Abstract:Pyrolysis process of (Fe2O3+SiO2) and PVC mixtures was studied. Weight loss of samples ((Fe2O3+SiO2)︰PVC=1︰9 to 3︰1) was monitored with TG-DSC at constant heating rate ranged from 10 to 50 K/min. Solid residues of different reaction stages were characterized by XRD and SEM-EDS. The results show that pyrolysis process can be divided into three stages from room temperature(R.T.) to 1 273 K according to weight-loss. Ferric oxide is chlorinated and reduced to ferrous chloride at the first stage (R.T. to 673 K). After reduction of Fe2O3 to Fe3O4, part of FeCl2 and Fe3O4 are reduced to iron metal at the second stage (673 K to 793 K). These two stages are in accordance with pyrolysis of PVC. However, quartz does not change during these two stages. When temperature further rises, Fe3O4 is reduced by carbon to FeO, iron metal and Fe3C consequently at the third stage (793 K to 1 273 K), while SiO2 reacts with FeO resulting in fayalite. Therefore, it is assured that SiO2 hardly affects co-pyrolysis process Fe2O3 and PVC mixtures if FeO is not present. It is possible to recycle waste plastic with hematite instead of Fe2O3 to cut cost.