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Showing papers on "Iron oxide published in 1969"


Journal ArticleDOI
TL;DR: In this paper, the infrared multiple reflectance spectra were used to record the growth of oxide films on copper and iron mirrors, and it was shown that the intensities of the infrared bands from the copper oxide and iron oxide films were directly proportional to the oxide film thickness.
Abstract: Infrared multiple reflectance spectra were used to record the growth of oxide films on copper and iron mirrors. Cuprous oxide and cupric oxide films were readily distinguished since they exhibit intense single bands at 640 cm−1 and ~560 cm−1, respectively. Iron oxide films of a single composition also exhibit highly characteristic bands in the 230 to 1100 cm−1 region of the reflectance spectra. Spectra of mixed iron oxide films were composed of many highly overlapping bands making quantitative interpretations difficult. The intensities of the infrared bands from the copper oxide and iron oxide films were directly proportional to the oxide film thicknesses. Using a seven reflection −73° incidence optical accessory, sensitivity to detect oxide films as thin as about 5Aa was achieved.

136 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effects of small additions of Fe2O3 to lead zirconate-lead titanate ceramics with compositions between 45 and 60 mol% lead ZIRconate and showed that the dielectric constant and dissipation factor for both rhombohedra1 and tetragonal materials were decreased by addition of iron oxide.
Abstract: An investigation of the effects of small additions of Fe2O3 to lead zirconate-lead titanate ceramics with compositions between 45 and 60 mol% lead zirconate has shown that, with 2 moles of PbO to balance each mole of Fe2O3, the solubility of Fe2O3 was about 0.8 wt% in compositions near the tetragonal-rhombohedra1 boundary. The dielectric constant and dissipation factor for both rhombohedra1 and tetragonal materials were decreased by addition of iron oxide, whereas the mechanical quality factor and frequency constant were increased. The dependence of the electromechanical properties on grain size was qualitatively similar for both undoped and iron oxide-doped materials; the presence of iron oxide inhibited grain growth and lowered the limiting grain size below which the electromechanical properties change rapidly with grain size.

121 citations


Journal ArticleDOI
TL;DR: Data strongly support the view that ferric iron is acting as an hydrogen acceptor in respiration, competing with nitrate for electrons that are mediated by the enzyme nitrate reductase.
Abstract: The occurrence of the iron-reducing phenomenon among some common fungi was studied. Results indicated that (i) the reduction of ferric iron to the ferrous state by fungi seems to be restricted to nitrate reductase-inducible strains such as Actinomucor repens, Alternaria tenuis, Fusarium oxysporum, and F. solani and (ii) the amount of dissolved ferrous iron may be reduced progressively by increasing the amount of nitrate added to the medium. Compared with a complex medium (Sabouraud medium), less iron became reduced if NO(3) was the only nitrogen source (Czapek Dox medium). These data strongly support the view that ferric iron is acting as an hydrogen acceptor in respiration, competing with nitrate for electrons that are mediated by the enzyme nitrate reductase. The significance of this property from an ecological viewpoint is discussed.

83 citations



Journal ArticleDOI
TL;DR: In this article, it is inferred that under favorable interstitial chemical conditions the iron oxide coatings age to hematite and the clay undergoes postdepositional alteration, yielding additional iron which ultimately forms additional hematitic pigment.
Abstract: Surface weathering on the Sonoran desert produces iron-bearing clay minerals which are concentrated in fine-grained sediments eroded from the desert. The clay fraction of the desert soils and desert-derived alluvium contains an average of about 4.5 percent total iron. An average of less than 1.0 percent iron occurs in oxide coatings on grains; the remainder is held in the clay-mineral lattices. It is inferred that under favorable interstitial chemical conditions the iron oxide coatings age to hematite and the clay undergoes postdepositional alteration, yielding additional iron which ultimately forms additional hematite pigment. Biotite, another important source of iron, commonly is associated with the clay and undergoes similar intrastratal alteration. It is concluded that the characteristic concentration of iron and hematite pigment in mudstones and shales in many ancient red beds, particularly in red beds that are associated with evaporites or aeolian sandstones, or both, reflects initial concentration of iron-bearing clay minerals and biotite in fine-grained sediments derived from desert source areas.

57 citations


Journal ArticleDOI
R.S. Montgomery1
01 Aug 1969-Wear
TL;DR: In this article, the main processes involved in run-in of cast iron are smoothing of the surface and formation of a surface coating derived largely from the graphite in the metal structure and iron oxide (Fe3O4).

