Activated carbon Ashing

[Eg.refiner]

Guys i need to Ashing activated carbon loaded with gold to get gold
Does any one know how to Ashing Activated carbon
1- can i calcine the activated carbon in graphite crucible and gas furnace ?
2- what is the required temprature ?
3- how many hours ?
4- does it calcone in open air or inert atmposphere ?

 

[stoneware]

When ashing activated carbon it burns very slow and does not show any flame but you can feel the heat coming off. I do mine in open air.

 

[rename]

Hi friends.
Activated carbon can be calcined if ground to 100 # and ground with dilute sodium nitrate solution.

 

[rename]

Analysis of gold in activated carbon.
1000 grs / ton

 

[Deano]

For practical purposes most people ash at 600 - 650C overnight in an electric muffle furnace, using a gas fired furnace will lead to losses due to the light ash blowing out the furnace exhaust.

The most important aspect of ashing is the depth of the carbon bed, if it is deeper than around 1 cm you will blanket the carbon with ash and the reaction will need rabbling of the bed at intervals to get complete ashing.

The door of the furnace is cracked open about 1 cm to allow the air access needed for ashing to proceed.

Always best to use coarse piece activated carbon as per what the gold industry uses, fine powder type carbon will adsorb gold quickly but is very prone to blanketing during ashing.

Asking is usually done in 316 ss trays with edge turn ups of around 1 cm.

You can layer the trays keeping about 40mm spaces between trays, use 25mm ss tube lengths as spacers at each corner of the trays.

Deano

 

[jadedalex]

Deano, glad to see you are still here. Your Pyrolization vessel is Genius. Eg.refiner, what Deano said...

 

[NanoCat]

For practical purposes most people ash at 600 - 650C overnight in an electric muffle furnace, using a gas fired furnace will lead to losses due to the light ash blowing out the furnace exhaust.

The most important aspect of ashing is the depth of the carbon bed, if it is deeper than around 1 cm you will blanket the carbon with ash and the reaction will need rabbling of the bed at intervals to get complete ashing.

The door of the furnace is cracked open about 1 cm to allow the air access needed for ashing to proceed.

Always best to use coarse piece activated carbon as per what the gold industry uses, fine powder type carbon will adsorb gold quickly but is very prone to blanketing during ashing.

Asking is usually done in 316 ss trays with edge turn ups of around 1 cm.

You can layer the trays keeping about 40mm spaces between trays, use 25mm ss tube lengths as spacers at each corner of the trays.

Deano

we used to use fine Mesquite charcoal straight up, i.e. not activated with OH. The Mesquite shot really clean on XRF. But then there's the ash factor, so I'm currently using micron scale Lamp Black pure C. I seem to be able to get to ash at 650F, door cracked, then stirring with rod will get more O2 going and generate orange heat glows. Takes at least 2 hrs. No more smoking and no more glowing and I pull it. Gives up extremely fine white metal. I then run that product in 20% H2SO4 hot for hours, to eliminate any residual C and cut out the junk metal, usually Fe, Cu.
Anyone ever use Lamp Black and ash? Maybe I should use more heat 1200F?

 

[Abdullah68]

After ashing active carbon how to recovery gold

 

[Deano]

Digest the ash in aqua regia, simmer until all of the brown fumes have stopped coming off and the fumes which do come off are white, continue simmering for another 10 minutes or so to get rid of the last traces of nitric acid.

Allow to cool, filter and you have your gold in solution.

Deano

 

[rename]

The product of burning activated carbon is ash and soluble metal salts and powdered gold.
Personally treat the ash with dilute nitric acid and the residue that remains from filtering is melt with borax and carbonate.

 

[Eg.refiner]

Analysis of gold in activated carbon.
1000 grs / ton

What flux i should use to melt the ash ? And what is the quantity of flux per 100 gram ash

 

[Eg.refiner]

Analysis of gold in activated carbon.
1000 grs / ton

What flux i should use to melt the ash ? And what is the quantity of per 100 gram ash

What flux i should use to melt the ash ? And what is the quantity of flux per 100 gram ash

 

[arwzim]

Hi
I have access to about 5 tons of spent activated carbons a month. I would like some ideas how l can ash a decent volume. Say around 200 to 250kgs at a time. I would like to purchase a commercial furnace set up but my budget won't allow it. I will be using Cyanide leaching to process ash.

What l would like to know
Any ideas on building and designing an ashing oven to do 250kgs plus at a time.
Something that can be built at a diy level.

Regards
Arwzim

 

[sethby]

Hi friends.
Activated carbon can be calcined if ground to 100 # and ground with dilute sodium nitrate solution.

Can this be done in a microwave?

 

[Yggdrasil]

Can this be done in a microwave?

No I don't believe so.
Which microwave can be kept at 600 C for 8-12 hours?

 

[kumbirai.mhere]

When ashing activated carbon it burns very slow and does not show any flame but you can feel the heat coming off. I do mine in open air.

What do you use to ash it in open air?

 

[Yggdrasil]

What do you use to ash it in open air?

One usually ash it in a suitable furnace/kiln where you can have a door open so it get access to Oxygen.
Best is electric, since they are easy controllable.

 

[jphayesjr]

Digest the ash in aqua regia, simmer until all of the brown fumes have stopped coming off and the fumes which do come off are white, continue simmering for another 10 minutes or so to get rid of the last traces of nitric acid.

Allow to cool, filter and you have your gold in solution.

Deano

And if the pellets are known to contain significant PGMs, Deano, especially PD?

 

[Yggdrasil]

And if the pellets are known to contain significant PGMs, Deano, especially PD?

AR and even Nitric will dissolve the Pd and Ag, for Pt and Au only AR will do.
This have to be done after ashing or the Carbon will “steal” some of the PMs

 

[Deano]

Aqua regia will put platinum and palladium as well as gold into solution from the ash, use whichever preferred recovery method you wish to recover these from solution.
Heated stronger aqua regia forms are recommended, 1:4 was used in South Africa in similar operations.
I do not play with platinum group metals because of health concerns.
Deano