Research on the characteristics of montmorillonite microcapsule inhibitors for suppressing coal dust explosion

To minimize the substantial amount of highly explosive flammable dust and coal dust present in coal mine working faces, relatively effective suppression measures have been adopted. Na-MMT@CS@PA-Na, a core-shell structural blast inhibitor, was experimentally synthesized using sodium-based montmorillonite (Na-MMT) with pore structure as the carrier and chitosan (CS) and sodium phytate (PA-Na) as the active components was used to analyze the physical and chemical properties of coal dust. The results showed that the synergistic effect of Na-MMT@CS@PA-Na eliminated the bright burning area of the flame, with the flame propagation speed being lower than the average speed of 1.469 m/s, and the peak temperature being limited to 89°C. The pressure parameters showed substantial reductions, reducing maximum overpressure (P
max
) by 92.9% and maximum pressure rise rate (dP/dt
max
) by 94.6%, far exceeding the performance of individual component materials. At interring ratios (α=0.045), a negative oscillation in the flame speed occurred, and it had significant inhibitory effects on both temperature and pressure. Conversely, individual PA-Na and Na-MMT only weakly reduced flame brightness or created non-luminous zones. The scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses reveal the physical suppression mechanism. Among them, Na-MMT@CS@PA-Na significantly reduces the explosion effect in multiple aspects. Its inhibitory effect is superior to that of Na-MMT and PA-Na, and the optimal inertization rate α=0.045. This study has achieved important experimental basis and theoretical reference for the flame propagation behavior of coal dust explosion in enclosed pipelines using new microcapsule materials.