44 citations


Journal ArticleDOI
01 Apr 1969-Nature
TL;DR: In this article, the 57Fe Mossbauer effect of two iron-manganese nodules in which the iron oxide phase could not be detected by X-ray or electron diffraction was investigated.
Abstract: IRON-MANGANESE nodules from the ocean floor have been extensively studied1–6 But, because of the fine grain size of the particles of the nodules, structural identification by X-ray and electron diffraction techniques is difficult and the mineralogy of the iron oxide phase has not been well characterized The observation of the Mossbauer spectrum—in which each nucleus absorbs γ-rays independently—is not limited by particle size in the same way as is the observation of Bragg peaks in diffraction measurements, in which radiation must be scattered coherently from a large number of atoms The magnetic hyperfine splitting in the Mossbauer spectrum of magnetic materials is affected, however, when the particles are so small that they become superparamagnetic7–10 We describe here an investigation using the 57Fe Mossbauer effect of two iron–manganese nodules in which the iron oxide phase could not be detected by X-ray or electron diffraction

38 citations


Journal ArticleDOI
TL;DR: In this paper, the preparation of submicroscopic elongated iron particles by pseudomorphic reduction of α-FeOOH with hydrogen has been studied, and it has been found that the reduction rate at low temperatures can be increased, and hence sintering diminished, by absorption of Ag+ or Co+ ions on the surface of the iron oxide particles, leading to iron powders with improved magnetic properties.
Abstract: The preparation of submicroscopic elongated iron particles by pseudomorphic reduction of α-FeOOH with hydrogen has been studied. At a temperature of 350°C rapid sintering occurs of the iron particles formed. At temperatures below 300°C sintering is largely absent but the reaction is too slow. It has been found that the reduction rate at low temperatures can be increased, and hence sintering diminished, by absorption of Ag+ or Co+ ions on the surface of the iron oxide particles, leading to iron powders with improved magnetic properties. When Sn2+is adsorbed the reaction rate decreases. Yet the coercivity of the iron powders obtained is considerably increased, probably also due to a diminished sintering.

33 citations


01 Jan 1969
TL;DR: In 2018, domestic production and use of iron oxide pigments (IOPs) decreased in 2018 from that of 2017 by three companies in three States as mentioned in this paper, with an estimated value of $74 million, significantly below the peak of 88,100 tons in 2007.
Abstract: Domestic Production and Use: Iron oxide pigments (IOPs) were mined domestically by three companies in three States. Production, which was withheld to avoid disclosing company proprietary data, decreased in 2018 from that of 2017. Six companies, including the three producers of natural IOPs, processed and sold about 52,000 tons of finished natural and synthetic IOPs with an estimated value of $74 million, significantly below the most recent sales peak of 88,100 tons in 2007. About 55% of natural and synthetic finished IOPs were used in concrete and other construction materials; 20% in coatings and paints; 5% in foundry sands and other foundry uses; 3% each in animal food and industrial chemicals; 2% each in cosmetics and plastics;1% in glass and ceramics; and 9% in other uses.

33 citations



Patent
10 Oct 1969
TL;DR: In this article, the authors removed the slime from gas mixture by contacting the mix-tures with an ABSORBENT COMPRISING IRON OXIDE and FLY ASH.
Abstract: HYDROGEN SULFIDE IS REMOVED FROM GASEOUS MIXTURES BY CONTACTING THE MIXTURES AT ELEVATED TEMPERATURE WITH AN ABSORBENT COMPRISING IRON OXIDE AND FLY ASH.

Journal ArticleDOI
TL;DR: The catalytic activity and the sintering property of iron oxide catalysts with and without potassium additives have been studied in this article and the effects of the promoter can be classified as structural and synergetic.
Abstract: The catalytic activity and the sintering property of iron oxide catalysts with and without potassium additives have been studied. The potassium oxide acts as a promoter and is effective under given conditions in increasing the activity of the catalyst from four to ten times. The effects of the promoter can be classified thus: (1) Structural promoter: The increase in the apparent bulk density and the shrinkage of the catalyst tablet upon calcination during the preparation of the catalyst are prevented by potassium additives. The differences in the specific surface area and in the pore volume of the catalyst between with and without potassium promoter are slight. These effects on iron oxide appear to be caused largely by the formation of K2Fe22O34. (2) Synergetic promoter: The potassium promoter changes the apparent energy of activation of the dehydrogenation reaction from 28 to 43 kcal/mol. The increase in the catalytic activity is due to the increase in the pre-exponential factor. The increase in the fact...

