Patents Assigned to Nittetu Chemical Engineering Limited
  • Process for recovering caustic alkali from spent alkali liquor
    Patent number: 4169131
    Abstract: A process for recovering caustic alkali from spent alkali liquor, in which a spent alkali liquor and iron oxide are roasted to obtain a product containing alkali ferrate and the product of roasting is hydrolyzed at a temperature over 110.degree. C. and under pressurized conditions where liquid phase is retained, thereby recovering caustic alkali in the form of an aqueous solution of a concentration higher than approximately 15 wt% containing dissolved iron in an extremely small concentration.
    Type: Grant
    Filed: March 14, 1978
    Date of Patent: September 25, 1979
    Assignee: Nittetu Chemical Engineering Limited
    Inventors: Yoshiaki Kinoshita, Toshiaki Kurihara, Yoshiyuki Imagire