Preparation and Characterization of the Ceramsites with Microscale Pores from Iron Tailing and Fly Ash

Background: Iron tailing causes great environmental and social problems. They contaminate water, air and soil. Therefore, it is of important significance to prepare iron tailing ceramsites with microscale pores which can recycle the deposited iron tailing. Objective: The aim of the research is to obtain iron tailing ceramsites with microscale pores and good mechanical performance. Methods: The iron tailing ceramsites have been characterized via Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Influence of the content of iron tailing, temperature and duration time on the mechanical performance of the obtained ceramsites was performed and the optimal sintering parameter was determined. The bulk density, apparent density and cylinder compressive strength of the obtained ceramsites increased as the iron tailing content, temperature and sintering time improved. Results: Duration time and sintering temperature play important roles in the formation and size of the pores of the ceramsites. The optimal iron tailing content and sintering parameter are 70 wt.%, 1100 °C for 40 min. The iron tailing ceramsites mainly consist of orthorhombic CaAl₂Si₂O₈, monoclinic CaSiO₃, hexagonal Ca₇Si₂P₂O₁₆, triclinic MgSiO₃, triclinic Al₂SiO₅, and triclinic Ca₂Fe₂O₅ phases. Iron tailing ceramsites from 1100 °C for 40 min are composed of irregular particles with several hundreds of micrometers improving the density and strength of the ceramsites. Conclusion: Iron tailing ceramsites containing microscale pores were prepared using iron tailing and fly ash, and exhibited excellent potential for application in the field of construction.