Showing papers on "Iron oxide published in 1970"

Nucleation and Growth of Iron Oxides in Olivines, (Mg,Fe)2SiO4

Abstract: Iron-rich olivines have been oxidized in air in the laboratory and the mechanism of their breakdown has been elucidated using X-ray diffraction and electron microscopy. Low-temperature oxidation (500–800 °C) produces well-oriented hematite- and magnetite-like precipitates together with amorphous silica. The reaction is a cellular one in which thin needles of oxide about 50–100 A apart grow into the matrix separated by regions of amorphous silica. Nucleation of spherical colonies of the iron oxide and silica occurs on dislocations. Although the hematite or magnetite always shows the same topotactic relationship with the matrix, the direction in which the needle-like precipitates grow is determined by the orientation of the nucleating dislocation. The small size and highly distorted nature of these precipitates accounts for the diffuseness of their X-ray reflections. Oxidation at 1000 °C produces undistorted equiaxed grains of the oxides about 0·2 μm in size. They are surrounded by silica, which produces a disordered electron diffraction pattern. As the temperature is raised, the silica achieves more structural order and the oxide grains increase in size.

Neutralization of ferrous iron-containing acid wastes

Abstract: Ferrous iron-containing acid waste waters are neutralized to form a dense, compact, and easily settleable sludge. Ferrous to ferric iron ratios are adjusted prior to neutralization by catalytic oxidation to conform approximately to that of magnetite; 1Fe to 2Fe . Neutralization of the acid waste and precipitation of a mixed valence iron oxide is accomplished using a finely divided limestone slurry as the preferred neutralizing agent.

Amorphous Iron Oxide Precipitates in Sediments Cored during Leg 5, Deep Sea Drilling Project

Abstract: The sediment column at Sites 37,38 and 39, Leg 5, of the Deep Sea Drilling Project (locality map, Figure 1) is dominantly a dark brown unconsolidated "mud", composed in part of a non-crystalline iron oxide mineral. X-ray diffraction studies by Rex (this volume) verify its non-diffracting, amorphous nature. This ferruginous material appears identical to metal oxide precipitates described by Bostrom and Peterson (1966), Bostrom et al. (1969), and Bostrom and Peterson (1969) which were associated with areas of high heat flow near the crest of the mid-ocean ridge system, particularly the East Pacific Rise. It is also similar, at least in textural detail, to the so-called Amorphous Goethite Facies of the Red Sea metalliferous sediments, described by Bischoff (1969). In all documented cases, these unusual sediments appear to be associated with the mid-ocean ridge system or with related rift structures. If the hypothesis of sea-floor spreading is correct, then such a metal-rich facies would be expected to occur as a basal deposit immediately overlying basaltic "oceanic basement" in many areas of the ocean basins. Site 9, Leg 2, of the Deep Sea Drilling Project encountered hematite-rich sediments just above igneous rock, and this occurrence was interpreted by Peterson et al, 1970, as being due to precipitation near hydrothermal sources at a prior oceanic ridge crest. The fact that basal iron-rich sediments were also encountered at Sites 37, 38 and 39, Leg 5, of the Deep Sea Drilling Project in areas remote from a present-day ridge system calls for a detailed description of the mineralogical and sedimentological associations occurring at these sites.

Method of and apparatus for reducing iron oxide to metallic iron

Abstract: This invention relates to a method and apparatus for reducing iron oxide to metallic iron, utilizing a continuous process employing a reducing gas with a high H2 and CO content made by catalytically reforming a mixture of gaseous hydrocarbon and reacted off-gas from the reduction process. The CO2 plus H2O present in the reacted off-gas are utilized as the hydrocarbon reforming oxidant, without the addition of reforming oxidant from an external source.

