Discovered around 800 A.D. by Iranian alchemist Abu Musa Jabir ebn Hayyan, aqua regia is a corrosive mixture of acids used to refine precious metals. "Royal water" in Latin, aqua regia is also used in etching and in cleaning glassware in certain applications. A foaming yellow or red combination of nitric and hydrochloric acids, aqua regia dissolves gold and platinum through oxidization. Certain other "noble" metals --- tantalum and iridium, for instance --- are impervious to aqua regia.
Things You'll Need
- Thick plastic buckets
- Goggles, rubber gloves and apron
- 2 tbs nitric acid per ounce of gold
- 8 tbs hydrochloric acid
Dissolve Gold in Aqua Regia
Place one thick plastic bucket on an outside table. Ensure good ventilation in the area and wear protective clothing.
Weigh gold on a scale and record the total weight. This figure will determine the amount of constituent acids required for the aqua regia.
Put small pieces of gold into the bucket. Large pieces will not dissolve efficiently and need to be melted down into smaller pieces before immersion in aqua regia. Rings and most jewelry do not need to be reduced in size prior to dissolving.
Pour 2 tablespoons of nitric acid into the bucket for each ounce of gold. Let the nitric acid react with the gold for at least 30 minutes. Brown fumes may be present at this time. If you are using a commercial nitric acid substitute, such as subzero, it is not necessary to wait for 30 minutes. Note that subzero does not typically produce fumes of its own and will not react with the metal until hydrochloric acid is introduced.
Add 8 tablespoons of hydrochloric acid per ounce of gold. Aqua regia may not react quickly at first, but the mixture will eventually turn hot and brown as the gold is dissolved. Limit your exposure to toxic and corrosive fumes by leaving the area.
If further refining the gold, wait at least one hour, and preferably overnight, to allow fumes time to dissipate.
Tips & Warnings
- Impurities dissolve along with the metal, resulting in a purer, refined product. Precipitate refined gold out of auqa regia using water or urea and selective precipitants. A commercial substitute, subzero, can be used instead of nitric acid; muriatic acid may be substituted for hydrochloric.
- Do not use aqua regia indoors. Limit exposure to toxic fumes such as chlorine gas and nitric oxide; these dangerous fumes are corrosive and will rust high-grade steel in seconds.
- Photo Credit Jupiterimages/Comstock/Getty Images
Gold Plating Recovery Solution
Just because a computer no longer works does not mean it is no longer valuable. Parts can be sold off to scrap...
How to Refine Gold With Nitric Acid
As valuable as pure gold is, gold is rarely pure. Gold ore found in the ground is bound to other (often undesirable)...
How to Chemically Refine Gold
The quality of gold is measured by a rating known as carats. This is why gold items are stamped with 10k, 14k,...
How to Test for Gold Ore
Gold has been a highly prized metal for many years. Not only is gold mining a multimillion dollar industry, it is a...
How to Dissolve Gold
Aqua Regia, quite simply, is the term for the chemical component created when you combine nitric acid and maximum-concentration (38%) hydrochloric acid....
How to Remove Real Gold From Ceramic Plates
Ceramic plates often have a border of gold around the edge for decoration. If you no longer want the border of gold...
What Dissolves Fiberglass Resin?
Fiberglass is a composite material made of glass filament and a plastic resin. The glass filament is made of thin fibers of...
What Happens When You Put Gold in Muriatic Acid?
Gold is probably the most treasured of the so-called precious metals, having been used in art and jewelry for centuries and more...
How to Make the Old Town Mixed Drink
The Old Town is a mixed drink with liqueur that's easy to make at home. Our professional bartender will show you how.