METHOD AND APPARATUS FOR DETOXIFYING NITROGEN TRIFLUORIDE GAS

摘要

PROBLEM TO BE SOLVED: To effectively detoxify NF3 gas by introducing a gas containing NF3 gas into a reaction tube packed with a metal powder upwardly from a bottom side and causing a reaction under a heating condition at a specified temperature while the gas is being brought in contact with the metal. SOLUTION: When a gas containing NF3 gas is detoxified, first N2 gas is introduced into a reaction tube 10 while an interior of the reaction tube 10 is heated by a heater 20, and in this state a gas produced by diluting the NF3 gas with the N2 gas is introduced into the reaction tube 10 through a gas introduction pipe 12. Two hours starting from a start of introduction is spent for raising temperature within the reaction tube 10 to 150-500 deg.C. At this moment, the metal powder 11 is circulated and moved by inertia of the introduced gas in the reaction tube 10 and each particle of the metal powder 11 is made to uniformly contact with the gas and is reacted with the NF3 gas. Surfaces of the metal powder 11 are coated with a fluoride film, surface lubrication characteristics are enhanced and powdery state is maintained. Then, NF3 concentration of the gas introduced into the reaction chamber 10 is raised and reaction is continued for additional two hours so as to complete detoxification treatment.