Desensitization Effect of Chemically Induced Coal Components at Room Temperature: an Experimental Study

This study was conducted to address the rock burst problem caused by serious stress concentrations in coal seams. Based on the principle of inducing agent corrosion affecting coal components to soften coal, different inducers were selected to study the desensitization effect of acid leaching induction on coal components. The microscopic behavior characteristics of coal under acid leaching were analyzed, and the qualitative and quantitative laws were obtained for different acid leaching times and microscopic behavior characteristics. The results show the following: (1) The mixed acid solution as an inducer has the effect of immersion, dissolution, and fracture on coal. During the reaction process, the internal pores of the coal expand, and the height of the external liquid decreases. The mixed acid solution had the best effect in terms of the removal of minerals in coal. (2) Under microscopic conditions, the internal crack width of the coal body expanded several times after mixed acid soaking; the difference in the unevenness before and after compression fracture was stable at 25–27%, and the mixed acid expanded the gap in the coal. (3) This practical study shows that the characterization changes of the mixed acid solution, injected into the borehole, combines the characteristics of the citric acid and phosphoric acid solution. The minerals around the borehole are dissolved, and the debris fuses with the solution. The liquid is viscous and forms a film on the surface of the solution. The mixed acid has a more obvious effect on the immersion and dissolution of coal.