Plastics have only been around for a little more than a century, but they’ve already infiltrated almost every aspect of our lives. Plastic materials are used in everything from children’s toys to food packaging in the twenty-first century. In reality, 8.3 billion metric tonnes of plastic have been manufactured in the last 70 years, with about 6.3 billion metric tonnes of that going to waste. Just 9% of the waste has been recycled so far. There are many explanations for this, and while our plastic waste continues to increase, technological advancements and improvements in how we consume are assisting in making it more sustainable and competitive.
Steps in the plastic recycling process
1. Collecting and processing
The processing of post-consumer materials from households, companies, and organisations is the first step in the mechanical recycling process. Local governments or private corporations may do this, with the latter being a common choice for businesses. Taking plastics to communal collection points, such as designated recycling bins or facilities, is another alternative. This may be as plain as a bottle bank on a street corner or as complex as a municipal solid waste site with vast areas for various recyclable and non-recyclable waste (MSW).
2. Categorizing and sorting
Sorting is the next step in the plastic recycling process. There are several different forms of plastic that recyclers must separate from one another. Plastics may also be classified based on their colour, thickness, and intended use. This is done by machines at the recycling plant and is an essential step in increasing plant productivity and avoiding final contamination.
Washing is an important step in the plastic recycling process because it removes impurities that can stymie the process or even ruin a batch of recycled plastic. Impurities such as product labels and adhesives, as well as dirt and food residue, are commonly targeted in this process. Although plastic is often washed at this point, it is important to note that it is always necessary to ensure that plastics are as clean as possible before disposal and collection.
After that, the plastic is fed into shredders, which shred it into much smaller bits. Unlike moulded plastic items, these smaller fragments can be recycled for reuse in subsequent stages. The resized plastic parts can also be used in other applications without further processing, such as as an asphalt additive or simply sold as a raw material.
5. Plastics identification and separation
The class and consistency of the plastic parts are tested here. They are separated based on density, which is determined by floating plastic particles in a container of water. Following that, a test for “air classification,” which defines the thickness of the plastic parts, is performed. The shredded plastic is placed in a wind tunnel, with thinner parts floating and larger/thicker pieces remaining at the bottom.
6. Compounding + extrusion
The shredded plastic particles are converted into a usable commodity for manufacturers in this final phase of the plastic recycling process. To make pellets, the shredded plastic is melted and ground together. Since it is not always possible to compound all forms, classifications, and qualities of plastic at a single facility, different grades of plastic are often sent to other recycling facilities for this final stage.
Why is plastic recycling important, and what are the industry’s challenges?
Plastic recycling is critical as a means of dealing with current waste and as part of a circular economy and zero-waste schemes that seek to minimise waste generation and increase sustainability. Our current waste generation and disposal practises have social, environmental, and economic implications, and whether it’s the problem of microplastics or an estimated $2.5 trillion in harm and lost capital to ecosystems, aquaculture, leisure activities, and global health, the effect is undeniable in plastic waste recycling process.
There is a lack of awareness about how to recycle more products today, as both customers and companies seek to do so. This causes contamination, either through combining non-recyclable plastics with recyclable plastics or by attempting to recycle plastics that have been soiled by items like adhesives, chemicals, or food remnants, which slows down the recycling process even further. Both of these issues will result in plastics being discarded rather than recycled.