How are plastic metal and paper prepared by shredding for recycling?

In the context of waste management, shredding is a critical mechanical process used to prepare materials for recycling by reducing them into a uniform mass of smaller, manageable pieces.12

Preparation Methods

• Plastic: After sorting by polymer type, plastic is typically chopped or ground into chips. This size reduction makes the material easier to clean and handle during subsequent processing steps, such as washing away labels or adhesives. Some plastics, such as thermosetting resins that cannot be remelted, are shredded specifically to be used as fillers or insulating materials.34
• Metal: Large items, such as automobile bodies or appliances, are first crushed and flattened before being fed into hammer mills. These machines shred the metal into small pieces, allowing for the efficient separation of ferrous metals using powerful magnets, while other materials are removed by hand or air jets.5
• Paper: Shredding is utilized to prepare paper for further processing, such as pulping, which converts the material into a slurry that can be manufactured into new paper products.1

This size reduction is generally accomplished using industrial equipment such as rotary shredders and hammer mills.2