How to Dissolve Base Metals
- 1). Grind your collection of metal to provide a higher surface area to interact with the acid. Make sure you remove any precious stones from the jewelry before placing it in the grinder. Only metal should be present in the grinder's input and output.
- 2). Place all the grindings into the large beaker. Place the beaker in the fume hood on top of the stir plate. Drop the stir bar into the beaker and turn it on.
- 3). Add enough acid to the metal in the beaker to bring the liquid level just above the metal grindings. Add the acid slowly to minimize the chance of a violent reaction. If the addition is too rapid, there is a chance that the beaker will overflow or blow some of the contents out of the beaker and onto you or the hood. As the acid and metal react, fumes will be emitted. Most of the metals will release hydrogen gas into the hood, while some metals will produce other noxious gases.
- 4). Allow the metal grindings and acid to react until there is no noticeable gas or bubbling. The acid will react with all the base metals but will leave the gold untouched.The time to complete this process depends on the amount of base metal present and how intricate the base metal is bound to the noble metals. If you still see base metal among the grindings, add more acid to the beaker. While the reaction is relatively fast if the grindings are stirred constantly, you should allow at least an hour or two to complete the process.
- 5). Continue adding acid periodically until all the base metal has gone into solution. The only metal in the bottom of the beaker at the completion of this process should be gold.
- 6). Neutralize the acid in the solution after filtering the gold particles from the solution. Slowly add small amounts of sodium carbonate to the solution until the is no longer a foaming or fizzing effect upon addition.
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