Patents by Inventor Douglas W. Fuerstenau

Douglas W. Fuerstenau 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: 5855771
    Abstract: The present invention relates to a process for separating pyrite from sulfide ores and coal during flotation separation which comprises the depressing of pyrite with from about 0.05 to 0.75 kilograms per ton of concentrate solids, using a pyrite depressant compounds selected from the group consisting ofR1--S (CH.sub.2').sub.n PO (OH).sub.2 (I)wheren is between 2 and 4, andR1 is selected from a group consisting of hydrogen (H) and amidine, and ##STR1## where Ro is a lower alkyl having carbon atoms in a range of 3 to 8 with 3 to 6 being preferred and a final pH in a range of 4 to 9 depending on the ore being processed, and therafter recovering the flotation concentrate thus obtained.
    Type: Grant
    Filed: June 17, 1997
    Date of Patent: January 5, 1999
    Inventors: Douglas W. Fuerstenau, Guy H. Harris
  • Patent number: 5853571
    Abstract: The present invention relates to a process for separating pyrite from sulfide ores and coal during flotation separation which comprises the depressing of pyrite with from about 0.05 to 0.75 kilograms per ton of concentrate solids using a pyrite depressant compounds selected from the group consisting ofR1, R2, R3 N.sup.+ O.sub.2 H.sub.4 SR4X.sup.- (I)where R1, R2 and R3 are lower alkyls wherein the final sum of the carbon atoms is in a range of 3 to 6, R4 is selected from a group consisting of hydrogen (H) and amidine and X is chlorine, bromine or iodine, ##STR1## where Ro is a lower alkyl having carbon atoms in a range of 3 to 8 with 3 to 6 being preferred and a final pH in a range of 4 to 9 depending on the ore being processed, and therafter recovering the flotation concentrate thus obtained.
    Type: Grant
    Filed: June 17, 1997
    Date of Patent: December 29, 1998
    Inventors: Guy H. Harris, Douglas W. Fuerstenau
  • Patent number: 5846407
    Abstract: The present invention relates to a process for separating pyrite from sulfide ores and coal during flotation separation which comprises the depression of pyrite with from about 0.125 to 1.250 pounds per ton of 2-S thironium-ethane sulfonate (IESA) as a pyrite depressant. The aforementioned depressant is surprisingly effective in pyrite removal, being substantially independent of the pH values of the treated ore or coal, compatible with conventional collector reagents such as xanthates in the case of copper sulfide bearing ores as well as being substantially unobtrusive in not depressing other useful ore sulfides, including but limited to chalcopyrite, bornite, chalcosite, etc.
    Type: Grant
    Filed: June 17, 1997
    Date of Patent: December 8, 1998
    Inventors: Douglas W. Fuerstenau, Guy H. Harris
  • Patent number: 4552652
    Abstract: A method for removing inorganic sulfides from finely ground, non-sulfide minerals is provided. A polymeric agent having a molecular weight of from about 1,000 to about 300,000 and with a plurality of xanthate groups per molecule is admixed into an aqueous suspension including inorganic sulfides and non-sulfide minerals. The polymeric agent adsorbs onto the inorganic sulfides and maintains them as a dispersion while the remaining minerals are selectively separated, as by flocculation.
    Type: Grant
    Filed: October 17, 1983
    Date of Patent: November 12, 1985
    Assignee: The Regents of the University of California
    Inventors: Yosry A. Attia, Douglas W. Fuerstenau