Closed loop incineration process

A process for combusting hazardous waste materials so that substantially all of the contaminants are removed from the resulting flue gas comprising:

• (a) feeding combustible waste material into a first combustion zone where they are combusted at a temperature from about 1400.degree. F. to about 2200.degree. F.;
• (b) passing the resulting flue gas stream from said first combustion zone to a second combustion zone where they are further combusted at a temperature from about 1800.degree. F. to about 2500.degree. F.;
• (c) passing the resulting flue gas stream from said second combustion zone to a cooling zone containing an aqueous solution or slurry containing acid salts or alkaline salts, or both, from a downstream wet gas scrubbing zone, wherein the flue gas stream is cooled by at least 1000.degree. F. with the formation of acid salts;
• (d) passing the flue gas/solids mixture from said cooling zone to a separation zone, where the solid material is separated and collected from said flue gas;
• (e) recycling a portion of the flue gas stream, to which oxygen is added to bring the oxygen content of said flue gas stream to at least about 20 volume, to said first combustion zone and/or second combustion zone;
• and
• (f) passing the remaining portion of said flue gas to a wet scrubbing zone, containing an aqueous alkaline solution or slurry, wherein acid gases and residual particulates are removed.