Patent
20 Oct 1969
TL;DR: In this article, the authors present a blend of additives, such as AMMONIUM HYDROXIDE, MINERAL ACID SUCH as HYDROCHLORIC ACID, CARBOHYDRATE BINDER SUCH AS MOLASSES, and WATER, providing the necessary low-temperATURE strength until a CERAMIC BOND is ESTABLISHED.
Abstract: IRON OR IRON OXIDE FINES SUCH AS BOF DUST, IRON ORE, AND MILL SCALE ARE FORMED INTO STRONG CERAMIC BONDED COMPACTS SUITABLE AS RAW MATERIAL FEED FOR STEEL MAKING OPERATIONS, E.G. BLAST FURNACE FEED. A NOVEL COMBINATION OF ADDITIVES, AMMONIUM HYDROXIDE, A MINERAL ACID SUCH AS HYDROCHLORIC ACID, A CARBOHYDRATE BINDER SUCH AS MOLASSES, AND WATER, PROVIDE THE NECESSARY LOW TEMPERATURE STRENGTH UNTIL A CERAMIC BOND IS ESTABLISHED. THE COMPACTS ARE FORMED FROM THE COHESIVE MASS, PREFERABLY BY EXTRUSION, DRIED AND FIRED IN A CONVENTIONAL MANNER.

Patent
29 Jan 1969
TL;DR: In this paper, a method of pre-preparing MAGNETICALLY STABLE IRON POWDER SUITABLE for magnetic recording in which IRON OXIDE HYDRATE, A-FEOI(OH) is PRECIPITATED from a STRONGLAING ALKALINE SOLUTION of FERROUS HYDROXIDE CONTAINING at LEAST ONE COMPOUND OF At LEAST One COMPOUND of at least one METAL SELECTED from the Group CONSISTING of GERMANIUM, TIN and ALUMIN
Abstract: A METHOD OF PREPARING MAGNETICALLY STABLE IRON POWDER SUITABLE FOR MAGNETIC RECORDING IN WHICH IRON OXIDE HYDRATE, A-FEOI(OH) IS PRECIPITATED FROM A STRONGLY REACTING ALKALINE SOLUTION OF FERROUS HYDROXIDE CONTAINING AT LEAST ONE COMPOUND OF AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF GERMANIUM, TIN AND ALUMINUM IN SUCH A CONCENTRATION THAT THE ATOMIC RATION OF THE LATTER METAL TO FE IN THE SOLUTION IS A LEAST 0.005 WHILE PASSING AN OXIDIZING GAS THROUGH THE SOLUTION. THE PRECIPITATE IS THEREAFTER SEPARATED FROM THE LIQUID, WASHED, DRIED, AND REDUCED IN HYDROGEN AT 250* TO 500* C.

Journal ArticleDOI

Patent
George Ratcliffe Eric1
16 Jan 1969
TL;DR: Pigment-grade ferric oxide is precipitated from a solution of a ferrous salt by aerating at ambient temperature while introducing substantially two equivalents of base at such rate as to maintain the pH between 5 and 6.
Abstract: Pigment-grade ferric oxide is precipitated from a solution of a ferrous salt by aerating at ambient temperature while introducing substantially two equivalents of base at such rate as to maintain the pH between 5 and 6.

Journal ArticleDOI
M Shelef1, K Otto1
TL;DR: In this paper, a dilute mixture of CO, O2 and NO in helium is passed over a catalyst consisting of iron oxide supported on carbon and a characteristic selectivity in the overall process is observed.

Patent
26 Feb 1969
TL;DR: In this article, an iron powder suitable for use as a magnetic recording medium is prepared by first subjecting a finely divided iron oxide or oxyhydrate such as Alpha -Fe203, gamma -Fe1903, Alpha-Fe00H, gamma-Fe304 or Fe304 to the action of a 0.002 to 1 molar solution in water of stannous chloride and thereafter reducing the iron oxide in hydrogen, followed by stabilizing the iron powder thus obtained.
Abstract: Iron powder suitable for use as a magnetic recording medium is prepared by first subjecting a finely divided iron oxide or oxyhydrate such as Alpha -Fe203, gamma -Fe203, Alpha -Fe00H, gamma -Fe00H or Fe304 to the action of a 0.002 to 1 molar solution in water of stannous chloride and thereafter reducing the iron oxide or oxyhydrate, preferably in hydrogen, followed by stabilizing the iron powder thus obtained.


Patent
16 Jun 1969
TL;DR: In this article, a process for removing PETROLEUM HYDROCARBONS from the surface of fresh or SALINE water by dispersing MAGNETIC IRON OXIDE in the PRESENCE of WETTING AGENT on the SURFACE of OIL-CONTAMINATED WATER, and REMOVING OILADSORBED METALLIC PARTICLES by means of MAGNETic ATTRACTION was described.
Abstract: A PROCESS FOR REMOVING PETROLEUM HYDROCARBONS FROM THE SURFACE OF FRESH OR SALINE WATER BY DISPERSING MAGNETIC IRON OXIDE IN THE PRESENCE OF WETTING AGENT ON THE SURFACE OF OIL-CONTAMINATED WATER, AND REMOVING OIL-ADSORBED METALLIC PARTICLES BY MEANS OF MAGNETIC ATTRACTION.

