Showing papers on "Iron oxide published in 1968"

Changes in soil properties associated with the removal of iron and aluminium oxides

Abstract: Summary Red soils representing the major groups in which iron oxides are thought to exert a favourable effect on physical properties, have been treated with Na-dithionite and citrate, or Na-dithionite and 0.05 n HC1. These treatments removed the free iron oxides and some aluminium oxides and silica. Changes in the physical properties of the soils were measured by permeability, wet-sieving, mechanical dispersion, and swelling methods. These were compared with the changes induced by corresponding control treatments in which the soils were treated with Na2SO4 and Na-citrate, or Na2SO4 and 0.05 n HC1. The control treatments extracted some aluminium oxide and minor amounts of iron oxides and silica. In general, the control treatments decreased the stability of aggregates, increased the proportion of clay and silt but had little effect on the swelling. The treatments, which removed all the free iron oxide, caused no changes in excess of those due to the controls. The specific surface areas of samples treated with dithionite and acid, or sulphate and acid were determined by nitrogen adsorption methods. Removal of free iron oxides led in all but one instance to a reduction in the specific surface area, whereas sulphate and acid invariably increased the specific areas of the samples. The results show that most of the free iron oxides in these soils are present as small particles having little effect on the physical properties of the soil. The changes in physical properties brought about by dilute acid treatment indicate that the ‘active’ oxides in these soils are composed partly or wholly of the aluminium, iron, and silicon oxides which are readily soluble in dilute acid.

Retention of Boron by Layer Silicates, Sesquioxides, and Soil Materials: III. Iron- and Aluminum-Coated Layer Silicates and Soil Materials1

Abstract: Boron retention as a function of pH was determined for Fe- and Al-coated layer silicates using a previously described procedure (15). Treating the Na⁺ and K⁺ forms of South Africa vermiculite material with Al³⁺ prior to B treatment resulted in equivalent B retention by the two forms. Coating kaolinite with hydroxy iron compounds initially decreased B retention in comparison to uncoated kaolinite. However, as the amount of coating was increased to 4.2% Fe₂O₃ the amount of B retained was slightly greater than that retained by uncoated kaolinite. Boron retention by the Al-coated kaolinite and by both Fe- and Al-coated montmorillonite was significantly greater than B retention by the uncoated clays. A single regression line represented B retention as a function of Fe₂O₃ content for both clays. Boron retention as a function of Al₂O₃ content for the two coated clays fell on two lines which led to the conclusion that hydroxy Fe and Al compounds in the layer silicates dominate over clay mineral species per se in determining B retention characteristics and that B retention characteristics may be conditioned by clay mineral species. Boron retention at pH 6 by nine soil materials was determined from the difference in the initial and final B concentrations of the saturating solutions. Relationships between B retention and various chemical properties of the soil materials were examined statistically. The highest correlations with B retention were found with free iron oxide content and 1.0N KCl (pH2) extractable Al₂O₃. It was concluded that B retention by these soil materials was in response mainly to their free iron oxide and Al₂O₃ contents.

Determination of surface compound formation by backscatter mössbauer spectroscopy

Abstract: The detection and identification of a surface compound formation on a steel surface was made using a backscatter Mossbauer effect technique. The compound was identified as β‐FeOOH from Mossbauer effect parameters of iron oxide and oxy‐hydroxide compounds. An estimate of the compound thickness is given based on a calculation of the backscatter amplitude versus distance into the sample. This technique can be used to identify corrosion products on the surface of iron bearing materials.

Method of making magnetic particles and recording tape

Abstract: METHOD OF MAKING MAGNETIZABLE ACICULAR GAMMA-FE2O3 PARTICLES MODIFIED WITH AMOUNTS COBALT OXIDE, WHICH PARTICLES ARE USEFUL FOR MAKING MAGNETIC RECORDING TAPE OF HIGH COERCIVITY AFFORDING SUPERIOR ABILITY TO STORE HIGH FREQUENCY INFORMATION. EVEN HIGHER COERCIVITY MAY BE ATTAINED BY CONTROLLING THE HEATING STEPS IN MAKING THE NOVEL PARTICLES TO PROVIDE UP TO 20% FEO BY WEIGHT OF THE TOTAL IRON OXIDE.

