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:
Jul. 01, 2003
Filed:
Nov. 28, 2001
Keigo Watanabe, Yamaguchi, JP;
Yasunori Nanri, Yamaguchi, JP;
Kazuaki Sakai, Kanagawa, JP;
Tatsuya Andoh, Kanagawa, JP;
Makoto Nakao, Tokyo, JP;
Other;
Abstract
In a process for producing kraft pulp, the process is made closed, the yield of pulp is improved and environmental problems are minimized. An alkaline solution containing Na S which flows in a process of producing kraft pulp, is electrolyzed by an electrolytic oxidation method; a liquid which is formed at an anode side and contains a polysulfide type sulfur in an amount of 6 g/l or more, is added, as it is or after being causticized, to the process before a chip has the maximum temperature, and a NaOH solution formed at a cathode side, is added to at least one step of the process after the chip has the maximum temperature till a final bleaching stage; and at least chemicals in the step wherein NaOH is added, among chemicals discharged in all steps from a cooking step till the final bleaching stage, are recovered and reused.