Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

  • To participate in the 911Metallurgist Forums, be sure to JOINLOGIN
  • Use Add New Topic to ask a New Question/Discussion about Hydrometallurgy.
  • OR Select a Topic that Interests you.
  • Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
    Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.
  • Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.

Leaching carbon (5 replies)

G
Teggry
6 years ago
Teggry 6 years ago

Hi,

I have touched on the subject before and am still looking for a cheap, inexpensive way to extract gold from old and undersized loaded carbon.

Question- is it possible to heap leach carbon? I.E. Stack carbon on a pad and leach the gold out of it into a tank/vat to run through an EW cell? 

It seems senseless to keep stockpiling loaded carbon for want of a way to extract the gold if there is a way to do it that doen't involve burning it like has been suggested. 

Something that would be a good project for a junior or graduate Met to get their teeth into.

Cheers

G

M
Mike Rockandel
6 years ago
Mike Rockandel 6 years ago

I vaguely recall a BIOX step in which they releach in presence of additional CN and regenerated carbon. Not a complete removal but there is a transfer of Au from the fine to the desired carbon. Fine partially depleted carbon is then rejected by screening.

renatomerino
6 years ago
renatomerino 6 years ago

The best method to recover the residual gold to activated carbon is by calcination and leaching of the calcine.

Just remember that the desorption of gold is done with high concentrations of cyanide and temperature. The residual gold is the limit that this process provides.

Coal is a fuel and its calcination is a conceptual problem.

T
Todd H
6 years ago
Todd H 6 years ago

Cant really heap leach this - not practical.  You need a flow across the carbon of an eluant that does not contain gold so that the carbon is stripped - soaking in a tank will lead to some extraction but with an equilibrium gold adsorption.  You would have to filter and change solutions a couple of times to get the gold loading down. Atmospheric strips tend to be slower and use more reagents.

You could develop a small strip circuit for this material with finer screens and use a conventional stripping system - AARL, Zadra etc...  You may find that the carbon gold content is as low as it can go - and that calcining is the only option.  You could experiment with an alternative strip solution like chlorides or alcohol (watch the fire hazard here) or glycol.

Todd Harvey - Global Resource Engineering http://www.global-resource-eng.com

r
rob riggir
6 years ago
rob riggir 6 years ago

Cheapest way is to ash the activated carbon and then direct smelt. You can use the same furnace for both stages although keep the temp down for the ashing.

T
TonyE
6 years ago
TonyE 6 years ago

Robs idea is the better option. However, I believe an intense cyanide leach with about 5% NaCN and 2% NaOH with vigorous agitation followed by filtration and a few rinses with soft water will achieve a reasonable stripping of the carbon.


Please join and login to participate and leave a comment.