Efficient utilization of waste plastics as raw material for metallic iron and syngas production by combining heat treatment pulverization and direct reduction

Abstract

For the clean and efficient utilizaiton of waste plastics, an integrated flowsheet, including low temperature heat treatment pulverization and composite pellet reduction, has been proposed and the fundamental research has been conducted. The PE film could be easily pulverized by heat treatment at 250°C for 20min after mixed with coal powder (mass ratio of PE 20 % of coal). The pulverized heated mixture had better reactivity than original coal and could be used as the reducing agent of composite pellet. The reducibility of heated mixture pellet was better than coal pellet with the C/O of 1.0. The appropriate reduction temperature should be around 1100°C and the metallization degree was bigger than 90 % when reduced for 30min. The off gas of heated mixture pellet contained more H2 and CO. The concentration value of H2 peak of heated mixture pellet was 5 times of that of coal pellet. However, the concentration value of largest CO peak of heated mixture pellet was about 48.7 % higher than that of coal pellet. The experimental results show the possibility that the novel technology can efficiently utilize iron ore and waste plastics to produce metallic iron and syngas.