Ferric Oxide Patents (Class 423/633)
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Patent number: 5139767Abstract: A method for producing goethite having an axial ratio of at least 7 and a specific surface area of 20-80 m.sup.2 /g and suitable for use in the production of .alpha.-iron powder, which method comprises intermittently feeding an oxidizing gas into a suspension of ferrous hydroxide, which has been obtained by reacting a ferrous salt with an alkali hydroxide, preferably while controlling the oxidation rate of ferrous hydroxide below 7% per each feeding-feed-stopping cycle of the oxidizing gas and also controlling the feeding time period of the oxidizing gas within 10 minutes and shorter than a quarter of the feed-stopping time period per each feeding-feed-stopping cycle of the oxidizing gas.Type: GrantFiled: January 4, 1991Date of Patent: August 18, 1992Assignee: Mitsui Toatsu Chemicals, IncorporatedInventors: Mitsurou Matsunaga, Isamu Morita, Nobuhiro Fukuda
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Patent number: 5076848Abstract: An improved process is disclosed for preparing iron yellow pigments from iron--(II) salt solutions, in the presence of iron scrap, by injection of air at elevated temperatures. After formation of the pigment, the reaction suspension is stirred without additional gas injection, whereby lighter, purer yellow pigments are obtained.Type: GrantFiled: February 26, 1990Date of Patent: December 31, 1991Assignee: Bayer AktiengesellschaftInventors: Bernd Krockert, Helmut Printzen, Gunter Buxbaum
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Patent number: 5064632Abstract: There is provided a process for the partial oxidation of solid ferrous chloride and the complete oxidation of all carbon that is present with molecular oxygen at 350.degree. C. to 675.degree. C., to produce ferric oxide and ferric chloride vapor without producing elemental chlorine.Type: GrantFiled: July 17, 1990Date of Patent: November 12, 1991Assignee: SCM Chemicals, Inc.Inventor: James P. Bonsack
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Patent number: 5039553Abstract: A process for the continuous production of cobalt-modified magnetic iron oxide. This process comprises carrying out a batchwise preliminary cobalt treatment by adding a magnetic iron oxide powder to an alkaline solution followed by the addition of a cobalt salt to cover the magnetic iron oxide powder with cobalt. A cobalt modification reaction is carried out continuously by passing the solution containing the preliminary cobalt-treated magnetic iron oxide powder under heat and pressure through a flow-type reaction vessel.Type: GrantFiled: April 3, 1990Date of Patent: August 13, 1991Assignee: Showa Denko K.K.Inventors: Yuji Fukumoto, Kazuyoshi Matsumoto, Yasushi Matsui
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Patent number: 5032367Abstract: A method for producing a powdered iron oxide comprises the steps of adjusting the pH of a crude iron chloride solution to 2.5-4.5; reducing the P content of the solution by mechanical stirring or air bubbling and filtering; and oxidizing the solution into a powdered iron oxide having a maximum P content of 0.005 wt. %. The P content of the solution may also be reduced by ultrafilter treatment. The soft ferrite made by using the powdered iron oxide by this process shows excellent magnetic properties.Type: GrantFiled: December 16, 1988Date of Patent: July 16, 1991Assignees: Chemirite, Ltd., TDK CorporationInventors: Naoe Hirai, Tohoru Murase, Katsunobu Okutani, Teruo Mori
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Patent number: 5032180Abstract: A process for the production of iron oxide yellow pigments by the Penniman-Zoph process from the raw materials iron (II) sulfate, sodium hydroxide and metallic iron, is disclosed in which iron (II) is oxidized to iron (III) by gassing with air in the presence of goethite nuclei, the iron (III) sulfate is dissolved to form iron (II) and the goethite nuclei are built up to iron oxide yellow pigments, characterized in that the gassing with air and dissolving of the metal are carried out in separate vessels.Type: GrantFiled: May 25, 1990Date of Patent: July 16, 1991Assignee: Bayer AktiengesellschaftInventors: Bernd Krockert, Helmut Printzen, Karl-Werner Ganter, Gunter Buxbaum
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Patent number: 5004504Abstract: In accordance with the instant invention red transparent iron oxide pigment is prepared from yellow transparent iron oxide pigment filter cake by drying and calcining in a single operation using a spray dryer employing a nozzle of the two fluid design.Type: GrantFiled: February 26, 1990Date of Patent: April 2, 1991Assignee: BASFInventors: Rodney G. Schroeder, Anand S. G. Sharangpani
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Patent number: 4994255Abstract: A process for recovering elemental chlorine from ferrous chloride produced during chlorination of a titaniferous ore or ore beneficiate by oxidizing ferrous chloride in a fluidized bed of particulate material which is inert, e.g., sand, continuously oxidizing first to ferric chloride and then to ferric oxide as one stage.Type: GrantFiled: April 28, 1989Date of Patent: February 19, 1991Assignee: SCM Chemicals, Inc.Inventor: Charles K. Hsu
