Process for refining nitrogen trifluoride gas using alkali earth metal impregnated zeolite 4A

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PURPOSE : A process for refining nitrogen trifluoride gas using zeolite 4A impregnated with alkali earth metal is provided to selectively adsorb NF3 only from NF3 containing CF4 by impregnating zeolite 4A with a proper amount of alkali earth metal, and a nitrogen trifluoride adsorbent used in the process is provided. CONSTITUTION : A process for refining nitrogen trifluoride gas comprises a step of recovering pure nitrogen trifluoride after selectively adsorbing nitrogen fluoride only and ventilating carbon tetrafluoride by flowing nitrogen trifluoride(NF3) gas containing carbon tetrafluoride(CF4) through a column packed with zeolite 4A impregnated with alkali earth metal, wherein an amount of the impregnated alkali earth metal is 0.5 to 10 wt.% of the total zeolite weight, wherein the alkali earth metal is magnesium(Mg), calcium(Ca), strontium(Sr) or barium(Ba), wherein the nitrogen trifluoride(NF3) gas containing carbon tetrafluoride(CF4) flows through a packing layer packed with an adsorbent at a temperature of -100 to 50 deg.C, wherein the nitrogen trifluoride(NF3) gas containing carbon tetrafluoride(CF4) flows through the packing layer along with 20 to 80 vol.% of an inert gas of argon, helium or nitrogen, and wherein adsorption and recovery of nitrogen trifluoride gas using zeolite 4A impregnated with alkali earth metal are repeatedly performed two or more times. © KIPO 2006