Showing papers on "Iron oxide published in 1974"
TL;DR: In this article, the authors explored the mechanism of formation of green rusts, Fe3O4, α-FeOOH, β-FeOH, γ-FeOILH, and amorphous ferric oxyhydroxide in aqueous solution at room temperature.
461 citations
01 Jan 1974
TL;DR: The products of air oxidation of mixed Fe(II)-Fe(III) chloride solutions at pH 6 and 7, at 20 and 60~ and at normal pressure contain green rust, maghemite, lepidocrocite, goethite, and a paracrystalline ferric hydroxide (ferrihydrite) as mentioned in this paper.
Abstract: AB S T R ACT: The products of air oxidation of mixed Fe(II)-Fe(III) chloride solutions at pH 6 and 7, at 20 and 60~ and at normal pressure contain green rust, maghemite, lepidocrocite, goethite and a paracrystalline ferric hydroxide (ferrihydrite). Among these maghemite, a cubic ferromagnetic iron oxide (Fe203) found in many soils, is favoured by slow oxidation rate, high total Fe concentration, the presence of small amounts of Fe(IlI) in the original predominantly Fe(lI) solution, higher temperature and at pH 7 rather than pH 6. The green rust is believed to be an essential precursor of maghemite. On slow oxidation it will form maghemite probably via magnetite. Fast oxidation prevents the cubic phase from being formed and lepidocrocite is the end product. At higher Fe(III) proportions ferrihydrite can be formed which under certain influences converts to goethite and/or hematite. The common iron oxides are seen to form from the same system from small variations in environment which is to be expected from their common associations in soils.
101 citations
TL;DR: The products of air oxidation of mixed Fe(II)-Fe(III) chloride solutions at pH 6 and 7, at 20 and 60°C and at normal pressure contain green rust, maghemite, lepidocrocite, goethite and a paracrystalline ferric hydroxide (ferrihydrite) as discussed by the authors.
Abstract: The products of air oxidation of mixed Fe(II)-Fe(III) chloride solutions at pH 6 and 7, at 20 and 60°C and at normal pressure contain green rust, maghemite, lepidocrocite, goethite and a paracrystalline ferric hydroxide (ferrihydrite). Among these maghemite, a cubic ferromagnetic iron oxide (Fe2O3) found in many soils, is favoured by slow oxidation rate, high total Fe concentration, the presence of small amounts of Fe(III) in the original predominantly Fe(II) solution, higher temperature and at pH 7 rather than pH 6. The green rust is believed to be an essential precursor of maghemite. On slow oxidation it will form maghemite probably via magnetite. Fast oxidation prevents the cubic phase from being formed and lepidocrocite is the end product. At higher Fe(III) proportions ferrihydrite can be formed which under certain influences converts to goethite and/or hematite. The common iron oxides are seen to form from the same system from small variations in environment which is to be expected from their common associations in soils
90 citations
TL;DR: In this paper, the formation of SO3 from SO2 and 02 is catalyzed by iron oxide in the fly ash from a coal-fired boiler, and the amount of produced SO3 is dependent on the iron oxide content of the fly-ash and on the oxygen concentration of the gas stream.
88 citations
TL;DR: In this paper, a study of the adhesion between clean surfaces, in a vacuum of 13nPa (10$^{-10}$ Torr), the influence of hardness, ductility, chemical bonding and adsorbed vapours was described.
Abstract: This paper describes a study of the adhesion between clean surfaces, in a vacuum of 13nPa (10$^{-10}$ Torr), the influence of hardness, ductility, chemical bonding and adsorbed vapours. The geometry was that of crossed cylinders so that the contact region could be well localized and changed from experiment to experiment. In addition, electrical resistance measurements (in the case of conducting solids) could be used to follow the formation and breaking of contact. The joining load was very small (of order 1 mN) with the result that, even for the softest metals the deformation during loading was primarily elastic. The observed adhesion, however, is found to depend markedly on the ductility of the solid. With hard elastic solids the adhesion is very small indeed: much smaller than that predicted by theory and the results suggest that this may be due to fine-scale surface irregularities scarcely larger than atomic dimensions. With metals with a limited number of slip planes the adhesion is higher but appreciably less than would be expected from the area of the junctions formed. With metals such as gold and copper the adhesion is high and equal to the tensile strength of the interfacial junctions. Adhesion of soft metals to a hard solid such as titanium carbide can be high and when the surfaces are separated fragments of metal are found attached to the harder surface. With other hard solids such as sapphire or diamond the adhesion of copper is appreciably less, indicating that the bonding between copper and these covalent materials is intrinsically weak. Experiments at room temperature show that argon and hydrogen have no detectable effect on adhesion, whereas oxygen has. If one of the pair is copper, oxygen reduces the adhesion if the exposure is relatively heavy. With iron a minute exposure of oxygen reduces the adhesion to a very small value. It is suggested that with copper an adsorbed film is formed which is relatively ineffective. By contrast, on iron, minute iron oxide nuclei are formed which reduce the amount of metal-metal contact and also interpose an interfacial region of very limited ductility.