Reduction of iron oxide minerals by a marine Bacillus

Abstract: Bacillus 29, previously isolated from a ferromanganese nodule, and a derivative strain,Bacillus 29A, were examined for their iron-solubilizing ability when reducing limonite, goethite and hematite with glucose.Bacillus 29A was the more active of the two cultures. It solubilized larger amounts of iron from limonite and goethite than from hematite. Several lines of evidence indicated that the mechanism by whichBacillus 29A carried out iron solubilization from limonite involved enzymatic reduction of the ferric iron in the mineral. Phenosafranin enhanced the reduction of the iron oxides by growing cultures, but anaerobiosis did not.

Method and arrangement for purifying water drawn from a ground-water well

Abstract: THE PRESENT INVENTION CONCERNS A METHOD FOR PURIFYING WATER DRAWN FROM A GROUND-WATER WELL, MOST SUITABLY FROM A DEEP WELL, FROM IRON BY INTRODUCING IN THE WATER OXYGEN OR AN OXYGEN-RELEASING SUBSTANCE AND BY FILTERING TO REMOVE THE IRON OXIDE WHICH IS PRECIPITATED. THE METHOD IS CHARACTERIZED IN THAT INTO THE GROUND WATER-CARRYING SOIL LAYER SURROUNDING THE WELL FEED WATER IS FED WHICH CONTAINS OXYGEN OR AN OXYGEN-RELEASING SUBSTANCE.

Heats of Preferential Adsorption of Boundary Additives at Iron Oxide/Liquid Hydrocarbon Interfaces

Abstract: Studies of preferential adsorption of several polar compounds from dilute solutions in n-heptane and n-hexadecane onto iron and iron oxides have been carried out using the flow microcalorimeter. The polar compounds studied included normal alcohols and carboxylic acids with alkyl chains ranging from 4 to 18 carbon atoms and a surface active material extracted from a mineral oil. The heats of adsorption suggest that on several iron oxides the long-chain compounds form adsorbed films composed of vertically oriented molecules, not always close-packed. The orientation of adsorbed molecules appear to differ markedly with the nature of substrate and concentration. Some substrates such as iron oxides, promote vertical orientation of alkyl chains as evidenced by relatively high heats of preferential adsorption. Iron surfaces formed under liquid hydrocarbon in the absence of oxygen possess a relatively low surface energy on which the long-chain molecules are adsorbed with very much less energy than on iron oxides. ...

Iron nitride,fe4n,as a material for magnetic recording and method of manufacturing same

Abstract: IT IS PROPOSED TO USE A POWDER OF IRON NITRIDE, FE4N, CONSISTING OR ROD-SHAPED PARTICLES AND HAVING A LONGITUDINAL AXIS OF FROM 0.5 TO 2 MICRONS, WHICH LONGITUDINAL AXIS IS AT LEAST 5 TIMES AS LONG AS THE LARGEST DIAMETER OF ANY CROSS-SECTION OF THE PARTICLE IN QUESTION AT RIGHT ANGELS TO SAID AXIS, AS A MATERIAL FOR MAGNETIC RECORDING. THE INVENTION FURTHERMORE RELATES TO A METHOD OR PREPARING SUCH A POWDER. ACCORDING TO THIS METHOD, A POWDER OR IRON OXIDE OR IRON OXIDE HYDRATE, THE PARTICLES OF WHICH HAVE APPROXIMATELY THE SAME SHAPE AND DIMENSIONS AS THE ABOVE-MENTIONED IRON NITRIDE PARTICLES, IS REACTED IN A FLUID BED AT A TEMPERATURE BETWEEN 350*C. AND 400* C. WITH A MIXTURE OF HYDROGEN AND AMMONIA. IF DESIRABLE, THE IRON NITRIDE FORMED IS SUBSEQUENTLY TREATED IN THE SAME FLUID BED WITH A WEAKLY OXIDIZING GAS MIXTURE SO AS TO STABILIZE IT, THAT IS TO SAY, DEPRIVE IT OF ITS PYROPHORIC PROPERTIES.

