Study on coupling chelating agent and surfactant to enhance coal wettability: Experimental and theoretical discussion

To further enhance the impact of water injection and dust reduction in the deep mining process of the coal mine, an efficient dust suppressant for water injection was synthesized by coupling a chelating agent and a surfactant. The optimal composition solution was determined by surface tension, pre-treatment settling time and contact angle. The experimental results display that the composite solution (0.20 wt%) of Tetrasodium iminodisuccinate (IDS) and Sodium dodecyl sulfate surfactant (SDS) has the best wetting influence on the coal. Under this condition, the surface tension, contact angle and settling time are 23.69 mN/m, 25.72° and 48 s, respectively. FTIR tests exhibit that the proportion of hydrophilic functional groups in the coal sample treated by IDS and SDS composite solution is the highest, reaching 94.23 %. The results of particle size distribution tests show that IDS and SDS composite solution effectively reduces the dust production capacity of the coal body. In addition, the synergistic mechanism of IDS and SDS molecules is discussed from two aspects: Enhancing the pore fluidity and improving the hydrophilicity of coal. In this study, the wetting effect of the dust suppressant is better than traditional surfactants, and the results have important reference significance for improving the water injection effect.