im not sure im even in the right place but here goes

[wittsendinc]

Can anyone help me with what I need to do to ph the aqua regia solution that I have, in order to be able to precipitate the gold out? Any help will be greatly apreciated!

[ecoli]

let me get this straight... you have a solution of aqua regia, with dissolved gold in in?

[wittsendinc]

that is correct. I have a rather large bath that should be full of gold. I want what I pull out to have the best possible chance to be as pure as possible. Any information that you can assist me with will be greatly appreciated. Thanks in advance. Mark

[DrDNA]

I found this on the web.....

Quote:

"HOW TO USE AQUA REGIA TO PURIFY GOLD

1. Place your gold or finely powdered ore in a Pyrex container or beaker.

2. Mix 1 part nitric acid to 3 parts hydrochloric acid in a separate glass or plastic container. When mixing the acids together, use great caution!

3. Add the acid mixture, very slowly, to the Pyrex container or beaker containing the ore.

4. On a stove or hot plate, simmer until the gold is in solution and the (START HERE) nitric acid is boiled off. It Will look like maple syrup and be a yellowish to orange color.

5. To make sure all the nitric acid has been boiled off, add a small amount of formic acid. If nitric acid is present, a reddish brown gas will be given off. Add hydrochloric acid, if necessary, to keep the material covered with liquid. Continue simmering until the nitric acid is gone.

6. Filter off any solids that are not in solution through a plastic strainer or funnel lined with a filter. Neutralize this material with lime juice and discard.

7. Add to the liquid solution an equal amount of water.

8. Drop a small amount of uniodized table salt into the mixture to check for silver. If silver is present, a white substance will fall to the bottom of the container. This is silver chloride. Continue dropper small amounts of salt in until the silver chloride stops falling.

9. Filter off the silver chloride through a plastic.

10. strainer or funnel lined with an ash-free or coffee filter. DO NOT DISPOSE OF THE ACID SOLUTION, SET IT ASIDE!

11. Rinse the filter containing silver chloride with water.

12. Dry the filter and silver chloride.

13. Place the filter and silver chloride in a clay crucible and burn the filter by lighting a match to it.

14. Cover the silver chloride and burned filter with soda ash.

15. Place the crucible in a furnace or oven and heat to a temperature of 2100 degrees F until the silver is a smooth honey-like liquid with no lumps in it.

16. Immediately pour the silver into a mold or let it set in the crucible until it is cool.

17. Remove the silver and wash with soap and water.

18. Take the solution that you had set aside (see step 9) and add a little sodium sulfite. The gold will start to fall. Continue to add the sodium sulfite until the gold stops falling. You should see black specks that look like pepper. This is gold sulfide.

19. Filter off the gold sulfide through a plastic strainer or funnel lined with a filter.

20. Rinse the filter containing gold sulfide with water.

21. Dry the filter containing gold sulfide.

22. Put the filter and gold sulfide into a clay crucible and burn the filter by lighting a match to it.

23. Cover the gold sulfide and burned filter with borax and place the crucible in a furnace or oven and heat to 1950 degrees F until the gold is a smooth, honey-like liquid with no lumps in it.

24. Immediately, pour the gold into a mold or let it set in the crucible until it is cool.

25. Remove the gold and wash with soap and water.

26. Add 1/4 cup lime juice to the acid mixture to neutralize it and dispose of it immediately."

End Quote

http://www.49ermike.com/aqua_regia_clean.shtml

[wittsendinc]

Thanks for the info