aqua regent

[sleuxx]

i have used the aqua regent solution for my floor sweeps and some bench filings and have nutralized it and now i have a emerald green solution but i cant get the gold to drop i have used a gold detecting agent and know there is gold presant but cant retrieve it any help?

 

[maynman1751]

More than likely you still have nitric in your solution preventing the gold from dropping out. It sounds like you need to do more research and study into processes before attempting these procedures. If you have read and studied the forum you wouldn't be asking this question. You are not ready to recover and refine. Check out all of the items that are listed under my signature line. These will help you better understand what you're doing. Read Hokes book!!! It's a must! Don't take off in your airplane without knowing how to land.

 

[sleuxx]

i have been refining about 1 oz at a time but tried to do a larger amount when this proble occured

 

[butcher]

Beside possible free nitric acid still in solution, the green color indicates other base metals in solution, which can also give trouble.

You could cement the values out of solution with elemental metal copper.

Use thick clean bar of copper like a electrical panel buss bar, the copper will use up any excess nitric acid, and cement values from solution.

The powders would not be pure and will need refined (but that will be the case even if you can precipitate them chemically), putting the cemented values back into solution is very easy, with the second refining, if you are new to aqua regia and its use I suggest you try the re-refining using HCl and NaClO (bleach), it is much easier to deal with the oxidizer in solution, and the fine powders of the cemented material will go into solution easily.

For cleaner results before re-dissolving these cemented powders giving them a good wash using Harold’s gold washing technique (see getting your gold pure and shining in the help needed section), will also give you a better end result.

Harold also has made very good posts on how he dealt with bench sweeps, reading those can also be very helpful if dealing with that type of material.
Hoke's book will also be very helpful with this type of materials, (actually Her book is helpful no matter what type of material your trying to refine).

Study also dealing with waste, found in the safety section.