Patents by Inventor Janos Leffler

Janos Leffler has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4649031
    Abstract: The invention relates to a method for recovering rare metals from the combustion residues of various coals, in particular brown coals. The recovery is performed by digestion, more particularly by aqueous and/or dilute alkaline and/or dilute acidic digestion, where two or three of these steps can be combined in any desired order or they may be carried out separately. During digestion the concentration of the solution is monitored and the subsequent digestion steps are terminated at a desired concentration. The solid and liquid phase are then separated and the rare metals are isolated from the liquid phase while the solid phase, optionally after neutralization and/or washing can be utilized for example as a source of energy.
    Type: Grant
    Filed: November 9, 1981
    Date of Patent: March 10, 1987
    Assignee: Tatabanyai Szenbanyak
    Inventors: Bela Matyas, Pal Gerber, Andras Solymos, Ferenc Kaszanitzky, Gyorgy Panto, Janos Leffler