Help?

[badestb]

So, I've been digesting circuit boards, gold fingers, and pretty much anything I can get my hands on that are gold plated in nitric acid for a few weeks now. I keep getting this grey or silver substance at the bottom of my beaker which doesn't disolve into the solution and keeps clogging up my filters really badly... At first I thought it was silver but then realized it would be dissolved in solution... What is this stuff? What do I do with and about it?

 

[FrugalRefiner]

Tin.

Dave

 

[badestb]

Really? How do you know? I mean how would I know?

 

[badestb]

It doesn't stick to my magnet in my magnetic stirrer at all so it can't be tin right?

 

[Noggin]

Check out information on metastannic acid.

 

[Swissgoldrefiner]

If i were you, i will filter the solution. Then test the liquid with stanous test and try to dissolve the remain ing powder in new batch with nitric.

 

[badestb]

If i were you, i will filter the solution. Then test the liquid with stanous test and try to dissolve the remain ing powder in new batch with nitric.

I have tested the solution with sanous cloride and it stays clear, the isn't any gold in the solution. And the nitric acid is still digesting plenty of other metals still... I will try to find a picture of it or a video with it in it to show you what it's like...

 

[canedane]

badestb Welcome to the forum. I am sorry to tell you are not ready to use chemicals yet, you have to study first and know what you are doing. Google is your freind here. If you cant find or understand an answer then use GRF, but try first your self. Merry xmas.​

Henrik

 

[Swissgoldrefiner]

I have tested the solution with sanous cloride and it stays clear, the isn't any gold in the solution. And the nitric acid is still digesting plenty of other metals still... I will try to find a picture of it or a video with it in it to show you what it's like...

I think there is anyway nothing inside as gold. For gold you need to add the chlorhydric acid as well...

 

[orvi]

So, I've been digesting circuit boards, gold fingers, and pretty much anything I can get my hands on that are gold plated in nitric acid for a few weeks now. I keep getting this grey or silver substance at the bottom of my beaker which doesn't disolve into the solution and keeps clogging up my filters really badly... At first I thought it was silver but then realized it would be dissolved in solution... What is this stuff? What do I do with and about it?

Acid isn´t magic thing where you put all junk and stuff, and you fish out shiny gold bar
Putting whole PCBs into nitric is generally a bad idea due to presence of tin (you learned hard way) and also iron/kovar and aluminium. These metals refuse to dissolve in nitric acid, and complicate the things.

More you separate the metals and materials, less messy and better yielding your procedure would be.

Picture of material will be good for making some advice that could potentially help.

 

[FrugalRefiner]

Really? How do you know? I mean how would I know?

You said you were putting "circuit boards, gold fingers, and pretty much anything I can get my hands on that are gold plated in nitric acid". Circuit boards have solder, and the main component of solder is tin. It doesn't dissolve in nitric and it clogs filters. So it's an educated guess.

You can know by studying the forum before you combine any more ewaste and acids. It takes a lot of commitment to learn how to do this properly. Start by studying what to do with the toxic waste you've created that now contains an unknown variety of heavy metals.

I'm not trying to be mean, but I want you to understand this tales a lot of study. You can start with my Tips for Navigating and Posting on the Forum thread.

Dave

 

[Noggin]

Hoke’s book specifically the chapter on observing the effect of acid on tin and the concept of acquaintance experiments should move you past this hurdle quickly.

 

[Yggdrasil]

I have seen it before and it will probably come again.
It is a English daily language thing.

It doesn't stick to my magnet in my magnetic stirrer at all so it can't be tin right?

Tin-can and other daily objects with tin in them. --> magnetic because it is not made of tin, but rather steel/iron thinly plated with tin (Sn) or other non corrosive white metal.

Many seem to make this misconception.

