Patents by Inventor David William Dew

David William Dew 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).

  • Recovery of precious metal from sulphide minerals by bioleaching
    Patent number: 6860919
    Abstract: A method of recovering a precious metal from a sulphide mineral slurry which contains the precious metal which includes the steps of subjecting the slurry to a bioleaching process, supplying a feed gas which contains in excess of 21% oxygen by volume to the slurry, and recovering precious metal from a bioleach residue of the bioleaching process.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: March 1, 2005
    Assignee: Billiton Intellectual Property, B.V.
    Inventors: Alan Norton, John de Klerk Batty, David William Dew, Petrus Basson
  • Recovery of copper from copper bearing sulphide minerals by bioleaching with controlled oxygen feed
    Patent number: 6833020
    Abstract: A method of recovering copper from a copper bearing sulphide mineral which includes the steps of subjecting the slurry to a bioleaching process, supplying a feed gas which contains in excess of 21% oxygen by volume, to the slurry, and recovering copper from a bioleach residue of the bioleaching process.
    Type: Grant
    Filed: July 19, 2002
    Date of Patent: December 21, 2004
    Assignee: Billiton Intellectual Property, B.V.
    Inventors: David William Dew, Petrus Basson, Deborah Maxine Miller
  • Recovery of nickel from nickel bearing sulphide minerals by bioleaching
    Patent number: 6733567
    Abstract: A method of recovering nickel from a nickel bearing sulphide mineral slurry which includes the steps of subjecting the slurry to a bioleaching process, supplying a feed gas which contains in excess of 21% oxygen by volume, to the slurry, and recovering nickel from a bioleach residue of the bioleaching process.
    Type: Grant
    Filed: July 19, 2002
    Date of Patent: May 11, 2004
    Assignee: Billiton Intellectual Property, B.V.
    Inventors: David William Dew, Petrus Basson, Alan Norton, Frank Crundwell
  • Bioproduct production during oxidisation of metal sulphide minerals by means of microorganisms
    Publication number: 20040038354
    Abstract: A method of producing bioproducts which includes the steps of establishing an environment wherein microorganisms oxidise a slurry containing metal sulphide minerals, supplying a feed gas containing in excess of 21% oxygen by volume to the slurry, and extracting bioproducts from the slurry.
    Type: Application
    Filed: May 23, 2003
    Publication date: February 26, 2004
    Inventors: David William Dew, Chris Andre Du Plessis
  • Recovery of nickel and copper from sulphide concentrates by bioleaching
    Patent number: 6582494
    Abstract: A process for recovering nickel and copper from a concentrate which includes the steps of subjecting the concentrate to a treatment phase to produce a first leach solution which contains predominantly copper and a second leach solution which contains predominantly nickel, subjecting the first leach solution to a process for copper recovery which includes a solvent extraction step to produce a raffinate which is high in sulphuric acid, recycling at least a portion of the raffinate to the aforementioned treatment phase and subjecting the second leach solution to a process for nickel.
    Type: Grant
    Filed: July 19, 2002
    Date of Patent: June 24, 2003
    Assignee: Billiton Intellectual Property, B.V.
    Inventors: David William Dew, Deborah Maxine Miller
  • Copper, nickel and cobalt recovery
    Patent number: 6245125
    Abstract: A process for the recovery of copper and nickel from a copper and nickel sulphide concentrate in slurry form. The slurry is subjected to a biological oxidation turning the copper sulphide to soluble copper sulphate and the nickel to nickel sulphate. The liquid containing the sulphates is separated from the slurry and treated with a solvent extraction reagent so that copper ions are exchanged by the reagent for hydrogen ions to produce a raffinate which is high in sulphuric acid and low in copper sulphate. The solvent extraction reagent is then stripped from the raffinate with a sulphuric acid solution. Copper is electrically harvested from the sulphuric acid solution and a portion of the copper depleted raffinate is returned to form a slurry with additional ore for subsequent biological oxidation. Nickel is recovered from the remaining portion of the raffinate.
    Type: Grant
    Filed: September 15, 1999
    Date of Patent: June 12, 2001
    Assignee: Billiton S.A. Limited
    Inventors: David William Dew, Deborah Maxine Miller