The present invention relates to a method of purifying gaseous nitrogen trifluoride
from CF4 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 NF3 with CF4 content
not over 10 ppm.
The proposed method of NF3 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.
