# gold recovery



## furaha (Nov 9, 2012)

Help please, how to precipitate gold with zinc


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## Lino1406 (Nov 9, 2012)

Is the gold in solution?


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## tek4g63 (Nov 9, 2012)

The pros will need much more details

What state is the gold in, salt, chloride, something else?

What was the source of the gold and how did you process it up to this point?

Have you tested to be %100 sure the gold is there?

Now a question for you, Have you read Hoke's book?

With more details and if possible, pictures, I'm sure that the pros can point you in the right direction to learn what you need to in order to successfully recover any values you may have, in the safest way possible.


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## furaha (Nov 9, 2012)

thanx for the comments, it is gold desorbed from carbons. I was using pressurized elution column but i couldnt get the good results while lab test shows the is gold in carbon and its solution. While troubleshooting i thought of precipitating gold in pregnant solution using zinc


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## butcher (Nov 9, 2012)

I am not clear on what your doing, or neither do I understand it. but carbon would absorb gold from solution not dissolve it into solution, so what do you expect the zink to do?.

If this is just gold and carbon burn off the carbon. if it is not just carbon and gold this could be a bad idea.

but if this is a solution of mercury or cyanide or some other substance we would need much more details of what this contains.


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## goldsilverpro (Nov 9, 2012)

It seems you are attempting the carbon-in-pulp method and are having trouble eluting all the gold from the carbon with the higher strength, higher pH cyanide and want to know if you can drop the gold with zinc from the weaker cyanide used to leach the ore. Is that correct?
http://en.wikipedia.org/wiki/Carbon_in_pulp
https://www.google.com/search?q=carbon-in-pulp&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a

If you are having problems eluting the gold in the CIP method, you are obviously doing something wrong. You should backtrack what you've done to find your error.

I assume you want to bypass the carbon. Maybe you can adapt to one of these methods. I haven't been around large scale cyanide leaching operations but I know the widely used carbon-in-pulp method is fairly recent. Before that, the Merrill-Crowe process, which used zinc dust to precipitate the gold from the cyanide leach, was popular. Before that, there was the cyanide MacArthur-Forrest process, which used zinc shavings in "zinc boxes" to precipitate the gold. 
https://www.google.com/search?q=merrill-crowe+zinc+precipitation&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a
https://www.google.com/search?q=macarthur-forrest+process&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a


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## donnybrook (Nov 9, 2012)

If you are precpitating from acid the pH has to be around 5 for the zinc to be effective.In the old cyanide revovery systems zinc in the form of a wool was placed in wooden troughs. The gold and zinc exchanged dropping the gold as a black powder.
donnybrook


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