The microwave absorption properties of residual carbon from coal gasification fine slag

Abstract

The resource utilization of coal gasification fine slag (FS) is very urgent. The residual carbon (RC) from coal gasification FS was obtained via a facile two-step acid leaching process. The structure, compositions, micromorphology, thermal stability, and electromagnetic parameters of the RC were tested by variously analytical techniques in details. The RC exhibits the unique layer morphology and partial graphitization. Results demonstrate that the RC shows good thermal stability and microwave absorption (MA) properties. The outstanding microwave-absorbing capability may be caused by dielectric loss and polarization relaxation. Significantly, the RC content in the mixture has a noticeable impact on its MA properties. The minimum reflection loss of the RC achieved −52.3 dB at 5.04 GHz when the adding content was only 20% in a paraffin matrix. With an easy treating process, the RC obtained via an acid leaching method from coal gasification FS is a competitively alternative and cheap source for microwave absorber.