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Patent number: 4960583Abstract: Oxides having the spinel structure of .gamma.-Fe.sub.2 O.sub.3 /Fe.sub.3 O.sub.4 type, substituted by trivalent and monovalent metals, or doped with non-spinel derivatives thereof, more particularly iron/aluminum/potassium oxides well suited as dehydrogenation catalysts, e.g., for dehydrogenating ethylbenzene into styrene, are prepared by thermally decomposing mixed iron, aluminum and potassium salts, notably the oxalates thereof, in the presence of air, then reducing the product of thermal decomposition at a temperature of less than 400.degree. C., advantageously in the presence of steam and hydrogen, and optionally oxidizing the product of reduction; oxides of .beta.-alumina structure are also produced.Type: GrantFiled: December 16, 1988Date of Patent: October 2, 1990Assignee: AtochemInventors: Abel Rousset, Belaid Maachi, Bernard Gilot, Michel Gougeon
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Patent number: 4940572Abstract: A process is disclosed for the production of micaceous iron oxide using metallic iron, for example scrap iron, as a feed stock for the preparation of an iron chloride and the resulting iron chloride is oxidized at an elevated temperature in the presence of a salt of an alkali metal or alkaline earth metal, preferably sodium chloride. A reaction may be effected in a packed tower reactor comprising a refractory tube 7 containing an inert packing material e.g. aluminosilcate ceramic balls. The reaction charge including packing material, metallic iron and the salt is introduced via hopper 13. A tube 7 is externally heated by electrical resistance elements 10 and chlorine and an oxidizing gas are introduced at inlet 8 and the off-gas removed at outlet 9. The micaceous iron reaction product is obtained as a coating on the inert packing material. Micaceous iron oxide is used as a pigment for the formulation of metal protective paints.Type: GrantFiled: July 5, 1989Date of Patent: July 10, 1990Assignee: Cookson Laminox LimitedInventors: Roy D. Laundon, Anthony J. Wickens, John H. W. Turner
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Patent number: 4935219Abstract: The process of the invention is carried out in gaseous phase by the action of ammonia on the aqueous solutions of iron salts in an appropriate reacting vessels.Type: GrantFiled: December 15, 1987Date of Patent: June 19, 1990Inventors: Luis Escolar, Helio Nupieri
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Patent number: 4913890Abstract: Finely divided acicular and pore-free .alpha.-Fe.sub.2 O.sub.3 is prepared from an iron(III) salt in the presence of one or more organic substances which form complexes with iron(III) ions, in alkaline supension at from 80.degree. to 250.degree. C., and is used for the preparation of magnetic materials suitable for magnetic recording media.Type: GrantFiled: February 24, 1989Date of Patent: April 3, 1990Assignee: BASF AktiengesellschaftInventors: Volker Arndt, Helmut Auweter, Rainer Feser, Ekkehard Schwab
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Patent number: 4898619Abstract: A pigment which comprises crystallites of iron oxide having an average particle size of less than 100 nanometers doped with from 10% to 80% by weight of aluminium as Al.sup.3+ based on the weight of iron, having the general formula (Al.sub.x Fe.sub.2-x)O.sub.3, where x=0.34 to 1.24 and having an orange color with the following color measurements:L (Lightness)>45.degree.C (Strength)>40.degree.H (Hue) 50.degree. to 60.degree.A pigment precursor composition is also provided which, on firing, produces the pigment as defined above.Type: GrantFiled: December 19, 1988Date of Patent: February 6, 1990Assignee: Cookson Group PLCInventors: John F. Clifford, Fiona C. R. Morrison
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Patent number: 4889697Abstract: According to the subject method of refining a ferrous ion-containing acid solution, a metal selected from a group including Al, Cr, V, B, and Zn or an acid solution of that metal is added to a ferrous ion-containing acid solution, such as an acid solution which remains after steel is washed with an acid. The pH value of the acid solution is controlled to be within the range of 3.5 to 6 by adding an alkali liquid to the acid solution, whereby a hydroxide salt of the added metal is produced in the acid solution and the impurities in the acid solution are captured by the produced hydroxide salt. As a result, the impurities can be eliminated from the acid solution such that the Si component (e.g., SiO.sub.2) content in the acid solution is within the range of 2 to 3 ppm or less. Since the content of the other impurities such as Al, Ti, and Cr can also be reduced, a high-purity iron oxide can be obtained from the resultant acid solution.Type: GrantFiled: December 5, 1988Date of Patent: December 26, 1989Assignees: NKK Corporation, Kokan Mining Co., Ltd.Inventors: Tsutomu Fukushima, Tsugio Nakao, Kasane Yamashita, Takao Komuro, Katsuhiro Nishi
