Patents by Inventor Richard N. Hill

Richard N. Hill 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).

  • Foam control during production of phosphoric acid
    Patent number: 4391784
    Abstract: Foam generated during the digestion of phosphate rock is removed from the slurry either by overflow, mechanical sweeps, or by vacuum from strategically located nozzles connected to vacuum lines. The foam, after liquefaction, is returned to the filter where it results in improved filtration and return of soluble P.sub.2 O.sub.5.
    Type: Grant
    Filed: August 18, 1981
    Date of Patent: July 5, 1983
    Inventors: Richard N. Hill, Sr., Charles D. B. Hill
  • Post precipitation control of low-iron phosphoric acid, without perlite
    Patent number: 4364912
    Abstract: The Hill process for control of post-precipitation in wet process phosphoric acid can be made to work on low-iron phosphate rock, without the need of added perlite or other aluminum silicate.
    Type: Grant
    Filed: July 20, 1981
    Date of Patent: December 21, 1982
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Stabilized wet process phosphoric acid
    Patent number: 4305915
    Abstract: Wet-process phosphoric acid products substantially free of post precipitation.
    Type: Grant
    Filed: July 3, 1979
    Date of Patent: December 15, 1981
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Aeration of phosphoric acid
    Patent number: 4294809
    Abstract: Aeration of Hill phosphoric acid, preferably with perlite, and preferably with a chemical oxidant, e.g., H.sub.2 O.sub.2. Gives good post-precipitation control with high-iron phosphate rock, even in winter conditions.
    Type: Grant
    Filed: September 29, 1980
    Date of Patent: October 13, 1981
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Phosphoric acid crystallizer underflow return
    Patent number: 4293311
    Abstract: In the Hill phosphoric acid process the crystallizer underflow is divided into a major stream and a minor stream. The major stream goes to the clarifier and the minor stream to the aluminum silicate addition vessel.
    Type: Grant
    Filed: January 10, 1980
    Date of Patent: October 6, 1981
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Oxidative control of post precipitation in phosphoric acid
    Patent number: 4279877
    Abstract: Improvement in the Hill phosphoric acid process. Fe.sup.++ in high iron feed is oxidized to Fe.sup.+++ to improve post-precipitation characteristics, optionally, a minor stream from the crystallizer is returned to the oxidation zone.
    Type: Grant
    Filed: January 10, 1980
    Date of Patent: July 21, 1981
    Assignee: W. R. Grace & Co.
    Inventors: Richard N. Hill, Moises G. Sanchez
  • Re-post precipitation control
    Patent number: 4250154
    Abstract: Prevention of re-post precipitation in concentrated wet process phosphoric acid by heating the acid at 55.degree. to 85.degree. C. thereby to dissolve solids without substantial re-post precipitation.
    Type: Grant
    Filed: October 22, 1979
    Date of Patent: February 10, 1981
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Production of stabilized wet process phosphoric acid
    Patent number: 4248846
    Abstract: This invention is directed to improvements in making wet process phosphoric acid substantially free from post-precipitation. The improvements include recycling to the reaction train a side stream produced by the process; cooling one or more of the streams of the process; and/or addition of sulfuric acid to an evaporator.
    Type: Grant
    Filed: July 3, 1979
    Date of Patent: February 3, 1981
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Reduction of magnesium and other cations in phosphoric acid
    Patent number: 4242198
    Abstract: Improvement in the reduction of Mg, Ca, Na, K and Al in crude phosphoric acid using an ion exchange resin bed, comprising preclarifying the feed acid with flocculant polymer and placing a filter aid precoat on the resin bed. As part of the preclarification process, a compatible soluble sodium compound, such as sodium carbonate, is added to the feed acid to speed the flocculation process.
    Type: Grant
    Filed: March 12, 1979
    Date of Patent: December 30, 1980
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Settling clarifier
    Patent number: 4222879
    Abstract: Settling clarifier for liquids carrying suspended solids, having a two-slope bottom section, with central stilling well for feed, rake system, clear overflow exit means, and sludge underflow means.
    Type: Grant
    Filed: March 12, 1979
    Date of Patent: September 16, 1980
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Production of stabilized wet process phosphoric acid
    Patent number: 4164550
    Abstract: Treatment of wet process phosphoric acid to inhibit post-precipitation by steps including addition of an aluminum silicate material such as perlite or the like to dilute acid from which a major portion of solids has been removed, concentration of the resulting dilute acid, and removal of resulting precipitate.
    Type: Grant
    Filed: March 6, 1978
    Date of Patent: August 14, 1979
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill
  • Production of stabilized wet process phosphoric acid
    Patent number: 4110422
    Abstract: Treatment of wet process phosphoric acid to inhibit post-precipitation by steps including addition of an aluminum silicate material such as perlite or the like to dilute acid from which a major portion of solids has been removed, concentration of the resulting dilute acid, and removal of resulting precipitate.
    Type: Grant
    Filed: July 1, 1977
    Date of Patent: August 29, 1978
    Assignee: W. R. Grace & Co.
    Inventor: Richard N. Hill