The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 03, 1991
Filed:
Jan. 10, 1991
Applicant:
Inventors:
Assignee:
Central Glass Company, Limited, Ube, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01B / ; C01B / ; B01D / ;
U.S. Cl.
CPC ...
4232 / ; 55 71 ; 55 75 ; 423406 ;
Abstract
The invention provides a selective adsorption method for refining NF.sub.3 gas containing CF.sub.4 as impurity. At a temperature not higher than 10.degree. C. the NF.sub.3 gas is brought into contact with a crystalline and porous synthetic zeolite, which is substantially uniform in pore size and about 4.9 .ANG. in effective pore size and is commerciallized under the name of molecular sieve 5A, on condition that the content of water of crystallinity in the synthetic zeolite is 1-10 wt. %, and preferably 6-10 wt. %. The synthetic zeolite efficiently adsorbs NF.sub.3 with little adsorption of CF.sub.4.