Characterization of road dust and formulation of a molasses-based dust suppressant for heavy-duty haul roads in open-pit coal mine

Abstract

To address the rapid evaporation of water during dust suppression on heavy-duty roads in open-pit coal mine, this study investigated the physicochemical properties of road dust and formulated a molasses-based dust suppressant with enhanced water retention, anti-evaporation, and consolidation capabilities. Analysis revealed that road dust contains high levels of TSP, PM₁₀ and PM_2.5, indicating significant dust pollution potential. The presence of hydrophilic components, confirmed by crystal structures and functional groups, was supported by the dust's small initial contact angle and short settling time. However, its low moisture content (1.24 %) highlighted poor water retention. To overcome this, molasses, an industrial by-product with excellent water retention and consolidation properties, was chosen as the primary component of the suppressant. Experiments demonstrated that a 30 % molasses solution combined with sodium dodecyl benzenesulfonate (SDBS) achieved optimal synergy. The addition of 2 % glycerol enhanced moisturizing performance, while 2 % CaCl₂ provided maximum moisture absorption. The optimized suppressant achieved an evaporation rate of 2.71 g/h, a failure resistance force of 136.69 N, and a penetration depth of 8.27 cm. Microscopic analysis showed that the consolidated dust layer exhibited a smooth, dense layer with firmly bonded dust particles. In its liquid state, the molasses-based dust suppressant wets and suppresses dust; upon water evaporation, it solidifies into a cohesive layer, providing lasting dust suppression. This study offers an efficient and environmentally sustainable solution for dust suppression on open-pit coal mine haul roads.