TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The hot gaseous medium has oxygen content of greater than 3, preferably 5-16 vol.%. The water content of the recycled gaseous medium is reduced to 2-15 wt.%. Preferred Parameters: The gaseous medium entering step is carried out at 425-500 degrees K. The gaseous medium exiting the drying step and is passed to the wind sifter in the second step is at 325-370 degrees K. Preferred Methods: The gaseous medium is obtained by burning hydrocarbon with air (5). The recycled gas phase is mixed with the hydrocarbon, particularly natural gas or liquefied petroleum gas. The temperature of preheated gaseous medium is obtained through heating a preheated gaseous medium with the use of steam.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The vessel is tubular vessel oriented horizontally. The tubular vessel is rotating along its horizontal axis. The horizontal axis of tubular vessel in inclined downwards in the direction of flow of the gaseous medium at 30 degrees and particles that are heavier and have better rolling behavior than cellulosic and thermoplastic material roll and move downward inside the tubular vessel and are separated from the cellulose/plastic waste mixture at the outlet of tubular vessel.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The cellulose/plastic waste mixture and gaseous mixture are concurrently passed through a vessel. The particulate cellulose/plastic waste mixture comprises cellulosic and thermoplastic materials. The materials heavier than the cellulosic and thermoplastic material comprise metal, stones, ceramics, glass, or thermosetting plastics. The mixture was pretreated prior to the first step by mechanical pressing to reduce water content. The cellulose/plastic waste mixture comprises thermoplastic material (5-less than 40 or 40-85 wt.%). The cellulosic material in the cellulose/plastic waste mixture originates from paper and/or cardboard. The thermoplastic material in the cellulose/plastic waste mixture is mainly based on polyethylene. Preferred Methods: The method includes separating purified cellulose/plastic mixture and gaseous medium by action of cyclone (11); compacting the purified cellulose/plastic mixture using pelletizing device producing pellets with diameter of less than or equal to 10 mm; comminuting pellets resulting from the fifth step to obtain powder; and grinding the pellets by using air turbulence mill. The separated gaseous medium is partially recycled to the gaseous medium. The purification step comprises wind sifter. Preferred Properties: The cellulose/plastic waste mixture comprises particles with maximum particle size of less than or equal to 150 mm before entering in the first step and less than 30 mm after the fourth step. EXAMPLE - A feed with contaminated paper and plastic from municipal waste was shredded to less than or equal to 100 mm, and transported through magnet and eddy current device to remove metals. The stream was transported to rotating drum dryer (1). The vessel was tilted 5 degrees with respect to the horizontal. The inlet heated gas at 423-523 degrees K was introduced. The dried waste was transported to wind sifter. The burner (3) was set to 640 m3 methane gas per hour with air feed of 33360 m3. The outlet of product was 12.3 ton/hour. Gas from two main product cyclones was cleaned over dust-cyclones and split, thus oxygen content was lowered and reduced the risk of explosion or fire. Heavy materials (1 wt.%) were collected at the dryer bottom. The waste stream was blown into vertical pipe. The dry mixture allows for separation of heavy material. The gas and waste mixture was forced to flow with the aid of two transport ventilators. The main waste stream was separated from gas stream into two consecutive cyclones. Small non-combustible material was removed from the particulate waste stream by passing resulting stream over sieve. Fine sand and glass shreds (2 wt.%) were separated off. The waste stream was transported to shredder that cut the particles into 30 mm length and width. The resulting clean waste stream was converted into solid particles by pressing through die. The mixture was heated to 100-115 degrees C or 120 degrees C depending on waste stream and speed of press. The resulting pellet comprises (wt.%) plastic and organic/cellulose fibrous material ( greater than or equal to 97, preferably greater than or equal to 98 wt.%).