Abstract: Using fly ash for CO₂ mineralization and sequestration, and applying its products to prevent and control spontaneous combustion of coal in goafs, is an important approach to achieve the synergistic governance of pollution reduction, carbon emission reduction, and disaster control. To address the problems of slow leaching rate of Ca²⁺, low mineralization efficiency in fly ash, as well as high energy consumption of traditional physical modification methods, this study proposes the idea of enhancing the CO₂ mineralization efficiency of fly ash through salt leaching treatment, with a focus on investigating the strengthening mechanisms of two typical salt reagents (sodium acetate and ammonium acetate) on the mineralization efficiency of fly ash. Laser particle size analyzer, low-temperature N₂ adsorption method, Fourier Transform Infrared Spectrometer (FTIR) and other techniques were used to analyze the modification effect of salt leaching on the physicochemical structure of fly ash; ion chromatograph was employed to study the Ca²⁺ leaching characteristics in fly ash slurry under salt leaching conditions; and a CO₂ mineralization reaction system combined with a pseudo-second-order kinetic model was utilized to explore the strengthening law of salt leaching treatment on the fly ash mineralization process. The experimental results show that ammonium acetate treatment increased the specific surface area and pore volume of fly ash by 62.63% and 300.00% respectively, and the D₅₀ decreased by 31.80% compared with the original sample, exhibiting a significant particle refinement effect. Sodium acetate treatment plays a role in depolymerizing the structure of fly ash to a certain extent, with a relatively weak modification effect. In terms of ion leaching, the mass concentration of Ca²⁺ in the fly ash slurry reached 4 478 mg/L after 30 minutes of ammonium acetate treatment, which was 375.37% higher than that of the control group; sodium acetate treatment increased the mass concentration of Ca²⁺ by 68.57%, indicating that salt leaching treatment effectively improved the leaching mass concentration and rate of Ca²⁺. Kinetic analysis of the mineralization reaction showed that after salt leaching treatment, the initial CO₂ mineralization reaction rate and carbon sequestration capacity of fly ash was significantly improved. The CO₂ sequestration capacity of fly ash samples treated with ammonium acetate reached 36.18 g/kg, which was 46.30% higher than that of the untreated samples, while the sequestration capacity of samples treated with sodium acetate reached 27.98 g/kg. In terms of inhibiting coal spontaneous combustion, when the mineralized products of ammonium acetate-treated fly ash were mixed with coal samples, the heat release during oxidation decreased by 17.48% compared with the original coal samples and by 9.20% compared with the coal samples treated with original fly ash, demonstrating more excellent inhibition characteristics. Salt leaching treatment, especially ammonium acetate treatment, can significantly enhance the mineralization and carbon sequestration capacity of fly ash through the synergistic effect of physical pore expansion, ion exchange, and chemical activation, providing a theoretical basis for the integrated application of fly ash carbon sequestration and coal spontaneous combustion disaster control.