The misconception that End of Life passenger car tires have no real value needs to be challenged and corrected. Today there are a few plants scattered around the world that crumb the material but it looks like the vast majority are incinerated as tire derived fuel (TDF). The approach to tire recycling thus far has been following the paths of least resistance with few technological strides of consequence. The primary problem in passenger car tires is the lower rubber recovery with a high fibre content,
which requires additional separation systems in the crumbing process. The prospect of having to deal with the disposal of the fibre when there is no conventional demand for it just compounds the problem.
In traditional rubber recycling the preference for crumb with a higher natural rubber based content as in the case of truck tires or commercial vehicle tires (CVT) tends to relegate passenger car tire crumb to the lowest of possible applications. Even in this there is a compromise where in most operations a certain proportion of passenger car tires are allowed to mixed in to the truck tires up to the threshold that does not require the additional separation systems and conforms with the minimum specifications. While in low end filler applications this is not an issue, once we move into devulcanization you end up muddying the waters in terms of recovery of properties.
This equation changes radically with 2 primary factors. The first being the availability of a volume based, high efficiency devulcanization technology and process, the second is a value added application for the fibre (long strands and finer particles) that will consume substantial quantities. Both are now realities so there really is no excuse for burning passenger car ELT’s as a coal substitute, certainly with the right expertise it makes no sense financially either, even with subsidies.
The simple facts are that the rubber content in Truck tires is mostly Natural rubber 80/20, while Passenger Car tires are mostly Synthetic rubber 60/40 (62.4/37.5). Once you have them segregated and devulcanized you have 2 different industrial raw material compounds that can be optimally utilized in different formulations based on properties and performance. Notice the words crumb, filler and scrap no longer have basis, the resultant compound now is valuable. Environmental sustainability and commercial viability are not mutually exclusive in this case.
Burning or incineration of tires as a source of energy should really not be an option, it’s time for a change.