80 citations
TL;DR: In this article, it was shown that ferromagnetic iron metal is formed in reduced PdFeAl2O3 catalysts as a result of the diffusion of hydrogen over the support surface from palladium particles to an oxide of iron.
79 citations
TL;DR: In this paper, a method for selective dissolution and analysis of amorphous material was used to study two Champlain Sea deposits in Quebec and Ontario, which contained 11 and 12 percent of the Champlain sea sediments.
Abstract: Post-glacial Champlain Sea sediments in Quebec and Ontario are often extremely sensitive. Suggestions of considerable amorphous material in these soils come from X-ray diffraction results, as well as electron micrographs. A method for selective dissolution and analysis of amorphous material is used to study two Champlain Sea deposits. The amorphous material removed amounts to 11–12 per cent of the soils and consists mainly of silica and iron oxide. The treated samples have enhanced X-ray diffraction peaks and much cleaner particles as seen by electron microscopy.
52 citations
Patent•
01 Aug 1974
TL;DR: A process for the reduction of iron oxides to produce molten iron in which olivine is introduced into a blast furnace in addition to iron oxide bearing materials and in which there is high content of alkali metal oxides in the materials charged into the furnace, resulting in minimizing or preventing "scaffolding" and improving the operation of the blast furnace is described in this article.
Abstract: A process for the reduction of iron oxides to produce molten iron in which olivine is introduced into a blast furnace in addition to iron oxide bearing materials and in which there is high content of alkali metal oxides in the materials charged into the furnace, resulting in minimizing or preventing "scaffolding" and improving the operation of the blast furnace. The disclosure also includes sinters and briquettes which contain olivine and processes of preparing them, and processes for furnace operation including the charging of such sinters or briquettes.
50 citations
Patent•
17 Jun 1974TL;DR: A spinel-type solid solution is formed from a unity in the sum of a molar fraction of at least one oxide selected from the group consisting of magnesium oxide, nickel oxide, cobalt oxide, manganese oxide and zinc oxide as discussed by the authors.
Abstract: A high temperature thermistor composition comprising essentially a spinel-type solid solution being formed from a unity in the sum of a molar fraction of at least one oxide selected from the group consisting of magnesium oxide, nickel oxide, cobalt oxide, manganese oxide and zinc oxide and a unity in the sum of a molar fraction of aluminum oxide, chromium oxide, and at least one oxide selected from the group consisting of iron oxide, manganese oxide, cobalt oxide and antimony oxide.
47 citations
TL;DR: In this article, the surface oxide films were analysed by both Auger emission spectroscopy (AES) and X-ray photoelectron spectrographs (XPS) after a number of ion bombardments, and the variation in composition with depth was established.
47 citations
Patent•
29 Aug 1974TL;DR: An acicular, magnetic iron oxide pigment containing about 0.1 to 2 percent by weight of zinc and phosphate ions is produced by growing seeds and subsequently reducing and optionally reoxidizing acicular FeOOH as discussed by the authors.
Abstract: An acicular, magnetic iron oxide pigment containing about 0.1 to 2 percent by weight of zinc and phosphate ions is produced by growing seeds and subsequently reducing and optionally reoxidizing acicular FeOOH. Said seeds were formed by precipitation from an iron (II) salt solution in the presence of about 0.1 to 4 percent by weight of zinc ions and about 0.1 to 2 percent by weight of phosphate ions based on the formed seeds.
TL;DR: In this article, the reduction rate of iron oxide contained in molten slags by rotating carbon rod or coke rod was measured, and the obtained rate equation is; the rate equation was derived from the first order of the estimated activity of iron dioxide contained in slags.
Abstract: The reduction rate of iron oxide contained in molten slags by rotating carbon rod or coke rod was measured. The range Qf temperature was from 1 350° to 1 450°C and of iron oxide concentration is from 5 to 90% . At the higher revolution s/Jeed of a rod, it has no ejJect on the reduction rate. Thus, in this range, the rate-determining step can be best inter/Jreted to be at the chemical reaction alld the reductioll rate -is pro/Jortional to the first order of the estimated activity of iron oxide contained in slags. The obtained rate equation is;
Journal Article•
Patent•
23 Dec 1974
TL;DR: In this paper, the processes for producing iron oxide products from a solution of ferrous salts selected from the group consisting of waste liquid containing ferrous salt and aqueous solution in which ferrous ions obtained from the waste liquid are dissolved, under acid, wet and high ferrous concentration conditions.
