Adhesion of a coal grain to a coal grain in an alcohol

Measurements of the destruction time of the coal sediment column structure formed from the following fractions of coal grains: (1) +100-200 mum, (2) 200-300 mum, (3) +300-400 mum, and (4) +400-500 mum have been carried out. Using the relationship between the reciprocal of the destruction time and t he average diameter of the size fractions of coal grains, the critical diam eter of the grains was determined. Next, using the critical diameter and su rface free energy components and parameters of the coal and alcohols, the c orrelation between the stability of the coal-alcohol-coal system and the wo rk of adhesion of coal to coal and alcohol to coal, and the viscosity, dens ity, and surface tension of alcohols were investigated. From the measuremen ts and the calculations it was found that the destruction time depended on the size of the coal fractions and the nature of the alcohol, but the criti cal diameter of the coal grains did not depend on these parameters. It was also found that the detachment a coal grain from another coal grain in an a lcohol occurred by disruption of the alcohol film present between the two c oal grains and that the increase in the attachment forces between the two c oal grains as a function of the molecular length of alcohols was caused by an increase in the perimeter of the contact plane.