THE PROPERTIES OF THE CALCITE - SOLUTION INTERFACE IN THE PRESENCE OF ADSORBED RESINS OR ASPHALTENES

The adsorption of three different samples of asphaltenes and resins onto alcite was studied. For all the samples the adsorption of asphaltenes was greater than that of resins, the plateaus being between 2 and 3 mg g-1 for asphaltenes and between 0.5 and 0.6 mg g-1 for resins. The adsorption process produced important changes in the wettability of calcite. The equilibrium contact angle measured at the calcite-water-toluene interface was between 80 and 95° for asphaltenes and between 60 and 85° for the resins fraction. These figures are lower than the corresponding values obtained for quartz. This result explains the presence of quartziferous particles in a greater amount than calcareous material in asphaltic sludges.