A double anti-seepage method based on coal-based solid waste

Abstract

The invention relates to the technical field of mine ecological restoration and management, in particular to a double anti-seepage method using coal-based solid waste for filling open pits, gullies, etc. The fly ash in the fly ash-based cementitious material cooperates with other components During the reaction, a small amount of harmful substances such as heavy metals, Hg, As and S in the fly ash are stabilized and fixed in the form of "participating in bond formation and solidification and storage". The internal structure of the cementitious material is dense and anti-seepage, forming a hard layer for the bottom of the pit Quality protective shell; the amount of fly ash added to the polymer waterproof coating on the surface of the cementitious material accounts for 60%-90% of the powder, which is a flexible protective film. According to the chemical principle of the colloidal interface, it is released during the cement hydration reaction Out of Ca 2+ , the hydrolyzed emulsion at Ca 2+ Under the action of bridging, react with fly ash surface groups to generate [R‑COO ‑ ] Ca 2+ [‑Si‑O ‑ ] is an organic-inorganic gelled product with a unit structure, forming an interface compatible, uniform and dense waterproof coating, repairing small cracks in the underlying gelling material, with a small permeability coefficient, and preventing leachate from seeping down.

Description

technical field [0001] The invention relates to the technical field of mine ecological restoration and treatment, in particular to a double anti-seepage method for filling open pits, ravines and the like by using coal-based solid waste. Background technique [0002] At present, mining waste coal gangue, slag tailings, construction waste, etc. are often used as fillers to backfill natural gullies and mining pits. However, coal gangue contains trace heavy metals, such as Cd, Pb, Ni, Zn, Cr, Cu, etc. There are also different heavy metals in different mining slag tailings. With the long-term rainwater leaching, the heavy metals in it will migrate and accumulate with the rainwater, causing pollution to the groundwater and surrounding land. [0003] In some foreign mines, the bottom of the pit is leveled before the waste residue is filled, and the geomembrane is pre-laid to prevent the leakage of the leaching solution. However, the cost of the geomembrane is high, and the mechan...

AI Technical Summary

Problems solved by technology

However, the cost of geomembrane is high, and its mechanical strength is limited. In the subsequent backfilling process, large waste residue blocks are easy to damage the geomembrane, resulting in leakage points. In addition, the geomembrane is prone to aging and failure, so that pollutants can diffuse to the underground environment.

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