How is Plastic Recycled?
Now that you have acquired a better understanding of plastic recycling, it is natural to be curious about the process itself. In this guide, we will discuss the step-by-step process involved in recycling plastic, highlighting the various techniques and technologies employed to transform discarded plastic into valuable resources.
1. Collecting Used Plastic
Collecting used plastic for recycling is an important step in reducing the amount of plastics that end up in the landfills and the environment. Plastic recycling companies collect plastic for recycling through various methods, including:
- Collection centers – Plastic recycling companies may operate collection centers where individuals and businesses can drop off their plastic. These collection centers are typically located in urban or suburban areas for easy access.
- Curbside pickup – Some recycling companies partner with local governments to offer curbside pickup of plastic. Residents can place their plastic in designated recycling bins and leave them at the curb for pickup on designated days.
- Partnerships with businesses – Recycling companies may also partner with businesses that generate large amounts of plastic, such as supermarkets, restaurants, and manufacturers. The recycling company may provide collection bins or pickup services for the business’s plastic.
It is important to sort plastic before recycling because different types of plastic have different properties and require different recycling processes. Sorting plastic helps ensure that the plastic can be processed efficiently and effectively to create new products. Some of the sorting techniques include:
- Manual picking – This is a process in which workers manually sort through plastic to remove contaminants and sort plastic by type before it is processed for recycling.
- Optic sorting machine – This uses sensors and cameras to identify and sort plastic by type. This technique is highly accurate and effective at removing contaminants, but it is also more expensive than other sorting techniques.
- Trommels – This involves using a rotating cylindrical screen, called a trommel, to separate different types of plastic by size. The trommel is perforated with small holes that allow smaller pieces of plastic to pass through, while larger pieces are retained and sorted.
- OCC screening – OCC (Old Corrugated Containers) screening is a technique used for sorting plastic for recycling. It is typically used to remove contaminants, such as paper, cardboard, and other non-plastic materials, from the plastic stream.
- Ballistic separator – This process involves passing the plastic through a rotating drum that contains a series of paddles or balls. As the drum rotates, the plastic is lifted and dropped by the paddles, causing the lighter materials, such as film and paper, to be separated from the heavier materials, such as rigid plastics and metals.
- Magnet separator – This uses magnets to separate ferrous and non-ferrous metals from plastic. This process is commonly used in combination with other sorting techniques to remove metal contaminants from the plastic.
- Eddy currents separator – This is a non-ferrous metal sorting process that uses a magnetic field to separate non-ferrous metals, such as aluminum and copper, from plastic.
- Sink-float separator – This process involves adding the plastic to a tank filled with a liquid of a specific density, such as water or air, which causes the plastic materials to float or sink depending on their density.
Reprocessing is a critical step in the plastic recycling process. It involves processing the collected and sorted plastic materials into a form that can be used to create new products.
4. Secondary Sorting for Quality Control
Secondary sorting involves a thorough inspection of the sorted plastic materials to identify any remaining contaminants, such as small pieces of paper or other non-plastic materials. The sorted plastic materials may also be tested for purity and quality to ensure that they meet the required specifications for use in manufacturing.
Washing is an essential step in the plastic recycling process that removes any remaining contaminants, such as dirt, labels, or food residue, from the sorted plastic materials. The washing process also helps to improve the quality of the recycled plastic materials and makes them suitable for use in manufacturing new products.
6. Shredding and Resizing
These processes involve breaking down the plastic materials into smaller pieces or granules, which makes them easier to handle and process. In the shredding process, the plastic is fed into a machine that cuts it into small pieces or strips. The shredding process helps to reduce the volume of the plastic, making it easier to transport and store. The resizing process involves melting the plastic and extruding it through a small opening to create long strands.
7. Extruding or Melting
Melting is the process of heating the plastic to a high temperature until it becomes a liquid. The melted plastic is then molded or shaped into new products using various techniques, such as injection molding or blow molding. The extruded plastic can also be cooled and cut into smaller pieces or pellets for further processing.