Process for beneficiation of titaniferous ores

Abstract: Process for beneficiating titaniferous ores to produce essentially pure titanium dioxide comprising alternatingly contacting the ore in a gas-solids reactor with carbon monoxide for a short period of time and then with chlorine for a short period of time and then repeating the alternate carbonylation and chlorination steps at temperatures of 700 to 1,150* C. under fluidizing conditions; converting iron oxide and oxides of metals other than titanium in the ore to iron and other metal chlorides and removing same by volatilization. The titanium dioxide produced is useful as a starting material for the preparation of titanium dioxide pigment.

Activity-composition relations at 1100°C in the system calcium oxide-iron oxide-manganese oxide in contact with metallic iron

Abstract: The extent of the solid miscibility gap in the system CaO−“FeO”−MnO at 1100°C has been determined termined by electron microprobe, point-counting, and X-ray diffraction analysis of coexisting phases within the miscibility gap. Activities of FeO in ternary solid solutions have been determined at 1100°C by equilibrating the solid solutions with metallic iron and a gas phase of known oxygen pressures. Activity-composition curves for CaO and MnO in the ternary system are calculated from a Gibbs-Duhem integration, and the data are extrapolated to the binary system CaO−MnO, which is shown to display a considerable positive deviation from ideality at 1100°C.

Magnetic recording tape

Abstract: MAGNETIC RECORDING TAPE HAVING A COATING OF ORIENTED MAGNETIZABLE PARTICLES IN A BINDER AFFORDING SUPERIOR ABILITY TO STORE HIGH FREQUENCY INFORMATION BY VIRTUE OF ORIENTED MAGNETIZABLE ACICULAR IRON OXIDE PARTICLES MODIFIED WITH SMALL AMOUNTS OF COBALT OXIDE, WHICH IRON OXIDE PARTICLES COMPRISE GAMMA-FE2O3. AT APPROXIMATELY TWO PARTS BY WEIGHT PER ONE PART OF BINDER AND PHYSICALLY ALIGNED, THE NOVEL PARTICLES PROVIDE IN THE ALIGNED DIRECTION A COERCIVITY HC EXCEEDING 350 OERSTEDS AND A BR EXCEEDING 800 GAUSS. HIGHER COERCIVITY MAY BE ATTAINED BY CONTROLLING THE HEATING STEPS IN MAKING THE NOVEL PARTICLES TO PROVIDE UP TO ABOUT 25% FEO BY WEIGHT OF THE TOTAL IRON OXIDE.

Barium promoted iron oxide for use as a catalyst in steam-iron process for producing hydrogen

Abstract: Barium is incorporated with iron oxide to prepare a catalyst or contact mass for use in steam-iron process for producing hydrogen. A process for producing hydrogen using such catalyst is set forth.

Single and polycrystalline semiconductors

Abstract: A class of either single crystal or polycrystalline ferromagnetic materials containing an iron oxide whose resistivity vs. temperature characteristic is such that the resistivity decreases substantially with increasing temperature. The class has non-linear current-voltage (I-V) properties (when employed in electric circuit devices) characterized by a high resistance branch and a negative resistance branch, and the class also exhibits binary characteristics in that devices embodying materials of the class can be made to operate either in a memory state (low resistance) or a normal state (high resistance). The material of the class is prepared by a process which modifies the electrical conductivity of the iron oxide, which is originally highly insulating and also ferromagnetic, to render the material slightly conductive or semiconductive. In the insulating state the oxide contains iron in the trivalent state (Fe3 ). The process includes reduction of the iron in the insulating oxide either by heat treating in a vacuum or a controlled atmosphere gas or by doping to reduce some of the trivalent iron (Fe3 ) to bivalent iron (Fe2 ). The material properties are such that when said devices are operated in either the negative resistance branch or in the memory state the ferromagnetic curie point of the material is exceeded and the ordered magnetic properties of the material are locally destroyed. The local destruction can be sensed optically or by other means. The materials of the class disclosed may be used simply in conductive devices, but they can also be used in apparatus, as, for example, the matrices discussed hereinafter, which employ their multi-faceted electrical characteristics as well as their magnetic properties. Materials, which exhibit characteristics of the high resistance branch and the negative resistance branch and are ferroelectric, are also disclosed, as are, also, iron oxide materials which exhibit such characteristics and are neither ferromagnetic nor ferroelectric.

