BURNING ACTIVATED CARBON
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goldmet
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In the leaching of auriferous gold ore it is dissolved and a way to recover those solutions is absorbing it with activated charcoal.goldmet said:
One way to recover gold that coal is burning. In the ashes is gold and these can be melted or disolved with aqua regia.
Does it make a lot of red gas when the nitre melts and burns the carbon? I would think if this weren't balanced right there could be some NOx. I know if you just melt salt peter or nitre, it decomposes to oxygen firstly, then eventually NOx.
I roasted my activated carbon with a pot and I used domestic gas cooker to ash the carbon. I smelted with borax and saltpeter (nitrate) but my gold is mixed with the slag. What's the process of digesting the ash carbon with both Nitric acid and aquaregia to recover both silver and gold from the ashed activated carbon. Thanks
Topher_osAUrus
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keemola said:
So you ashed your activated carbon? And then you tried smelting the ash/gold mixture with borax and saltpeter?
Why?
If the carbon is all completely white ashed, you could just process the gold like its ic chips, or jeweler sweeps I would imagine..
What was the gold from in the first place? If it was pure gold, a nitric leach would have no effect on your gold/ash residue.
-i suppose it (nitric) would eat away the borax and liberate your gold.. But, if its stuck as prills in the slag, you could add fluorspar to make it more fluid so they could agglomerate.
Also, you could add silver (75%) and then it would capture the gold, pour cornflakes, digest in nitric, then take the gold up into solution and do the normal things one would do.....
Do you have a picture you could post? Im intrigued
The pictures are the ashed carbon and the slag that mixed with gold. How can I recover gold from both materials. I intially used borax and saltpeter to smelt the ash but we discovered the gold is mixed up with slag in particle form after grinding the slag into powder. How can I recover gold from both ashed carbon and slag. I read in a post that I could use acid digestion for the ash. Thanks as awaiting ur contributions and directions.
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goldmet said:
Oxygen is formed when high (above 600°C) heating of sodium nitrate NaNO3:
2NaNO3 t→ 2NaNO2+O2,
thereby can interact with nonmetals
2NaNO3 + C = 2NaNO2 +CO2
maltodextrin acts as a binder, like gelatin in the marmalade
what would the mixture is crumbled.
I think that maybe fast(turbulent) combustion, :!: because the mixture of sodium nitrate and carbon are used in the manufacture of gunpowder.
Sorry for bad English...
anachronism
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650 degrees C is the magic number. Too low and it doesn't work. Too high and you get complications. You cannot be random about it.
Whats next after ashing the carbon. I tried to digest the ashes in nitric acid and aquaregia. For ash in nitric acid, the solution has a greenish colour and some particles settled. For ash in aquaregia, the solution turned brownish and undisolved particles also settled bellow the liquid. The aquaregia later turned thick and pastelike. how do I recover the gold?
anachronism
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If you are getting particles after a FULL digest- note FULL digest, then you have un-ashed carbon so you will need to filter the solution and re-ash that residue. Remember that un-ashed carbon will have also taken values from your AR so don't throw it away.
If your AR solution is thick and sludgy then you have either not added enough liquid and the digestion is not complete, or you have a huge amount of un-ashed carbon and then you need to look further at your ashing process.
I used to initially treat with Nitric before digesting in AR but I have reverted to Deans original instructions of putting the ash straight into AR because it simply works best.
Now one point to note (and an Australian friend of mine is probably going to have a wry chuckle as he reads this) is that you MUST elevate the temperature of your AR to a simmer to fully digest- around 90 degrees Celsius. NOT a boil but a simmer. Then you will see a vast difference in the digestion.
This process is great however it MUST be done properly otherwise you lose all the benefits of this method over others.
If your AR solution is thick and sludgy then you have either not added enough liquid and the digestion is not complete, or you have a huge amount of un-ashed carbon and then you need to look further at your ashing process.
I used to initially treat with Nitric before digesting in AR but I have reverted to Deans original instructions of putting the ash straight into AR because it simply works best.
Now one point to note (and an Australian friend of mine is probably going to have a wry chuckle as he reads this) is that you MUST elevate the temperature of your AR to a simmer to fully digest- around 90 degrees Celsius. NOT a boil but a simmer. Then you will see a vast difference in the digestion.
This process is great however it MUST be done properly otherwise you lose all the benefits of this method over others.
Eg.refiner
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Can i use coconut shell carbon for water treatment size 6x12 in jinchan solution or it should be gold activated carbon
There is no such thing as gold activated carbon.
The carbon is activated by physical or chemical way.
Fully activated carbon is a fine fluffy powder. I guess it can be pelletized for easier use in canisters and such, but it will loose some if its surface area and effectivity.