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Patent number: 4869735Abstract: Here is provided an adsorbent for adsorbing and removing an arsenic compound which becomes a catalyst poison in a selective contact reduction process for removing nitrogen oxides (NOx) from a combustion exhaust gas by the use of an ammonia as a reducing agent and a denitrating catalyst.The adsorbent of the present invention comprises a material in which the total volume of pores is 0.2 to 0.7 cc/g and the volume of the pores having a pore diameter of 300 .ANG. or more is 10% or more with respect to the total pore volume, and the material is a specific element, its oxide, an ion-exchanged zeolite or the like.In addition, the present invention is directed to a method for removing the arsenic compound from the combustion exhaust gas by injecting the adsorbent into the flow of the gas on the upstream side of the denitrating catalyst.Type: GrantFiled: April 28, 1988Date of Patent: September 26, 1989Assignees: Mitsubishi Jukogyo K.K., Chemical Ind. Sakai, Mitsubishi Petrochemical Co., Ltd., Petrochemical Engineering Co., Ltd. Mitsubishi, Catalysts & Chemical Co., Ltd.Inventors: Masaki Miyazawa, Norihisa Kobayashi, Hiromu Takatsuka, Atsushi Morii, Toshio Koyanagi, Touru Seto, Kozo Iida, Shigeaki Mitsuoka, Hiroaki Rikimaru, Makoto Imanari, Takeo Koshikawa, Akihiro Yamauchi, Masayuki Hanada, Morio Fukuda, Kiyoshi Nagano
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Patent number: 4865833Abstract: A process is disclosed for the production of micaceous iron oxide using metallic iron, for example scrap iron, as a feed stock for the preparation of an iron chloride and the resulting iron chloride is oxidized at an elevated temperature in the presence of a salt of an alkali metal or alkaline earth metal, preferably sodium chloride. A reaction may be effected in a packed tower reactor comprising a refractory tube 7 containing an inert packing material e.g. aluminosilicate ceramic balls. The reaction charge including packing material, metallic iron and the salt is introduced via hopper 13. A tube 7 is externally heated by electrical resistance elements 10 and chlorine and an oxidizing gas are introduced at inlet 8 and the off-gas removed at outlet 9. The micaceous iron reaction product is obtained as a coating on the inert packing material. Micaceous iron oxide is used as a pigment for the formulation of metal protective paints.Type: GrantFiled: January 15, 1988Date of Patent: September 12, 1989Assignee: Cookson Laminox LaminoxInventors: Roy D. Laundon, Anthony J. Wickens, John H. W. Turner
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Patent number: 4826671Abstract: Finely divided, acicular and pore-free .alpha.-Fe.sub.2 O.sub.3 is prepared from iron(III) salts in the presence of one or more organic substances which form complexes with iron(III) ions, in alkaline suspension, at from 80.degree. to 250.degree. C.Type: GrantFiled: March 11, 1987Date of Patent: May 2, 1989Assignee: BASF AktiengesellschaftInventors: Volker Arndt, Rainer Feser, Werner Steck, Helmut Jakusch
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Patent number: 4806335Abstract: A process for producing acicular .alpha.-FeOOH particle powder having a narrow particle size distribution and a rectified shape and being highly dispersed is provided, which process comprises mixing with stirring an aqueous solution of a Fe(II) salt with an aqueous solution of an alkali in an equivalent ratio of alkali to Fe(II) salt of 1.5 or more, oxidizing the mixture with a O.sub.2 -containing gas, heat treating the resulting suspension of iron .alpha.-FeOOH particle powder to 60.degree. to 100.degree. C., further adding an aqueous solution of a FE(II) salt in a proportion of atom to molecule of Fe(II)/.alpha.-FeOOH of 0.5 to 10% and again oxidizing the mixture with a O.sub.2 -containing gas at 35.degree. to 55.degree. C.Type: GrantFiled: November 12, 1987Date of Patent: February 21, 1989Assignee: Chisso CorporationInventors: Masayoshi Saito, Jiro I
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Patent number: 4798622Abstract: Very small iron-containing particles that are in the shape of facetted nodules. Such particles can be non-magnetic particles such as delta ferric oxide hydrate particles or magnetic particles such as magnetic iron oxide particles or metallic particles. Magnetic layers containing such magnetic particles combine excellent remanent magnetization with increased output signal level. The facetted nodular particles are prepared in a process in which (a) an aqueous solution of ferrous salt is added to an aqueous solution of alkaline hydroxide while avoiding substantial local excesses of the ferrous salt, and subjecting the ferrous salt solution to reducing conditions before or during its addition to the alkaline hydroxide solution and (b) the ferrous hydroxide particles are oxidized to delta ferric oxide hydrate particles in the presence of an iron complexing agent, for example, pyrogallol, that is capable of selectively forming ferric iron complexes that are soluble in the reaction medium.Type: GrantFiled: October 8, 1986Date of Patent: January 17, 1989Assignee: Eastman Kodak CompanyInventor: Bernard J. Pingaud
