Trommel screens are used in any type or sifting or separation work. As material passes through the screened cylinder, the smaller particles pass through the openings, while the larger pieces are kept inside, thus separating the material by size. They are used for a variety of applications, including the separation of sand/gravel, lumber mill by-products and municipal solid waste (MSW) and in compost production. At an MRF, the screens are used to separate the biodegradable fraction of mixed MSW and separate smaller debris such as broken glass from larger recyclables, making them a practical addition to any Tuffman® sorting station.
Trommel screens are also useful in excavation sifting. They can separate the debris into topsoil to be sold to farms, nurseries and site-work, and rock that can be cleaned and used for aggregates and landscaping, allowing a contractor to reuse or resell waste rather than paying transportation and disposal fees.
Crossbelt magnets are ideal for recycling operations and are widely used for sorting co-mingled metals and separating ferrous and nonferrous metals. When suspended over the conveyor belt of a sorting station, they pick up the ferrous metal, removing it from the sorting line. Because it is difficult to tell ferrous from non-ferrous metal just by looking at it, use of a crossbelt magnet ensures that only non-ferrous metal is picked.
Ferrous scrap metal includes iron and steel recovered from autos, farm equipment, household appliances, structural steel, etc, and non-ferrous scrap is all metals other than iron and steel, such as aluminum, copper, zinc, lead and nickel. Non-ferrous scrap metal represents a smaller percentage of scrap metal, but has a higher market value.