High-efficiency 'SAA' wetting agent for coal mine dust control: from preparation and mechanism to field application.

Abstract

Coal mines generate large amounts of coal dust during mining operations. This is particularly true for coal seams at great depths, where stress concentrations, high coal strength, and poor permeability increase the likelihood of dust generation during mining. Furthermore, the mixed metallic substances in the coal hinder the penetration of water injection solutions into the pores and fractures of the coal mass. Traditional water injection methods struggle to effectively wet the coal mass, resulting in limited dust suppression. Therefore, to address these practical challenges, a composite wetting agent was developed, consisting of sodium gluconate (SG), fatty alcohol polyoxyethylene ether (AEO-3), and sodium fatty alcohol polyoxyethylene ether sulfate (AES), abbreviated as SAA. This wetting agent effectively reduces the solution's surface tension and contact angle, increases the number of oxygen-containing functional groups on the coal surface, and promotes agglomeration of micron-sized coal dust, resulting in a 22.58% increase in the median D₅₀ particle size compared to the original. Experiments using a custom-built dust-suppression simulation system revealed that the SAA wetting agent achieved an effective dust-suppression rate of 71.50%, which is 2.17 times that of traditional water-mist dust suppression. During on-site dust suppression tests conducted at the 3^-1802 working face of a certain mine using water injection with SAA wetting agent, the average coal dust particle size increased to 2.53 times the pre-injection value. The total dust suppression rate at various underground monitoring points reached 60-84%, effectively improving underground environmental quality and reducing the tendency of coal to fracture and generate dust. This approach successfully bridges laboratory mechanism analysis and underground field trials. It offers a new strategy to enhance the effectiveness of coal seam water injection and demonstrates significant engineering application value for occupational health and safety in deep coal mining.