Back to results
US 7,842,125 B2Granted
Process for refining nitrogen trifluoride gas using alkali earth metal exchanged zeolite
AssigneeHyosung Corporation
InventorsYong-Chul Park, Woo-Sik Jeong, Kwang-Chul Hyun, Jang-Won Lee, Ik-Hyeon Kwon
Life of this patent
Estimating the term…
Abstract
Disclosed herein are a process for the refinement of nitrogen trifluoride gas and an adsorbent used therein. A nitrogen trifluoride (NF3) gas including carbon tetrafluoride (CF4) as an impurity is permeated into a bed of the zeolite 3 A, 4A or 5 A which is ion exchanged with alkali earth metal and is thermally treated at 150 to 600° C. for 0.5 to 100 hours so as to selectively adsorb nitrogen trifluoride onto the bed, followed by the desorption of the nitrogen trifluoride therefrom.
Claims6
A process for refining nitrogen trifluoride gas, comprising:
- introducing a gas mixture of nitrogen trifluoride (NF3) and carbon tetrafluoride (CF4) into a bed of zeolite 3A, 4A or 5A to selectively adsorb nitrogen trifluoride onto the bed, with the carbon tetrafluoride passing through the bed, said zeolite 3A or 4A being ion-exchanged with magnesium, calcium, strontium or barium or said zeolite 5A being ion-exchanged with magnesium, strontium or barium;
- and recovering the nitrogen trifluoride from the bed.
Dependencies are inferred from the claim text.