Instructions
for Silver Refining using Acid
Back
to Refining Main Page
Silver refining in acid is very simple, requires almost no
investment in time, equipment or supplies and it can be done by almost anybody.
However, it requires the use of concentrated acid and
the fumes it produces are very corrosive. Therefore,
it must be done out-of-doors, protective clothing should be worn and reasonable
care must be taken.
The process is quite simple:
- the silver is dissolved in nitric acid
- the acid with the dissolved silver is poured into another
container. Undissolvable contaminants are left behind.
- the silver is turned back into silver by adding silver
precipitant crystals (SPC) to the acid.
- the acid is poured off and neutralized. The silver is
washed with water, dried and melted.
Equipment needed:
- melting furnace (optional)
- five gallon buckets
- concentrated nitric acid
- stir rod (plastic, glass or wood)
- rubber gloves
- rubber apron
- goggles or face shield
- filter (optional)
- tap water
- distilled water
It's best for the silver to have as much surface area as
possible. That makes for much faster dissolution. So, if possible and
convenient, melt your silver and pour it into the form of shot. Open-up granules
are best. If gold is mixed with the silver, it is important that the gold be no
more than 20% of the total weight. Otherwise the gold will interfere with the
dissolving process. If you believe the gold content to be more than 20%, alloy
down with copper to reduce the percentage of gold.
Weigh the silver and put it in one or more 5 gallon buckets.
Add 150 ml nitric acid for every ounce of metal in the bucket(s). The acid will
tend to react violently to the metal, bubbling and fuming. Make sure there is
enough extra room in the bucket to accommodate the foaming (2-3 times, or more,
the volume taken up by the silver).
When the acid stops foaming and all the metal appears to be
dissolved. Pour off the acid ( filtering it if possible ) into another bucket or
buckets. Do not allow any solids to be poured off with the acid or they will
contaminate the final silver.
Add to the acid 1 ounce of SAC (silver precipitant
crystals) for every 40 ounces of silver that is dissolved. As the SAC
hits the acid, it will form a white precipitate (silver ) that will sink to the
bottom of the acid.
Give the SAC about 30 minutes or more to work and then
pour off, neutralize and dispose of the acid. If possible, filter the acid when
pouring it off to make sure that no particles of silver are lost.
Wash the silver repeatedly in water to remove any traces of
acid. Add a couple of drops of aqua ammonia to the silver after your last rinse
to test. If you see any color of blue, rinse some more. Use only a few drops of
aqua ammonia. Ammonia not only smells strong, it can dissolves some of the fine
particles of silver.
Wash the silver mud thoroughly and repeatedly with tap water,
making a final rinsing with distilled water.
Dry and melt.
Alternate Method
How to
REFINE SILVER using baking soda, Karo pancake syrup, table
salt, Red Devil drain cleaner and water: First dissolve your silver in
nitric acid. You can do this in a plastic bucket but be sure to wear protective
clothing like rubber gloves and to do it out of doors. When the silver is all
dissolved, pour the acid into another plastic bucket. Be sure not to pour any
particles along with the acid. Add ordinary table salt to the acid until the
salt stops making white clumps in the acid. Pour off the acid. Add baking soda
to the acid to neutralize it. Do not pour off the white "precipitate" that the
salt formed. This is pure silver chloride. Rinse the silver chloride with water.
To the silver chloride add Red Devil brand drain cleaner (lye) until all the
silver chloride has turned black. Rinse with water. Add Karo syrup (dextrose)
until all the black material (silver oxide) turns to pure silver