Process for upgrading tar sand bitumen

A method for upgrading a concentrate of tar sands bitumen containing colloidal clay in which solvent-diluted bitumen is contacted for a short time in a riser with hot attrition-resistant substantially catalytically inert fluidizable microspheres, causing a selective vaporization of the lighter high hydrogen content components of the bitumen. A portion of the heavier asphaltenes and most of the components which contain metals, sulfur and nitrogen remain on the attrition-resistant microspheres. Colloidal clay in the bitumen feed also deposits on the microspheres instead of being carried over with the vaporized hydrocarbon product. The contact material, with deposit, is passed to a burner provided with high velocity air jets which attrites the colloidal clay away from the microspheres and the material removed by attrition is recovered. The heated microspheres are reintroduced into the riser for further contact with incoming diluted bitumen charge.