Patents Assigned to Recupac
  • Patent number: 6500229
    Abstract: A method for treating steel works dust in order to recuperate elements capable of being upgraded. The method comprises attrition in water followed by hydraulic grading of the resulting load. The method is characterized in that is further comprises: a washing step to separate the water soluble saline fractions of the insoluble oxides; hot treatment to eliminate metals in the form of free oxides such as zinc and lead; treatment by heating at a temperature ranging between 240 and 800° C.; treatment with sulphuric acid having a concentration between 5 and 8%.
    Type: Grant
    Filed: October 6, 2000
    Date of Patent: December 31, 2002
    Assignee: Recupac
    Inventors: Gilles Roux, Farouk Tedjar
  • Patent number: 6022406
    Abstract: A method for preparing inorganic pigments from steel mill dust, particularly electric steel mill dust, wherein (a) the dust is separated into a magnetic fraction and a non-magnetic fraction; (b) the non-magnetic fraction is subjected to a basic leaching reaction; (c) the resulting solid batch is rinsed until neutralized and then separated; (d) the resulting batch is calcined at 450-650.degree. C.; (e) the calcined batch is treated with sulfuric acid in the presence of a catalyst; (f) the inorganic pigments are recovered; and (g) the solutions from (c) and (e) are used to precipitate other pigments.
    Type: Grant
    Filed: May 27, 1998
    Date of Patent: February 8, 2000
    Assignee: Recupac
    Inventors: Gilles Roux, Farouk Tedjar