Patents by Inventor Howard L. Allen

Howard L. Allen 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).

  • Phosphate flotation
    Patent number: 4377472
    Abstract: Use of reverse flotation for phosphate rock ore treatment, wherein starch is added first to depress phosphate rock particles, followed by addition of cationic reagent, e.g., amine to float the silica. Phosphate rock is recovered as sink concentrate and silica is recovered as float tailings.
    Type: Grant
    Filed: November 1, 1978
    Date of Patent: March 22, 1983
    Assignee: W. R. Grace & Co.
    Inventor: Howard L. Allen