Patents by Inventor Ramamritham Sridhar
Ramamritham Sridhar 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).
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Patent number: 7329396Abstract: A process for leaching a value metal from oxidic materials, such as a lateritic nickel ore, comprising the step of leaching the ore with a lixiviant comprising a cationic salt (e.g., magnesium chloride) and hydrochloric acid is disclosed. An oxidant or additional metal chloride (such as that which results from the leaching operation) may be added. In one embodiment, the process comprises recovery of a value metal from ore comprising the steps of: leaching the ore with a lixiviant; separating a value metal-rich leachate from the ore in a first solid-liquid separation; oxidizing and neutralizing the value metal-rich leachate so obtained; and separating a solution of magnesium chloride from the leachate so obtained in a second solid-liquid separation. In another embodiment, the lixiviant solution is regenerated from the solution of magnesium chloride. In a further embodiment, regeneration of the lixiviant solution includes a step of producing magnesium oxide from the solution of magnesium chloride.Type: GrantFiled: May 13, 2004Date of Patent: February 12, 2008Assignee: Jaguar Nickel Inc.Inventors: G. Bryn Harris, Vaikuntam I. Lakshmanan, Ramamritham Sridhar
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Publication number: 20050142051Abstract: A process for leaching a value metal from a titanium-bearing ore material comprising the step of leaching the ore material at atmospheric pressure with a lixiviant comprising a chloride and hydrochloric acid is disclosed. The leaching conditions are such that titanium is leached and remains in solution. The temperature is maintained at less that 85° C., and the concentration of hydrochloric acid is preferably less than 20% (mass ratio). The preferred chloride is magnesium chloride. The lixiviant may contain oxidant e.g. sodium chlorate or chlorine.Type: ApplicationFiled: November 4, 2004Publication date: June 30, 2005Inventors: Vaikuntum Lakshmanan, Ramamritham Sridhar, G. Harris, George Puvvada
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Publication number: 20050118081Abstract: A process for leaching a value metal from a base metal sulfide ore, comprising the step of leaching the ore with a lixiviant comprising a chloride, an oxidant and hydrochloric acid is disclosed. The leaching is controlled, by use of low concentrations of hydrochloric acid and a redox potential, to effect formation of hydrogen sulfide from the base metal sulfide ore. The hydrogen sulfide is stripped from the leach solution, thereby reducing the amount of sulfate generated in the leach to very low levels. The leaching may also be conducted to limit the co-dissolution of platinum group metals and gold with the base value metals. The leach forms a value metal-rich leachate and a solids residue. The solids residue may be subsequently leached to recover the platinum group metals and gold. The value metal-rich leachate can be is oxidized and neutralized to recover the value base metals. In an embodiment, the chloride is magnesium chloride and lixiviant solution is regenerated.Type: ApplicationFiled: September 28, 2004Publication date: June 2, 2005Applicant: Jaguar Nickel Inc.Inventors: G. Harris, Vaikuntam Lakshmanan, Ramamritham Sridhar, George Puvvada
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Patent number: 6878356Abstract: A method for extraction of zinc values from an aqueous alkaline solution of zinc, especially a solution obtained by the stripping of a galvanized coating from a ferrous metal product e.g. steel, or from electric arc furnace dust. The method comprises subjecting the aqueous alkaline solution to solvent extraction using an organic solution of an oxine i.e. an organic extractant containing an 8-hydroxyquinoline group, and separating the organic solution from aqueous alkaline solution. Zinc values are recovered from the organic solution e.g. by stripping with acid and subjecting the resultant aqueous solution containing zinc values for recovery of zinc e.g. to electrowinning or to precipitation of zinc carbonate. The method may be used in the preparation of galvanized steel for recycle to a steel manufacturing plant, with recovery of zinc and for recovery of zinc values from electric arc furnace dust.Type: GrantFiled: May 13, 2002Date of Patent: April 12, 2005Assignee: Process Research Management Inc.Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Mohamed Shafiqul Alam
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Publication number: 20040228783Abstract: A process for leaching a value metal from oxidic materials, such as a lateritic nickel ore, comprising the step of leaching the ore with a lixiviant comprising a cationic salt (e.g., magnesium chloride) and hydrochloric acid is disclosed. An oxidant or additional metal chloride (such as that which results from the leaching operation) may be added. In one embodiment, the process comprises recovery of a value metal from ore comprising the steps of: leaching the ore with a lixiviant; separating a value metal-rich leachate from the ore in a first solid-liquid separation; oxidizing and neutralizing the value metal-rich leachate so obtained; and separating a solution of magnesium chloride from the leachate so obtained in a second solid-liquid separation. In another embodiment, the lixiviant solution is regenerated from the solution of magnesium chloride. In a further embodiment, regeneration of the lixiviant solution includes a step of producing magnesium oxide from the solution of magnesium chloride.Type: ApplicationFiled: May 13, 2004Publication date: November 18, 2004Applicant: Jaguar Nickel Inc.Inventors: G. Bryn Harris, Vaikuntam I. Lakshmanan, Ramamritham Sridhar