Cleaning of ferrous metal surfaces

Abstract: The invention is based on the discovery that upon adding a polyamine having intralinear amino groups to an aqueous alkaline solution of an ammoniated or aminated polycarboxylic acid chelating agent, a new and improved metal cleaning solution is provided. Upon bringing such cleaning solution into contact with a ferrous metal surface having hardness and/or iron oxide scale, and copper, thereon and the solution being maintained at a temperature above about 155 DEG C. for a time sufficient to dissolve all the hardness and iron oxides, the copper is dissolved and neither precipitates from solution nor deposits on the ferrous metal surface.

Multiple promoted iron oxide-antimony oxide catalysts for oxidation of olefins

Abstract: This invention provides a multiple promoted iron oxide-antimony oxide catalyst composition having the empirical formula: Fe10Sb5-60Me0 01-1Te0 05-5X0-1O22-151 wherein Me is V, Mo or W, and X is P or B.

Preparation of iron carbide (fe3c)

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°-550°C.

Process for the production of ferro-vanadium directly from slag obtained from vanadium-containing pig iron

Abstract: A PROCESS IS PROVIDED FOR THE PRODUCTION OF FERROVANADIUM FROM SLAG OBTAINED FROM VANADIUM-CONTAINING PIG IRON OR OTHER VANADIUM-CONTAINING MATERIAL, CHARACTERIZED IN THAT THE REDUCTION OF THE SLAG IS CARRIED OUT IN TWO STEPS: (1) IN THE FIRST STEP A REDUCING AGENT IS ADDED IN SUCH AMOUNTS THAT THE SUBSTANTIAL PORTION OF THE IRON OXIDE IN THE SLAG IS SUBSTANTIALLY REDUCED TO METALLIC IRON, WHEREAS PRACTICALLY NONE OF THE VANADIUM OXIDE IS REDUCED; WHEREUPON AFTER REMOVING THE METALLIC IRON FROM THE SLAG, THE FLUID VANADIUM-RICH SLAG IS SUBJECTED TO A FURTHER FINAL REDUCTION STEP (2) BY ADDING A POWERFUL REDUCING AGENT THERETO, SUCH AS SI-RICH FERRO-SILICON IN SUCH AMOUNTS THAT THE REMAINING IRON OXIDE IN THE SLAG AND THE MAJOR PART OF THE VANADIUM OXIDE THEREIN IS REDUCED, AND WHEREBY THE REDUCING AGENT IS ADDED GRADUALLY UNDER CONTINUOUS AGITATION TO AVOID LOCAL CONCENTRATIONS OF THE REDUCING MATERIAL AND THE THUS-OBTAINED FERROVANADIUM IS REMOVED FROM THE SLAG IN A CONVENTIONAL MANNER.

Oil base fluid composition

Abstract: An oil base drilling fluid having very low oil fluid loss even under extreme conditions of borehole temperature and pressure contains a primary weight material comprising barium sulfate or the like and a small amount of a secondary weight material comprising inert particulate material having a particle size less than about 3 microns. Inert metallic oxides such as iron oxide and titanium dioxide are suitable secondary weighting materials.

The Role of Diffusion in Corrosive Wear

Abstract: Oxygen diffusion through the lubricant film is an important factor in corrosive wear, a type of wear where the primary attack is the formation of iron oxide at the rubbing surface. Experimental data were obtained in a ball-on-cylinder device and quantitatively correlated with oxygen availability by a mathematical model. This model assumes two parallel surfaces separated by a small distance, one surface moving with respect to the other. The lubricant at the inlet is saturated with oxygen, which diffuses to the stationary surface to form iron oxide. The iron oxide is removed immediately by the rubbing motion. From the analysis the average clearance predicted was about 10 microinches, a reasonable figure. For the condition used experimentally, essentially all of the oxygen entering the system will diffuse to the surface and be consumed. Thus, differences in mass diffusivity are not important in determining the wear rate. The experimental observations, in agreement with the theoretical prediction, show that c...

