Method and apparatus for making a pollutant harmless

1. Field of the Invention A method for making harmless a material to be treated containing a pollutant, including the steps of arranging a pair of ejecting nozzles such that nozzle openings thereof are opposed to each other inside a pressure-proof furnace, thermally treating that material, ejecting the thermally treated material through each of the nozzle openings of the nozzles, respectively, and colliding the material ejected through one of the nozzles with that ejected through the other in a space inside the pressure-proof furnace and between a pair of the nozzle openings such that a portion of the pollutant of the material remaining non-decomposed by the thermal treatment may be decomposed.