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

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

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Determining if leaching is complete (4 replies and 4 comments)

L
Lazaro
1 year ago
Lazaro 1 year ago

Hello!! I want to know how can I determine if the leaching is complete or not during vat leaching  process of Gold, and if there is a method what are the chemistry behind that process.Thanks

SmartDog
1 year ago
SmartDog 1 year ago
  1. You will never get all the gold.  Depending on your ore and how you processed it before leaching 75 to 80 % would be phenomenal (50% would not be unheard of).
  2. Usually you will set a a minimum cutoff grade for the leachate, some number you are happy with (e.g. it makes it worthwhile to process).
  3. Also when you need the vat for fresh ore. 
  4. There are no clear guidelines, just what works for you.
R
sbccbalaji
11 months ago
sbccbalaji 11 months ago

you can test the pregnant solution if it contains gold. If not then it is over. 

L
Lazaro
10 months ago

Thanks so much 🙏

J
Jorge
11 months ago
Jorge 11 months ago
1 like by Lazaro

I think, sometimes vat leaching is a tricky process. It is important to evaluate other process such as heap leaching or direct leaching. Obviously, the gold grade and the reserves are key aspects to consider in this kind of study.

if the vat leaching operation is not in steady state, any sample taken to evaluate the process will not representative. 

If you want to determine the maximum gold extraction, you should perform bottle roll tests at different sizes (e.g. 1", 3/4", 1/2", 1/4" or finer). Also, it is important to maintain the cyanide strength, pH and slurry density. It is necessary to take samples of pregnant solution at 2, 4, 8, 12, 24, 48, 72 and 96 hours. In this way, you will have a complete profile of the gold extraction. 20 liters plastic bottles are appropriate to perform the tests.

 

S
Kazimiry
11 months ago

As Smartdog said leaching at 100% is inevitable. just commit color test every morning to monitor extraction behevior of you tanks.
by using zinc dust.

L
Lazaro
10 months ago

Exactly but can I get the chemistry behind color test by zinc dust...??

SmartDog
10 months ago
Tich
10 months ago
Tich 10 months ago
1 like by Lazaro

Basic chemistry for color test is from the reactivity series,.

in a gold solution if you add zinc,The gold will be displaced in the solution because Zinc is more reactive. Gold will deposit, the gold is then dissolved by Aqua regia in a boil,the resultant solution is a gold solution.

the solution is left to cool down.An stannous chloride indicator is used,in the presence of gold it shows a colour ,the darker it is the more Au it contains. If its clear then no leaching has ended.

 


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