Rapid large-scale morphological control of desulfurized fly ash enables high performance desulfurization material

The high-value utilization of desulfurized fly ash (DFA), a by-product of coal-fired flue gas desulfurization, is important for reducing the accumulation of desulfurization solid waste. However, the conventional multi-stage counter-current water-washing process has high energy consumption and operational costs, and limited impurity-removal capacity, resulting in low resource recovery efficiency. To address these challenges, this study proposes a new scalable super-liquid-film-reactor (SLFR) strategy to rapidly and broadly functionalize DFA with greatly enhanced desulfurization activity. The results demonstrate that the SLFR significantly enhances mass transfer rates and dramatically improves both the purification efficiency and the effective calcium (CaO) activity of the fly ash. The overall impurity removal rate reached about 94.85 %, with the reaction time drastically reduced to 5 min. The carbonation rate of the activated and washed ash was greatly accelerated to achieve a high carbonation ratio of 94.73 %, enabling the potential utilization of the SLFR-treated ash as an available desulfurization raw material with a greatly decreased treatment cost (from 516.54 CNY ton^-1 to 149.24 CNY ton^-1) This approach substantially reduces wastewater volume generated during purification and enables high-value utilization of solid waste, providing a new strategy for sustainable, low-cost waste valorization and demonstrating both technical and economic feasibility.