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Patent number: 6730161Abstract: A finely ground powder comprising a mixture of fly ash and a compound selected from the group consisting of alkali and alkaline earth metal salts, alkali and alkaline earth metal oxides, and metakaolinite. Preferably, the amount of said compound is 0.4 to 1% by weight of the powder. A composition comprising Portland cement and finely ground powder, said finely ground powder being a mixture of fly ash and a compound selected from the group consisting of alkali and alkaline earth metal salts, alkali and alkaline earth metal oxides, and metakaolinite. A method for the treatment of fly ash comprising the step of subjecting a mixture of fly ash and a compound selected from the group consisting of alkali and alkaline earth metal salts, alkali and alkaline earth metal oxides, and metakaolinite, preferably in which the fly ash has been treated for removal of carbon and in particular to increase the amount of crystalline phase.Type: GrantFiled: June 20, 2002Date of Patent: May 4, 2004Assignee: Process Research Ortech, Inc.Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Noel Paul Mailvaganam, V. Mohan Malhotra
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Patent number: 6699446Abstract: A method for the production of titanium metal from titanium-bearing ore. The method comprises leaching said ore or a concentrate thereof with an aqueous solution of a hydrogen halide; separating solids from the leach solution, to provide a leachate solution. The leachate solution may be subjected to extraction with an immiscible organic phase to selectively remove iron values to provide high purity iron products. Titanium may be separated from raffinate as TiO2 or solvent extract and thermal stripping. TiO2 may also be separated in the initial leach solution. Preferably, the titanium halide is titanium tetrachloride.Type: GrantFiled: January 25, 2001Date of Patent: March 2, 2004Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Marc Murray Rishea, Robert Joseph de Laat
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Publication number: 20030079656Abstract: A finely ground powder comprising a mixture of fly ash and a compound selected from the group consisting of alkali and alkaline earth metal salts, alkali and alkaline earth metal oxides, and metakaolinite. Preferably, the amount of said compound is 0.4 to 1% by weight of the powder. A composition comprising Portland cement and finely ground powder, said finely ground powder being a mixture of fly ash and a compound selected from the group consisting of alkali and alkaline earth metal salts, alkali and alkaline earth metal oxides, and metakaolinite. A method for the treatment of fly ash comprising the step of subjecting a mixture of fly ash and a compound selected from the group consisting of alkali and alkaline earth metal salts, alkali and alkaline earth metal oxides, and metakaolinite, preferably in which the fly ash has been treated for removal of carbon and in particular to increase the amount of crystalline phase.Type: ApplicationFiled: June 20, 2002Publication date: May 1, 2003Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Noel Paul Mailvaganam, V. Mohan Malhotra
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Publication number: 20030012716Abstract: A method for extraction of zinc values from an aqueous alkaline solution of zinc, especially a solution obtained by the stripping of a galvanized coating from a ferrous metal product e.g. steel, or from electric arc furnace dust. The method comprises subjecting the aqueous alkaline solution to solvent extraction using an organic solution of an oxine i.e. an organic extractant containing an 8-hydroxyquinoline group, and separating the organic solution from aqueous alkaline solution. Zinc values are recovered from the organic solution e.g. by stripping with acid and subjecting the resultant aqueous solution containing zinc values for recovery of zinc e.g. to electrowinning or to precipitation of zinc carbonate. The method may be used in the preparation of galvanized steel for recycle to a steel manufacturing plant, with recovery of zinc and for recovery of zinc values from electric arc furnace dust.Type: ApplicationFiled: May 13, 2002Publication date: January 16, 2003Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Mohamed Shafiqul Alam
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Patent number: 6500396Abstract: A method for the production of titanium metal from titanium-bearing ore. The method comprises leaching said ore or a concentrate thereof with an aqueous solution of a hydrogen halide; separating solids from the leach solution, to provide a leachate solution. The leachate solution may be subjected to extraction with an immiscible organic phase. Titanium halide is separated from the organic phase by stripping. Preferably, the titanium halide is titanium tetrachloride.Type: GrantFiled: November 17, 1999Date of Patent: December 31, 2002Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Marc Murray Rishea, Robert Joseph de Laat
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Publication number: 20010007646Abstract: A method for the production of titanium metal from titanium-bearing ore. The method comprises leaching said ore or a concentrate thereof with an aqueous solution of a hydrogen halide; separating solids from the leach solution, to provide a leachate solution. The leachate solution may be subjected to extraction with an immiscible organic phase to selectively remove iron values to provide high purity iron products. Titanium may be separated from raffinate as TiO2 or solvent extract and thermal stripping. TiO2 may also be separated in the initial leach solution. Preferably, the titanium halide is titanium tetrachloride.Type: ApplicationFiled: January 25, 2001Publication date: July 12, 2001Inventors: Vaikuntam Iyer Lakshmanan, Ramamritham Sridhar, Marc Murray Rishea, Robert Joseph de Laat
