Interfacial stabilization of coal particulate assemblies against wind erosion and rainfall wash-off using a multiphase emulsion-based system

Deposited coal particulate layers in open-pit mines are susceptible to wind-induced re-entrainment and rainfall wash-off, whereas conventional water spraying cannot simultaneously provide rapid wetting, moisture retention, particle consolidation, and surface protection during drying and erosion. To coordinate these functions, an O/W emulsion-based composite dust suppressant (OWD) was formulated using OT/OP-10 mixed surfactants, xanthan gum/sodium alginate, and white oil. The formulation was selected through surfactant screening and an L9 orthogonal design based on the overall balance among coal wettability, emulsion-droplet size distribution, apparent viscosity at 35 s-1, water retention, and macroscopic stability, rather than optimization of a single indicator. Component-resolved comparisons revealed a stage-dependent functional division: OT/OP-10 primarily governed initial spreading on the coal surface, the polysaccharides restricted water loss and supported interparticle consolidation, and the white-oil phase assisted intermediate emulsion spreading and contributed mainly to later-stage surface shielding. In separate laboratory tests, the OWD-treated 10–40 mesh coal bed lost 0.80% of its dry mass at the maximum tested wind speed of 12 m/s and retained 99.90% of its pre-rainfall dry mass after 10 min of simulated rainfall. FTIR and SEM observations, together with qualitative electrostatic-potential maps, were consistent with a proposed wetting-bridging-shielding mechanism. These results demonstrate that the stabilization of deposited coal particulate layers can be enhanced by coordinating complementary functions within a multiphase system rather than by maximizing an isolated performance property.