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HOW TO USE AQUA REGIA TO PURIFY GOLD
by Tom Ashworth
Tom Ashworth (the author) shall not be liable for incidental or
consequential damages in connection with or arising out of the furnishing or use of this
material. I have no control over how you do these procedures. This procedure works for me
and if something gets messed up it is your problem, not mine!
- The processes contained herein entail the use of high heat, and very dangerous acids,
and must be performed in a well ventilated area. Always use mercury, sulfuric acid,
Hydrochloric and nitric acid in a well-ventilated area. DO NOT breathe the fumes.
- Fumes from many ores are deadly when heated.
- Nitric acid can be absorbed through the skin causing nitric acid poisoning. WEAR
RUBBER ACID GLOVES. Always add acid to water, NEVER ADD WATER TO ACID!
- Aqua regia, Hydrochloric and nitric acid can kill if swallowed.
- Nitric acid can ruin your clothes and shoes.
- Always wear rubber gloves, plastic safety glasses and a plastic or rubber apron.
- When adding aqua regia to ore, there can be a red gas given off; THIS RED GAS WILL
- Sometimes the ore will bubble over, so watch it carefully.
- Use the aqua regia in an open area and add it to the ore very slowly. Aqua regia cannot
be boiled or simmered in the house or where it is not well ventilated. This can cause
serious illness or KILL YOU!
- Use a vent hood with an exhaust fan or simmer in the open.
- Hydrochloric acid is very dangerous. It can burn to the bone and is extremely painful.
In most cases, it has burned before you know it.
- Aqua regia can ruin your clothes and shoes.
IF YOU DO NOT UNDERSTAND ALL OF THE ABOVE WARNINGS, DO NOT GO ANY
- Pyrex Beaker container
- Hot plate
- Plastic spoon for stirring or a glass rod can be used
- Squeeze bottle, such as a soap bottle, containing distilled spring water for washing the
- Ash-free or a coffee filter (An ash-free filter best, but it costs more and is harder to
- A plastic funnel with strainer to use to filter the bottle or beaker
- Gold or finely powdered ore (100 mesh crushed black sand, ore, etc.)
- Hydrochloric acid
- Nitric acid
- Formic acid
- Sodium sulfite
- Distilled water
- Uniodized salt
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 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
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
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