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:
Jun. 04, 1996
Filed:
Dec. 15, 1993
Satoshi Shikami, Kurashiki, JP;
Hitoshi Satoh, Okayama, JP;
Chlorine Engineers Corp., Ltd., Tokyo, JP;
Abstract
Sulfuric acid used in the process of fabricating semiconductor devices, etc., can be recycled to reduce the amount of sulfuric acid to be discarded. A sulfuric acid effluent is fed to an anode chamber of a sulfuric acid-concentrating electrolyzer partitioned by at least one cation exchange membrane to concentrate sulfuric acid and generate oxidizing substances, so that the sulfuric acid can be used at the step of using sulfuric acid, and, when the concentration of impurities built up in the system exceeds a certain level, a part of sulfuric acid in the system is fed to a unit for refining sulfuric acid, where the sulfuric acid is refined and whence the refined sulfuric acid is fed back to the system. According to this recycling process, it is possible to obtain sulfuric acid having high oxidizing power with no addition of an oxidizing substance such as hydrogen peroxide thereto.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile