Wetting process and surface free energy components of two fine liberated middling bituminous coals and their flotation behaviors

XQ density fractions has a relatively lower surface energy estimated by Washburn equation and Van Oss-Chaudhury-Good theory, and poorer selectivity of the regressive release flotation test, which was reflected in its LHR and the base part of surface free energy. Results of elemental analysis and FTIR coincide well with the coal sample surface properties.