Effect of bacterial solution to cementation solution ratio on dust suppression effect of microbial dust suppressant and mechanism analysis

Dust suppression agent based on Microbially Induced Carbonate Precipitation (MICP) was a new and efficient dust suppression method in recent years, but the environment had a significant impact on its dust suppression effect, and its mechanism of action was complex. This article conducted a dust suppression study by adjusting the volume ratio of bacterial solution and cementation solution in MICP. It was found that the dust suppression efficiency was the highest when the bacterial solution to cementation solution ratio was 2:1, and the wind erosion rate in 15 days was 0.68 %. In the early stage, the nutrients in the bacterial solution bound the coal dust to suppress the dust, but the dominant factor for the continuous performance of the subsequent dust suppression was the deposition and adhesion of CaCO₃ formed by biomineralization. As the reaction progressed, the CaCO₃ crystal form gradually changed from the initial vaterite to calcite. When the proportion of bacterial solution was high, it promoted the convert of crystal form and stabilized the cementation. However, at low bacterial solution proportions, the transformation time of vaterite to calcite was prolonged and the proportion of calcite decreased. The microbial dust suppressant with a high bacterial solution to cementation solution ratio had poor infiltration, causing it to concentrate on the surface of coal dust, resulting in high hardness of the mineralized coal dust consolidation body. At low Bacterial solution to cementation solution ratio, the wettability of the microbial dust suppressant increased, leading to a more uniform consolidation and increased thickness.