Synthetic Zeolites Prepared By Metal Ion Exchange, Preparation Method Of The Same And Purification Method Of Nitrogen Trifluoride Using The Same

摘要

PURPOSE: A method for preparing zeolite having extraordinarily reduced adsorption capacity for NF3 and greatly improved adsorption capacity for CF4 by metal ion exchange, and a method for refining high purity NF3 by separating CF4 contained in NF3 as impurity from NF3 using the prepared zeolite are provided. CONSTITUTION: The preparation method of synthetic zeolite comprises the process of exchanging bivalent or trivalent metal ions as 2A group, 2B group or 3B group metal salts on synthetic zeolite in which Si/Al ratio in molecular composition in zeolite is 1.0 to 2.0, and weight ratio of Ca cations for Al cations is 0.4 to 0.6, wherein the 2A group, 2B group or 3B group metal salts are one or more compounds selected from the group consisting of CaCl22H2O, ZnCl2, MgCl2, CaCl2, SrCl2, BaCl2, ZnCl2, CdCl2, AlCl3, AlCl36H2O, Ga2Cl4 and Ga2Cl6. The refining method of NF3 comprises the processes of packing the prepared zeolite into column so that packing density of the zeolite is maintained to 0.01 to 1.00 g/cc; removing moisture existing in the zeolite by passing inert gas through the zeolite packed into the column as maintaining temperature of the column to 400 to 900 deg.C; and separating CF4 contained in NF3 as impurity from NF3 in the state that reaction temperature is 50 to -150 deg.C, and pressure is 0 to 5 kg/cm¬2 in the column after naturally dropping temperature of the column.