Fe_xO_y/C/Ceramic Matrix Composite Absorbing Material Was Constructed Based On Coal Gasification Reside-Red Mud System

With the development of the internet year,people’s lives have become increasingly convenient.However,this has also resulted in an increasing amount of electromagnetic pollution.Developing efficient absorbent materials is generally recognized as an effective way to solve the increasingly serious problem of electromagnetic pollution and interference.At the same time,with the rapid development of gasification technology and the alumina industry,a large amount of gasification residue and red mud waste have been produced,posing a great threat to the ecological environment and production efficiency.Therefore,how to effectively utilize these solid waste materials is currently an urgent issue.In this context,this essay intends to use solid-phase synthesis technology to successfully prepare Fe_xO_y/C/ceramic composite absorbent materials by utilizing the reaction between gasification residue（CHR）and red mud（RM）,providing an effective way for the resource utilization of these solid waste materials.The specific research work is as follows:（1）The Fe_xO_y/C/ceramic composite absorbers were successfully prepared by roasting in a tube furnace at different temperatures under Ar atmosphere.The results show that the Fe₃O₄/C/ceramic and Fe/C/ceramic composite absorbers were prepared at 700℃ and 900℃ with a mass ratio of CHR to RM of 0.6:1.The Fe/C/ceramic composite had the lowest microwave reflection loss of -48.3dB at a thickness of 1.5 mm,and the effective absorption bandwidth of 4.6 GHz.The slightly poor performance of the Fe₃O₄/C/ceramic composite absorbing material may be due to the fact that the initial system cannot guarantee the impedance matching of both products at the same time.In addition,the strong intrinsic attenuation of the material is mainly caused by dielectric losses,including conduction losses due to graphitic carbon and interfacial polarization relaxation losses caused by numerous phase boundaries,and the solid combination reaction involving Na₂O weakens the strong alkalinity introduced by RM.The work in this paper provides new ideas for the economical synthesis of magnetic particle/carbon-based MA absorbers and the rational treatment of CHR and RM.（2）By adjusting the mass ratio of coal gasification residue to red mud and sintering at Ar atmosphere and 700℃,it is found that the initial system composition has a large effect on the MA properties of the material.When the initial mass ratios of CHR and RM were 0.4:1 and 0.5:1 and the matched thickness was 1.5 mm,the effective absorption bandwidth（EAB）of both could reach 4.9GHz and 4.6 GHz,while the lowest reflection loss reached -26.2 dB and -22.5dB for the matched thickness of 2 mm,showing the best absorption performance.（3）The mixture of coal gasification residue and red mud was treated in Ar atmosphere at 900℃ to adjust the composition range of the system,and it was found that the obtained Fe/C/ceramic composite absorbing material showed the best microwave absorption performance when the mass ratio of coal gasification residue to red mud was 0.6:1.