Tin ore treating process

Abstract: A method of beneficiating crushed and ground tin oxide ores, including concentrates, by first sulfidizing to produce stable tin sulfides SnS2, Sn2S3 and SnS, and then, after initial separation of magnetic iron sulfide constituents, subjecting to progressive and selective flotation to remove the several tin sulfides formed. Flotation is ordinarily first carried out under alkaline conditions and then under conditions of increasing acidity. Nonmagnetic iron sulfide may be removed by flotation under mildly acid conditions and any residual magnetic iron sulfide may be removed by further magnetic separation. When elemental sulfur is used as the sulfidizing agent, as when pyrite is used as the sulfur source, iron oxide minerals in the tin ore or concentrates are preferentially sulfidized to form magnetic and nonmagnetic iron sulfide components. This characteristic enables the iron oxide minerals to be separated from the tin oxide ore by magnetic separation and progressive flotation.

The reaction between iron(III) oxide and barium carbonate in vacuo

Abstract: The reaction between iron(III) oxide and barium carbonate was studied in vacuo, thus enabling the collection of the carbon dioxide evolved. The extent of reaction was calculated from the amount of carbon dioxide and from the X-ray analysis of the solid products.When a highly reactive iron oxide was used, reaction was detected at a temperature ca. 100° below that with a sintered iron oxide. Only three compounds of barium, iron, and oxygen were found, namely BaO, Fe2O3, 2BaO, Fe2O3, and BaO, 6Fe2O3.The ferrite BaO, Fe2O3 results from the direct reaction of barium carbonate with iron oxide at low temperatures. The reaction of BaO, Fe2O3 with Fe2O3 to give BaO, 6Fe2O3 requires higher temperatures. The observations appeared to be explicable in terms of Tammann temperatures.

Treatment of molten metal

Abstract: 1,170,168. Casting processes. FOSECO INTERNATIONAL Ltd. 1 March, 1968 [17 March, 1967], No. 12759/67. Heading B3F. [Also in Divisions C5 and C7] Molten ferrous metal, e.g. steel is desulphurized and deoxidized in a ladle or an ingot mould by adding an exothermic additive comprising: Parts by weight Lime (CaO) .. .. 40 to 80 Iron oxide .. .. 5 to 30 Oxidizable material .. 5 to 25 the weight of lime being at least twice that of iron oxide which is present in a quantity stoichiometrically insufficient to oxidize all the oxidizable material. The iron oxide may be haematite, magnetite or millscale. The oxidizable material may be a finely divided metal or mixture thereof, e.g. Al, ball mill dust (20% Al), Mg or Ca/Al, or Si, Fe-Si, a silicide (e.g. of Ca), or Ca/Si. Besides iron oxide, other oxidizing agents may be present, such as an alkali metal nitrate or chlorate (e.g. NaNO 3 , KNO 3 or NaClO 3 ), MnO 2 or perchlorates. Other optional ingredients present may be siliceous blast furnace slag, fluorspar or other fluorides (e.g. NaF, KF or cryolite), alumina or silica flour or Na 2 CO 3 . For ingot moulds, the additive has an anti-chilling effect.

Diffusion in Iron Oxide Melts

Abstract: The interdij!usivities of iron and ox)'gen in iron oxide melts have been measured by the capillary method over the temperature range from 1 430° to 1 550°C and the composition range from r( = Fe3+ / ~" Fe ) = 0.12 to 0.42. At 1 550°C, the interdiffusivity is 4 X 10' to 5 x 105 cIll2 /sec, which is very high as com/Jared with the diffusivities of silicate slags. Activation energies for diffusion are 10.7±0.6 and 16.6±0.2kcal/mol at 1' = 0.12 and 0.33, respectively . The diffusivity decreases with increase of r. At higher Fe3+ content (r> to 0.25) , this decrease of diffusivity becomes more conspicuous. The observed reslllts arc interpreted in relation to the cOllstitution of the melts and other /Jroperties sllch as electrical condllctivity and viscosity.

Electrical conductivity and sintering in iron oxides at high temperatures

Abstract: Two raw materials were chiefly used, namely laboratory ferric oxide and a high grade hematite. All experiments were carried out in an oxygen atmosphere, in the range 600 to 1300° C.

Process for simultaneously producing powdered iron and active carbon

Abstract: Iron, in the form of iron powder or a soft readily powdered agglomerate thereof, is prepared simultaneously with powdered active carbon, by heating an iron oxide, in the form of powder or a soft readily powdered agglomerate thereof with a stoichiometric excess of a powdered coal char which will react with carbon dioxide at the temperature employed at a rate above 10 percent per hour, at a temperature controlled so that the charge is maintained throughout the reaction at between 1,775* F. and 1,875* F. The temperature is most readily maintained in production units by passing the gases used to supply the necessary extraneous heat across the path of travel of the charge, rather than along the path of travel.

