Preparation and characterization of corundum-mullite conductive ceramic using coal gangue by one-step sintering process

Coal gangue, a typical bulk solid waste from coal mining and washing, presents significant challenges for its valorization. In this study, carbon-reinforced conductive ceramics were prepared via dry pressing and one-step sintering using coal gangue and alumina as raw materials, with thermosetting phenolic resin, corn starch, and white dextrin employed as organic carbon sources. Effects of the addition of different carbon sources on the phase compositions, microstructure, physical properties, and electrical properties of the ceramics were investigated in detail. Additionally, the conductive mechanism of the ceramic was explored. The experimental results indicated that the addition of organic carbon sources was beneficial to the formation of a continuous conductive network within the ceramic matrix, thereby endowing insulating ceramics with excellent electrical conductivity. The ceramic with 15 wt% thermosetting phenolic resin addition exhibited the best comprehensive performance, with a density of 1.98 g/cm 3 , a porosity of 11.76%, an electrical conductivity of 1.27×10 3 S/m, and a compressive strength of 40.16 MPa.