The complex transformation of phosphorus (P) during municipal solid waste (MSW) incineration fundamentally dictates its partitioning and subsequent recovery potential. However, its in-situ behavior in circulating fluidized bed (CFB) incinerators remains poorly understood. In this study, the spatial migration and mineralogical stabilization of P in a full-scale MSW CFB incinerator were systematically investigated. The elevated phosphorus concentration observed in the circulating ash (CA, 11.1 mg g −1 ) may be attributed to conditions within the circulating loop, including the particle-rich hydrodynamic environment, particularly in the cyclone separator, where enhanced gas–solid slip velocities and high local solids concentrations create favorable conditions for volatile P capture. Conversely, the bottom ash (BA) and fabric filter ash (FFA) retain significantly lower P contents (1.70 and 5.35 mg g −1 , respectively) due to profound mass and sorbent dilution effects. Micro-scale characterization reveals the co-localization of P with Ca/Mg in high-temperature ash residues (>850 °C), which may originate from calcium phosphates in the feedstock. Subsequently, residual volatile P undergoes heterogeneous condensation in the mid-temperature convective pass (400–600 °C). Environmental assessments indicate that the heavy metal leaching concentrations of CA are below Chinese regulatory landfill limits (GB 16889–2024), supporting a targeted partial bypass discharge strategy to minimize hazardous terminal FFA generation at the source. Meanwhile, the severe heavy metal leaching risk of downstream FFA necessitates thermochemical detoxification. These insights propose a targeted ash management strategy and highlight the imperative of future agronomic bioavailability validation for the recovered phosphate products.
Sun et al. (Tue,) studied this question.