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Patent number: 4358430Abstract: Selenium-bearing materials are treated to convert selenium values to water-soluble form in a process which comprises producing a wet pellet product of uniform composition having a specified moisture content and size from an aqueous slurry containing the selenium-bearing material and dissolved sodium carbonate-containing reagent. In a preferred embodiment the slurry is pH-adjusted to neutralize free acid and/or to precipitate nonferrous base metals. spThis is a continuation of application Ser. No. 151,349 filed May 19, 1980, abandoned.Type: GrantFiled: October 14, 1981Date of Patent: November 9, 1982Assignee: Inco LimitedInventors: Grigori S. Victorovich, Ramamritham Sridhar, Malcolm C. E. Bell
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Patent number: 4168967Abstract: A granulate consisting of smooth irregularly shaped granules is produced by preparing a molten bath of nickel and/or cobalt containing amounts of carbon and silicon which are correlated so that:8.03 C-4.42 C.sup.2 +7.23 Si>3.6pouring the molten alloy at a temperature 50.degree.-100.degree. C. above its liquidus temperature onto the surface of a pool of water which is agitated and maintained at 30.degree.-60.degree. C.Type: GrantFiled: July 27, 1978Date of Patent: September 25, 1979Assignee: The International Nickel Company, Inc.Inventors: Ramamritham Sridhar, Warren L. Shellshear, Carlos A. Landolt, William Kantymir, Howard L. Schooley
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Patent number: 4168217Abstract: A copper-containing sulfidic material is dead-roasted at a temperature of at least 750.degree. C. and the resulting calcine is leached in a sulfuric acid solution to dissolve most of the copper in preference to any iron, nickel and cobalt in the material.Type: GrantFiled: April 10, 1978Date of Patent: September 18, 1979Assignee: The International Nickel Company, Inc.Inventors: Ashok D. Dalvi, Ramamritham Sridhar, Malcolm C. E. Bell
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Patent number: 4135918Abstract: A sulfide containing copper and one or more of iron, nickel and cobalt, is dead-roasted at a temperature of 750.degree. C or above, then subjected to a pressure leach under reducing conditions to produce elemental copper and an aqueous solution of the other metals.Type: GrantFiled: March 2, 1978Date of Patent: January 23, 1979Assignee: The International Nickel Company, Inc.Inventors: Victor A. Ettel, Eric A. P. Devuyst, Ramamritham Sridhar, Charles E. O'Neill
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Patent number: 4049444Abstract: Recovery, by thermal upgrading, of nickel values from nickeliferous lateritic ores containing a silicate fraction is improved by forming agglomerates of the ore, a reagent containing at least one member selected from the group consisting of alkali or alkaline earth metal compounds in a small but effective amount to increase nickel recovery from the silicate fraction and a liquid hydrocarbon in an amount between about 1 and 12%, based on the weight of the ore and heating a static, shallow bed of the agglomerates established on a moving bed to partially melt the agglomerates to reduce and coalesce the nickel values into easily recoverable ferronickel concentrate. The grade of the ferronickel concentrate can be increased by incorporating a sulfur-bearing material in the agglomerates.Type: GrantFiled: September 30, 1974Date of Patent: September 20, 1977Assignee: The International Nickel Company, Inc.Inventors: Malcolm Charles Evert Bell, Ramamritham Sridhar
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Patent number: 4038066Abstract: Base metal chlorides are recovered from fused alkali metal or alkaline earth metal halide salts by precipitation with at least one reagent selected from the group consisting of hydrogen, hydrogen sulfide or aluminum. Advantageously, the bulk of the base metals are precipitated by combinations of hydrogen sulfide and hydrogen to produce a precipitate having a controlled sulfur content that is molten at temperatures between about 750.degree. C. and 900.degree. C., and final salt cleaning is achieved by precipitating residual base metals with aluminum. The melting point of the precipitate is also controlled by the ratio of nickel to other base metals in the salt.Type: GrantFiled: June 24, 1974Date of Patent: July 26, 1977Assignee: The International Nickel Company, Inc.Inventors: Malcolm Charles Evert Bell, Thijs Eerkes, Ramamritham Sridhar
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Patent number: 3984232Abstract: Manganiferous oxide minerals, particularly sea nodules, containing at least one metal value selected from the group consisting of cobalt, copper, iron, molybdenum and nickel and a reductant are heated to a temperature above about 1100.degree.C. to selectively reduce the metal values to metal and only minor amounts of the manganese values to metal and to coalesce the reduced metal values. The coalesced metal values are recovered by techniques such as magnetic separation, flotation and tabling to produce a concentrate of the metal values.Type: GrantFiled: August 19, 1974Date of Patent: October 5, 1976Assignee: The International Nickel Company, Inc.Inventors: Malcolm Charles Evert Bell, Ramamritham Sridhar
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Patent number: 3938989Abstract: Nickel matte containing at least about 28% sulfur is refined with respect to arsenic, antimony or bismuth by contacting molten matte with gaseous chlorine to chlorinate and volatilize arsenic, antimony or bismuth from the nickel matte. Advantageously, the molten nickel matte is provided with a halide flux to minimize volatilization of any nickel chloride that is formed.Type: GrantFiled: June 24, 1974Date of Patent: February 17, 1976Assignee: The International Nickel Company, Inc.Inventors: Malcolm Charles Evert Bell, Ramamritham Sridhar