
Give a complete description of your steps and we will find the fault and the solution.
Hence my link to the last thread: why are questions left unanswered, because most people can not understand the answer and will harm themselves You need a certain level of understanding and experience to proceed.

I can explain you how a guillotine works, but supervision might be needed the first couple times... it looks like you still have your hand in the wrong place for now. Let's correct that first.

So now i know there was a HCl wash and there is dropped gold somewhere, but where? Still in the green goo? Have you filtered? Are the pcb's in the mess?

My point exactly.

It might look really simple to you, but that's the danger of it. Have you read the links i gave you?

 

[Yggdrasil]

I have a new dayjob now and it kind of steal my time and energy so I have been a bit absent a few days.

But any way Martijn has told the most important stuff.
Any way here is the study material

We ask our new members to do 3 things.
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

Forum rules : https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/post-327766

 

[Striker578]

Welcome tot the forum. The foam and the paste will be from the junk you put in AR that not belongs there.
Sorry for the harsh words, but you applied a refining process to material that was not even prepared enough for a recovery process.

You will probably get some must read info from Yggdrasil, and here is one for now:
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
looking at the picture, i really want to ask you to take a step back and study safety first. that BBQ grid can not be used for food ever again! and that's just one observation of many.
You need a safe workspace with a cath basin if you do tip over unstable setups like yours.

stay alive and go study a bit first. Then ask us about the theory you're working on before putting it in practice.

why?
because:
https://goldrefiningforum.com/threa...imple-question-and-get-a-simple-answer.21412/
Martijn.

Aside from the photo image (not my actual setup), I searched the files and found one possible remedy. I have washed the residue, set aside and wait until I comprehend it's makeup then reprocess or discard after treatment.
Thank's much

 

[Martijn]

We still do not have sufficient info to help you, so good to hear you've found one yourself.
But as I say to all new members, please present your plan here before you do anything. We can prevent loss.

If you have the solution and you know what you did wrong, please share it here for others to learns from.
My comments are not to judge, but to help you in a good way.

So if you want to get your challenge analyzed and get advise on possible solutions, we're still here.

some questions to clarify your case: how much AR in what ratio? what is 4X foam? 4 times the volume of your solution? you still had to drop gold but now it's dropped. did you filter before dropping it? did you perform a stannous test on the solution? Did you really let the AR boil or just heated until hot? why didn't you pass through a fine filter after AR? Your gold should be in solution, so no need to keep any solids before precipitating.

i think we can improve your steps, but again, we need info.

good luck, and be safe.

 

[Striker578]

I had 400g of assorted pins, trimmed fingers & SIM cards in a 3000mL beaker.
I did not Incinerate first nor boil with HCL before the AR treatment (mistake). The AR ration was 300mL HCL & 50mL HNO3 to start with an addition of 25mL for a total of 300/75mL. About 15 minutes into a rolling boil foam started appearing. Removed watch glass & stirred it for 30 mins. Still foaming with 900+mL of foam. Shut down then pulled samples of cards from AR, gold dissolved. Panic & wrote then researched. Strained liquid & saved foam. Filtered liquid then tested. Positive test. Dried foam & paste then Incinerated the remains. After cooling treated ash with AR, filtered & tested positive. I dropped the Au with SMB after making sure it was deNOx.

I had some remaining scrap. In it was Soft flexible plastic backing I missed that got dissolved in the mix creating the issue. I put a few into tube with AR & found the ones dissolving. So in my case a Roasting was needed to prevent this trouble.

Edited 6/2/23

 

[Yggdrasil]

I had 400g of assorted pins, trimmed fingers & SIM cards in a 3000mL beaker.
I did not Incinerate first nor boil with HCL before the AR treatment (mistake). The AR ration was 300mL HCL & 50mL HNO3 to start with an addition of 25mL for a total of 300/75mL. About 15 minutes into a rolling boil foam started appearing. Removed watch glass & stirred it for 30 mins. Still foaming with 900+mL of foam. Shut down then pulled samples of cards from AR, gold dissolved. Panic & wrote then researched. Strained liquid & saved foam. Filtered liquid then tested. Positive test. Dried foam & paste then Incinerated the remains. After cooling treated ash with AR, filtered & tested positive. I dropped the Ag with SMB after making sure it was deNOx.

I had some remaining scrap. In it was Soft flexible plastic backing I missed that got dissolved in the mix creating the issue. I put a few into tube with AR & found the ones dissolving. So in my case a Roasting was needed to prevent this trouble.

