Method of purifying gaseous nitrogen trifluoride

摘要

The present invention relates to a method of purifying gaseous nitrogen trifluoride from CF 4 as impurity. The method comprises selective adsorption of nitrogen trifluoride by dehydrated erionite at a temperature of from -30 to 30°C, displacement of carbon tetrafluoride by an inert gas, desorption and condensation of the purified nitrogen trifluoride. The purification yields 99.99% pure NF 3 with CF 4 content not over 10 ppm. The proposed method of NF 3 sorption purification makes it possible to carry out the process at an ambient temperature and with long operating life of the sorbent. The method is practically feasible, economically expedient, and easy to implement under industrial conditions.