Effect of particle size on the hydrophobicity characterization of low-rank coal surfaces

Abstract

ABSTRACTIn the present communication, four particle size fractions, namely 0.500–0.250 mm, 0.250–0.125 mm, 0.125–0.074 mm, and 0.074–0.045 mm, were conducted to investigate the effect of particle size on the hydrophobicity characterization of low-rank coal surfaces using induction time instrument. To reduce the heterogeneity effect of low-rank coal on hydrophobicity during induction time measurements, experimental coal samples with low ash content and a percent attachment parameter were adopted. X-ray photoelectron spectrometer results demonstrated that after the grinding process, the content change in hydrophilic and hydrophobic functional groups played a small effect on the hydrophobicity of low-rank coal samples during the induction time measurements. Moreover, the steepness of percent attachment vs. induction time curve demonstrated that particle size played a greater effect on induction time. Furthermore, the induction time is sensitive to low-rank coal particle sizes ranging from 0.250 mm to 0.074 mm.