You do not drop Silver (Ag) with SMB but Gold (Au).
Do not put whole items containing base metals in AR as the Gold will dissolve and then cement out again until ALL base metals are dissolved.
It is expensive and unnecessary complex creating more waste than needed.

Edit for spelling

 

[Striker578]

Sorry I miss typed my symbol without my glasses and used Ag instead of Au. I'm not use to typing on this small phone. I really appreciate getting & giving help. Look forward to more .

 

[Martijn]

I had 400g of assorted pins, trimmed fingers & SIM cards in a 3000mL beaker.
I did not Incinerate first nor boil with HCL before the AR treatment (mistake). The AR ration was 300mL HCL & 50mL HNO3 to start with an addition of 25mL for a total of 300/75mL. About 15 minutes into a rolling boil foam started appearing. Removed watch glass & stirred it for 30 mins. Still foaming with 900+mL of foam. Shut down then pulled samples of cards from AR, gold dissolved. Panic & wrote then researched. Strained liquid & saved foam. Filtered liquid then tested. Positive test. Dried foam & paste then Incinerated the remains. After cooling treated ash with AR, filtered & tested positive. I dropped the Ag with SMB after making sure it was deNOx.

I had some remaining scrap. In it was Soft flexible plastic backing I missed that got dissolved in the mix creating the issue. I put a few into tube with AR & found the ones dissolving. So in my case a Roasting was needed to prevent this trouble.

If there was no solder on the material, not roasting or leaching is not that big of a problem.
The AR is for refining cleaned recovered gold or pins if you need to have a fast result.
The AP process is perfect for trimmed fingers and thin pins.
You can then collect the foils and refine them with relative ease.
Back yo your case, did all metal dissolve?
If not, your gold may have partially or substantially cemented out on said metal.
Did you rinse your filtered foam and material very well free of acid before roasting?
And most important, how much gold did you recover?

 

[Striker578]

If there was no solder on the material, not roasting or leaching is not that big of a problem.
The AR is for refining cleaned recovered gold or pins if you need to have a fast result.
The AP process is perfect for trimmed fingers and thin pins.
You can then collect the foils and refine them with relative ease.
Back yo your case, did all metal dissolve?
If not, your gold may have partially or substantially cemented out on said metal.
Did you rinse your filtered foam and material very well free of acid before roasting?
And most important, how much gold did you recover?

I did rinse the sediment 2 times to clear before roasting it. I have 3 specific boards that AR didn't touch & no other metals remain. The 3 boards seem to be coated with a epoxy of sorts. I saved it to do later. I won a bid on eBay over 600g of assorted materials at 55.00 for this Test. I still have over 200g to process later. It's loaded with more dissolvable plastic that must be handled first..

I normally do Silver with excellent results. I wanted to try Gold to see if worth my time. So far I've collected .872g of powder. I know other metals are mixed & I have loss in the process.This was a learning experience and if I get a return of what's spent I'm . If not a costly lesson of all materials for me.

 

[orvi]

I had 400g of assorted pins, trimmed fingers & SIM cards in a 3000mL beaker.
I did not Incinerate first nor boil with HCL before the AR treatment (mistake). The AR ration was 300mL HCL & 50mL HNO3 to start with an addition of 25mL for a total of 300/75mL. About 15 minutes into a rolling boil foam started appearing. Removed watch glass & stirred it for 30 mins. Still foaming with 900+mL of foam. Shut down then pulled samples of cards from AR, gold dissolved. Panic & wrote then researched. Strained liquid & saved foam. Filtered liquid then tested. Positive test. Dried foam & paste then Incinerated the remains. After cooling treated ash with AR, filtered & tested positive. I dropped the Au with SMB after making sure it was deNOx.

I had some remaining scrap. In it was Soft flexible plastic backing I missed that got dissolved in the mix creating the issue. I put a few into tube with AR & found the ones dissolving. So in my case a Roasting was needed to prevent this trouble.

Edited 6/2/23

You "dissolved" the plastics, lacquer, varnish, resin and all organic stuff in AR. That is the foam you see. AR is harsh to some plastics and espetially older PCBs. It destroy the epoxy/resin/plastic to sticky gooey mess which is pain to deal with afterwards. Avoid this practice unless you try one smaller bit first to observe how it would behave.

To dissolve 1kg of copper material (pins and similar stuff) you need 4L of HCL and 1L of HNO3 just to put metals into the solution. If you substract dead weight of PCBs and connectors, you will easily calculate how much acid do you roughly need. Pour in the calculated HCL ammount and add 1/3 of required nitric. When reaction dies down, add slowly more nitric to still hot AR to maintain the reaction.