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Patent number: 4774072Abstract: Acicular .alpha.-Fe.sub.2 O.sub.3 is prepared from iron(III) salts by heating an alkaline aqueous suspension of iron(III) hydroxide in the presence of one or more organic substances which form complexes with iron(III) ions to a temperature of 100.degree. C. or less.Type: GrantFiled: March 11, 1987Date of Patent: September 27, 1988Assignee: BASF AktiengesellschaftInventors: Volker Arndt, Bernd Meyer, Rainer Feser, Werner Steck, Helmut Jakusch
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Patent number: 4758415Abstract: The subject matter of this invention relates to a process for removing the soluble metal cations contained in iron oxide pigments comprising washing said iron oxide pigments with a ligand compound having a pH greater than 6.0. The pigments can be used as colorants for substances ingested by man and animals, and they can also be used to stabilize plastics against ultraviolet degradation, and as pigments in base-coat clear-coat automotive finishing operations.Type: GrantFiled: May 10, 1985Date of Patent: July 19, 1988Assignee: BASF CorporationInventor: Arvind S. Patil
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Patent number: 4705762Abstract: A process for producing ultra-fine ceramic particles with the particle size of less than 1000 .ANG., which comprises the steps of forming powdered dust cloud of metal powder such as Si constituting a portion of aimed ceramic particles in a reaction gas containing the other portion of said aimed ceramic particles, igniting said powdered dust cloud to cause explosive burning and synthesizing said aimed ceramic particles and gathering said resulting ceramic particles. By the process, ceramic particles such as Al.sub.2 O.sub.3, MgO, SiO.sub.2, TiO.sub.2, TiN having particle size of 10-100 nm can be produced.Type: GrantFiled: February 8, 1985Date of Patent: November 10, 1987Assignee: Toyota Jidosha Kabushiki KaishaInventors: Kazuhide Ota, Susumu Abe
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Patent number: 4701221Abstract: A process for the production of black iron oxide pigments having a magnetite structure from iron ion-containing acidic waste water which comprises precipitating the iron ions with alkaline substances in a first stage at ambient temperature to produce a raw slurry and in a second stage, concentrating the raw slurry adjusted to a pH of from 5.0 to 8.0 with acidic substances and then ripening the concentrated slurry at temperatures above 70.degree. C.Type: GrantFiled: May 9, 1986Date of Patent: October 20, 1987Assignee: Bayer AktiengesellschaftInventors: Horst Brunn, Gerd-Hermann Schulten, Werner Fuhr
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Patent number: 4670357Abstract: A ferric hydrous oxide of a character that retards the deposition of iron based compounds on the walls of a conduit is prepared by flowing an aqueous solution containing iron-based compounds including magnetite into a vented chamber, and boiling the solution at atmospheric pressure.Type: GrantFiled: June 17, 1985Date of Patent: June 2, 1987Assignee: International Fuel Cells CorporationInventor: William A. Taylor
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Patent number: 4655839Abstract: A solid, water impervious landfillable composition of a process for treating iron chloride wastes such as those obtained when chlorinating titanium ore is disclosed. The process involves reacting the iron chlorides with limestone in molten CaCl.sub.2.xH.sub.2 O, where x equals 3-6. The composition comprises CaCl.sub.2.xH.sub.2 O where x is from 3-6 and FeO.sub.Y where Y is from 1.0-1.5 and the weight ratio of CaCl.sub.2.xH.sub.2 O (calculated as CaCl.sub.2.2H.sub.2 O)/FeO.sub.Y is from 1/9-4/1.Type: GrantFiled: January 17, 1985Date of Patent: April 7, 1987Assignee: E. I. Du Pont de Nemours and CompanyInventors: Tze Chao, Jack K. Nyquist
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Patent number: 4652433Abstract: The method of the present invention is a novel comprehensive process for maximizing the recovery of valuable mineral values from coal ash. Options may also be included for the production of saleable inorganic chemical by-products. The process employs both physical and chemical extraction techniques that maximize the yield of products while reducing the quantity of waste produced. Valuable minerals and chemicals such as cenospheres (hollow microspheres), carbon, magnetite (Fe.sub.3 O.sub.4), alumina (Al.sub.2 O.sub.3), iron oxide (Fe.sub.2 O.sub.3) and iron chloride (FeCl.sub.3) may be produced. Due to removal of carbon, magnetite, and iron oxide from the coal ash, the processed ash comprises a quality pozzolan.Type: GrantFiled: January 29, 1986Date of Patent: March 24, 1987Assignee: Florida Progress CorporationInventors: Robert A. Ashworth, Larry A. Rodriguez, Antonio A. Padilla, Ned B. Spake, W. Wes Berry, Rae A. Schmeda
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Patent number: 4631140Abstract: Ferrimagnetic particles which are useful as magnetic material for magnetic recording media and consist of a core of a magnetic material exhibiting multiaxial anisotropy and a coating which surrounds the core and is composed of a magnetic material possessing uniaxial anisotropy, and a process for their preparation.Type: GrantFiled: October 15, 1985Date of Patent: December 23, 1986Assignee: BASF AktiengesellschaftInventors: Werner Steck, Helmut Jakusch
