Conveyor belts were first used in mines to carry out ore – eclipsing the pit boys and pit ponies that once hauled the coal to the surface. From here they were quickly adopted by innovators in the manufacturing field. Most notably, conveyor belts were used by the industrialist Henry Ford in his pioneering Model T production line.
Conveyor systems are absolutely essential in modern recycling plants. They allow for the quick and efficient movement of materials between the various processing and sorting stations. Many recycling plants are built around conveyor networks in order to maximize efficiency. Belt and roller systems are all relatively common.
In order for recyclable material to be efficiently transported and stored, it needs to be baled. Baling involves the crushing of materials into a cube using powerful pistons before wrapping it in galvanized stem wire or plastic. Because the materials are compacted when they are crushed, they take up far less space when baled. Most recycling plants have several kinds of balers – each suited to a different recyclable material. Auto-tie balers are the most popular in plastic and paper recycling operations. These balers automatically constrict the bales in wire – negating the need for a separate machine.
All recycled material needs to be separated into distinct material types before it can be effectively recycled. There are several kinds of separators that are used in recycling plants. Electromagnetic separators pull out iron-based objects so that they can be recycled efficiently, weight filters remove heavier materials and leave paper and plastic in place, and centrifugal separators can distinguish between different kinds of plastic. Despite the use of mechanical separators, human beings are still necessary to pick out materials that have found their way through the process to the wrong section.
Universal shredders do exactly what their name suggests: shred, universally. These machines are often multi-bladed closed affairs into which recyclable material can be fed. Shredding is essential in the recycling industry. It allows for the processing and movement of objects through the rest of a recycling plant network.
Paper refiners separate recyclable paper into its constituent fibers. This enables said fibers to be effectively bonded into paper that is just as strong as it was originally. The fibers are then washed thoroughly with high-pressure water. Paper is one of the most recyclable of materials, and paper refiners have a large part to play in this.
When plastic is being processed for melting and recycling, it is usually passed through a granulator. Granulators shred plastics into tiny pellets that can be more easily transported, as in this form it acts more like a liquid. Although granulation is currently the only practical way of moving large amounts of plastic around before melting, it is a process that has become controversial. Any plastic pellets that are spilled into the environment are immensely hard to clean up. Because most developed countries ship much of their plastic waste to poorer countries with worse reporting, these plastic pellets travel the world – with lots of opportunities to go missing.