THERMAL REDUCTIVE DESTRUCTION OF PERFLUOROCARBONS INTO SAFE PRODUCTS THROUGH IN-SITU GENERATION OF ALKALI METALS IN HEATED SOLID MIXTURES

摘要

The complete destruction of CF_4, C_2F_6, and C_3F_8 was successfully achieved by flowing the gas through a heated reagent bed (400 -950℃) that contained powder mixtures of alkali halides, CaO, and Si. The CF_4 destruction efficiencies with the solid reagent containing the alkali halide, MX, increased in the order of Li~Na < K < Cs for alkali cations and I < Br < Cl < F for halide anions. This trend agreed with the endothermicity of the alkali metal generation reaction. The production of alkali metals increased with NaF, KF, CsF in this order. The solid product analysis by X-ray diffraction (XRD) showed the formation of CaF_2 and the depletion of Si with black carbon particles formed in the solid reagent residue. No CO/CO_2 and toxic HF and SiF_4 formation were detected in the exhaust gas.