According to research by Ronald Geyer, professor at the University of California, Santa Barbara, conducted with two colleagues, of all the plastic waste generated by humanity since the start of its industrial use in the 1950s, only 9 percent had been recycled by 2015.
Plastic, however, is highly recyclable. Of the most commonly used plastics only thermosets are difficult to recycle, because they cannot be re-deformed with heat, and that’s because these plastics are used precisely for conditions where they encounter high temperatures or wear, such as on electronic chips or in dental fillings. The rest of the massively used plastics can be recycled using a rather simple mechanical process.
This process entails grinding the material, washing it, drying it, extruding it, and converting it into pellets. Once pelletized, it can be reused as raw material for new products. Extrusion is a process in which heat and pressure are used to melt the plastic back into the shape of a small continuous cylinder, which is then cross-cut to make it into pellets. A temperature of no more than 200° C is required to extrude plastic. Recycling glass, for example, requires furnaces that must reach 1000° C. The carbon footprint of plastic recycling is therefore quite low.
The biggest difficulty in plastic recycling is that there are several types of plastic and they cannot be mixed in the extrusion process, because if mixing occurs the raw material produced will not be of good quality. This is why the recycling process requires strict control in selecting the plastics to grind, as well as further quality control once it has been pelletized. Both processes are needed to ensure the homogeneity of the end product.
Wenco’s Greenplast subsidiary has been recycling polyethylene (PE) and polypropylene (PP) since 2012, and is the leading company in Chile for recycling rigid plastics. In Peru, Plaz recycles PET from plastic bottles and other containers.