Please do not spam the forum like you did today. Ask your question once at one location.
Many of your questions today was asked to old posts. The recipients may not even be here anymore.
Eg.refiner
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Thank you for your info , i'm sorry
Geo
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It is much easier to use any hardwood that grows in your area or buy "lump charcoal", wherever you buy charcoal. To activate the charcoal it needs to be submerged for a prescribed length of time in at least one of the several chemicals that can be used that will neutralize the acid and create an oxide or carbonate with the precious metal salts. Charcoal is very easy to crush into a powder and formed into shapes. Niter or NaNO3 is added to help the carbon burn evenly to ensure complete combustion.
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Most water filtration activated carbon, is treated with Silver somehow. This reduces and/or eliminates bacterial microbes. I am not sure if this AC is good for gold adsorption or not. Any moderators want to jump in on this?
I just add that nitrate do not form nitrogen oxides when oxidize carbon. Instead it will form sodium or potassium carbonate the very principal burning equation of black gunpowder, if you do not add sulfur to the equation.
Of course, with non-stoichiometric ammount of nitrate to charcoal (black powder is roughly 75% KNO3 15% C and 10% S to burn practicaly "in balance", i would be worried that not all carbon will burn easily and remain in the ashes. Controlled burning of such made pellets would certainly easen the process, but it will be probably needed to incinerate the remaining ashes anyway. When burning nitrate/charcoal mixtures, good ammount of sparks could arise from it, possibly with your gold flying in ashes all over the place.
Another problem I see is the quite a big ammount of carbonate produced, which in the end need to be neutralized with unhealthy excess of acid just to allow adding acid for actual gold dissolution, when you use AR to get your gold into the solution.
Way how big guys do it: use small pelletized charcoal, not the "flour" or powdered stuff. You add the pellets or small lumps to the pregnant leaching solution, fish them out with strainer after adsorption (carbon will float on top) and after washing and killing possible cyanide, dry and burn in furnance or on steel pan over gas burner. Pretty much nothing is left, ammount of ash is very small. And you can clearly see when it is done, judging by the colour of the ashes. With incomplete burning with nitrate, various funky greyish stuff/slag-like junk form, which stay greyish practically forever, no matter how long you bake it
the very principal burning equation of black gunpowder, if you do not add sulfur to the equation. Of course, with non-stoichiometric ammount of nitrate to charcoal (black powder is roughly 75% KNO3 15% C and 10% S to burn practicaly "in balance", i would be worried that not all carbon will burn easily and remain in the ashes. Controlled burning of such made pellets would certainly easen the process, but it will be probably needed to incinerate the remaining ashes anyway. When burning nitrate/charcoal mixtures, good ammount of sparks could arise from it, possibly with your gold flying in ashes all over the place.
Another problem I see is the quite a big ammount of carbonate produced, which in the end need to be neutralized with unhealthy excess of acid just to allow adding acid for actual gold dissolution, when you use AR to get your gold into the solution.
Way how big guys do it: use small pelletized charcoal, not the "flour" or powdered stuff. You add the pellets or small lumps to the pregnant leaching solution, fish them out with strainer after adsorption (carbon will float on top) and after washing and killing possible cyanide, dry and burn in furnance or on steel pan over gas burner. Pretty much nothing is left, ammount of ash is very small. And you can clearly see when it is done, judging by the colour of the ashes. With incomplete burning with nitrate, various funky greyish stuff/slag-like junk form, which stay greyish practically forever, no matter how long you bake it
Try doing the obvious testwork on your carbon.
This involves putting a 3 particle thick layer on a stainless steel or porcelain tray.
Ash overnight at 650C in an electric furnace with the door cracked open 5mm for air ingress.
In the morning allow the tray to cool, transfer the ash to a beaker containing 1:4 aqua regia.
Simmer until the brown nitric fumes have stopped evolving, then give it a further 10 minutes or so to get rid of any trace residual nitric.
After cooling, filter, make to volume and assay the liquor, best done by AAS on a DIBK/Aliquat 336 organic extract.
Compare the results from this analysis with any alternative methods, the losses from the alternatives are horrendous.
Deano
This involves putting a 3 particle thick layer on a stainless steel or porcelain tray.
Ash overnight at 650C in an electric furnace with the door cracked open 5mm for air ingress.
In the morning allow the tray to cool, transfer the ash to a beaker containing 1:4 aqua regia.
Simmer until the brown nitric fumes have stopped evolving, then give it a further 10 minutes or so to get rid of any trace residual nitric.
After cooling, filter, make to volume and assay the liquor, best done by AAS on a DIBK/Aliquat 336 organic extract.
Compare the results from this analysis with any alternative methods, the losses from the alternatives are horrendous.
Deano
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