Patents Assigned to Leadville Silver and Gold
  • Patent number: 5232490
    Abstract: A process for separating precious metals from an MnO.sub.2, sulfidic or carbonaceous refractory ore or refractory feed such as tailings is provided. The process includes the step of leaching a feed with a leach liquor that includes an acid selected from the group of HCl and H.sub.2 SO.sub.4 in the presence of MnO.sub.2 and a reductant. A source of chloride ion is added to the leach sufficient to dissolve at least about 50% of the precious metals present in the ore. A portion of the leach is removed and precious metals are recovered from the removed portion. A portion of the chloride carrier is recycled to the leach to carry chloride values to the leach. In one embodiment, HCl is regenerated by pyrohydrolysis, which minimizes harmful waste products. The present process can advantageously avoid the use of noxious reagents.
    Type: Grant
    Filed: March 3, 1992
    Date of Patent: August 3, 1993
    Assignee: Leadville Silver and Gold
    Inventors: Fredrick N. Bender, James E. Reynolds, Robert L. Elder