Advancing ceramsite technology: the impact of microwave sintering on MWIFA-muck blends for enhanced heavy metal solidification and structural properties

Abstract

This research delves into the properties of sintered ceramsite from muck, enhanced with municipal waste incinerated fly ash (MWIFA), using microwave sintering technology. It specifically investigated the effects of the MWIFA mix ratio, sintering temperature, and holding time on ceramsite’s key performance, including one-hour water absorption, porosity, and apparent density. The microstructural attributes were quantified through X-ray diffraction (XRD) and scanning electron microscopy (SEM), coupled with an evaluation of ceramsite’s capability to solidify heavy metals. The results demonstrate that ceramsite prepared with a 10% MWIFA ratio, sintered at 1100 °C, and maintained for a 15-minute holding period, exhibited optimal properties: a low one-hour water absorption rate of 0.2%, minimal porosity at 0.4%, and a substantial apparent density of 2.14 g/cm³. Furthermore, microstructural analyses confirm the existence of mineral phases including quartz, augite, andesine, albite, and labradorite. Significantly, the ceramsite showed high efficiency in immobilizing heavy metals, achieving solidification rates of 92% for Zn, 98% for Cu, and 100% for Cr. These findings offer valuable insights and serve as a practical guide for the recycling of MWIFA and muck, endorsing the use of microwave sintering technology in ceramsite production.