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[Display omitted] • High-sulfur coal fly ash residues was used to fix CO 2 and produce high purity carbonates. • The extraction efficiency of calcium was significantly influenced by pH and acidic conditions favored calcium release. • Adding acid progressively slows down silicon polymerization and promotes calcium leaching. • Gaseous CO 2 can simultaneously dissolve calcium and form carbonates on the solid surface. The aim of this study is to characterize potential utilization pathways of high-sulfur fly ash from coal combustion plants for the purpose of fixing CO 2 and producing high purity carbonates via carbon mineralization process. Unlike other typical fly ashes, the feedstock in this study contains a mixture of fly ashes and desulfurization residues. We present a multi-step approach for utilizing this industrial waste to provide a sustainable and economical alternative to landfilling or generating low-value products. The solubility of gypsum from the desulfurization residue limits the dissolution behavior of calcium, therefore, developing an efficient process to extract Ca for subsequent carbonation is needed. The dissolution process of different elements (Ca, Si, Fe, Al) was conducted under different pH values ranging from 0 to 13, various reaction temperatures, slurry densities and methods of dosing leaching agents. It was found that the extraction efficiency was significantly influenced by the pH, and the acidic conditions favored calcium release. Progressively adding acid at fixed pH during dissolution can slow down the polymerization of silicon which promotes calcium leaching compared with the rapid addition of acid. Gaseous CO 2 can act as a dissolution agent to dissolve calcium and simultaneously produce nano-crystalline calcite on the surface of the fly ash as a direct carbonation approach. Stepwise dissolution and carbonation combined with a pH swing process can produce high purity calcium carbonates and the carbonate polymorphs can be adjusted via controlling operating conditions. The findings presented in this study provide implications for how to sustainably utilize high-sulfur fly ash and design processes for its utilization. [ABSTRACT FROM AUTHOR]

• Resource utilization of industrial wastes in energy storage system. • Synergistic adsorption-electrocatalysis effectively suppresses the shuttle effect. • MCFA separator can effectively reduce internal resistance and polarization of LSBs. • MCFA helps to improve the transformation kinetics of LiPSs. The notorious shuttle effect severely limits the practical application of Lithium-Sulfur Batteries (LSBs). In line with the concept of "green chemistry", industrial solid waste is reasonably applied to the design of battery's interlayer. The modified coal fly ash (MCFA) can effectively accelerate the redox kinetics of the electrode and optimize the nucleation and decomposition of Li 2 S. The synergistic adsorption and catalytic action from rich pore structure and polar metal oxides can effectively capture and fix free polysulfide (LiPSs), which realizes the inhibition of shuttle effect. The LSBs with MCFA interlayer exhibit good cycle stability (decay-rate: 0.05% per cycle) and rate capability (703 mAh g−1 at 3C). Even under extreme conditions of poor electrolytes (E/S = 7.8 μL /mg), Cell-MCFA/PE with a high S loading (7.5 mg cm−2) still performs well (732 mAh g−1 after 100 cycles). This work provides an economical and environment-friendly strategy for the design of interlayer, which is conducive to the commercialization process of LSBs. [ABSTRACT FROM AUTHOR]