Preparation of high-performance bitumen carbon-based microwave absorbing materials from different coal bitumens toward efficient treatment of industrial waste bitumen

The increasing development of communication technology and electromagnetic pollution have accelerated the research and optimization of electromagnetic microwave absorbing materials. There are few studies and reports on the creation electromagnetic microwave absorbing materials from industrial waste, despite the abundance and promise of research preparing of microwave absorbing materials utilizing sustainable resources from biomass. Herein, we prepared carbon-based microwave absorbing materials GCB-800, HTCB-800, and CDLB-800 using three different industrial solid waste bitumens, namely, coal direct liquefaction bitumen, high-temperature coal bitumen, and globular coal bitumen, as raw materials by using the thermal activation method. Due to the excellent porous carbon skeleton structure and the Fe2O3 contained in its internal ash after the heat treatment, which enhances the internal dielectric properties, the CDLB-800 was found to perform very well at the filler amount of 10 wt% obtained minimum reflection loss (RLmin) is −52.41 dB at 10 wt% filler and matched thickness d = 2.1 mm, and the effective absorption bandwidth (EAB) is 4.88GHz, with 87.14% absorption for X-band in the 2-18GHz. This work not only promotes the development of the comprehensive utilization of solid waste in this field, effectively reduces the burden of solid waste on the environment, but also points out the direction for the development of microwave absorbing materials in the future.