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Showing papers on "Iron oxide published in 1973"


Journal ArticleDOI
TL;DR: The sedimentary textures of the Sokoman Iron Formation are similar to those of limestones; therefore the classification of textural elements in limestone (Folk) can be applied to the iron formation.
Abstract: The sedimentary textures of the Sokoman Iron Formation are similar to those of limestones; therefore the classification of textural elements in limestone (Folk) can be applied to the iron formation. The authors recognized the following textural elements: (a) femicrite (a matrix of iron silicate and carbonate) and matrix chert, both analogous to micrite; (b) cement chert and carbonatic cements; (c) aggregated particles, comparable to Folk9s allochems: pellets, intraclasts, ooliths, and pisolites. Shard textures are derived from ooliths and intraclasts by compaction. Rock types are defined by the combination of textural elements they contain. The iron formation suffered extensive epigenetic alteration. Dessiccation, shrinkage of silica-gel, compaction, and cementation are early diagenetic. Primocrystallization of quartz concludes the early diagenetic stage. It leads through a cryptocrystalline stage to the end phase of micropolygonal quartz. Quartz re-crystallized further during late diagenesis (burial metamorphism?) and again during a synkinematic to postkinematic regional metamorphism. Hematite dust is the oldest iron oxide. Much of the microscopic magnetite and specularite formed during early diagenesis. Migration of iron occurred; iron has been enriched in magnetite- or hematite-rich layers (“metallic” layers) during early diagenesis. Renewed crystallization of iron oxides occurred during the regional metamorphism. Microgranular siderite is perhaps primary. Porphyroblasts and glomero-porphyroblastic concretions of siderite, ankerite, and ferriferous calcite are early diagenetic. Minnesotaite and stilpnomelane are late diagenetic minerals. Riebeckite (and perhaps talc) formed during the regional metamorphism.

91 citations


Journal ArticleDOI
TL;DR: In this paper, a defect model for corundum is proposed to explain the sintering data for transition-metal-ion-doped Al2O3, and the contribution of surface diffusion during initial-stage Sintering is estimated by combining shrinkage and neck-growth data.
Abstract: Alumina powders with varying iron oxide contents were prepared by coprecipitation. The powders were spheroidized by passing them through an oxygen-acetylene flame. The spheres were sized, annealed, and sintered in air and in N2 with 132 ppm O2. Isothermal studies were combined with constant-rate-of-heating studies to identify the mechanism of sintering and to calculate the diffusion coefficients. The contribution of surface diffusion during initial-stage sintering of Fe-doped Al2O3 was estimated by combining shrinkage and neck-growth data. The effect of Ti on the sintering rate of Fe-doped Al2O3 was also studied. Both Fe2+ and Ti4+ ions enhanced the sintering rate of Al2O3. A defect model for corundum is proposed to explain the sintering data for transition-metal-ion-doped Al2O3.

53 citations


Journal ArticleDOI
TL;DR: The reduction of NO with CO over alumina supported iron oxide and chromium oxide is a relatively fast process as mentioned in this paper, although this was shown to be due to inhibition by H 2 O, which is a primary product of the NOH 2 reaction.

40 citations


Patent
25 Sep 1973
TL;DR: In this article, the authors present a method to eliminate toxic substances contained in exhaust gases, especially nitrogen oxides, from automobiles by using a catalyst composition consisting of at least a member selected from the group consisting of copper, beryllium, zinc, lead, indium, lanthanum, cerium and oxides.
Abstract: Toxic substances contained in exhaust gases, especially nitrogen oxides contained in exhaust gases from automobiles, can be effectively eliminated, even in the presence of oxygen, by contacting such exhaust gases with a catalyst composition comprising iron or iron oxide, silver or silver oxide, at least a member selected from the group consisting of copper, beryllium, zinc, lead, indium, lanthanum, cerium and oxides of these metals, and a carrier. Especially good results can be obtained by employing a catalyst composition obtained by treating a composition comprising iron or iron oxide, silver or silver oxide, copper or copper oxide and a carrier with hydrogen sulfide, or by employing a catalyst composition comprising sulfides of iron, silver and copper supported on a carrier.

