Calcium Carbide Patents (Class 75/10.56)
  • Patent number: 8157884
    Abstract: The invention concerns a method for the continuous or discontinuous extraction of a metal or several metals from a slag that contains the metal or a compound of the metal, in which the liquefied metal-containing slag is heated in a primary or secondary smelting unit (1). To provide an improved method for extracting metals, especially copper, from slags, the invention provides that the metal-containing slag is heated in a primary or secondary smelting unit (1) designed as an alternating-current electric furnace, and the molten material is then fed from the primary or secondary smelting unit (1) into a furnace (2) designed as a direct-current electric furnace, in which the metal to be extracted is subjected to an electrolytic separation, where a reducing agent in the form of calcium silicide (CaSi), calcium carbide (CaC2), ferrosilicon (FeO), aluminum (Al), and/or reducing gases is added and/or injected into the primary or secondary smelting unit (1).
    Type: Grant
    Filed: October 25, 2007
    Date of Patent: April 17, 2012
    Assignee: SMS Siemag Aktiengesellschaft
    Inventors: Rolf Degel, Jürgen Kunze