Cyanide Destruction/Disposal

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Topher_osAUrus

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FrugalRefiner said:
When I read the AR on goldfilled idea, I was dubious too. But it has some merit. He processes it like some folks do processors. By adding the AR in small batches, and allowing it to run to exhaustion, any gold that dissolves cements back out on the remaining base metals. Decant off the barren solution and add some fresh AR. Of course, stannous test every step. The last batch of AR will dissolve the gold but most of the base metals will have been decanted off.

At least, I think that's what he described. Then again, I'm old, and that may have been someone else's idea.

It's actually a frugal approach 8) ; kind of an AP on steroids. It's cheaper to dissolve most of the base metals as chlorides, but it's slow. Nitric is faster, but more expensive. I expect the AR approach would cheaper than nitric but slower (waiting for each batch of AR to be exhausted), and more expensive but faster than AP.

Dave

He describes it as FASTER!
Heh
Cheaper, yes. Faster, no. Not when you are waiting overnight for it to cool and cement back out. Then having to do that multiple times/days.

I can get a batch of goldfilled done pretty darn quick with nitric. Usually between 2-3 days, start to finish (unless its watchbands that I have to remove, painstakingly)
..Granted, he mentioned his lot being 50lbs, and that is a pretty good sized load, I would still prefer the nitric. Solely for the fact of -what happens to all of his silver from the pieces of vermeil? :eek:
 

saadat68

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Hi
I have 100 millilitre solution with maximum one gram sodium cyanide. Can someone say to me how much bleach need to destruction of cyanide in this solution?
Yes I know, I must use ORP meter or potassium iodide paper.
In https://www.pfonline.com/articles/cyanide-destruction-a-new-look-at-an-age-old-problem I found approximately 23 gallons of 12.5% sodium hypochlorite solution destroy one ounce of cyanide. Is that true?

I really need 3 or 4 liter bleach to destroy just one gram sodium cyanide in just 100 mill water?!
So this method produces a lot of sewage!!!
 

Lino1406

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By theory for destroying 1 mole KCN, 2.5 mole NaOCl are needed. But you take an excess of course, and should study the process very well (it includes 2 stages).
 

saadat68

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If I add 20 or 30 of millilitre 40% H2O2 to 100 millilitre cyanide solution with PH 11, Is it possible PH decrease under 9 and produce HCN gas? I ask this because PH of 40% H2O2 is about 4.5!
 

Lino1406

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Cyanide is destroyed by H2O2 in presence of copper salt
H2O2 + CN- → CNO- + H2O
CNO- + H+ + H2O → CO2 + NH3
the 2nd stage seems to increase pH somewhat
 

saadat68

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Thanks lino
What about first stage? Does it decrease pH?
As you know second stage will not happen completely.
 
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