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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Fine carbon from CIL plant , (1 reply)

A
Ajouhi
2 weeks ago
Ajouhi 2 weeks ago

We operate a CIL plant (8000 t/d), we recover fine carbon after elution and regeneration. I am concerned that the fine carbon recovered after screening the regenerated carbon has a higher grade (1000 ppm) compared to the eluted sterile carbon (100 ppm on average). 

Can anyone explain how this is possible? We have checked all the carbon circuits and nothing seems to be wrong.

thank you for your help explain how this is possible? We have checked all the carbon circuits and nothing seems to be wrong. 

thanks for your help 

 

J
Jorge
2 weeks ago
Jorge 2 weeks ago

It is well known that most of the gold absorbed by activated carbon can be removed during elution. But it is also possible that the carbon has the Ca(Au(CN)2)2 complex present, which can be partially removed during the acid wash because the addition of HCl can decompose the compound to form Au(CN). The source of calcium is mainly from the addition of lime. Also, the acid wash opens the pores and allows a better exposure of these to the acid wash. Lime is almost totally removed and Au(CN) is reported in the carbon. The reaction is shown below,

Ca(Au(CN)2)2 + 2HCl → 2Au(CN) + 2HCN + CaCl2


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