# Hydrofluoric acid to remove ceramic bits?



## jmfranc (Nov 19, 2013)

I have filtered all of my last piles of cermaic cpu bits, glass specs, gold flakes, and dust (created from smashing the cpus).I want to dissolve the ceramic and possibly the glass. 

What ratio? I have powdered Ammonium Bifluoride 98% and Sulphuric acid concentrated to98%. Mixing the two should give me Hydrofluoric acid, correct?

I was thinking - why not just dissolve the ceramics and get it out of the way? Of course, I could just nail it with Agua Regia and get the gold and other metals but I have other uses for Hydrofluoric acid if this works. And I like to get my gold and clean as possible before AR.

I would eventually like to run ceramic cpu chunks through Hydrofluoric acid to separate the different materials so that I can get access to everything in cpu. And it might even eat the glass away leaving me with just a pile of gold flakes. The glass came from old early 80's tv cpu's that had a good bit of gold on them but the glass had to be smashed to access the processor.


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## grance (Nov 19, 2013)

Uuhh most here probably dont use hydrofluric because its so dangerous. I would suggest you rethink useing it aswell. Hydrocloric and nitric well get what ever you need done and a little less dangerous. They are still vary dangerous if you dont know what you are doing.


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## rickbb (Nov 19, 2013)

No one in their right mind would even think about using hydrofluoric acid.

It's that dangerous, don't, just don't.


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## nickvc (Nov 19, 2013)

As Grance said we don't really advise anyone to use hydrofluoric acid here on the forum due to its extreme capacity to maim or even kill if your not fully aware of the risks. Again I agree with Grance use AR and leave the ceramics etc in the filter, if your gold isn't clean enough re refine it. Whatever use you think you have for hydrofluoric acid I suggest you google it and it's dangers before even trying to make or use it, it doesn't take prisoners!


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## samuel-a (Nov 21, 2013)

Let me join the party too...

I don't know your level of education, your setup, experience and your over all intelligence.
But judging just by the fact that you even ask what you just asked, is a sure sign you don't really know much about what you are talking about. Messing around with HF will most likely kill you.
BTW, It makes no economical sense as it will requires very large amounts of HF to dissolve ceramics.

pls, don't go toward the bright light just yet... stay with us for a while.


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## mls26cwru (Nov 21, 2013)

HF is nasty.... it is a calcium seeker...it is absorbed into you skin very quickly (in vapor or liquid form) and heads straight to your bones... where it eats through your skin from the inside out. Stay clear of this stuff unless you have FULL hazmat gear, fully contained breathing apparatus, and a lab equipped to deal with it.


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## Captobvious (Dec 15, 2013)

Seriously.... people need to watch Breaking Bad before messing with HF :roll:


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## goldsilverpro (Dec 15, 2013)

In 47 years of refining, refining about every type material under the sun, I have never, not once, had a need to use HF. I have used it for electroplating and analysis, but never in refining.


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## eagle2 (Dec 19, 2013)

Also, every wiff you inhale accidentally or otherwise permanently damages your lungs.


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## Harold_V (Dec 20, 2013)

jmfranc said:


> I have filtered all of my last piles of cermaic cpu bits, glass specs, gold flakes, and dust (created from smashing the cpus).I want to dissolve the ceramic and possibly the glass.
> 
> What ratio? I have powdered Ammonium Bifluoride 98% and Sulphuric acid concentrated to98%. Mixing the two should give me Hydrofluoric acid, correct?


Such contamination is removed after dissolution of the values, and is accomplished by filtration. 

I'm confused by your comment about filtering your cpu bits. Did you mean screen? If you did not, and these particles contain values, you've filtered at the wrong point in time, unless your objective was to eliminate any dissolved base metals. If you'll dissolve the values, they can be separated from the solids easily. 

When I filtered material, the filter and contents were incinerated, then stored for future processing (by furnace). That way, any traces of values that may be present (including silver chloride) will be recovered. If your flux is proper for the application, glass will be dissolved, and ceramic bits absorbed by the resulting slag. Do NOT endanger your well being pursuing something that is not worthy of being pursued. 

Harold


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## NobleMetalWorks (Dec 22, 2013)

There is no reason you should ever need to use HF when processing ceramic CPUs. There already exist well documented, as well as video instructions, on how to process CPUs. You do not need to re-invent the wheel or attempt to find some better method to process CPUs, specially when you are just starting out.

As you have already read, HF is extremely dangerous. Just one lungful of the gas from 70% hydrofluoric acid is enough to kill a person, and getting the same concentration of the acid on just 2% of skin results in death. Considering these facts, I wouldn't play at attempting to make HF, nor entertain the thought of using it.

There is another issue you may not have considered. If you dissolve silicates, glass, ceramic, etc into your solution that also has values, how are you going to recover all the values? Everything you put into solution has to be separated, so by dissolving only what you must in order to process any given material for it's values, is always the best option. Dissolving other things you have no need to dissolve, into a solution with values, is just wasting time, effort and energy.

Scott


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