What you need to know about chemical recycling of plastics
Faced with an ever-increasing volume of plastic waste and the limitations of certain traditional recycling processes, new recovery solutions are emerging. And in industrial sectors faced with complex flows that are difficult to process mechanically, we can now rely on chemical recycling.
Complementary to mechanical recycling, this method aims to transform plastic waste into a raw material of equivalent quality to the original. But what does this process actually involve? What are its advantages, limitations and practical applications? Knauf Industries reveals all about chemical plastic recycling in this article.
This article in brief
- Chemical recycling enables in particular contaminated plastics or or hard-to-recycle plastics to recycle mechanically to be processed.
- It is based on the breakdown of polymers into basic molecular building blocks.
- This technology paves the way for the production of recycled plastics of almost the same quality as virgin ones, which can be used in sensitive applications such as the food industry.
What is chemical recycling of plastics?
Chemical recycling is a material recovery process that breaks down plastic polymers into their basic chemical constituents. Unlike mechanical recycling, which relies on a physical transformation of the material (grinding, melting), chemical recycling relies on various thermal or chemical processes, such as solvolysis, pyrolysis or gasification.
These processes convert plastics into basic molecules (monomers) or intermediates such as naphtha. These products can then be used to manufacture new plastics, transformed into fuels and chemical intermediates, or integrated into existing petrochemical processes.
For manufacturers, this process is of strategic interest: it increases the overall recovery of plastics, by expanding the pool of available recycled materials. In addition to processing certain complex waste streams (contaminated plastics, multi-layer materials, blends), chemical recycling also helps improve the quality of already recyclable resins such as polypropylene (PP), in order to meet higher performance requirements.
What types of plastics are involved?
In addition to processing certain complex waste streams (contaminated plastics, multi-layer materials, blends), chemical recycling also helps improve the quality of already recyclable resins such as polypropylene (PP), in order to meet higher performance requirements.
This includes :
- Plastics used in demanding technical and industrial applications
- Resins requiring properties equivalent to those of virgin material
- Certain complex or specific flows, in addition to existing mechanical processes
How does the chemical recycling of plastics work?
Chemical recycling encompasses several technologies, but all are based on a common principle: the molecular transformation of matter. To achieve this, manufacturers follow a three-stage process:
1) Preparing waste
In addition to processing certain complex waste streams (contaminated plastics, multi-layer materials, blends), chemical recycling also helps improve the quality of already recyclable resins such as polypropylene (PP), in order to meet higher performance requirements.
2) Polymer decomposition
Several processes are available:
- Pyrolysis: heating in the absence of oxygen to produce liquid or gaseous hydrocarbons
- Gasification: conversion into synthesis gas
- Depolymerization: return to the original monomers via chemical reactions
Each technology is adapted to specific types of plastics and recovery objectives.
3) Reintegration of raw materials into the production chain
Finally, these materials are reintroduced into production lines as secondary raw materials for the manufacture of new plastic products. This process makes it possible to recreate products or packaging with properties equivalent to those of virgin resins.
The advantages of this method
Chemical recycling of plastics offers several major industrial and environmental advantages, the first of which is its ability to recover complex waste streams.. Indeed, as highlighted earlier in this article, one of the major benefits of this method is its ability to process waste that could not previously be recycled mechanically.
it should also be noted that,by breaking down into basic molecules, chemical recycling enables the production of materials with properties close to those of virgin materials, thus avoiding the degradation associated with other recycling methods
Finally, chemical recycling is a key driver of the circular economy. By allowing plastic waste to be reintroduced into production cycles, it helps to reduce dependence on fossil resources and diversify recovery solutions.
The differences between chemical and mechanical recycling
Chemical recycling of plastics offers several major industrial and environmental advantages, the first of which is its ability to recover complex waste streams.. Indeed, as highlighted earlier in this article, one of the major benefits of this method is its ability to process waste that could not previously be recycled mechanically.
it should also be noted that,by breaking down into basic molecules, chemical recycling enables the production of materials with properties close to those of virgin materials, thus avoiding the degradation associated with other recycling methods
Finally, chemical recycling is a key driver of the circular economy. By allowing plastic waste to be reintroduced into production cycles, it helps to reduce dependence on fossil resources and diversify recovery solutions.
