Study on the relationship between the hydrophilic–lipophilic balance values of non-caking coal and sulfonate-type dispersants and prediction model for slurry concentration

This study quantified the hydrophilic–lipophilic balance (HLB) of non-caking coal and precisely adjusted the HLB values of sulfonate anionic dispersants to systematically investigate their matching relationship. The optimal match was found to be dispersant HLB2=HLB1±0.200. Matched dispersants better adapted to hydrophilic/hydrophobic microregions on coal surfaces, forming thicker adsorption layers that enhanced steric hindrance and promoted uniform particle dispersion in water. Interaction energy analysis revealed that coal samples with high HLB and low ζ-potential exhibited weak energy barriers, leading to aggregation, whereas those with low HLB and high ζ-potential showed strong electrostatic repulsion and higher energy barriers, favoring colloidal stability. Molecular dynamics simulations confirmed effective adsorption of matched dispersants onto corresponding coal surfaces, with concentration distribution maps revealing significant interfacial overlap of dispersant, water, and coal molecules, forming a tightly bound transition layer. A partial least squares prediction model for constant-viscosity concentration (Y) was established: Y=52.748+0.893HLB1+0.210HLB2. The model yields an average absolute error of 2.86%, demonstrating high predictive accuracy for the constant-viscosity concentration of coal samples. This work provides a rational HLB-matching strategy for designing efficient dispersants in coal-water slurry systems.