A method and system for controlling heavy metals throughout the entire process of coal gasification slag cemented backfilling

Abstract

This invention discloses a method and system for controlling heavy metals throughout the entire process of coal gasification slag cemented backfilling, belonging to the field of coal-based solid waste resource utilization and mine backfilling technology. The method includes: S1, based on the characteristic that heavy metals are enriched in residual carbon, scrubbing and microbubble flotation are performed on the coal gasification slag raw material to obtain carbon-rich components and low-carbon slurry, achieving source risk reduction; S2, deep cone concentration is performed on the low-carbon slurry, and a composite curing agent composed of cementing components, reducing stabilizing components, and chemical chelating components is added to prepare a cemented backfill paste, achieving process-based synergistic curing; S3, a multi-barrier system including an anti-seepage isolation layer, a solidified backfill body, and a buffer isolation interlayer is constructed in the goaf area to achieve long-term end-stage sealing. This invention solves the heavy metal migration risk problem in coal gasification slag backfilling through source separation-process curing-multi-layer barrier control, and has the advantages of low environmental risk, good long-term stability, and high resource utilization.

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