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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Leaching of gold ore with higher amounts of base metals. (4 replies)

Fahmy
2 years ago
Fahmy 2 years ago

Hi guys, I’d like to know what does the blue color indicate in the barren solution from VAT leaching, plus excessive dropping of cyanide concentration, I understand this occurs from the presence of higher amounts of other metals in the ore, but I don’t know exactly what are the metals. And how can you treat the metals for efficient and lower cost leaching.

J
Jorge
2 years ago
Jorge 2 years ago
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A blue color indicates the presence of copper. It is important to determine the mineralogical specimens in the ore. A bottle roll testing program can be performed to determine the gold extraction and the dissolution of copper. Sometimes, it is not economic to process this kind of material. 

If you have logging data, you should review it to get an idea of the ore quality.

Mike
2 years ago
Mike 2 years ago
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As jore said, the color is probably due to copper.  Copper being soluble in cyanide can (usually) lead to excess cyanide consumption.  See: https://www.911metallurgist.com/blog/dissolution-of-precious-metals-in-copper-cyanogen-complexes)

This does not mean that the ore cannot be leached, but does mean a more complex process maybe needed.  Such as an ammonical leach for the copper followed by cyanide for the precious metals.  This will require vat or tank leaching.

An alternative is flotation, especially if the ore grades (including copper) are high enough.  See: https://www.smartdogmining.com/topics/Cyanide%20Alternative.html

 

H
Zimbo
2 years ago
Zimbo 2 years ago
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A related question. Has anyone seen a "purpleish" coloured solution when doing a cold cyanide wash of loaded carbon from an auriferous copper cyanide leach? If so do you know what it is?

This cold wash is of course to reduce copper loading before elution.

H
Zimbo
2 years ago
Zimbo 2 years ago
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herewith a photo

 

IMG 4757
https://www.911metallurgist.com/wp-content/uploads/2022/02/IMG_4757-scaled.jpg

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