Thin films of alpha fe2o3 and method of forming

Abstract: A METHOD OF MAKING THIN FILMS OF ALPHA FE2O3 BY APPLYING TO AN UNHEATED SUBSTRATE A FILM OF A HIGHLY PERMEABLE NON-CRYSTALLINE FORM OF IRON OXIDE BY SUBJECTING THE SUBSTRATE TO VAPOR PRODUCED BY EVAPORATING A SOURCE OF IRON OXIDE AT A PRESSURE LESS THAN 10-4 TORR AND THEREAFTER HEATING THE DEPOSITED FILM IN AN OXIDIZING ATMOSPHERE AT A TEMPERATURE OF AT LEAST 425*C. FOR A PERIOD OF TIME SUFFICIENT TO CONVERT IT TO A STABLE, CRYSTALLINE FILM OF HEMATITE, ALPHA FE2O3. A FILM OF HEMATITE SO FORMED HAVING A THICKNESS IN THE RANGE OF 1000 A.-3600 A. ON A SUBSTRATE OF TRANSPARENT, ALKALI-FREE GLASS MAY BE PATTERNED TO FORM A MICROCIRCUIT MASK HAVING INCREASED TRANSMISSION IN THE VISIBLE PORTION OF THE SPECTRUM.

Inhibition of iron-catalyzed neopentyl polyol ester thermal degradation through passivation of the active metal surface by tricresyl phosphate

Abstract: To investigate the role of tricresyl phosphate (TCP) in inhibiting the iron-catalyzed thermal degradation of a neopentyl polyol ester gas turbine lubricant base stock, various TCP/ester combinations were encapsulated in mild steel tubing and heated at 500 F up to 96 hours. The relative degradation rates of the individual mixtures were measured by monitoring the effusion site of hydrogen (a degradation byproduct) through the capsule all. The capsule interiors were then examined by electron microscopy and diffraction to determine whether correlation assisted between the features of the surface films formed and the reserved degradation rates. Distinctive films were produced in each test mixture. When ester degradation was inhibited by the addition of 2–10% TCP, characteristic iron oxide layer was always found at the ester/steel interface. It was postulated that TCP induces the formation of this film, that the film is the agency of inhibition, and that it is similar in action and genesis to the iron oxide pas...

Apparatus for direct reduction of iron oxide compacts

Abstract: Apparatus for the direct reduction of iron oxides in compact form by preheating iron oxide compacts and enveloping them in hot inert particulate solids at the top of a columnar reactor then passing the mixture downwardly through the reactor countercurrent to an upward flow of natural gas that is introduced into the reactor bottom. Contact of the natural gas and the compacts with the hot solids results in reformation of the natural gas by reaction with carbon dioxide and the production of hydrogen and carbon monoxide, which hydrogen and carbon monoxide reduce the iron oxide of the compacts. Hot gases from the reactor are passed upwardly through a preheater for incoming iron oxide pellets and are then cooled, cleaned, and a portion returned to the bottom of the reactor. The reduced heated compacts are separated from the inert solids at the bottom of the reactor and are passed countercurrent to the natural gas that is being conducted to the reactor to heat it prior to introduction of the gas into the reactor bottom.

Production of metal pellets from metallic oxides

Abstract: A process and apparatus for producing pellets of iron from finely divided iron oxide materials is provided in which the process includes: (1) admixing the finely divided iron oxide materials with alkaline earth metal oxides or hydroxides; (2) forming pellets of the admixture; (3) simultaneously drying and carbonating the pellets; and, (4) reducing the iron oxide materials to iron. Moreover, to produce steel from the finely divided iron oxide materials, the reduced pellets are immediately charged into a conventional steelmaking furnace.

