NOVELTY - A rotary friction dryer or gasifier (1) comprises entrance stage (10) and exit stage (30) in which entrance stage contains intake throat (15) and temperature of each stage is controllable, decompression zone (20) provided so that it separates entrance and exit stages, multi-stage compression screw (7) in which a portion of screw is in entrance stage, decompression zone, and exit stage, mixing unit (40) coupled to screw, greater than or equal to 1 exhaust vent (25) located in decompression zone, and greater than or equal to 1 discharge outlet (35) located in exit stage.    USE - A rotary friction dryer or gasifier for separating mixture of water, solid materials, and chemicals (claimed).    ADVANTAGE - The rotary friction dryer or gasifier can efficiently dry and gasify biomass at low cost and improve processability of resultant solid discharge material.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) method of separating mixture of water, solid materials, and chemicals which involves providing rotary friction dryer or gasifier (1), feeding mixture of water, solids, and chemicals into entrance stage (10) to form biomass, causing biomass to be mixed and heated as it progresses from entrance stage into decompression zone (20), forming processed material, allowing water vapor to exit rotary friction dryer as steam through exhaust vent (25) located in decompression zone, causing processed material to be further mixed and heated as it progresses from decompression zone into exit stage (30), allowing chemicals and solid materials to exit rotary friction dryer through discharge outlet (35) located in exit stage, and collecting chemicals and/or solid materials; and    (2) chemicals or solid materials separated and collected by the method.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the rotary friction dryer or gasifier.    Rotary friction dryer or gasifier (1)    Multi-stage compression screw (7)    Entrance stage (10)    Intake throat (15)    Decompression zone (20)    Exhaust vent (25)    Exit stage (30)    Discharge outlet (35)    Mixing unit (40)