United States Patent (19) 11, 3,927,177 Okabe Et Al
United States Patent (19) 11, 3,927,177 Okabe et al. (45) Dec. 16, 1975 54 REMOVAL OF NITROGEN OXDES FROM 2,940,821 7/1960 Carus et al.......................... 423/599 GASEOUS MIXTURES USENG AOUEOUS 2,940,822 7/1960 Carus et al.......................... 423/599 ALKALINE MANGANATE OR 3,780, 158 121 1973 Welsh ................................... 423/49 PERMANGANATESOLUTIONS 3,780, 159 12/1973 Welsh ................................... 423149 (75) Inventors: Taijiro Okabe; Akitsugu Okuwaki, FOREIGN PATENTS OR APPLICATIONS both of Sendai; Shigetoshi 131,460 1919 United Kingdom................. 423/599 Nakabayashi, Shinminato, all of 219,461 1968 U.S.S.R............................... 423/239 Japan 226,568 1968 U.S.S.R............................... 423/239 (73) Assignees: Mitsubishi Kinzoku Kogyo Kabushiki Kaisha, Ote; Nippon Primary Examiner-Herbert T. Carter Chemical Industrial Co., Ltd., Assistant Examiner-Eugene T. Wheelock Tokyo, both of Japan Attorney, Agent, or Firm-Wenderoth, Lind & Ponack (22) Filed: Oct. 5, 1973 (21) Appl. No.: 403,974 57) ABSTRACT Nitrogen oxides in a gaseous mixture are removed 30 Foreign Application Priority Data therefrom by a removal method which comprises Oct. 6, 1972 Japan.............................. 47-100512 causing the gaseous mixture to contact an absorbent comprising a manganate or a permanganate or a man (52) U.S. Cl. ................ 423/235; 423/385; 423/395 ganese-containing substance, which forms a manga 51) Int. Cl’.......................................... C01B 21/00 nate or a permanganate at the time of use, oxidizing 58) Field of Search....... 4231235, 239, 49, 50, 385, manganese oxides formed at the treatment by the re 423/395, 599 duction of the manganate or permanganate with the nitrogen oxides, thereby to generate the oxy-acid salt 56 References Cited of manganese, and circulating the same.
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