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comparison between thiosulphate and direct cyanidation (4 replies and 3 comments)

3 months ago
kahonde 3 months ago

hie i am a student metallurgist at Mrasta mining pvt ltd in Zimbabwe.recently we have been facing challenges in trying to vat leach sulphide-gold ore.i proposed to change the lixiviant,better yet do a comparison between cyanide and ammonical-thiosulphate.i want to hear your views on thiosulphate leaching,thank you.

stephen barrington
3 months ago
stephen barrington 3 months ago
1 like by kahonde

Good day i am also in Zimbabwe and looking to get involved in cyanide gold leaching. Please contact me as I would like to learn want to do and how to do it.

I am really new to all this many thanks.

3 months ago
max skinner
3 months ago
max skinner 3 months ago

One good way is a process I have been working with, nano grinding in an attritor, or something like an Isa mill. You do this in a solution of sodium or ammonium thiosulfate, I have been getting recoveries in the high 90's, you can google this process. Likely cyanide would also work as in my case this is more of a liberation grind thing. I have gone to the thiosulfate because I am in California and cyanide is very difficult to permit here. 

3 months ago

Max, are your ores high in sulfide?

3 months ago

yes they are

3 months ago
David 3 months ago
3 months ago
Bhaduri 3 months ago
2 likes by Charlie and kahonde

Kahonde, Ammoniacal thiosulfate w/Cu+2 as a catalyst is good for leaching Au from carbonaceous ores; unlike cyanide where the dissolved AuCN complex will be "preg-robbed" by the organic carbon (humates); if the Au is encapsulated in refractory sulfides such as pyrite, orpiment, realgar & the like, a pre-treatment step such as roasting is necessary for liberation; if Au is present in the grain boundaries of a sulfide mineral such as marcasite (same composition as pyrite but structurally different), it may be possible to liberate the metal for cyanidation or thiosulfate leaching by a soda ash/caustic leach @60C...there are reams of publications in your local library, SME (Society of Mining Engrs, http://www.smenet.org) & galore freebie publications on the web...all you need is the inclination to spend time doing some research.

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