Method and apparatus for carbonizing and desulfurizing coal-iron compacts

Abstract: Method and apparatus for preparing compacts of an iron and carbonized coal having a low sulfur content Coal and iron oxide or metallic iron are formed into compacts, heated, and contacted within an enclosed reactor with a gas containing elemental hydrogen Hydrogen sulfide is formed by reaction of the hydrogen with sulfur in the compacts and off-gasses are formed from this reaction and from carbonization of the coal The hydrogen sulfide is separated from the off gases and a portion of the off gases returned to the enclosed reactor Desulfurized compacts are discharged from the reactor and contain carbonized coal and iron metal, the compacts being low in sulfur content and especially useful in metallurgical processing

Method of preparing a magnetically stable metal powder consisting mainly of iron and meant for magnetic recording

Abstract: THE INVENTION RELATES TO A METHOD OF PREPARING METAL POWDERS MAINLY CONSISTING OF IRON AND MEANT FOR MAGNETIC RECORDING BY REDUCTION OF AN IRON OXIDE OR AN IRON OXIDE HYDRATE AND IS CHARACTERIZED IN THAT A MEASURED UANTITY OF SILVER IS PREVIOUSLY DEPOSITED ON THE MATERIAL TO BE REDUCED. AS A RESULT OF THIS THE REDUCTION SPEED IS ALSO CONSIDERABLY INCREASED SO THAT THE REDUCTION OCCURS AT SPEEDS WHICH CAN BE USED IN PRACTICE ALSO AT TEMPERATURES LOWER THAN THOSE AT WHICH SINTERING OF THE FORMED METAL PARTICLES WHICH IS DISTURBING FOR THE APPLICATION IN VIEW TAKES PLACE.

Process for preparing a chromium-promoted iron oxide catalyst

Abstract: HIGH TEMPERATURE SHIFT CATALYSTS COMPRISING IRON OXIDE ARE PREPARED FROM SOLUTIONS OF SOLUBLE IRON SALTS BY PRECIPITATION WITH AN ORGANIC ACID REAGENT, SUCH AS OXALIC ACID, GIVING PRECIPITATES IN A VERY COARSE, EASILY-WASHED FORM. TREATMENT OF THE WELL-WASHED PRECIPITATE WITH ALKALLI REGENERATES THE ORGANIC ACID REAGENT AND GIVES A HIGHLY FLOCCULENT IRON OXIDE OF HIGH SPECIFIC SURFACE AND EXTREMELY LOW SULPHUR CONTENT. THIS IS PARTICULARLY SUITABLE FOR PROMOTION WITH PBO, WHICH IS NOTED AS BEING VERY SENSITIVE TO SULPHUR CONTAMINATION.

Catalytic formation of double bonds

Abstract: IN THE IODINE-CATALYZED OXIDATIVE DEHYDROGENATION OF ORGANIC COMPOUNDS, IT HAS BEEN FOUND THAT THE USE OF CATALYST PROMOTER COMPOSITIONS CONSISTING ESSENTIALLY OF ABOUT 0.01 TO 1 PERCENT BY WEIGHT VANADIA OR IRON OXIDE ON AN INERT SUPPORT INCREASES CONVERSIONS AND YIELDS AT LOWER DEHYDROGENATION TEMPERATURES.