 

[Striker578]

You "dissolved" the plastics, lacquer, varnish, resin and all organic stuff in AR. That is the foam you see. AR is harsh to some plastics and espetially older PCBs. It destroy the epoxy/resin/plastic to sticky gooey mess which is pain to deal with afterwards. Avoid this practice unless you try one smaller bit first to observe how it would behave.

To dissolve 1kg of copper material (pins and similar stuff) you need 4L of HCL and 1L of HNO3 just to put metals into the solution. If you substract dead weight of PCBs and connectors, you will easily calculate how much acid do you roughly need. Pour in the calculated HCL ammount and add 1/3 of required nitric. When reaction dies down, add slowly more nitric to still hot AR to maintain the reaction.

Thank you, I learned that the painful way. I blame my excitement for the lesson. I still have a bit of unprocessed left to treat properly before AR & recovery.
With the previous 400g I used enough HCL to cover the materials and then used less than 4 to 1 to start the reaction. I didn't want excess NOx as I had very little conversion acid at the time. I'm conservative with HNO3 due to cost.

 

[Martijn]

If nitric is expensive or hard to get and you're not in a hurry the AP process might be a better option for you.

 

[Striker578]

I'm thinking boiling in HNO3 to release the gold, & dissolve the silver with other metals avoid the plastic consumption? With NO3 not eating most plastic & it's low boil point compared to AR? I have a mix of trimmings to process & prefer as few steps as needed. How would you process this? (pic worth 1000's words) Nitric/Water then AR?
I'm going to study up on the AP process & I understand Salt & Vinegar will dissolve with time (I have plenty). A friend has 27lbs of RS232 end to do. Just need to setup everything properly & safely

 

[Yggdrasil]

I'm thinking boiling in HNO3 to release the gold, & dissolve the silver with other metals avoid the plastic consumption? With NO3 not eating most plastic & it's low boil point compared to AR? I have a mix of trimmings to process & prefer as few steps as needed. How would you process this? (pic worth 1000's words) Nitric/Water then AR?
I'm going to study up on the AP process & I understand Salt & Vinegar will dissolve with time (I have plenty). A friend has 27lbs of RS232 end to do. Just need to setup everything properly & safely

First, you need to separate it into relatively homogeneous batches, since each kind of material has its own best way of processing.
Remove all plastics while doing this so you don’t risk locking up your Gold in gooey plastic.
After that you can use dilute Nitric if you access to Nitric. Or AP it is cleaner and has no risk of creating Metastannic acid.
Vinegar has no use in recovery or refining.
Acetic acid and Salt forms a weak HCl but also creates a much larger amounts of waste and some of that can be extremely toxic. Read about Lead Acetate.
When you have “liberated” your foils, wash it well and decant all liquids.
Then dissolve with your preferred method and precipitate accordingly

 

[Yggdrasil]

I'm thinking boiling in HNO3 to release the gold, & dissolve the silver with other metals avoid the plastic consumption? With NO3 not eating most plastic & it's low boil point compared to AR? I have a mix of trimmings to process & prefer as few steps as needed. How would you process this? (pic worth 1000's words) Nitric/Water then AR?
I'm going to study up on the AP process & I understand Salt & Vinegar will dissolve with time (I have plenty). A friend has 27lbs of RS232 end to do. Just need to setup everything properly & safely

After replying I had a second look at your material, some of this I think is better incinerated, cleaned/washed and dissolved directly in AR, HCl/Peroxide or similar.
Hence the reason for proper separation.

 

[Striker578]

I was thinking along those lines. I am sorting out the plastic parts from the metals to incinerate then process it. The 100% metals will go directly into AR. I don't want to create highly toxic or explosive reactions it the process of removal. My next time I'll get presorted scrape & save the headache.
I've read about "Electrolysis Removal of foil. What are your thoughts?

 

[andu]

I'm thinking boiling in HNO3 to release the gold, & dissolve the silver with other metals avoid the plastic consumption? With NO3 not eating most plastic & it's low boil point compared to AR? I have a mix of trimmings to process & prefer as few steps as needed. How would you process this? (pic worth 1000's words) Nitric/Water then AR?
I'm going to study up on the AP process & I understand Salt & Vinegar will dissolve with time (I have plenty). A friend has 27lbs of RS232 end to do. Just need to setup everything properly & safely

If you add hydrogen peroxide to vinegar, and some, but not too much salt to allow the oxygen to stay in solution, you can get somewhat exciting results on copper, and perhaps aluminium but I haven't tested that one.
I would say , if you put silver in AR (which should be present around tin) you could have silver chloride which, even if little, generates quite a bit of volume.