Patents Assigned to Environchip Technologies, Inc.
  • Nitric acid process for ferric sulfate production
    Patent number: 5624650
    Abstract: Ferric sulfate is produced by treating ferric ammonium sulfate, ammonium jarosite or a similar iron complex with nitric acid. The ferric ammonium sulfate or ammonium jarosite can be formed by treating a sulfuric acid leaching solution, e.g., a solution used to leach zinc or copper ore concentrate, with a solution of ammonium nitrate. Thereafter, upon addition of dilute nitric acid at a temperature of about 60.degree. C., ferric sulfate forms and is recovered.
    Type: Grant
    Filed: February 22, 1996
    Date of Patent: April 29, 1997
    Assignee: Environchip Technologies, Inc.
    Inventors: Thomas D. McEwan, William E. Pfaffenberger