The Dangers Of Nitric Acid
Nitric acid can kill if swallowed!
Nitric acid can be absorbed through the skin, causing nitric acid poisoning. WEAR RUBBER GLOVES!
Always use nitric acid in a well-ventilated area. Do not breathe the fumes!
Nitric acid can ruin your clothes and shoes.
Always add nitric acid to water. Never add water to nitric acid!
Always wear rubber gloves, plastic safety glasses and a plastic or rubber apron.

Equipment Used

• Photographic film.
• Five – gallon plastic bucket.
• Furnace or oven.
• Plastic strainer or funnel.
• Coffee filters or ash-free filters.
• Clay crucibles.
• Beaker or Pyrex container.

Ingredients Used

• Nitric acid.
• Uniodized table salt.
• Bleach (such as purex).
• Soda ash.
• Distilled or spring water.

Photographic silver recovery procedure

1. Fill a five-gallon plastic bucket with bleach.
2. Dip the film into the bleach and move it around. When the film is transparent, all the silver has been removed. When the bleach has taken all the silver it can hold, it will no longer make the film transparent. Time for a new batch of bleach. The bleach will bubble and get hot when it is saturated. Set the bleach aside and let the silver settle to the bottom.
3. Filter off the silver from the bleach by pouring through a plastic strainer or funnel lined with a coffee or ash-free filter. The silver will look very dark gray or maybe black.
4. Dry the filter and silver and burn it in a clay crucible.
5. Cover the burned material with soda ash and heat in a furnace or oven to 2100 degrees F. When the liquid looks like honey and lays flat with no lumps in it, remove it from the furnace and quickly pour it into a mold or let it set and cool in the crucible.
6. Place the silver in a beaker or Pyrex container.
7. Add 3 parts distilled water to 1 part nitric acid.
8. Place on stove or hot plate and simmer until all of the silver is gone.
9. Take un-iodized table salt and drop into acid solution. You should find a white substance that looks like cottage cheese. This substance is silver chloride. When the salt stays in the bottom of the solution and the silver chloride stops falling out, then the silver should be broken down.
10. Add 10 parts tap water.
11. Filter off the silver chloride through a plastic funnel or strainer lined with a filter.
12. Rinse the filter containing silver chloride with water and dry it.
13. Burn the filter by putting it in a clay crucible and lighting it with a match.
14. Cover the burned filter and silver with soda ash.
15. Place the crucible in a furnace or oven and heat to 2100 degrees F. When the silver looks like honey and lays flat with no lumps in it; it is ready. Quickly pour into mold or let it set in the crucible until the silver has cooled.
16. Remove the silver and wash it with soap and water. Add ½ cup lime juice to the left over acid solution to neutralize it and dispose of it immediately.

More on photographic silver recovery.