TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The overall thermal treatment takes place at a pressure of 100-300 Pa. The pet-coke is present up to 25 wt.%. The gas containing oxygen and water vapor is fed with an incremental differentiated modality. The drying or pre-heating time is 30-60 minutes. The gas containing oxygen consists of substantially pure oxygen, air or air enriched in oxygen e.g. up to 50 vol.%. The solid residue is vitrified with a plasma torch for 30-60 minutes and using a torch with a nominal power of 100-150 kW.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The inertization takes place by means of plasma torches, where at least one anodic and one cathodic, having a length of 1000-1200 mm with a nominal power of 100-150 kW are positioned at a distance from the bottom of 300-400 mm having an electric arc length of 100-150 mm and with an argon flow-rate for the cathodic torch of 20-40 l/minutes and for the anodic torch of 30-60 l/minutes. The apparatus internally comprises a cleaning and advance system with scraping blades constantly kept in contact with the internal part of the drying chamber by means of at least one elastic element. EXAMPLE - Sludge (50 kg/hour) was introduced into the drying section at 120 degrees C for 40 minutes at a pressure of -15 mm water and dried sludge (22 kg/hour) was left in the section and sent to the gasification section at 850 degrees C for 30 minutes at a pressure of -15 mm water together with 345 Nm3/hour of fumes at 620 degrees C, which were subsequently sent to the fume treatment section and 28 kg/hour of vapors at 110 degrees C. The dried sludge was sent to the gasifier into which air was sent for the treatment and from which 4.9 kg/hour of ashes are discharged and sent to the inertization section at 1400 degrees C for 20 minutes at a pressure of -15 mm water to obtain a vitrified solid residue, and 85 Nm3/hour of syngas at 850 degrees C sent to the burner. The syngas was then sent to the burner together with 210 Nm3/hour of air. 308 Nm3/hour of fumes at 910 degrees C were taken from the burner, also reached by the vapors of the drier, which, after possible treatment in a powder reduction cyclone were sent to the drying section.