37 citations


Patent
29 Nov 1973
TL;DR: Gaseous streams containing carbonyl compounds are reduced by reacting a vapor phase with catalyst comprising as the major cation portion at least two metals of Periodic Table Groups 1b, 2b, 4b, 6b, 7b and 8b as discussed by the authors.
Abstract: Gaseous streams containing carbonyl compounds are reduced in carbonyl compounds by reacting a vapor phase with catalyst comprising as the major cation portion at least two metals of Periodic Table Groups 1b, 2b, 4b, 6b, 7b and 8. Reactor effluent from oxidative dehydrogenation reaction to produce butadiene-1,3 is reacted with iron oxide - copper chromite on AMC catalyst to remove carbonyl compounds.

31 citations


Journal ArticleDOI
01 Apr 1973-Fuel
TL;DR: In this paper, it is shown that when brown coals containing inorganic carboxylates are carbonized, the reactive functional groups which are present will begin to decompose below 400 °C and their decomposition is completed by 600 °C.

30 citations


Patent
14 Mar 1973
TL;DR: In this article, a void containing iron chloride when the ore is being beneficiated at a temperature of about 1,250* to 1,380* K is described. But this void contains iron chloride only when the iron oxide and unreacted ferric chloride are recycled to the reactor.
Abstract: Chlorine and iron oxide are produced by the oxidation of iron chlorides and mixtures thereof, produced in the chloride process for beneficiating titaniferous ores, by injecting oxygen in the gas space above the fluidized bed. This void contains iron chloride when the ore is being beneficiated at a temperature of about 1,250* to 1,380* K. The oxygen and iron chloride form a partially oxidized mixture which is passed to a flue and cooled to about 1,025* K to complete the oxidation. The iron oxide and unreacted ferric chloride are recycled to the reactor.

25 citations


Patent
26 Dec 1973
TL;DR: In this paper, an economical process is provided for the direct reduction of iron ore by the efficient production of a reducing gas when the external source of fuel used in the process is a liquid or solid.
Abstract: An economical process is provided for the direct reduction of iron ore by the efficient production of a reducing gas when the external source of fuel used in the process is a liquid or solid. A gasifier facility converts a minimal amount of fuel to a gas comprised principally of reductants which is supplemented with reductants reclaimed from the reacted off-gas produced in the reduction process. A controlled amount of water vapor is added to the gas mixture which is heated to approximately reduction furnace temperature before undergoing a shift reaction to equilibrium externally of the furnace to produce a reducing gas having a preferred gas composition.

24 citations


Journal ArticleDOI
TL;DR: The electrification of iron oxides pretreated at various temperatures from 600 to 1200 °C has been investigated in water by measuring the ζpotential as a function of the pH.
Abstract: The electrification of iron oxides pretreated at various temperatures from 600 to 1200 °C has been investigated in water by measuring the ζ-potential as a function of the pH. From the surface-chemical point of view, iron oxides pretreated at temperatures lower than 800 °C behave differently from those pretreated at higher temperatures ; the isoelectric point of the former samples reaches an equilibrium value in a few hours, while that of the latter samples increases slowly to an equilibrium value with an increase in the surface hydration. On the other hand, the equilibrium isoelectric point of iron oxide decreases sharply upon heat treatment at 800–1000 °C, corresponding to the change in the chemical composition of iron oxide from Fe2O3 to Fe3O4.

24 citations


Patent
15 Feb 1973
TL;DR: In this paper, a pure iron carbide in high yield is prepared by reducing iron oxide in the presence of carbon monoxide at temperatures in the range of 500 DEG -550 DEG C.
Abstract: Essentially pure iron carbide in high yield is prepared by reducing iron oxide in the presence of carbon monoxide at temperatures in the range of 500 DEG -550 DEG C.

22 citations


Patent
Lutz Dr Leitner1, Franz Hund1
11 Jan 1973
TL;DR: In this paper, the production of acicular, ferromagnetic iron oxide of high coercive force by oxidizing an iron (II)-hydroxide suspension with an oxygen-containing gas to form acicular iron (III) oxide hydroxide, optionally tempering, reducing and/or reoxidizing this into magnetic iron oxide, is described.
Abstract: In the production of acicular, ferromagnetic iron oxide of high coercive force by oxidizing an iron (II)-hydroxide suspension with an oxygen-containing gas to form acicular iron (III) oxide hydroxide and dehydrating the iron (III) oxide hydroxide, optionally tempering, reducing and/or reoxidizing this into magnetic iron oxide, the improvement which comprises effecting the oxidation of the iron (II)-hydroxide suspension at a pH of at least about 13, the suspension including SiO2 in the form of a sol or soluble salt, the resulting iron (III) oxide hydroxide having SiO2 deposited thereon.

