- Lead smelting and refining (secondary) (1)
- Secondary precious metals (1)
- Gold smelting and refining (secondary) (2)
- Silver recovery from used photographic film (1)
- Silver smelting and refining (secondary) (1)
- Aluminum smelting and refining (secondary) (1)
- Babbitt metal smelting and refining (secondary) (2)
- Recovery and refining of nonferrous metals (3)
