Separation of bitumen from dry tar sands

摘要

A process for the separation and recovery of bitumen from dry tar sands or sands with negligible quantities of connate water. The process includes comminuting the tar sands to an average particle size of approximately one centimeter in diameter and digesting the comminuted tar sand in a hot, aqueous solution having a pH within the range of pH 10 to pH 14. Optimal digestion is obtained by assuring that the tar sand in the digester is within the range of 50 to 80% solids so as to provide the necessary high shear environment. The digested tar sand is thereafter subjected to a flotation process wherein additional water is introduced to lower the temperature and the solids concentration. Preferably, the pH of the separation cell is maintained above about pH 10. Air is bubbled into the mixture to carry the separated bitumen particles to the top of the separation cell for subsequent recovery.