Abstract
In Japan, the amount of plastic wastes is about 10 million tons per year and a part of them undergoes recycling processes such as melting/molding followed optionally by liquefaction, gasification, use as a reduction agent in blast furnaces, etc. In some other processes, the energy liberated by the incineration of the plastic wastes is recovered with high efficiency. Nevertheless, the other part of the plastic wastes is not suitable for such processes and is disposed by land filling or by simple incineration. Among the refractory plastics, PVC is especially difficult to treat and in Japan only about 400 thousand tons of PVC out of 1 million tons of PVC wastes are recycled every year, the remainder being disposed by land filling or incineration as stated above. However, when PVC is incinerated, hazardous compounds such as dioxins and HCl are liberated in the atmosphere, leading to a pressing requirement for new low cost safe disposal technologies. Accordingly, we are now intending to develop an advantageous process preventing the formation of such pollutants while recovering the enormous quantities of hydrogen present in PVC for a use as a clean energy source for, for instance, the fuel cells. In order to propose a rational solution, we gathered detailed statistics concerning the PVC production/use/disposal in Japan. We also examined and compared the existing and emerging PVC recycling technologies. Further, Na-containing wastes were considered inter alia as good candidates for a low cost HCl neutralization process, and subsequent qualitative/quantitative investigations were accordingly performed.
