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

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction2017-04-04T06:57:36-04:00
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Cyanide Alternative in Gold Leaching (6 replies)

Tarun Karakoti
4 years ago
Tarun Karakoti 4 years ago

Can Sodium Ferrocyanide replace Sodium Cyanide in mining?

4 years ago
Oberfuhrer 4 years ago

Sodium cyanide, NaCN, is by its anion CN-, a strong complexing agent for precious metals, and therefore used in gold leaching. Sodium ferrocyanide, Na4[Fe(CN)6], is by its anion [Fe(CN)6]4- also a strong complexing agent for most transition metal ions with oxidation state +II, e.g. Cu2+, Pb2+, Zn2+, but not for the precious metals. And it is fairly non-toxic. Another name for ferrocyanide is hexacyanoferrate. The short answer is - no.

4 years ago
(unknown) 4 years ago

Actually, no, but it is rather thiourea that is gearing up to replace Sodium cyanide. Go to the onemine.org site and you would get more information for thiourea and its activities in the mineral processing industry. Sodium Cyanide has been used for 100 years and over but it replacement is on the way coming and Sodium ferrocyanide is not part of the variables being considered.

Jean Rasczak
4 years ago
Jean Rasczak 4 years ago

If scientist can also research deeply into hypochlorite! Then it can also be used to replace NaCN.

4 years ago
(unknown) 4 years ago

What is in the comparison of hypochlorite to NaCN, can I get some details?

4 years ago
Oberfuhrer 4 years ago

In flotation a small addition of cyanide is sometimes used to depress pyrite. One possible reason it works might be through creation of an insoluble and hydrophillic iron-hexacyanoferrate on the mineral surface. So, in theory an addition of ferrocyanide might have a similar function.

Do you have any specifics; you can share, on your client's use of ferrocyanide?

Zander Barcalow
4 years ago
Zander Barcalow 4 years ago

Ferrocyanide appears to be an attractive depressant for pre-activated pyrite. Some work of ours has shown that ferrocyanide can play a similar role to DETA, by attacking collector-Cu at the surface of pyrite and taking some of it into solution, leaving the overall Cu loading much reduced. At the same time, some Fe(CN)6(4-) stays at the surface, and much of the remaining surface Cu is in the Cu(II) form. We are finishing some spectroscopic work on this at present to publish following our work on DETA (Agorhom et al., Minerals Engineering, 57, 36-42 (2014)).

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