Patents by Inventor John K. Litchfield
John K. Litchfield 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: 5495979Abstract: Metal bonded carbon fiber-reinforced composites are disclosed in which the metal and the composite are strongly bound by (1) providing a matrix-depleted zone in the composite of sufficient depth to provide a binding site for the metal to be bonded and then (2) infiltrating the metal into the matrix-free zone to fill a substantial portion of the zone and also provide a surface layer of metal, thereby forming a strong bond between the composite and the metal. The invention also includes the metal-bound composite itself, as well as the provision of a coating over the metal for high-temperature performance or for joining to other such composites or to other substrates.Type: GrantFiled: June 1, 1994Date of Patent: March 5, 1996Assignees: Surmet Corporation, Castle Technology CorporationInventors: Suri A. Sastri, J. Paul Pemsler, Richard A. Cooke, John K. Litchfield, Mark B. Smith
-
Patent number: 5151262Abstract: High purity synthetic pyrite is produced in a two-step and also in a one-step sulfidation reaction of iron powder. In a two-step process, a hydrogen-annealed iron powder is first reacted with molten sulfur at a temperature of from about 200.degree.-455.degree. C., while subjecting the reaction mass to mixing for a period sufficient to convert the iron powder to pyrrhotite, which is then reacted in a second step with sulfur vapor at a temperature of from about 420.degree.-550.degree. C., while subjecting the reaction mass to mixing for a period sufficient to convert the pyrrhotite to substantially pure pyrite. In a one-step process, iron powder is gradually heated from room temperature to about 550.degree. C. in the presence of sulfur while continuously mixing to prevent sintering and agglomeration.Type: GrantFiled: February 7, 1991Date of Patent: September 29, 1992Assignee: The United States of America as represented by the Secretary of the NavyInventors: J. Paul Pemsler, John K. Litchfield
-
Patent number: 4339348Abstract: Dioxime extractants having the following general formula: ##STR1## where R and R' may be any of a variety of organic hydrocarbon radicals such as aliphatic, alkyl and aryl radicals. R and R' may also be hydrogen. Preferably R is an unsaturated hydrocarbon or branch chain alkyl group containing from about 3 to 20 carbon atoms and R' is hydrogen or an unsaturated hydrocarbon or branch chain alkyl group containing from about 1 to 10 carbon atoms. Preferably, there is a difference of about 3 to 10 carbon atoms between R and R' resulting in dissymmetry of the resulting dioxime molecule. Preferably, the dioximes also contain a total of about 5 to 32 carbon atoms. Representative compounds are methyl octyl dioxime and methyl hexyl dioxime.Organic preparations containing such dioximes are useful for the extraction of copper, nickel and cobalt metal values from acid or basic aqueous solution.Type: GrantFiled: April 17, 1980Date of Patent: July 13, 1982Assignee: Kennecott CorporationInventors: Ralph W. M. Lai, John K. Litchfield
-
Patent number: 4301124Abstract: Dioxime extractants having the following general formula: ##STR1## where R and R' may be any of a variety of organic hydrocarbon radicals such as aliphatic, alkyl and aryl radicals. R and R' may also be hydrogen. Preferably R is an unsaturated hydrocarbon or branch chain alkyl group containing from about 3 to 20 carbon atoms and R' is hydrogen or an unsaturated hydrocarbon or branch chain alkyl group containing from about 1 to 10 carbon atoms. Preferably, there is a difference of about 3 to 10 carbon atoms between R and R' resulting in dissymmetry of the resulting dioxime molecule. Preferably, the dioximes also contain a total of about 5 to 32 carbon atoms. Representative compounds are methyl octyl dioxime and methyl hexyl dioxime.Organic preparations containing such dioximes are useful for the extraction of copper, nickel and cobalt metal values from acid or basic aqueous solution.Type: GrantFiled: June 24, 1980Date of Patent: November 17, 1981Assignee: Kennecott CorporationInventors: Ralph W. M. Lai, John K. Litchfield
-
Patent number: 4248837Abstract: Dioxime extractants having the following general formula: ##STR1## where R and R' may be any of a variety of organic hydrocarbon radicals such as aliphatic, alkyl and aryl radicals. R and R' may also be hydrogen. Preferably R is an unsaturated hydrocarbon or branch chain alkyl group containing from about 3 to 20 carbon atoms and R' is hydrogen or an unsaturated hydrocarbon or branch chain alkyl group containing from about 1 to 10 carbon atoms. Preferably, there is a difference of about 3 to 10 carbon atoms between R and R' resulting in dissymmetry of the resulting dioxime molecule. Preferably, the dioximes also contain a total of about 5 to 32 carbon atoms. Representative compounds are methyl octyl dioxime and methyl hexyl dioxime.Organic preparations containing such dioximes are useful for the extraction of copper, nickel and cobalt metal values from acid or basic aqueous solution.Type: GrantFiled: February 9, 1979Date of Patent: February 3, 1981Assignee: Kennecott Copper CorporationInventors: Ralph W. M. Lai, John K. Litchfield
-
Patent number: 4211753Abstract: Molybdenum is recovered from dilute, ammoniacal, molybdenum containing solutions by adding ferrous ions to the solution to precipitate an iron hydroxide-ammonium molybdate complex. The precipitate is separated from the aqueous raffinate and is treated with acid to resolubilize the molybdenum in the complex. Molybdenum values are recovered from the resulting acid solution by ion exchange. The aqueous raffinate is purged of iron and is reused.Type: GrantFiled: November 20, 1978Date of Patent: July 8, 1980Assignee: Kennecott Copper CorporationInventors: J. Paul Pemsler, John K. Litchfield
-
Patent number: 4197117Abstract: Copper is recovered from dilute, ammoniacal, copper containing solutions by adding ferrous ions to the solution to precipitate metallic copper and iron oxides. The mixed precipitate is separated from the aqueous raffinate. The precipitated copper and iron oxides are separated from each other to enable the copper to be recovered.Type: GrantFiled: November 20, 1978Date of Patent: April 8, 1980Assignee: Kennecott Copper CorporationInventors: J. Paul Pemsler, John K. Litchfield
-
Patent number: 4005173Abstract: Organic acids are added to ammoniacal leach liquors containing base metals such as copper, nickel and cobalt. Ammonia and carbon dioxide are then stripped from the leach liquor by heating the leach liquor sufficiently to drive off the ammonia and carbon dioxide. The resulting loss of ammonia and carbon dioxide causes the pH of the leach liquor to drop and enables the metal values to load onto the organic acid. Metal values are selectively stripped from the loaded organic acid.Type: GrantFiled: March 3, 1975Date of Patent: January 25, 1977Assignee: Kennecott Copper CorporationInventors: J. Paul Pemsler, John K. Litchfield
-
Patent number: 3950487Abstract: A process in which copper, nickel, cobalt and molybdenum are recovered by leaching comminuted raw manganese nodules with an aqueous ammoniacal leach solution containing cuprous ions. An improvement is disclosed in which the metal values are extracted directly from the leach slurry with an organic extractant. To accomplish such extraction the amount by weight of solids in the slurry is maintained at less than 20 percent, the pH of the slurry is lowered to 9.5, the volumes of slurry and organic are maintained at a ratio so that the organic is the continuous phase and the organic and slurry are mixed with gentle agitation.Type: GrantFiled: June 13, 1974Date of Patent: April 13, 1976Assignee: Kennecott Copper CorporationInventors: J. Paul Pemsler, John K. Litchfield