Study on preparation and performance of iron tailings-based porous ceramsite filter materials for water treatment

Porous artificial ceramsite filter material (ACFM) with sewage treatment function is prepared with iron tailings and fly ash as raw materials to reduce environmental pollution, reduce resource consumption, and realize the sustainable development of “using waste to treat waste.” The sintering temperature is optimized by calculating the SiO2-Al2O3-CaO/MgO system thermodynamics. Furthermore, the reliability of the thermodynamic analysis validated through experiments. The preparation process of ACFM is optimized using a single factor and orthogonal experiments, and its mechanical properties and leaching toxicity are tested. The results show that the ratio of raw materials has almost no effect on the properties of the porous ACFM within the range required by the Riley phase diagram. A liquid channel can be formed at a sintering temperature of only 1060 °C due to the presence of flux CaO/MgO in raw materials, which is beneficial to the migration of elements, resulting in the solidification of toxic and harmful elements in the ACFM. Additionally, the specific surface area, porosity, and hydrochloric acid solubility of porous ACFM are 1.185 m2·g−1, 62%, and 0.41%, respectively, and all performance parameters meet the national industry standard. This work provides an economical, environment-friendly, and effective solid waste recovery process.