Abstract: The processes for producing iron oxide products from a solution of ferrous salts selected from the group consisting of waste liquid containing ferrous salts and aqueous solution in which ferrous salts obtained from the waste liquid are dissolved, under the acid, wet and high ferrous concentration conditions. More particularly, the processes for purifying said waste liquids comprising the bivalent iron removing steps.
Patent•
17 Jun 1974TL;DR: A fused and solidified iron oxide catalyst containing at least 96.5% of iron oxide having an atomic ratio of oxygen to iron of 1.2:1 to 1.4:1 is activated by heating in hydrogen and used for the hydrogenation of organic compounds especially of adiponitrile to hexamethylene diamine.
Abstract: A fused and solidified iron oxide catalyst containing at least 96.5% of iron oxide having an atomic ratio of oxygen to iron of 1.2:1 to 1.4:1 is activated by heating in hydrogen and used for the hydrogenation of organic compounds especially of adiponitrile to hexamethylene diamine.
Patent•
04 Jun 1974TL;DR: In this paper, a process for alkylating the ortho-position of a phenol compound is described, which involves bringing a compound containing at least one hydrogen atom at its ortho position and an alcohol into contact with a catalyst in the gaseous phase.
Abstract: A process for alkylating the ortho-position of a phenol compound which comprises bringing a phenol compound containing at least one hydrogen atom at its ortho-position and an alcohol into contact with a catalyst in the gaseous phase, said catalyst being selected from the group consisting of A. a mixture of iron oxide and silica in which the atomic ratio of Fe to Si is 100 : 0.03 - 200, and B. a mixture of iron oxide, silica and chromium oxide in which the atomic ratio of Fe to Si to Cr is 100 : 0.1 - 5 : 0.1 - 5.
TL;DR: There are many practical environments in which iron oxide, in the form of surface rust, may be exposed to atmospheres containing hydrogen sulphide at various concentrations, such as gas lines, chemical plant, distillation units, crude-oil cargo and storage tanks as discussed by the authors.
Abstract: THERE are many practical environments in which iron oxide, in the form of surface rust, may be exposed to atmospheres containing hydrogen sulphide at various concentrations. Gas lines, chemical plant, distillation units, crude-oil cargo and storage tanks are examples.
Patent•
ARCO1
TL;DR: In this paper, a method of regenerating used particulate contaminant-removing material, such as iron oxide or iron sulfide, that has been used to remove a contaminant such as arsenic, from a synthetic hydrocarbonaceous feed and effect deposition of the contaminant within the material, characterized by a multi-step process as follows.
Abstract: A method of regenerating used particulate contaminant-removing material, such as iron oxide or iron sulfide, that has been used to remove a contaminant, such as arsenic, from a synthetic hydrocarbonaceous feed and effect deposition of the contaminant within the material, characterized by a multi-step process as follows: (1) the used, or spent, contaminant-removing material is intimately contacted with a sulfur-containing material, such as hydrogen sulfide or sulfur, in an inert atmosphere of non-oxidizing fluid and at elevated temperature; (2) the contaminant deposited in the contaminant-removing material is reacted with the sulfur in the sulfur-containing material at the elevated temperature and the resulting sulfides of the contaminant; for example, arsenic sulfides; are converted to gaseous form to separate them from the regenerated contaminant-removing material; and (3) the sulfides of the contaminant are condensed and oxidized to form the oxides of the contaminant; for example, arsenic oxides. The oxides are, ordinarily, commercially desirable products that can be sold. Also disclosed are respective embodiments and the specific reaction conditions for carrying out the invention.
TL;DR: An aerosol generator has been constructed which produces submicronic iron oxide particles from the combustion of iron pentacarbonyl, Fe(CO)5. The particles reach the pulmonary alveolar surface where they are readily recognized by light and electron microscopy as discussed by the authors.
TL;DR: The formation of SrFe12O19 in the Fe2O3-Na2CO3-SrSO4 system was found to proceed through three stages as discussed by the authors, first an endothermic reaction between Fe 2O3 and Na 2CO3 to form Na2Fe2O4 and CO2, second an exo...
Abstract: The formation of SrFe12O19 in the Fe2O3–Na2CO3–SrSO4 system was found to proceed through three stages, first an endothermic reaction between Fe2O3 and Na2CO3 to form Na2Fe2O4 and CO2, second an exo...
Patent•
28 Jan 1974
TL;DR: Galvanic cell for measuring oxygen potential in furnace atmospheres uses a tubular solid electrolyte probe containing a mixture of iron and iron oxide as a standard electrode as mentioned in this paper, which is hermetically sealed by a layer of finely divided alumina, while shorting between conductors attached to the exterior and interior of the probe is inhibited by a bed of refractory sand.