Journal ArticleDOI
TL;DR: A 56-day survey of suspended paniculate and iron concentrations in the Windsor area is reported in this paper, where the two pollutants show different spatial patterns due to the presence of very local sources of iron oxide.




Journal ArticleDOI
TL;DR: A review of the iron-oxide reduction research at the University of Toronto can be found in this paper, where the authors focus on the kinetics of hydrogen reduction of sintered briquettes made from reagent grade iron oxide with and without small additions of impurities.

Patent
03 Nov 1969
TL;DR: In this paper, an ALUMINOTHERMIC REACTIVE MIXTURE consisting of at least one metal-reducible oxide and one non-aluminum oxide having a particle size in the range of about 0.05 to 50 U.
Abstract: THIS INVENTION RELATES TO AN ALUMINOTHERMIC REACTION MIXTURE CONSISTING ESSENTIALLY OF ALUMINUM AND IRON OXIDE AND CONTAINING ABOUT 0.1 TO 5 PERCENT BY WEIGHT, BASED ON THE TOTAL WEIGHT OF THE MIXTURE, OF AT LEAST ONE ALUMINOTHERMICALLY REDUCIBLE OXIDE HAVING A PARTICLE SIZE IN THE RANGE OF ABOUT 0.05 TO 50U.

Patent
16 Dec 1969
TL;DR: In this article, a method of producing active electrode material consists of fusing an elemental sulfur, selenium, or tellurium additive coating onto iron oxide and/or hydrated iron oxide, within a temperature range dependent on the melting point of the additive.
Abstract: A method of producing active electrode material consists of fusing an elemental sulfur, selenium, or tellurium additive coating onto iron oxide and/or hydrated iron oxide, within a temperature range dependent on the melting point of the additive.


Patent
31 Jul 1969
TL;DR: In this paper, the mixtures of hydrogen and carbon monoxide are adjusted to maintain a continuously increasing H2:CO ratio in the direction the charge passes through the vertical reduction zone while maintaining about the same temperature, below about 1,100* C., throughout the entire reduction zone.
Abstract: Molten iron is produced directly from high grade iron oxide ore by the direct reduction in a vertical shaft furnace of preheated ore with hydrogen and carbon monoxide gaseous mixtures. The mixtures of hydrogen and carbon monoxide are adjusted to maintain a continuously increasing H2:CO ratio in the direction the charge passes through the vertical reduction zone while maintaining about the same temperature, below about 1,100* C., throughout the entire reduction zone.

Patent
24 Nov 1969
TL;DR: A TITANIUM DIOXIDE CONCENTRATE as mentioned in this paper was used for chlorination FEED MATERIALs in the early 1800s, where it was used as a chloreination feed mill.
Abstract: A TITANIUM DIOXIDE CONCENTRATE SUITABLE FOR USE AS CHLORINATION FEED MATERIAL IS PRODUCED BY AN OXIDATION-LEACH ING PROCESS WHEREIN THE METALLIC IRON IS AN UPGRADED METALLIZED ILMENITE HEREINAFTER REFERRED TO AS A METALLIZED ORE CONCENTRATE, IS LEACHED OUT OF THE METALLIZED CONCENTRATE BY VIGOROUSLY AGITATING THE LATER IN AN AQUEOUS SOLUTION CONTAINING FERROUS AND FERRIC IONS AND IN THE PRESENCE OF AIR OR OXYGEN WHEREBY THE METALLIC IRON IS OXIDIZED TO SOLUBLE FERROUS IRON WHICH IS WASHED OUT OF THE DISCRETE PARTICLES OF METALLIZED ORE CONCENTRATE WITH MINIMAL LOSS OF TI02 VALUES AND THEREAFTER OXIDIZED TO FORM SOLID PARTICULATE IRON OXIDE WHICH IS SEPARTED FROM THE RESIDUAL TI02 CONCENTRATE BY FILTRATION. THE PROCESS MAY BE A BATCH TYPE OPERATION BUT IS PREFERABLY A CONTINUOUS OPERATION WHEREIN THE FILTRATE CONTAINING FERROUS OR FERRIC IONS IS RECOVERED AND RECYLED IN WHOLE OR IN PART TO LEACH ADDITIONAL METALLIZED ORE CONCENTRATE.