Various procedures for mechanical recycling are functioning today in several areas of application.
After mechanical separation, grinding, washing and treatment to eliminate impurities, it is reprocessed using various techniques (granulated or powder) and reuse in the production of, among others, electrical duts, flooring, welding, soles, parts of shoes, some successful cases are:
- Mineral water bottles are transformed, after appropriate treatment, into drain pipes or into textile fibers.
- Used floor covering are recycled into the base layer of identical new products.
- Window frames and used tubes are reintroduced into the manufacturing cycle of these same objects.
- Blends of polymers can be used in the production of anti-noise screens, of pickets fences, etc.
The quantities of PVC (and other polymers) are constantly increasing; the technologies are improving, but mechanical recycling is only one option among many for making use of products at the end of their life cycle despite of is the most common method.
Chemical recycling: a hope
Mechanical recycling cannot always be applied to the flow of plastic wastes which, besides PVC, contain other materials (electrical cables, material coatings, blends of plastic materials, etc.).
Chemical recycling (return to the basic raw materials) constitutes one alternative to mechanical recycling and is the object of advanced studies. Experiments currently under way are aimed at breaking down the molecular chains of the polymers. In this way gases and oils are obtained, components normally present at the beginning of the production process of the polymers. he existence of PVC in the blend being treated leads to the freeing of chlorine in the form of HCl which can be isolated as is or in the state of its salts and for which re-use can be envisaged at the technical level.
The Vinyloop® Process: PVC's second life
This new technology, already in use in industrial scale, makes it possible to solve one of the only obstacles to recycling:
the separation of the PVC from the other materials. Stated simply, the procedure includes four steps: crushing,
selective dissolving, separation and drying.
Vinyloop® is a closed process wherein a recyclable solvent is used to dissolve the PVC. The process generates a minimum
quantity of residues. This process may be used for the treatment of synthetic leathers, wires and cables, tarps, flooring,
blister packs, car panels, etc.
The limits of recycling
Even with the best technologies, it will be never conceivable to recycle everything. Selective collection, as well as the
treatments of sorting and of purification, can prove to be so costly in energy that the ecological and economic
balance sheets are not very favorable to recycling.
The PVC compound is a material that can be used as an energy source when burned. As it is a chlorate material, its
incineration produces the emission of chloride acids. Thus, the resulting gases must be treated, and the technologies
for that purpose are well-understood and employed.
In this context, thermal use can constitute an effective complementary solution, economical and ecological, thanks
to progress made in the course of the last few years.
