Patents by Inventor Robert R. Stanforth

Robert R. Stanforth 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: 6590133
    Abstract: A method for reducing the solubility of lead during digestion or in the environment has been developed. Lead is incorporated into a solid material formed by the in situ oxidation of iron. This can be accomplished by introducing ferrous iron into the soil, either in solid or liquid form, and then oxidizing the iron with either air or an introduced oxidant. Solubility of the lead is significantly reduced even under very acidic conditions by incorporation into the iron oxide material. Acid generated during the oxidation and precipitation of iron can be neutralized using common neutralizing agents such as limestone, lime, magnesium oxide, or magnesium hydroxide. In another method, the calcium or magnesium can be added either as neutral salts or as salts of alkaline anions, e.g., calcium carbonate. The calcium and magnesium ions form strong complexes with digestive enzymes, preventing the lead from forming soluble lead complexes with the enzymes. This reduces the bioavailability of the lead.
    Type: Grant
    Filed: December 15, 2000
    Date of Patent: July 8, 2003
    Assignee: National University of Singapore
    Inventor: Robert R. Stanforth
  • Publication number: 20020115899
    Abstract: A method for reducing the solubility of lead during digestion or in the environment has been developed. Lead is incorporated into a solid material formed by the in situ oxidation of iron. This can be accomplished by introducing ferrous iron into the soil, either in solid or liquid form, and then oxidizing the iron with either air or an introduced oxidant. Solubility of the lead is significantly reduced even under very acidic conditions by incorporation into the iron oxide material. Acid generated during the oxidation and precipitation of iron can be neutralized using common neutralizing agents such as limestone, lime, magnesium oxide, or magnesium hydroxide. In another method, the calcium or magnesium can be added either as neutral salts or as salts of alkaline anions, e.g., calcium carbonate. The calcium and magnesium ions form strong complexes with digestive enzymes, preventing the lead from forming soluble lead complexes with the enzymes. This reduces the bioavailability of the lead.
    Type: Application
    Filed: December 15, 2000
    Publication date: August 22, 2002
    Inventor: Robert R. Stanforth
  • Patent number: 5859306
    Abstract: A method of treating arsenic-contaminated matter using an aluminum compound in conjunction with an alkaline buffer, thereby stabilizing the arsenic contained in the contaminated matter and decreasing leaching ability. Preferably, the aluminum compound is a soluble aluminum salt such as aluminum sulfate and the alkaline buffer is magnesium oxide.
    Type: Grant
    Filed: March 4, 1997
    Date of Patent: January 12, 1999
    Assignee: RMT, Inc.
    Inventor: Robert R. Stanforth
  • Patent number: 5851278
    Abstract: The present invention involves a method of removing paint containing heavy metal from a surface without the production of hazardous wastes. Specifically, this method involves applying a coating preparation to the heavy metal containing paint prior to its removal from its surface. The preparation contains lead reactive chemicals such as phosphates, metal sulfides and organic sulfides. The preparation may also contain buffers such as magnesium oxide and magnesium hydroxide. These chemicals react with the heavy metals rendering them nonhazardous. The invention also involves the coating preparation itself.
    Type: Grant
    Filed: June 9, 1997
    Date of Patent: December 22, 1998
    Assignee: RMT, Inc.
    Inventors: Robert R. Stanforth, Paul V. Knopp
  • Patent number: 5827574
    Abstract: The present invention involves a method of removing paint containing heavy metal from a surface without the production of hazardous wastes. Specifically, this method involves applying a coating preparation to the heavy metal containing paint prior to its removal from its surface. The preparation contains lead reactive chemicals such as phosphates, metal sulfides and organic sulfides. The preparation may also contain buffers such as magnesium oxide and magnesium hydroxide. These chemicals react with the heavy metals rendering them nonhazardous. The invention also involves the coating preparation itself.
    Type: Grant
    Filed: June 9, 1997
    Date of Patent: October 27, 1998
    Assignee: RMT, Inc.
