High-Temperature Dechlorination Performance of Solid Waste-Based Dechlorination Agents
The escalating volume of municipal solid waste in China necessitates effective disposal strategies. Industrial kiln co-processing offers a promising route, but high-temperature decomposition of chlorinated components releases HCl and Cl2, causing severe equipment corrosion and operational issues. This study investigates the high-temperature dechlorination performance of fly ash and red mud, two abundant industrial solid wastes, as potential dechlorination agents. Using a high-temperature tube furnace system, dechlorination efficiencies were evaluated across 600–900 °C. At 700 °C, fly ash achieved a peak dechlorination efficiency of 93.33%, while red mud reached 88.61%. However, efficiencies declined with further temperature increase, dropping to 65.6% and 58.27% at 900 °C for fly ash and red mud, respectively. To enhance performance at higher temperatures, fly ash was modified via alkali (NaOH) treatment. The modification increased surface roughness and porosity, disrupted Si-O-Si and Si-O-Al networks, and exposed active sites. Consequently, the alkali-modified fly ash exhibited a peak dechlorination efficiency of 94.98% at 800 °C, a 23.08% improvement over unmodified fly ash (71.9%). These findings demonstrate the technical feasibility of utilizing solid wastes as dechlorination agents, offering a dual benefit of waste valorization and cost-effective high-temperature gas purification. The study provides a foundation for scaling up this approach in industrial kiln applications, contributing to sustainable waste management and reduced environmental impact.