- Secondary precious metals (3)
- Gold smelting and refining (secondary) (1)
- Silver recovery from used photographic film (1)
- Silver smelting and refining (secondary) (1)
- Aluminum smelting and refining (secondary) (6)
- Babbitt metal smelting and refining (secondary) (4)
- Brass smelting and refining (secondary) (3)
- Copper smelting and refining (secondary) (3)
- Nickel smelting and refining (secondary) (1)
- Recovery and refining of nonferrous metals (3)
