2019 年 59 巻 4 号 p. 679-686
Plastic waste is recycled in a coke oven and a blast furnace. An alternative to these existing methods has been studied by infiltrating plastic into a lump ore with a high content of combined water. A plastic mixture containing plastic materials is used in this study instead of plastic waste. Pyrolysate recovered from a thermally decomposed gas of the plastic mixture is used for plastic infiltration. The lump ore is dehydrated at an elevated temperature, immersed in a plastic fluid of the pyrolysate, and cured for drying. Dehydration generates pores inside the ore and the plastic fluid infiltrates the ore through the pores by immersion. The plastic-infiltrated ore cured at 450°C and above contains carbon and hydrogen but generates no tar condensation from an outlet gas through a reduction test. This ore causes no problematic tar condensation at the upper shaft and exhaust gas treatment facilities of the blast furnace. The lump ore with a high content of combined water has a tendency toward reduction disintegration at a blast furnace shaft but the plastic-infiltrated ore has less reduction disintegration. The degree of reduction at the softening–melting temperature of the lump ore is lower than that of a sinter. However, the degree of reduction at the softening–melting temperature of the plastic-infiltrated ore becomes equivalent to or higher than that of a sinter.
