Recycling of waste red mud for production of ceramic floor tile with high strength and lightweight

Low-cost ceramic floor tiles were successfully produced from recycling red mud with addition of kaolin. (NH4)(6)Mo7O24 were used as catalyst to alter the mullitization reaction pathway and promote the growth of mullite crystals. The effects of molybdate content and sintering temperature on morphologies and performances of resultant specimens were characterized in detail. The phase evolution and microstructure observation were conducted by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results indicate the ceramic floor tile with 6 wt% (NH4)(6)Mo7O24 addition exhibits a flexural strength of 185.6 MPa, bulk density of 1.45 g/cm(3) and water absorption 5.5%, an intergrown microstructure composed of anisotropically grown mullite at 1180 degrees C. This work opens up the possibilities of the sintered ceramic as a building material since the ceramic system has good performances in flexural strength and bulk density. (C) 2018 Elsevier B.V. All rights reserved.