Patent
31 Aug 1973
TL;DR: In this paper, a process for hydrogenating aromatic compounds containing sulfur impurities by contacting the same, at a temperature in the range of from 200 DEG to 450 DEG C and under a pressure of from 10 to 200 Kg/cm2, in a first step, with a catalyst containing a desulfurizing element selected from the oxides and/or sulfides of molybdenum, tungsten, nickel and cobalt, and an iron oxide, deposited on an alumina carrier used in an amount of 0.25 to 4 times the iron
Abstract: Process for hydrogenating aromatic compounds containing sulfur impurities by contacting the same, at a temperature in the range of from 200 DEG to 450 DEG C and under a pressure of from 10 to 200 Kg/cm2, in a first step, with a catalyst containing a desulfurizing element selected from the oxides and/or sulfides of molybdenum, tungsten, nickel and cobalt, and an iron oxide, deposited on an alumina carrier used in an amount of 0.25 to 4 times the iron oxide amount, and in a second step, with a metal hydrogenation catalyst.

Patent
09 May 1973
TL;DR: In this paper, a process for the fabrication of a supported iron oxide pattern involves electromagnetic wave irradiation of a blank, which results in insolubilization so that delineation is accomplished by immersing the processed blank in a suitable solvent.
Abstract: A process for the fabrication of a supported iron oxide pattern involves electromagnetic wave irradiation of a blank. The blank consists of a layer of iron oxide which is soluble in, for example, an acid medium. Irradiation results in insolubilization so that delineation is accomplished by immersing the processed blank in a suitable solvent.

PatentDOI
TL;DR: The use of iron oxide sorbents to remove oxides of nitrogen (NOx) from gaseous mixtures containing small amounts of NOx such as the exhaust from an internal combustion engine or flue gases, without interference from carbon oxides or water vapor and thermally regenerable at relatively low temperatures, is disclosed in this article.
Abstract: The use of iron oxide sorbents to remove oxides of nitrogen (NOx) from gaseous mixtures containing small amounts of NOx such as the exhaust from an internal combustion engine or flue gases, without interference from carbon oxides or water vapor and thermally regenerable at relatively low temperatures, are disclosed. A preferred sorbent is supported ferric oxide for sorption of NOx from gaseous mixtures containing oxygen. Ferrous or ferrosoferric oxide sorbents are also suitable in the presence or absence of oxygen.

Patent
12 Jan 1973
TL;DR: In this paper, a powder magnetic material for use as a magnetic recording medium and a method of its manufacture are disclosed, and the material is adapted to provide a magnetic record medium of low electric resistance.
Abstract: A powder magnetic material for use as a magnetic recording medium and a method of its manufacture are disclosed. More particularly, the disclosed powder magnetic material is adapted to provide a magnetic recording medium of low electric resistance. In particular, an alloy of cobalt and at least one element selected from the group consisting of vanadium, molybdenum, copper, manganese, nickel, zinc and iron is deposited onto the surface of particles of magnetic iron oxides such as Fe3 O4 or γFe2 O3 to provide a powdered magnetic material of high coercivity, high magnetic flux density and low electric resistance.


Patent
02 Nov 1973
TL;DR: In this paper, a solution of a ferrous salt is oxidized in the presence of α-FeO(OH) seed, a basic precipitant, and phosphoric acid or a water soluble salt thereof, which can be dehydrated, optionally tempered, reduced and reoxidized to needle-shaped γ-Fe 2 O 3.
Abstract: Process for producing ferromagnetic iron oxides whereby a solution of a ferrous salt is oxidized in the presence of α-FeO(OH) seed, a basic precipitant, and phosphoric acid or a water soluble salt thereof to form α-FeO(OH), which can be dehydrated, optionally tempered, reduced and re-oxidized to needle-shaped γ-Fe 2 O 3 . The resulting product has high coercive force values which make it especially useful for magnetic impulse recording and reproduction.

