Exploring mechanical properties and long-term environmental impact of ceramsites derived from diverse solid wastes

Abstract

The escalating global issue of soil pollution by heavy metals, particularly incinerated municipal solid waste fly ash (IMSWFA), necessitates effective remediation strategies. The prevailing approach for safely disposing and utilization of IMSWFA involves high-temperature sintering. In this work, we propose a cost-effective method to produce ceramsites by utilizing IMSWFA, municipal sludge (MS), contaminated soil (CS), and iron tail slag (ITS). After conducting a comprehensive analysis and comparison of outcomes obtained from orthogonal experiments and single-factor experiments, it was determined that the optimal preparation conditions for achieving desirable results are preheating at a temperature of 400 °C for 15 min followed by sintering at a temperature of 1150 °C for 10 min. The optimal ratio of raw materials for ceramsites is 15 % IMSWFA, 15 % MS, 58 % CS, and 12 % ITS. The ceramsites, prepared in accordance with the specified process and raw material ratio, exhibit remarkable properties including robust stability, minimal water absorption, reduced weight, and elevated cylindrical compressive strength. The ceramsites demonstrate an exceptionally high heavy metal loss ratio ranging from 91 % to 100 %, while exhibiting significantly lower leaching quantities of these metals compared to the raw materials. Additionally, aging tests of ceramsites were performed under UV light and acid/alkaline etching to simulate the real-world environment. This work can be utilized to investigate the long-term environmental impact of ceramsites derived from municipal solid waste (MSW), thereby making a valuable contribution to the advancement of solid waste management technology.