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Patent number: 4624845Abstract: A process is disclosed for the production of micaceous iron oxide using metallic iron, for example scrap iron, as a feed stock for the preparation of an iron chloride and the resulting iron chloride is oxidized at an elevated temperature in the presence of a salt of an alkali metal or alkaline earth metal, preferably sodium chloride. A reaction may be effected in a packed tower reactor comprising a refractory tube 7 containing an inert packing material e.g. aluminosilicate ceramic balls. The reaction charge including packing material, metallic iron and the salt is introduced via hopper 13. A tube 7 is externally heated by electrical resistance elements 10 and chlorine and an oxidizing gas are introduced at inlet 8 and the off-gas removed at outlet 9. The micaceous iron reaction product is obtained as a coating on the inert packing material. Micaceous iron oxide is used as a pigment for the formulation of metal protective paints.Type: GrantFiled: February 22, 1984Date of Patent: November 25, 1986Inventors: Roy D. Laundon, Anthony J. Wickens, John H. W. Turner
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Patent number: 4624843Abstract: Chlorine may be recovered from residues from the fluidized bed chlorination of iron-containing metalliferous oxidic materials, such as ilmenite, bauxite, chromite, wolframite, scheelite, tantalite or columbite, the residues containing condensed iron chloride and blow-over bed solids, by heating the residue to revolatalize the iron chloride and reacting it with oxygen. The quantity of iron chloride in the oxidic material is controlled relative to the quantity of blow-over carbon so that the quantity of carbon is sufficient on combustion to provide the required heat but is insufficient to cause undue dilution of the chlorine produced by virtue of its combustion products. Chlorine of a concentration suitable for direct recycle to a chlorination process, e.g. of 30% to 50% volume concentration is produced.Type: GrantFiled: June 10, 1985Date of Patent: November 25, 1986Assignee: SCM Chemicals LimitedInventor: Michael Robinson
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Patent number: 4622281Abstract: A magnetic color toner stable to heat and light which does not fade or discolor for a long period of time is prepared by incorporating .gamma.-Fe.sub.2 O.sub.3 particles as a magnetic component in a toner.Type: GrantFiled: January 3, 1986Date of Patent: November 11, 1986Assignee: Canon Kabushiki KaishaInventors: Eiichi Imai, Hiroyuki Kobayashi, Yasuo Mitsuhashi
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Patent number: 4597958Abstract: In a method of producing a hydrated iron oxide as a starting material for a magnetic powder by aging a suspension of a ferric hydroxide prepared by reacting a ferric salt with an aqueous solution of alkali, the aging temperature is controlled between 20.degree. and 100.degree. C. and pH is controlled between 1 and 6 for the first 5 to 240 minutes while nuclei of hydrated iron oxide crystals generate, and then the aqueous solution of alkali is added again to adjust the pH value to 10 to 13.5 to make the crystals grow. This production method is capable of producing an acicular hydrated iron oxide having a reduced particle-size distribution range and also capable of controlling the length of the crystals as desired.Type: GrantFiled: September 17, 1984Date of Patent: July 1, 1986Assignee: Mitsui Mining & Smelting Co., Ltd.Inventors: Nobuo Takagi, Masakazu Konno, Takeo Kobayashi
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Patent number: 4560544Abstract: A process for preparing acicular .alpha.-FeOOH by partially neutralizing and then oxidizing a ferrous salt solution in the presence of phosphoric acid or a salt thereof to form seed crystals of .alpha.-FeOOH and optionally further oxidizing said solution while neutralizing said solution with an alkali to grow said seed crystals, wherein pyrophosphoric acid or a salt thereof is used as said phosphoric acid and the seed crystals of .alpha.-FeOOH are formed at a temperature of 50.degree. to 100.degree. C. The .alpha.-FeOOH obtained according to the process of this invention is composed of fine particles and appreciably improved in acicularity and particle size distribution. Also, a magnetic recording medium made from the magnetic iron oxides derived therefrom in a usual way have a low noise characteristic and, are excellent in coercivity and other magnetic properties.Type: GrantFiled: December 10, 1984Date of Patent: December 24, 1985Assignee: Ishihara Sangyo Kaisha, Ltd.Inventors: Kazuo Nakata, Tsuneo Ishikawa, Taro Amamoto, Toshihiko Kawamura