Patent
Peter Woditsch1, Lutz Dr Leitner1
12 Apr 1973
TL;DR: In the production of acicular ferrimagnetic gamma -iron oxide containing about 0.5 to 10 atom % of cobalt including the steps of producing cobalt-containing iron oxide hydroxide, dehydrating the oxide to oxide, reducing the oxide and reoxidizing it into Ferrimagnetic iron oxide, the improvement which comprises tempering the material at a temperature of about 600 DEG to 800 DEG C prior to dehydration or reduction as mentioned in this paper.
Abstract: In the production of acicular ferrimagnetic gamma -iron oxide containing about 0.5 to 10 atom % of cobalt including the steps of producing cobalt-containing iron oxide hydroxide, dehydrating the oxide hydroxide to oxide, reducing the oxide and re-oxidizing it into ferrimagnetic iron oxide, the improvement which comprises tempering the material at a temperature of about 600 DEG to 800 DEG C prior to dehydration or reduction, whereby the resulting ferrimagnetic iron oxide upon being thermally stressed retains more than 90% of its remanence.

01 Feb 1973
TL;DR: In this article, the overall reaction is a coupling of the following two component reactions, viz. gasification of carbon C(S) CO2 (g) = 2C0 (g), reduction of iron oxide mFe.
Abstract: Theoretical considerations and experimental findings point out that reduction of iron Oxides and Ores by Carbon proceed via the gas phase, whenever the later is present. The overall reaction is a coupling of the following two component reactions. viz. Gasification of carbon C(S) CO2 (g) = 2C0 (g) & Reduction of iron oxide mFe.0y(S) -f- CO (g) = nFezOw [S) CO2 (g) Recent kinetic studies have established that the gasifi-cation reaction controls the rate of the overall process under the circumstances normally encountered. A critical evaluation of these studies have been pres-ented. The available information on the kinetics and mechanism of the two component reactions have also been critically reviewed.

Patent
23 Aug 1973
TL;DR: In this article, the authors describe an iron oxide catalysts prepared by absorbing iron pentacarbonyl upon a suitable support, followed by oxidation to iron oxide, which they call IROCO catalysts.
Abstract: Iron oxide catalysts prepared by absorbing iron pentacarbonyl upon a suitable support followed by oxidation to iron oxide.

Patent
05 Oct 1973
TL;DR: In this paper, a highly sorbent iron oxide is prepared by reducing hematite to magnetite followed by a low temperature oxidation prior to contact with sulfur dioxide, which is a more effective form of iron oxide sorbent for the oxides of sulfur.
Abstract: A highly sorbent iron oxide is prepared by reducing hematite to magnetite followed by a low temperature oxidation prior to contact with sulfur dioxide. The oxidized solids obtained in this manner are a more effective form of iron oxide sorbent for the oxides of sulfur.


Journal ArticleDOI
TL;DR: The role of titanium oxide in some important refractory systems was elucidated by studying selected equilibria in the system CaO-MgO-iron oxide-titanium oxide at O2 pressures of 0.21 atm (air) and 10−9 atm and under the extreme reducing conditions imposed by the presence of metallic Ti in contact with the oxide phases as discussed by the authors.
Abstract: The role of titanium oxide in some important refractory systems was elucidated by studying selected equilibria in the system CaO-MgO-iron oxide-titanium oxide at O2 pressures of 0.21 atm (air) and 10−9 atm and under the extreme reducing conditions imposed by the presence of metallic Ti in contact with the oxide phases. Solidus relations were determined for the system CaO-MgO-TiO2 in air; 6 composition triangles were delineated, within each of which 3 crystalline phases coexist in equilibrium with liquid at a constant solidus temperature. The solidus temperatures range from 1407° to 1670°C. There is also a composition area within which MgO coexists with a Ca4Ti3O10-Ca3Ti2O7 solid solution, with solidus temperatures varying continuously from 1659° to 1670°C. Studies of reactions between MgO and titanium oxide in contact with metallic Ti in a closed system indicate that the mutual solubility between MgO and TiO at 1400°C is very small. Addition of 5 wt% TiO2 to the system CaO-MgO-iron oxide at 1500°C in air and in 10−9 atm O2 decreases the amount of iron oxide which can be absorbed by a CaO-MgO body without formation of a liquid phase; hence, titanium oxide has a strong deleterious effect on the refractoriness of such bodies.

Patent
Larry F. Thompson1
09 May 1973
TL;DR: Patterned iron oxide films are produced on substrates by oxidative decomposition of polyvinyl ferrocene as mentioned in this paper, where the polymer may be applied to the substrate in the form of a solution by spinning.
Abstract: Patterned iron oxide films are produced on substrates by oxidative decomposition of polyvinyl ferrocene. The polymer may be applied to the substrate in the form of a solution by spinning. Resultant films may be relatively soluble or relatively insoluble in acidic media depending upon processing conditions. Soluble films are of interest for hard copy masks designed for use in the fabrication of printed circuits. Such masks may be pattern-delineated by photoresist techniques or by selective insolubilization. Alternatively, patterns may result from selective deposition or removal of the polymer prior to decomposition.

