Tar sand extractions with microemulsions II. The dispersion of bitumen in microemulsions

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Abstract
Aqueous solutions containing the active components of microemulsions, i.e. surfactants and polar cosurfactants, are not effective in dissolving bitumen and consequently in extracting tar sands. On the other hand, if a light hydrocarbon such as benzene, toluene or cyclohexane is added to the active components, the microemulsion becomes a very effective extractant. To investigate this phenomenon, phase diagrams of pseudo‐ternary systems (active mixture‐hydrocarbon‐bitumen) were determined at 25°C and in some cases in the temperature range 25 to 80°C. In most experiments, the cosurfactant was taken as 2‐butoxyethanol and the hydrocarbon as toluene. Three surfactants were examined: cetyltrimethylammonium bromide, aerosol OT and sodium dodecylbenzenesulfonate. Various regions can be identified on the phase diagrams: suspensions of solid surfactants, microemulsions, stable and unstable emulsions. The extent of the various regions depends significantly on the relative concentrations of the various components. In general, the extent of the dispersed bitumen region increases with temperature.