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.

Does solution grade negatively affect gold solubility (5 replies and 1 comment)

H
Henley Munn
5 years ago
Henley Munn 5 years ago

Hello

In a gold heap leach is there a relationship between the ILS Au ppm, the dissolution rate of gold from ore, the ore grade and amount of free cyanide.

If there is still free cyanide in solution will gold in ore still be soluble or is the dissolution retarded by high aurocyanide concentration in solution, is there an equilibrium point or a general rule of thumb for determining it?

Maybe this can only be accurately determined through test work?

Any info or research papers you can suggest would be greatly appreciated.

J
John R
5 years ago
John R 5 years ago

It is unlikely that the gold tenor affects gold leach rate.  Gold tenors are generally in the mg/L and it is a product, not reactant.  Oxygen and cyanide concentrations are however almost always important.  It is also free cyanide that is important, not cyanide complexed with copper, iron or even H+.

Ron G
5 years ago
Ron G 5 years ago

I agree with John R. The gold cyanide complex remains soluble >50g/l. One is very unlikely to be anywhere near that for leaching. The important aspect is the absence of other competing metal ions, especially copper, that could sequester the free cyanide. 

H
Henley Munn
5 years ago
Henley Munn 5 years ago

Thanks for the info guys.  We do have higher levels of copper in the ore.  The head grade of the stacked ore is between 0.5 and 0.6g/t.  Below is a bit of a discharge profile from our heap.  

(Cell1 - 0.74pp Au, 4.14ppm Cu)  (Cell4 - .114 ppm Au, 1.05ppm Cu)  (Cell 7- .193ppm Au, 2.17 ppm Cu)  (Cell 9 - .901ppm Au, 24.84ppm Cu)

If the ILS grade is 0.164ppm Au, would pumping it onto cell 4 still upgrade the solution in your opinion? 

We run ILS at 170ppm NaCN and ph of 11.

T
Todd H
5 years ago
Todd H 5 years ago

Agree with those above - free cyanide and oxygen are main issues.  The level of copper in your solution is not terribly high. Are you getting a lot of copper in your ADR circuit, that is the first indication of an issue.  You may want to look into a SART process to treat a bleed stream to keep the copper in check.  What is your cyanide consumption like?

 

Regards

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

H
Henley Munn
5 years ago

Consumption is around 0.39kg/t Ore is agglomerated with the agglo water at a ppm of 1000. off flow from the heap typically has a cyanide ppm of 10, although the first two cells can range up to 40ppm, likely drops off as the cyanide in agglomerate is used up.

T
Prince Mulaja
5 years ago
Prince Mulaja 5 years ago

i am trying to work out the cobalt recover during the precipitation process. in fact the precipitation take place into six thanks of 470m3 each and the flow of the raffinate (Feed) is 350m3/h the grade of cobLt into the feed is 2,5 percent. the precipitation reagent is magnesia. i have been ask to calculate the amout of cobalt precipitate or recover as well as the amount of magnesia consume. anyone can help


Please join and login to participate and leave a comment.