Patent
H Laurensberg1, J Wegener1, P Greene1
26 Feb 1973
TL;DR: In this article, a method of preparing a metal powder which consists mainly of iron by reduction of finely divided acicular iron oxide hydrate is described, where the iron oxide is doped with a metal which is catalytic for hydrogen reactions.
Abstract: A method of preparing a metal powder which consists mainly of iron by reduction of finely divided acicular iron oxide hydrate. The iron oxide hydrate particles are doped with a metal which is catalytic for hydrogen reactions (for example Co, Ni, Ru). The reduction to metal then occurs more rapidly.

Patent
25 Sep 1973
TL;DR: In this article, a method for reducing iron oxide in a melt of iron by maintaining a reduction layer on the surface of the molten iron and passing the molten metal from the melt through vertical channels which communicate at the bottom of the metal melt an with a space at the top of the melt which is above that of the reduction layer, was presented.
Abstract: A method for reducing iron oxide in a melt of iron by maintaining a reduction layer on the surface of the molten iron and passing the molten metal from the melt through vertical channels which communicate at the bottom of the metal melt an with a space at the top of the melt which is above that of the reduction layer so as to pass the melt including the oxide there through the reduction layer, the molten metal being lifted up through the channel by means of a gas lift pump action and heating the molten metal by inductive heating while it is flowing through the channel

Patent
16 Jan 1973
TL;DR: In this article, the process for preparing indoles by the vapor phase catalytic reaction of the 2-alkyl-and/or 2alkenylanilines at an elevated temperature in the substantial absence of molecular oxygen is described.
Abstract: In the process for preparing indoles by the vapor phase catalytic reaction of the 2-alkyl-and/or 2-alkenylanilines at an elevated temperature in the substantial absence of molecular oxygen; the improvement which comprises carrying out said vapor phase catalytic reaction in the presence of a catalyst comprising iron oxide and an alkali metal compound in the presence of steam.

Patent
22 Mar 1973
TL;DR: In this article, a process of producing metallic iron from iron oxides in an oxide containing material comprising iron oxide and a non-ferrous metal oxide is described, in which the oxide contains material is heated in the presence of hydrogen chloride, flux and a solid carbonaceous material to a temperature below that at which a slag is formed.
Abstract: A process of producing metallic iron from iron oxides in an oxide containing material comprising iron oxide and a non-ferrous metal oxide wherein the oxide containing material is heated in the presence of hydrogen chloride, flux and a solid carbonaceous material to a temperature below that at which a slag is formed.

Patent
A Berleue1, W Dumbaugh1
26 Mar 1973
TL;DR: In this article, the authors used iron oxide to stabilize infrared transmitting, lead and cadmium bismuthate glasses, and found that the resulting glasses contain, in cation percent, 8 to 80% Bi2O3, 0-57% PbO, 0 -32% CdO, at least 5% Pbo + CdOs, 5-32.5% Fe2O 3, and 0-15% miscellaneous other oxides.
Abstract: Iron oxide is used to stabilize infrared transmitting, lead and cadmium bismuthate glasses. The resulting glasses contain, in cation percent, 8 to 80% Bi2O3, 0-57% PbO, 0-32% CdO, at least 5% Pbo + CdO, 5-32.5% Fe2O3, and 0-15% miscellaneous other oxides.

Patent
29 Oct 1973
TL;DR: In this paper, nonferrous metal values, such as nickel, cobalt or copper, contained in oxide ores, or roasted sulfide ores that also contain iron, are selectively reduced to the metallic state, and the selectively reduced metal values are reacted with molecular chlorine by passing gaseous chlorine through an aqueous pulp of the reduced ore to produce a pregnant solution containing the chlorinated metal values.
Abstract: Non-ferrous metal values, such as nickel, cobalt or copper, contained in oxide ores, or roasted sulfide ores, that also contain iron, are selectively reduced to the metallic state, and the selectively reduced metal values are reacted with molecular chlorine by passing gaseous chlorine through an aqueous pulp of the reduced ore to produce a pregnant solution containing the chlorinated metal values from which solution the metal values can be recovered.