Graphite crucible would be not a smartest dish to ash something. To successfully ash material you need a lot of air (oxygen) accessing the material, so a steel plate or pan would be much better choice. And you need mixing, for air/oxygen to access deeper layers of material.
IC chips gold recovery
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Good catch, I missed that part.
When you are ashing things you need to do it in an as open as possible vessel and with plenty of oxygen.
So if you ash it properly your graphite crucible will burn as well.
Find something like a cast iron frying pan or similar where you easily can stir it.
PS!
When you have used it in your refining it stays in refining for the rest of its life.
Honestly, thick walled graphite crucibles does not burn that quickly. It is very dependent on the temperature of the crucible. But they burn and shrink, that is for sure
When I am treating smaller Pd(DMG)2 batches, I am used to incinerate in induction furnance on very low power, as graphite conducts heat very well and the temperature can be precisely monitored with IR contactless thermometer.
Of course, some carbonaceous residue is always left mixed with Pd sponge. So in order to burn it, I crank the crucible to dull red heat, and after the emisson of gasses stops, I take the oxygen line and gently blow the oxygen to the carbon/Pd mixture.
At this temperature, graphite isn´t burning that badly, but crucible is hot enough to kickstart the burning of carbonaceous residue inside. I conveniently use oxy/propane burner to deliver oxygen to the inside of crucible (NEVER USE ANY PLASTIC OR COMBUSTIBLE STUFF TO DELIVER OXYGEN TO BURNING THINGS).
And it is also very easy to see if the burning is finished. As oxygen touch red glowing powdery carbon, it start to burn rapidly and you clearly see brighter spot in the place where you are blowing. After a while top layer of carbon is gone and when you are blowing, this top burnt layer is cooled by the oxygen (which is obviously cooler than crucible) and you will clearly see darker spot. This indicates that you burned up all carbon on that spot. Then you mix whole vessel with stainless or graphite rod, apply gentle stream of oxygen again and observe. When you stop seeing any brighter spots as you put the oxygen closer to the material, you are done
Obviously, it is better to take old stainless bowl or pot, where you can easily spread the material to be incinerated - this can greatly speed up the process. Carbon start to burn at ca 400-450 °C, but usable burning rate is over 550-600 °C (in my opinion and from my experience).
I am well aware of the incineration process now. But we don't have propane here, neither Mapp. Have got to work around with a butane gas torch. I know it takes a lot more than the other but this is the best source of ignition that I have. I may DIY a coal burner but that's for later.
Will take this approach then.
Coal, gasoline, butane what ever will do, you only need 600-700 C max.
What is important is: air, time and stirring.
And the heat of course.
Noted with many thanks! Hoping I just don't mess it up
nickton
Well-known member
Whether you incinerate or not it appears like you'll need to put your gold into solution using aqua regia. Why not classify it with a fine mesh screen to extract what looks like some pretty big pieces of the black stuff, then use ar, thus skipping the potentially noxious incineration process? The ar won't do anything to plastic. Maybe I' m wrong but it seems potentially easier.
Also you don't even know if that brown residue is in fact gold. All that incinerating would be for naught if not, no?
I don't really like incinerating unless absolutely necessary. The best low tech way as far as I know is to use a perforated tin to make a primitive afterburner so the fumes get burned off by flames.
Also you don't even know if that brown residue is in fact gold. All that incinerating would be for naught if not, no?
I don't really like incinerating unless absolutely necessary. The best low tech way as far as I know is to use a perforated tin to make a primitive afterburner so the fumes get burned off by flames.
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If you have done your studies, you would know that the carbon in the blacks will bind up Gold that will then be unreachable.
That is the main reason for incineration.
It may or may not be feasible to do a smelting instead when all base metals are removed.
Then you will need to properly refine after, so there is no way around AR.
This is what I fear, but I guess I'll have to do what is recommended.
Also @Yggdrasil has pointed out now and has been discussed many times earlier, I have understood the hang of getting rid of the carbon concept because of its nature to entrap the gold particles when being dissolved or to remove it before gravity separation as it has a tendency to again hold onto some particles with and can drag it in the washing process.
However, two things I still need minute clarifications with,
1, Should I blow and ash it directly? Or try do it the way with a steel pot in a DIY furnace with an open head? (I couldn't find a post focusing on the process of re-incineration of the powdered carbon)
2, Will HCL boil take care of the residue I have remaining or would it be a waste of time and create useless chemical wastage in the end?
Many thanks.
You are misunderstanding, it do not trap Gold particles, it captures dissolved Gold.
That is why they use activated Carbon to capture the Gold from Cyanide or other leaches in mining.
After they treat it to recover the Gold, something not feasible for small projects like this.
Take the powders, put it in a shallow and wide metal/steel container.
Heat it from below and stir it, no need for blowing or other forced air.
When it is at a low red temperature and no sparks come when raking/stirring it and it has an even grey colour it is done.
No need for HCl
Hmm then I think it may take me more time to understand this concept... I'll do this research when I'm free.
Perfect! Close to how I'd imagined it.
Thanks for your help!So I just carried out the said procedure for about an hour and a half and the result seems to be same as it started. I dont feel much of a difference before and after.. is it supposed to be like this? What indication should I be looking for? It all seems greyish black crushed silicon as it was before.
No change.
How should I proceed henceforth?
No change.
How should I proceed henceforth?
Attachments
Recovery of Precious metals :
1. Mechanical Separation of all metallics from non metallics
2 Separation of metallics (Iron /Al and Cu plus Precious Metals)
3. Melting of Cu+PM - Anodes
4. Cu refining and collecting PM Anode slime
5. Recovery PM by Hydrometallurgy
Most Economical, Portable, Feasible and high accountability
1. Mechanical Separation of all metallics from non metallics
2 Separation of metallics (Iron /Al and Cu plus Precious Metals)
3. Melting of Cu+PM - Anodes
4. Cu refining and collecting PM Anode slime
5. Recovery PM by Hydrometallurgy
Most Economical, Portable, Feasible and high accountability
That flame from your propane burner appears to be orange is that just the tip of the flame because when the flame is blue it’s hotter . Strong blue flame not a “lazy / dancing orange “ flame
My bad I see it’s coal now, cut a hole in the bottom of that container get 3-4” inch duct and a blower fan and install to induce a better draft. Then you can melt iron with that “
It looks cold to me. For natural air circulation, not forced oxygen. Not even red hot.
Hydrometallurgy isn´t the only way to do this, and yes, it is the worst option here. One of the fastest ways to process IC´s is thorough incineration, where you benefit from combustion heat to sustain the burning in nicely isolated furnance, only then aid with some heatgun hot air to continue incinerating till carbon free. Separate the magnetic legs and powder. Smelt the powder with some collector of your choice, lead/bismuth molten dip the magnetics.
Your final product will be enriched metallic bead from ashes and lead/bismuth blob, which can be easily cupelled. Eventually you combine these two together and cupell at once. Some people just pyrolyze the chips, then sluice the powder and treat legs with AP. There is many possibilities how to do this.
But with incineration/smelt/molten Pb/Bi dip - no AP leaching, no gallons of greenish-black acidic junk you need to treat and dispose. Molten lead/bismuth dip isn´t 100% efficient, but you can always bath the legs the second time and save this Pb/Bi wash for next batch. All in all, hydro in this case also isn´t 100 % efficient
