For this post to make sense, you’ll need to have at least scanned How Is Recycled Plastic Made? (Part 1) as it goes through the first stages of recycling plastic.
Plastics Optic Sorting Machine
Each type of plastic allows different light levels to radiate through. Optical sorting machines recognise the varieties of plastic at high speed using near-infrared sensors.
The material is fed onto a conveyor belt and dispersed onto a single layer. Then it’s scanned close up. The different plastics are separated with air jets.
Sink-float Separator
This process washes and separates the pieces of plastic; all the heavy plastic sinks in the deep water while the lighter stuff floats. After this process, the material is sent to a plastic reprocessor.
Most reprocessors redo some or all the steps above and in part 1 to make sure all contaminates are gone.
Rewashing Plastic
Washing removes glues, food waste left in containers, stickers and other contaminates. Removing this improves the quality of recycled plastic. There are a few ways this is done in reprocessor centres
Friction washers (friction separators) are used to clean mixed plastic with heat and pressure. Shredded plastic is passed through rotary washers to remove oils and foodstuffs.
Shredding
A required step in recycling plastic is shredding plastic into smaller flakes. After the sorted plastic gets washed, it’s shredded or pulverized. After this step, the plastic gets melted.
Extrusion
This process melts the plastic and forces it through an extruder. The extruder cuts the plastic into pellets which are sold.