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Patent number: 4543197Abstract: A process for producing magnetic metallic oxide which comprises the steps of pulverizing at least one member selected from the group consisting of ferro-manganese, ferro-nickel, electrolytic manganese, electrolytic iron and electrolytic zinc, adding to the substance thus pulverized at least one member selected from the group consisting of oxides of Fe, Mn, Ni, Cu, Mg, Zn and Co and salts of Fe, Mn, Ni, Cu, Mg, Zn and Co which become oxides by heating, wet pulverizing and mixing the mixture upon oxidation, thereby producing a slurry, and heating said slurry at 800.degree. to 1450.degree. C. By this process, a magnetic ferrite can be stably and inexpensively synthesized.Type: GrantFiled: April 25, 1983Date of Patent: September 24, 1985Assignees: Japan Metals & Chemicals Co., Ltd., Magune Co., Ltd.Inventors: Tadayoshi Karasawa, Katsumi Kawano, Katsuji Uchiyama, Michio Yamazaki
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Patent number: 4532113Abstract: A process for treating iron chloride wastes such as those obtained when chlorinating titanium ore is disclosed. The process involves reacting the iron chlorides with limestone in molten CaCl.sub.2.xH.sub.2 O, where x equals 3-6 and separating the resulting iron oxide from the molten CaCl.sub.2.xH.sub.2 O.Type: GrantFiled: September 6, 1983Date of Patent: July 30, 1985Assignee: E. I. Du Pont de Nemours and CompanyInventors: Tze Chao, Jack K. Nyquist
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Patent number: 4495164Abstract: A process for producing acicular magnetite or maghemite of high axial ratio, which comprisespreparing an iron (II) hydroxide suspension at a pH of at least 11 with a magnesium sulfate or magnesium chloride in an amount of 0.5 to 7.0 atomic % based on the amount of the iron (II) hydroxide in the suspension and calculated as the ratio of Mg to Fe (II),oxidizing the resultant suspension with the oxygen-containing gas to form an acicular iron (III) oxide hydroxide in the form of particles having a long axis length of 0.3 to 2.0 .mu.m and an axial ratio of more than 20:1,reducing said acicular iron (III) oxide hydroxide into the acicular magnetite, and oxidizing the resultant acicular magnetite to form the acicular maghemite, if necessary.Type: GrantFiled: July 11, 1983Date of Patent: January 22, 1985Assignee: Toda Kogyo Corp.Inventors: Yosiro Okuda, Tosiharu Harada
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Patent number: 4459276Abstract: Yellow iron oxide crystals having lengths in the range of 100 to 1000 nm and a major axis/motor axis length ratio in the range of 1.5 to 4.5 are produced by adding an aqueous ferric salt solution to an aqueous alkali solution, causing the two solutions to react with each other at a temperature in the range of -5.degree. to 30.degree. C. thereby inducing precipitation of iron hydroxide, allowing the precipitate to age, then subjecting the aged precipitate to a hydrothermal treatment thereby producing crystals and, when necessary, further allowing the crystals to grow.Type: GrantFiled: August 31, 1982Date of Patent: July 10, 1984Assignees: Agency of Industrial Science & Technology, Ministry of International Trade & IndustryInventors: Soichiro Nobuoka, Takashi Asai, Kazuaki Ado
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Patent number: 4436681Abstract: A process for producing an iron oxide weighting material from an iron chloride solution. The iron chloride solution is introduced into an elevated temperature reactor as an atomized mist. The moisture is evaporated from the mist to form iron chloride solids which then react with the steam produced during the evaporation to form particulate iron oxides and hydrogen chloride gas. The iron oxides then are compacted and introduced into a calcination zone maintained at a temperature in the range of from about 400.degree. C. to about 1300.degree. C. The compacted iron oxide is calcined to reduce the surface area of the particles. The calcined iron oxide then is ground to a predetermined particle size.Type: GrantFiled: May 17, 1982Date of Patent: March 13, 1984Inventors: Virgil J. Barczak, Haywood A. Perkins, O. L. Daigle
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Patent number: 4414196Abstract: A method of producing single crystalline, acicular .alpha.-ferric oxide particles of narrow particle size distribution is provided. The method comprises heating an aqueous suspension of ferric hydroxide at temperatures of 100.degree.-250.degree. C. at an alkaline pH in the presence both a water soluble organic or inorganic compound capable of forming complexes with iron as a growth regulating agent and .alpha.-ferric oxide seed crystals of minor axes not larger than 0.4 microns in average in amounts of 0.1-25 mole % in terms of the Fe content thereof in relation to the ferric hydroxide.Type: GrantFiled: November 18, 1981Date of Patent: November 8, 1983Assignee: Sakai Chemical Industry Co., Ltd.Inventors: Seiji Matsumoto, Tadashi Koga, Kiyoshi Fukai, Hideji Yamamoto
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Patent number: 4404254Abstract: Synthetic, hexagonal, lamellar iron oxide particles, suitable as corrosion-inhibiting or decorative colored pigments, containing about 0.1 to 12% by weight of at least one oxide of an element of the IVth, Vth or VIth Main and Secondary Groups and of the IInd Secondary Group of the Periodic System of Elements.Type: GrantFiled: July 7, 1981Date of Patent: September 13, 1983Assignee: Bayer AktiengesellschaftInventors: Gerhard Franz, Franz Hund