 

[badestb]

badestb Welcome to the forum. I am sorry to tell you are not ready to use chemicals yet, you have to study first and know what you are doing. Google is your freind here. If you cant find or understand an answer then use GRF, but try first your self. Merry xmas.​

Henrik

I don't know why you think I have been doing anything but studying, & a HARD crash course at that! With all due respect brother, I bet that there isn't one person who has done this gold recovery stuff in all of history who hasn't had to learn thru trial and error... Every single one of us has had questions throughout... But that's the joy of a site like this! It gives us a chance to come together, when we normally would have to struggle alone the whole way, and help each other through our mistakes... So I don't think you have any business judging me or telling me I shouldn't be using chemicals, who are you to make such a call? Then insult me more by telling me Merry Xmas? Wow! Thanks for welcoming a new person into the wonderful hobby, you really made me feel welcome!

badestb Welcome to the forum. I am sorry to tell you are not ready to use chemicals yet, you have to study first and know what you are doing. Google is your freind here. If you cant find or understand an answer then use GRF, but try first your self. Merry xmas.​

Henrik

 

[badestb]

Hoke’s book specifically the chapter on observing the effect of acid on tin and the concept of acquaintance experiments should move you past this hurdle quickly.

I really appreciate that suggestion, I recently started to read that book and am grateful to be pointed in the right direction... Even as trivial as everybody appears to find my question. We thout questions, how am I supposed to learn?

 

[Yggdrasil]

I don't know why you think I have been doing anything but studying, & a HARD crash course at that! With all due respect brother, I bet that there isn't one person who has done this gold recovery stuff in all of history who hasn't had to learn thru trial and error... Every single one of us has had questions throughout... But that's the joy of a site like this! It gives us a chance to come together, when we normally would have to struggle alone the whole way, and help each other through our mistakes... So I don't think you have any business judging me or telling me I shouldn't be using chemicals, who are you to make such a call? Then insult me more by telling me Merry Xmas? Wow! Thanks for welcoming a new person into the wonderful hobby, you really made me feel welcome!

Now.
I kind of agree with CaneDane to some extent. Your questions and use of terminology indicate, but just indicate that you are not up to speed on certain areas.

It may or may not be just your use of terminology.
When it goes to the way he greeted you, well it was harsh and less than welcoming. His primary language is not English, so things may have been garbled in transmission. Anything else he can fill in for himself.

Your reaction was probably out of frustration, we have all been there, and the one thing that do not work, is biting back when corrected.
Suck it up and keep studying.

And not out of disrespect, I do wish you a Merry and fruitful Christmas.

Regards Per-Ove


Edit to add:
Welcome to our forum by the way

 

[MicheleM]

@badestb you wrote: "I don't know why you think I have been doing anything but studying". It is self-evident . I do not know if you tried to study but simply not enough. I suggest you to read ALL the threads on this forum before any attempts to recover precious metals.

 

[Noggin]

I really appreciate that suggestion, I recently started to read that book and am grateful to be pointed in the right direction... Even as trivial as everybody appears to find my question. We thout questions, how am I supposed to learn?

Don’t take that comment too much to heart. Lots of these threads seem to invite these. Where it’s justified is when someone is doing something highly dangerous or polluting. You’re not that guy imho. Welcome to the forum!

 

[MicheleM]

In my opinion we should never underestimate the dangers coming from precious metals recovery and refining, the vast majority of reaction products are highly toxic.

 

[Martijn]

Welcome to the forum Badestb.

Dissving pcb's and gold plated items in nitric is a waste of time and money.
Because to avoid metastannic acid (That grey white stuff you've created) you will first have to leach the solder off with HCL.

Then to avoid creating weak AR while digesting with nitric, you will have to wash and rinse all HCL residue thoroughly. Porous materials will be nearly impossible to rinse good enough.

And the tiny amount of plated gold (microns thick) on a solid piece of basemetal is not worth the chemical waste created and acids used to recover the gold.

Acid peroxide would be a better way imo.

Martijn.

And yes, judging your approach to this suggest you need to study a lot more.
And ask away if you have a question.
Have you read Dealing with waste?
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=85&t=10539