Composite plates utilizing dealkalized red mud, acid leaching slag and dealkalized red mud-fly ash : Preparation and performance comparison

Dealkalized red mud, fly ash and acid leaching slag served as reinforcements to prepare composite plates by a molding method using an open mill and vulcanizing press. The optimal dosage of dealkalized red mud, acid leaching slag, and dealkalized red mud-fly ash was 40 wt%, 30 wt%, and 40 wt%, respectively, and the modifying agent aminopropyl triethoxysilane content was 3 wt%. The tensile strength and bending strength of the prepared composite plates were 23.5 MPa and 28.7 MPa, respectively, and the limiting oxygen index was 27.3%. Moreover, in order to improve electromagnetic performance and thermal conductivity of the composite plate, carbon powder, graphene and graphite ores were added to the composite plate respectively when dealkalized red mud-fly ash served as filler. It is found that the absorption peak decreased to −21.45 ranging from 9 to 12 GHz in the composite plate with graphene. SEM observation indicates that there is effective combination between the filler of dealkalized red mud-fly ash and PP in the composite plate. The manufacturing process of composite plate has less environmental impact and lower production cost. It could be applied to the field of construction, such as decorative panels and tubular products potentially.