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Patent number: 4396596Abstract: A method of preparing gamma ferric hydroxyoxide in which ferrous ions are reacted in an alkaline solution to produce a suspension of ferric hydroxide, the resulting suspension is treated with an oxidizing gas in a first oxidizing step at a relatively high oxidation rate, sufficient to cause nucleation of gamma ferric hydroxyoxide to occur, and then the oxidation rate is reduced in a second oxidizing step to cause crystal growth to occur on the nuclei formed in the first oxidizing step. The resulting product has magnetic and physical characteristics making it extremely suitable for use in the manufacture of magnetic recording media.Type: GrantFiled: October 19, 1981Date of Patent: August 2, 1983Assignee: Sony CorporationInventors: Kenji Ogisu, Makoto Inoue, Kenji Yazawa, Haruko Masuya
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Patent number: 4389391Abstract: An improved method of beneficiating ilmenite using two chlorinators in order to oxidize by-product iron chlorides to chlorine in the vapor phase and eliminate the necessity of separating the chlorine from combustion gas by cryogenic methods comprising using a first stage which produces beneficiated ore, and, inter alia, carbon dioxide, iron chlorides, predominantly ferrous chloride, which are condensed to gain the separation from CO.sub.2 ; solid iron chlorides are fed to an oxidation zone in the void above the second stage beneficiator and reacted with oxygen; heat required for vaporization of the condensed chlorides is supplied in part by beneficiation within the second stage. The fluidized bed overflow of the second stage beneficiator is magnetically separated to separate practically pure T.sub.1 O.sub.2, useful as a starting material for T.sub.1 O.sub.2 pigment and a recycle stream of magnetic partially beneficiated ore.Type: GrantFiled: June 28, 1981Date of Patent: June 21, 1983Inventor: Wendell E. Dunn, Jr.
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Patent number: 4378252Abstract: A process for increasing the color purity of iron oxide pigment particles admixed with color-modifying impurities and obtained by the Penniman process or the aniline process, comprising introducing the particles into a magnetic field, and removing from the magnetic field two fractions of different magnetizability, the first fraction being iron oxide pigment particles of increased color purity and the second fraction being enriched in impurities.Type: GrantFiled: May 29, 1981Date of Patent: March 29, 1983Assignee: Bayer AktiengesellschaftInventors: Peter Kiemle, Franz Hund, Ingo Pflugmacher, Wolfgang Rambold
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Patent number: 4376656Abstract: Yellow iron oxide pigments having improved heat stability are prepared by subjecting an alkaline slurry of conventional yellow iron oxide, a soluble ferric salt, sodium aluminate, and a third metal component, exemplified by antimony ion or a zinc ion/titanium ion combination, to a hydrothermal (autoclave) treatment at about 100.degree.-240.degree. C. The separated solid product has a heat stability temperature (based on the color change from yellow to red when heated) appreciably higher than that of the starting iron oxide.Type: GrantFiled: October 16, 1981Date of Patent: March 15, 1983Assignee: Titan Kogyo K.K.Inventors: Jihei Senda, Yoshihiro Inoue, Toshiaki Uenishi, Hidefumi Harada, Kouji Nakata, Akio Akagi, Yakanori Yamasaki
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Patent number: 4374677Abstract: Yellow iron oxide pigments having improved heat stability are prepared by subjecting an alkaline slurry of conventional yellow iron oxide, a soluble ferric salt, and sodium aluminate to a hydrothermal (autoclave) treatment at 100.degree.-240.degree. C., separating and slurrying the resultant solid product, and subjecting that product to a second hydrothermal treatment of 250.degree.-350.degree. C. The original iron oxide has a heat stability (based on color change from yellow to red) temperature of about 203.degree. C., while the final product shows a change at 270.degree. C.Type: GrantFiled: October 5, 1981Date of Patent: February 22, 1983Assignee: Titan Kogyo K.K. JapanInventors: Jihei Senda, Yoshihiro Inoue, Toshiaki Uenishi, Hidefumi Harada, Kouji Nakata, Akio Akagi
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Patent number: 4374676Abstract: Yellow iron oxide pigments having improved heat stability are prepared by mixing a conventional yellow iron oxide pigment with an aqueous alkaline solution of a soluble antimony compound. This yields a yellow pigment whose particle surface is coated with "antimony-bloom", and this product has a higher heat stability temperature than does the starting yellow iron oxide. When the product coated with "antimony-bloom" is subjected to hydrothermal treatment (autoclaving), the resultant material has a yet-higher heat stability temperature. Other, related treatments furnish products with improved heat stability temperatures.Type: GrantFiled: December 7, 1981Date of Patent: February 22, 1983Assignee: Titan Kogyo K.K.Inventors: Jihei Senda, Yoshihiro Inoue, Toshiaki Uenishi, Hidefumi Harada, Kouji Nakata, Akio Akagi, Takanori Yamasaki