Abstract: Galvanic cell for measuring oxygen potential in furnace atmospheres uses a tubular solid electrolyte probe containing a mixture of iron and iron oxide as a standard electrode. The interior of the cell is hermetically sealed by a layer of finely divided alumina, while shorting between conductors attached to the exterior and interior of the probe is inhibited by a bed of refractory sand in which one conductor is embedded.
Patent•
28 Mar 1974
TL;DR: A tubular electrode contains a feeding tube forming an annular passage between its outside and the inside of the electrode as discussed by the authors, which forms an arc between it and a carbonaceous iron bath in an enclosed hearth having a gas outlet.
Abstract: A tubular electrode contains a feeding tube forming an annular passage between its outside and the inside of the electrode. With the electrode forming a cathode, an arc is formed between it and a carbonaceous iron bath in an enclosed hearth having a gas outlet. Iron oxide material in flowable form is fed through the inner tube to the arc while a non-oxidizing gas is fed via the passage formed between the two tubes, to the arc. The carbonaceous iron bath is made the anode and the action of the current forms an upward bulge in the metal in the arc, gravitationally freeing the bath from any slag at the arc. In this way the iron oxide material is melt reduced, the iron component being continuously added to the bath which may be continuously tapped to provide a supply of crude iron.
TL;DR: In this article, a mechanism for the undercutting of scratched lacquers on black plate (uncoated low-carbon steel sheet) is proposed and some tests carried out to confirm it are summarized.
Abstract: A mechanism for the undercutting of scratched lacquers on black plate (uncoated low‐carbon steel sheet) is proposed. Experimental evidence leading to its postulation and some tests carried out to confirm it are summarized. It is believed that the undercutting at breaks in coatings on black plate is initiated by the electrochemical reduction of the air‐formed iron oxide film between metal and lacquer effectively to enlarge the break in the film. The subsequent corrosion of exposed steel results in the final undercutting. The stability to reduction of the chromium oxide in the chrome coating of TFS and the absence of iron oxide therein, are the reasons for the resistance of TFS to undercutting.
Patent•
02 Aug 1974TL;DR: In this paper, a pelletized iron ore or concentrates containing about 0.5 to about 3.0% silica, 0.1 to 1.5% bentonite and 96.0 to 99.0 % moisture is pelletised, the pellets are surface-coated with about 1 to about 4.5 % limestone and fired at a temperature of about 2100° to about 2400°F.
Abstract: Iron ore or concentrates containing about 0.5 to about 3.0% silica, 0.5 to 1.0% bentonite and 96.5 to 99.0% iron oxide together with 7.0 to 12.0% moisture is pelletized, the pellets are surface-coated with about 1 to about 4.5% limestone and fired at a temperature of about 2100° to about 2400°F., the formed pellets being suitable for direct reduction temperatures above 1400°F in a shaft furnace with a minimum of clustering.
Patent•
31 May 1974TL;DR: In this paper, a method of making a semi-transparent photomask of the iron oxide type comprising depositing a thin film of nickel or of a nickel alloy on a glass substrate, forming on the nickel or nickel alloy film a pattern of a resist which is the negative of the desired photomasks was proposed.
Abstract: A method of making a semi-transparent photomask of the iron oxide type comprising depositing a thin film of nickel or of a nickel alloy on a glass substrate, forming on the nickel or nickel alloy film a pattern of a resist which is the negative of the desired photomask, electrolytically depositing a layer of iron on the areas of the alloy film not covered by the resist, removing the resist and heating the assembly in an oxidizing atmosphere to convert the iron layer to iron oxide and also to convert the nickel or nickel alloy film to transparent oxides, at the same time providing improved adherence.
Patent•
11 Jun 1974
TL;DR: In this paper, the reduction is carried out in the final reducing zone under a pressure of from 3 to 30 atmospheres and at a temperature of from 600 DEG to 1,000 DEG C, using a reducing gas containing hydrogen and impurities.
Abstract: Lumpy or agglomerated materials containing iron oxide are reduced in shaft furnaces by treating such materials with hydrogen-containing reducing gases under elevated pressure The reduction is carried out in the final reducing zone under a pressure of from 3 to 30 atmospheres and at a temperature of from 600 DEG to 1,000 DEG C, using a reducing gas containing hydrogen and impurities consisting of, at most, 5 percent by volume carbon monoxide, 5 percent by volume carbon dioxide, 5 percent by volume methane, and 2 percent by volume steam
TL;DR: In this paper, chemical vapor deposition techniques were used to extract 5-10% divalent iron and large amounts of chemisorbed and chemically bonded CO 2, and the carbonate ion was decomposed by heating to 500°C and converted to well crystallized α-Fe 2 O 3.