Soil reconstruction using coal industry solid wastes: Linking pollution control with climate variability across...

Global solid wastes from the coal industry, including coal gangue, fly ash, and flue gas desulfurization gypsum, generate over 1.5 billion tons annually. They not only occupy large areas of land but also trigger heavy-metal pollution, while soil degradation in mining areas is continuously intensifying. Traditional soil remediation methods are expensive, which makes soil reconstruction using these solid wastes a priority measure. This review synthesizes relevant research progress: coal gangue provides structural support for reconstructed soil, fly ash optimizes soil pore structure and improves water retention capacity, and flue gas desulfurization gypsum supplies Ca²⁺ to promote the formation of soil aggregates. Meanwhile, the review discusses current bottlenecks, such as leaching risks under extreme climate conditions and low efficiency in translating laboratory research results to on-site applications, and establishes a framework that connects material properties, structural evolution, and ecological effects. This study contributes to understanding how mining solid waste reuse and soil reconstruction mitigate emission- and leachate-driven contamination under variable climatic conditions.