Abstract: A process for producing alumina from bauxite by the Bayer process. Bauxite slurry is pressure digested in caustic soda solution to dissolve aluminum hydroxides in the bauxite as sodium aluminate while leaving most of the remaining constituents of the bauxite in solid form as red mud. The red mud is separated from the digested slurry to obtain a caustic-aluminate pregnant liquor, alumina hydrate is precipitated from the pregnant liquor and the alumina hydrate is calcined to obtain the alumina. The separation of the red mud from the digested slurry is carried out at a temperature above the boiling atmospheric temperature of the liquor phase of the slurry.