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.

Optimum Heap Leach Crush Size (10 replies)

Tarun Karakoti
8 years ago
Tarun Karakoti 8 years ago

What is the minimum size of ore in gold heap leach? Without problem of percolation!

(unknown)
8 years ago
(unknown) 8 years ago

It depends on what the particle is, if it is a clay or expanding shale you would want it fairly coarse, if it is quartz or similar the finer the better. If you look at tank leaching, the sizes are in the - 300 micron range. But usually the question is the reverse, what is maximum size which allows lixiviant contact with gold particles (no contact no leaching).

Tarun Karakoti
8 years ago
Tarun Karakoti 8 years ago

Finer particles lead to more recovery. Can apply particles for instance with P80 about 1 mm or finer without any problem like percolation?

Helena Russell
8 years ago
Helena Russell 8 years ago

The premise, no problem of percolation is really not a relevant question. The solution is to test what size distribution after test work gives the optimum gold recovery. Sometimes it is beneficial using agglomeration incorporating cyanide.

O
OberstGruppen
8 years ago
OberstGruppen 8 years ago

It depends on mineralogy with some swelling clays. But the use of cement agglomeration fine particles (flotation tails) can be heap leached. Percolation is influenced by the irrigation rate. But the real question to answer for new ore bodies is how coarse can the ore be leached. What is the material you wish to heap leach?

(unknown)
8 years ago
(unknown) 8 years ago

But I have a question so further size reduction in Vat leaching will it not defeat the purpose of it as we mostly treating low grade ores so crushing or grinding further wont it increase cost? What’s the minimum, optimum and economic size for vat leach is my question? If it makes any sense

Sachin Prakash
8 years ago
Sachin Prakash 8 years ago

Simple oxide ore (host is limestone)

Helena Russell
8 years ago
Helena Russell 8 years ago

Vat leaching low grade ore is normally not economically if grinding is needed to get any useful extraction however a series of column tests will give you a pointer of what is required in size reduction by crushing.

O
OberstGruppen
8 years ago
OberstGruppen 8 years ago

Bench tests will help to understand the optimum crush size. I suggest that the residue grade be used for defining optimum P80 size. The use of percent extraction does not account for the differences in calculated head grade between samples. Differences in residue grade are directly related to value.

Vat leaching should be used if the volume of ore treated is small. Otherwise I would recommend a permanent heap. I worked on one ore that had no new ore placed for 6 years and the production rate was 5000 oz Ag/day. I have worked on Cu heaps that had no new ore for over 20 years, yet production was 100 tpd. Note the amount of ore under leach to obtain these productions was significant. The example of Cu was a change in residue grade per year was 0.001%. This is lower than sampling and assay error. Small amounts of metal extracted per ton per unit time add up to a significant amount if the tonnage leached is high enough.

David
8 years ago
David 8 years ago

Heap leaching is a low-cost method that is most suitable for treatment of low-grade materials that do not justify the higher costs of grinding and agitation leaching. Ores can be treated either at a run-of-mine size or as crushed material, with the optimum size determined as a trade-off between gold recovery and crushing costs. Material handling requirements may also play a role in optimizing particle size for heap leaching because large particles may be difficult to transport by conveyor systems. This is an important factor in situations where conveying presents the most efficient method of material transport.

https://books.google.ca/books?id=OuoV-o_Xf-EC&lpg=PA266&ots=As4y-hzpv5&dq=Optimum%20Heap%20Leach%20Crush%20Size&pg=PA266#v=onepage&q=Optimum%20Heap%20Leach%20Crush%20Size&f=false

Use the Social Share Bar on the Left. Tell everyone you can about https://www.911metallurgist.com/metallurgy/ It's FREE & GOOD.

N
Nurettin
6 years ago
Nurettin 6 years ago

 

minimim size depends on screening quality and stacking homogeneity and partical shape.

if you have a bad size distribution percolation will increase but leaching quality will decrease. 

if you have good size distribution percolation will decrease but leaching quality will increase. 

Focus on stacking homogeneity. 

More homogenity will increase leaching quality and percolation optimization. And will help to you for decreasing maximum partical size.


Please join and login to participate and leave a comment.