Preparation of titanium dioxide concentrates and iron oxide pigments from ilmenite

Abstract: ILMENITE, PREFERABLY AFTER PRE-OXIDATION, IS REDUCED TO CONVERT IRON OXIDE CONTAINED THEREIN TO IRON, THE ILLMENITE IS TREATED WITH NITROBENZENE AT ABOUT 20 TO 100*C. AND A PH OF 3 TO 7 OXIDIZE THE IRON TO IRON OXIDE PIGMENT WHICH CAN BE SEPRATED IN RELATIVELY PURE FORM FROM THE TITANIUM DIOXIDE CONCENTRATE. THE CONCENTRATE IS THEN PREFERABLY LEACHED WITH ACID TO REMOVE RESIDUAL IRON IMPURITIES AND LEAVE A RELATIVELY PURE TITANIUM DIOXIDE SUITED FOR CHLORINATION. MODIFYING AGENTS PRESENT DURING THE NITROBENZENE OXIDATION WILL AFFECT THE COLOR OF THE IRON OXIDE PIGMENT. TO FACILITATE CLEAN SEPARATION OF THE IRON OXIDE PIGMENT FROM THE TITANIUM DIOXIDE CONCENTRATE THE REDUCED ILMENITE SHOULD NOT CONTAIN AN APPRECIABLE AMOUNT OF PARTICLES WITH GRAIN SIZES OF LESS THAN ABOUT 40 MICRONS.

Process for treating low-iron nickeliferous ores

Abstract: Low iron nickeliferous weathered serpentine is mixed with an iron oxide bearing additive material. The mixture is calcined under controlled reducing conditions to convert contained nickel values to a leachable stage. The calcine material is then leached with an aqueous ammoniacal ammonium carbonate solution in contact with free oxygen containing gas to extract nickel values. The additive is substantially free of substances which would contaminate the leach solution and is substantially free of nickel or contains nickel in such form or amount that the additive is not, in itself, amenable to treatment by the above described calcining and leaching process. The additive is added in an amount sufficient to provide an iron content in the mixture of up to about 60% by weight.

Technique for the preparation of iron oxide films by cathodic sputtering

Abstract: A technique for the preparation of iron oxide films designed for use as photomasks for thin film and semiconductor processing involves sputtering iron in a carbon monoxide ambient containing carbon dioxide upon a substrate member.

Method for activation of iron oxide containing dehydrogenation catalysts

Abstract: A METHOD OF ACTIVATION OF THE SELF-REGENERATING IRON OXIDE CATALYSTS EMPLOYED TO DEHYDROGENTATE ETHYLBENZENE TO STYRENE BY OPERATING THE REACTOR CONTAINING SUCH CATALYST SO AS TO PRODUCE ABNORMALLY HIGH CONVERSIONS OF ETHYLBENZENE FOR A PERIOD OF AT LEAST TWO DAYS. THEREAFTER, THE ACTIVITY OF THE CATALYST IS IMPROVED AT THE USUAL LEVELS OF CONVERSION.

Dehydrogenation of hydrocarbons employing a catalyst of iron oxide-containing activated carbon

Abstract: OLEFINS, SUCH AS PROPYLENE, ARE PRODUCED BY CONTACTING A MIXTURE OF AN ALKANE, SUCH AS PROPANE, AIR, STEAM, AND OPTIONALLY HYDROGEN SULFIDE OR SULFUR DIOXIDE WITH AN IRON OXIDE-CONTAINING ACTIVATED CARBON AT AN ELEVATED TEMPERATURE AND RECOVERING THE PRODUCT.

Highly fluxed iron oxide pellet

Abstract: A highly fluxed iron oxide pellet containing about 50 percent to about 95 percent iron oxide, about 20 percent calcium oxide plus magnesium oxide, not more than 10 percent silica, not more than 2 percent alumina, the remainder incidental impurities. The ratio of the calcium oxide plus magnesium oxide to the silica plus alumina in the pellet may be from about 0.5:1 to about 4.5:1. The ratio of calcium oxide to magnesium oxide on a weight basis in the pellet is from about 90 to 10 percent to about 80 to 20 percent, respectively. The pellet of the invention is produced by forming a mix of about 60 to 95 percent iron ore concentrate, about 40 to about 5 percent flux, a binder and moisture. The mix is balled in an apparatus, for example a balling disc. The green balls are dried at a temperature not higher than 500* F. The dried green balls are fired within a temperature range of 2150* F. to 2350* F. to form pellets. The pellets are cooled to room temperature.