Abstract: To address the environmental risks and resource wastage associated with the long-term stockpiling of high-alumina coal gangue in the Jungar mining area, a three-level synergistic integrated technology system of short-flow aluminum-silicon co-smelting-targeted enrichment and recovery of trace elements-high-value material conversion of calcium silicate residue was proposed, aiming to overcome the systemic limitations of traditional single-element extraction technologies, such as low resource utilization efficiency and high yield of secondary solid waste. By constructing a coupled model of material flow analysis and life cycle assessment, the resource utilization efficiency, environmental benefits and economic feasibility of this system were quantified. A simulation was conducted based on a demonstration scale with an annual processing capacity of 200 000 tons. The results indicated that the integrated system achieved a comprehensive resource utilization rate of 92.3%. It could annually produce approximately 70 000 tons of aluminum-silicon alloy (aluminum + silicon≥95%) and 1.04 tons of high-purity metallic gallium (purity≥99.9%), while fully converted 130 000 tons of calcium silicate residue into high-performance foamed ceramics (compressive strength≥3.5 MPa), which realized near-zero discharge of solid waste. Comparative analysis of life cycle assessment revealed that, compared to the conventional one-step acid leaching process, the global warming potential of the integrated technology route reduced by 38.5%, the cumulative energy demand reduced by 40%, and the acidification potential and eutrophication potential reduced by 42% and 34%, respectively. This study provided a engineering-feasible systematic solution and quantitative decision-making basis for the large-scale, high-value-added, and low-carbon utilization of coal gangue in mining areas.

Key words: high-alumina coal gangue, three-level synergy, material flow analysis, life cycle assessment, circular economy, near-zero discharge of solid waste