In view of the serious dust pollution of fully mechanized mining and the poor effect of spraying water on the wetting and capturing of coal dust, the large molecular weight of traditional spray dust reducing agents,the viscosity of the solution is not easy to atomize and the unsatisfactory dust reduction effect,etc.,in order to improve the comprehensive mining face spray dust removal efficiency,reduce the dust concentration in the work area,under low temperature conditions,by introducing polydopamine into the acrylamide polymerization reaction system to control the degree of polymerization,generate a highly efficient atomized dust-reducing agent molecule PDA-PAM,and use infrared spectroscopy to study its functional group structure. The product is compounded with surfactants and hygroscopic inorganic salts. Orthogonal experiments are designed with the contact angle of the solution to the coal sample and the sedimentation speed of coal dust in the solution as evaluation indicators. The formula of the dust depressant solution 0. 8%PDA-PAM,0. 05% dodecyl dimethyl benzyl ammonium chloride and 0. 05%NaCl is finally determined. Based on CFD numerical simulation technology,under the disturbance of 1. 3 m/ s wind flow in Bailu Coal Mine 4307 fully mechanized mining face,the atomization of spray dust reducer solution at 1—8 MPa was simulated,revealing the influence law of spray dust reducer on spray atomization characteristics. Numerical simulation results show that there is a power function relationship between the average particle size of the droplets and the spray pressure;compared with the clean water spray,the average droplet size of the fog field produced by adding the compound spray dust suppressant is smaller and the distribution is more uniform;when the spray pressure is 8 MPa,the ratio of the droplet size of the fog field generated by spraying the dust-reducing agent solution in the optimal size range of 20—100 μm reaches 90. 31%. It is verified by experiments of moisturizing and accelerating coagulation that the spray dust reducer solution developed can quickly wet coal dust and condense into shells, and can achieve the dual dust control effect of moisturizing and accelerating coagulation. The dust reducer is applied on site. Through actual measurement,the average total dust and respiratory dust concentration at each measuring point of the working face have been reduced to 72 mg/ m3 and 44 mg/ m3,the average total dust reduction rate has reached 84. 2%,and the average respiratory dust reduction rate has reached 82. 7%. The developed spray dust reducer solution can efficiently atomize to produce a relatively ideal droplet size,and has a strong condensing and wrapping effect on coal dust,which can effectively reduce dust pollution on the work site and ensure the occupational health and safety of workers. © 2023 Cailiao Daobaoshe/ Materials Review. All rights reserved.
