What is the mechanical recycling of plastics?
Collection and sorting processes are the first steps in ensuring that separated items are provided to recycling plants. Improvements in both the collection schemes and sorting technologies are essential to achieve higher recycling rates. Recycling rates for plastic waste are ten times higher when collected separately compared to mixed collection schemes.
Recycling waste and creating materials that can be reused again is a key sustainability benefit. It reduces the need for resources to manufacture new plastics from raw materials. Recycling also saves the energy required and emissions generated by the refining and manufacturing processes.
How does mechanical recycling work?
Mechanical Recycling is the process of collecting plastic waste, washing, melting and transforming the waste into raw material for a new plastic transformation production process. This is the most traditional method in the world. The plastic granules that are a by-product of this process can be used to produce new material; such as garbage bags, flooring, hoses, non-food packaging and auto parts, among others.
Mechanical recycling steps
- Fragmentation (grinding) – the waste is fed to a mill that reduces its size.
2. Washing and Separation – the fragments, flakes, are washed with water and the separation is done because the denser materials sink and the less dense ones remain on the surface of the water.
3. Drying – The separated flakes are dried in large dryers with hot air circulation.
4. Extrusion: the dried flakes are fed into an extruder machine where they are melted by heating and conveyed by a screw conveyor to a die where continuous filaments (“spaghetti”) are formed, cooled in a bathtub with water at room temperature, cut in a granulator, forming granules of recycled plastic material that are packaged.
The purpose of chemical recycling
The Recyclers send the raw material to “Transformers” of the Plastic Production Chain. They are the ones who develop the plastic products that are an integral part of our daily lives and provide innovative solutions to all sectors of the industry.
One of the limitations for recycling is its heterogeneity. Therefore, there are other types of recycling:
Chemical recycling: processing of plastic products, transforming them into chemicals or raw materials, almost always involving depolymerization processes.
Energy recovery and incineration: burning of waste to generate heat, steam or power. It is used in places where separate collection has not yet been carried out or when all mechanical recycling possibilities have been exhausted. Incinerated waste is actually considered waste. It is estimated that incineration of plastic waste provides an 85-90% reduction in the volume of plastic material.
Advantages of mechanical recycling
- Less waste sent to landfills
- Reduced resources used to produce virgin polymers
- Reduced plastic pollution and associated environmental impacts.
- Reduced greenhouse gas emissions
What are the different types of recycling?
Paper and cardboard waste
Recycling paper is vital to ensure that you reduce your environmental impact and to reduce overall unnecessary waste.
There are around 50 different groups of plastics, with hundreds of different varieties. Most types of plastic are recyclable and, because of this, should be recycled to reduce the amount of waste sent to landfills and help prevent trash from ending up in the oceans.
All grades of ferrous and non-ferrous metals are recyclable for future use. Because metals do not lose quality when recycled, we can recycle metal many times over.
E-waste recycling is for the recycling of waste electrical and electronic equipment, which is almost anything that runs on a battery or a plug, such as computers, cell phones and televisions.
Wood is the ultimate renewable material because of its many different uses.
Wood can be reused as a building material, recycled into mulch for landscaping. Even low-grade wood is useful because we can use it as fuel to generate green energy.
Glass is 100% recyclable and never loses purity or quality when recycled, which means we can recycle it many times.
Glass can take around a million years to fully decompose, which is a big problem for overfilled landfills. It is critical to ensure that we recycle as much glass as possible.
Clothing and Textiles
With the rise of “fast fashion” in recent years, we are buying more clothes than ever before and therefore have more textile waste than ever before.
Brick and Inert Waste Recycling
We can recycle hard rubble into usable materials for many uses in other building and construction projects.
Bricks can also be cleaned and reused as “salvaged bricks” in another building or project to reduce costs.
Alternatively, we can crush them into brick chips for use as landscape material.