    Inventors: Robert R. Stanforth, Paul V. Knopp
  • Patent number: 5637355
    Abstract: The present invention involves a method of removing paint containing heavy metal from a surface without the production of hazardous wastes. Specifically, this method involves applying a coating preparation to the heavy metal containing paint prior to its removal from its surface. The preparation contains lead reactive chemicals such as phosphates, metal sulfides and organic sulfides. The preparation may also contain buffers such as magnesium oxide and magnesium hydroxide. These chemicals react with the heavy metals rendering them nonhazardous. The invention also involves the coating preparation itself.
    Type: Grant
    Filed: April 22, 1996
    Date of Patent: June 10, 1997
    Assignee: RMT, Inc.
    Inventors: Robert R. Stanforth, Paul V. Knopp
  • Patent number: 5202033
    Abstract: A method of treating solid waste in soil or solid disposed waste containing unacceptable levels of leachable metals, such as lead, cadmium, arsenic, zinc, copper and chromium, includes mixing the solid waste or soil in place with a phosphate source or a carbonate source or ferrous sulfate. After the solid waste and the additive are mixed, if needed an additional pH controlling agent is mixed into the soil or waste and additive. After the solid waste and additive and pH controlling agent are mixed under conditions which support reaction between the additive, pH controlling agent and metals, the metals will be converted to non-leachable forms which are relatively stable under normal environmental conditions.
    Type: Grant
    Filed: September 30, 1991
    Date of Patent: April 13, 1993
    Assignee: RMT, Inc.
    Inventors: Robert R. Stanforth, Ajit K. Chowdhury
  • Patent number: 5037479
    Abstract: A method of treating solid hazardous wastes containing unacceptable levels of leachable metals such as lead, cadmium and zinc includes mixing the solid waste with a buffering agent selected from the group consisting of magnesium oxide, magnesium hydroxide, reactive calcium carbonates and reactive magnesium carbonates, and with an additional agent which is an acid or salt containing an anion that forms substantially nonleachable forms of the metals, which additional agent is selected from the group consisting of triple superphosphate, ammonium phosphate, diammonium phosphate, phosphoric acid, boric acid and metallic iron so that under both acidic and nonacidic leaching conditions the metals in the mixture will be converted to substantially nonleachable forms.
    Type: Grant
    Filed: April 20, 1990
    Date of Patent: August 6, 1991
    Assignee: RMT, Inc.
    Inventor: Robert R. Stanforth
  • Patent number: 4950409
    Abstract: A method of treating solid hazardous waste containing unacceptable levels of leachable metals such as lead and cadmium includes mixing the solid waste with lime and an agent selected from the group consisting of carbon dioxide and bicarbonate. After the solid waste and agent are mixed under conditions which support reaction between the agent and metals, the metals will be converted to nonleachable forms which are relatively stable under normal environmental conditions. If the solid waste material and agent are both dry when mixed, it may be beneficial to add water to facilitate the mixing of the solid waste and agent and the conversion of the metals into nonleachable forms.
    Type: Grant
    Filed: December 8, 1989
    Date of Patent: August 21, 1990
    Inventor: Robert R. Stanforth
  • Patent number: 4889640
    Abstract: A method of treating solid hazardous waste containing unacceptable levels of leachable metals such as lead and cadmium includes mixing the solid waste with an agent selected from the group consisting of reactive calcium carbonate, reactive magnesium carbonate and reactive calcium magnesium carbonate. After the solid waste and agent are mixed under conditions which support reaction between the agent and metals, the metals will be converted to nonleachable forms which are relatively stable under normal environmental conditions. If the solid waste material and agent are both dry when mixed, it may be beneficial to add water to facilitate the mixing of the solid waste and agent and the conversion of the metals into nonleachable forms.
    Type: Grant
    Filed: June 10, 1988
    Date of Patent: December 26, 1989
    Assignee: RMT, Inc.
    Inventor: Robert R. Stanforth