Emulsions separate into the component liquids on standing because:
Difference in miscibility.
Surface tension at the surface.
Viscosity of the Continuous phase.
Difference in the density of liquids.
Sedimentation occurs when the dispersed droplets in an emulsion are not uniformly distributed, and they tend to move under the influence of gravity. The density difference between the two immiscible liquids contributes to the creaming or sedimentation process.