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Patent number: 4362702Abstract: A hydrometallurgical process for the treatment of a raw material which contains oxides and ferrites of zinc, copper and cadmium is disclosed, wherein the raw material is neutral leached by means of a sulfuric-acid-bearing solution to leach the oxides without substantial dissolving of the ferrites, a ferrite-bearing residue is separated, and a sulfuric-acid-bearing or ferrisulfate-bearing solution is mixed with the residue in order to leach the ferrite and to precipitate the iron in the form of jarosite in the presence of alkali or ammonium ions under atmospheric conditions at 80.degree.-105.degree. C., and the solid phase is separated from the solution.Type: GrantFiled: September 29, 1981Date of Patent: December 7, 1982Assignee: Outokumpu OyInventors: Jussi K. Rastas, Jens R. Nyberg, Kauko J. Karpale, Lars-Goran Bjorkqvist
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Patent number: 4358431Abstract: In the production of needle-shaped magnetic iron oxide pigments by treating iron with a nitro-aromatic in the presence of .alpha.-FeOOH nuclei to form .alpha.-FeOOH particles and an amino-aromatic, and thereafter dehydrating the .alpha.-FeOOH particles and reducing them, the improvement which comprises forming the .alpha.-FeOOH nuclei at about 0.degree. to 90.degree. C. in a suspension of metallic iron, an iron-(II)-salt and a nitro-aromatic by adding a basic precipitant in about 10 to 95% of the amount required for the complete precipitation of the iron in the iron-(II)-salt. Advantageously the metallic iron comprises cast iron, the nitro-aromatic comprises nitrobenzene, the amino-aromatic comprises aniline, the basic precipitant comprises at least one of ammonia and a basically reacting alkali metal, alkaline earth metal or ammonium salt, the nuclei formation is carried out at about 10.degree. to 60.degree. C.Type: GrantFiled: July 23, 1981Date of Patent: November 9, 1982Assignee: Bayer AktiengesellschaftInventors: Horst Brunn, Peter Kiemle, Franz Hund, Heribert Bade
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Patent number: 4355005Abstract: A process for the treatment of a raw material which contains oxides and ferrites of zinc, copper and cadmium is disclosed, in which the raw material is neutral leached with a sulfuric-acid-bearing solution in order to leach the oxide without substantial dissolving of ferrite, the ferrite-bearing residue is separated, and a sulfuric-acid-bearing or ferrisulfate-bearing solution is mixed with the residue in order to leach the ferrite and to precipitate the iron as jarosite in the presence of alkali ions or ammonium ions under atmospheric conditions at 80.degree.-105.degree. C., the sulfuric-acid-bearing or ferrisulfate-bearing solution being added to the ferrite-bearing residue in such an amount that approximately 50-60% of the ferrite dissolves and its iron precipitates as jarosite, the solid phase is dried and heated to so high a temperature that the zinc of the solid phase is converted to zinc sulfate and its iron to hematite according to the following reaction:(8) 3ZnFe.sub.2 O.sub.4(s) +2A[Fe.sub.3 (SO.Type: GrantFiled: September 29, 1981Date of Patent: October 19, 1982Assignee: Outokumpu OyInventors: Jussi K. Rastas, Pekka J. Saikkonen, Risto J. Honkala
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Patent number: 4349456Abstract: Shaped and fired, porous or impermeable nonvitreous ceramic microcapsules of metal oxide, preferably transparent and polycrystalline, are made by a non-melt process comprising the liquid-liquid extraction of aqueous metal oxide precursor with a dehydrating liquid having a limited water solubility, and drying and firing the resulting gelled microcapsules. For example, an aqueous titania sol is added to an agitated body of n-butanol to form a dispersion of droplets of said sol and water is rapidly extracted from the droplets to form gelled microcapsules; the latter are recovered by filtration, dried, and fired to convert them into transparent, sealed or heat-sealable, non-vitreous ceramic, spherical microcapsules of polycrystalline titania. The microcapsules can be used as fillers for plastic and other composites or filled with a selected solid, liquid or gas for purpose of storing, transporting, or facilitating the use of the same.Type: GrantFiled: August 27, 1979Date of Patent: September 14, 1982Assignee: Minnesota Mining and Manufacturing CompanyInventor: Harold G. Sowman
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Patent number: 4339425Abstract: Acicular hydrated ferric oxide particles are produced by premixing an aged ferric hydroxide with a newly formed ferric hydroxide or a mixture of ferrous hydroxide and an oxidizing agent and treating the pre-mixture by a hydrothermal reaction of said pre-mixture at 100.degree. to 250.degree. C.Type: GrantFiled: November 25, 1980Date of Patent: July 13, 1982Assignee: TDK Electronics Co., Ltd.Inventor: Yasumichi Tokuoka