Preparation and dust suppression mechanism of a double network gel dust suppressant based on “prior penetration followed by cross-linking”

To address the problem of respirable dust control during coal seam mining, this paper proposed a stepwise polymerization strategy – “prior penetration followed by cross-linking” – and developed a double network (DN) gel dust suppressant HPMC-g-HPA/AM. Composed of the dust suppressant base solution (DSP) and the initiator, the dust suppressant can achieve in-situ cross-linking and solidification within coal seams to control dust. Experimental results demonstrated that DSP exhibits low viscosity, high permeability and excellent wettability, and can efficiently penetrate coal seams, while the initiator has even lower viscosity and better permeability, with a penetration rate 2.11 times that of DSP. The significant rheological difference between the two ensures the implementation of the stepwise strategy. After DSP and the initiator successively penetrate fractures and pores of coal seams, they undergo in-situ cross-linking to form a “flexible – rigid” DN gel. This significantly enhances the moisture retention capacity and mechanical properties of coal. The gel improves the dust adsorption and agglomeration capacity through the chemical anchoring effect combined with polar groups of coal, and further inhibits dust dispersion through the physical encapsulation effect, thereby reducing the dust generation rates by 47.16 % (≤180 μm) and 55.89 % (≤75 μm). The respirable dust proportion decreases from 12.08 % to 7.58 %, achieving effective respirable dust control and ensuring occupational safety.