test for gold with stanous chloride crystals

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arthur kierski

Well-known member
Joined
Feb 10, 2008
Messages
1,090
Location
são paulo---brazil
i test for gold in a solution with stanous chloride crystals-----i put one or two crystals into a becker,and spread over a small quantity of a solution that i suspect,that contains gold---if the solutions darkens ,indicates gold--the darker the solution,more the concentration of gold in it----this dark solutions, of what i think is coloidal gold, i put in a stock pot----now i acumulated 2liters of this solution which i think is coloidal gold-----How to get back the gold from this coloidal solution? i think ,that it is not much--but is still gold(a few grams) -----------thanks for the help------
Arthur
 
Make up a stock solution of stannous chloride. I think it's a gram tin to 30 ml water. Enough acid to keep it acidic.

Transfer 1 drop of solution to be tested to a white plastic spoon. Now add one drop of stannous.

Wash spoon into dedicated receptacle. Save and process as a batch when you have enough. The amount of tin therein is not so large that it will cause problems, but if it does, simply precipitate all metals with naoh and filter. Melt with excess silver and excess borax using a heavily oxidizing flame. The tin will oxidize into the borax leaving you with silver and other pm's.




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Arthur personally I’d evaporate it down as far as possible using either the sun or put it on heat, ideally you want to dry it out so you can incinerate the powder left then treat with a hot Hcl soak to remove the tin and then proceed by method of your choice.
 
Thanks Snoman and Nickvc,it is easier for me,to evaporate the solution,and to the powder left add Hcl to dissolve the sn, and be left with the gold in the botton of the becker-----------
 
I have a client in Dallas who built what is essentially a cold frame to evaporate solutions on their roof. It is always closed in the event of unexpected rain but vented so air flows over the solution and evaporates the liquid. And it captures the suns heat to make quick work of it. Neutralize it first so you aren't dealing with azeotropes not wanting to evaporate.

In Sao Paulo you should be getting enough sun to become our resident solar evaporation consultant!
 
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