Measurements of the thermal conductivity of thin films of magnetite

Abstract: Measurements have been made of the thermal conductivity of iron oxide layers in the `as-formed' condition for oxide thicknesses in the range 0027-048 mm over the temperature range 50-80°C. A steady-state method, involving the use of a calibrated thermopile for determining the surface temperature of the oxide, has been developed for these measurements. Observed values of the thermal conductivity k0 range from 000625 to 00139 w cm−1 degc−1, and are correlated as a function of oxide porosity P by the relation k0=00124±00018-915×10−5 P w cm−1 degc−1. Within the limited range of oxidation conditions used in the preparation of the specimens for this investigation, i.e. CO-CO2 gas containing up to 1200 p.p.m. by volume (v.p.m.) of water at temperatures from 400 to 600°C and pressures from 10 to 20 atm, there does not appear to be any correlation between the porosity and the oxidation conditions of the specimens.

Treatment of iron-containing particles

Abstract: IRON-CONTAINING PARTICLES SUCH AS FUME IN STEEL FURNACE GASES ARE REMOVED BY EXPOSING THE GAS TO LIME AT SELECTED MHIGH TEMPERATURE AND UNDER CONTROLLED CONDITIONS, E.G. OF CO AND CO2 CONTENT IN THE GAS, SUCH THAT THE PARSULTS, WITH SUBSTANTIAL PENETRATION OF THE LIME PIECES BY IRON OXIDE, AT LEAST IN PART PRODUCING A COMPOUND IDENTIFIED AS DICALCIUM FERRITE. LIMESTONE AND ADVENCING VOLVES CONTINUOUSLY CALCINING LIMESTONE AND ADVANCING THE CALCINED LIME LUMPS THROUGH A REACTION ZONE WHILE THE FUME-LADEN GAS PASSES COUNTERCURRENTLY THROUGH THE SOLIDS, HEAT BEING SUPPLIED FOR THE INCOMING GAS AND FOR THE LIMESTONE CALCINATION AS NEEDED. AN IRON-CONTAINING LIME PRODUCT RESULTS, PREFERABLY IN DISCRETE, NON-CLINKERED PIECES, HAVING GOOD PHYSICAL PROPERTES AND SPECIAL ADVANTAGEOUS OF REACTIVE AVAILABILITY WHEN USED AS LIME FEED IN IRON AND STEELMAKING OPERATIONS, ACCOMPLISHED BY EFFICIENT RECOVERY AND USE OF IRON VALUES.

Iron oxide pigments

Abstract: Coloring matter deposited on iron oxide particles obtained by precipitation, produces stable light-fast pigments with enhanced tinctorial value. These composite pigments, which have a greatly diminished tendency to separate into their component colors, are useful in coloring concrete, bricks, plastics, textiles and paints.

Process for liberating copper from sulfide ores

Abstract: IN THE PRODUCTION OF COPPER FROM SULFIDE ORES, IT IS CONVENTIONAL TO PREPARE BY MINERAL-DRESSING OPERATIONS A FINELY DIVIDED CONCENTRATE COMPOSED PRINCIPALLY OF COPPER SULFIDES AND IRON SULFIDES. INSTEAD OF FORMING THE CONCENTRATE INTO A MATTE AND CONVERSION OF THE MATTE TO BLISTER COPPER, THE CONCENTRATE IS ROASTED WITHOUT MELTING UNDER OXIDIZING CONDITIONS TO A FINELY DIVIDED MIXTURE OF COPPER OXIDES AND IRON OXIDES. THIS INTERMEDIATE PRODUCT IS THEN HEATED UNDER SELECTIVE REDUCING CONDITIONS TO REDUCE THE COPPER OXIDE TO METALLIC COPPER WITHOUT APPRECIABLY REDUCING THE IRON OXIDE. BY VIRTUE OF THIS SERIES OF HEATING STEPS WHERE THE COPPER IS FIRST OXIDIZED AND THEN REDUCED, AN OPPORTUNITY IS PROVIDED FOR THE GROWTH IN SIZE OF THE COPPER PARTICLES. THE PRODUCT WILL THEREFORE CONTAIN METALLIC COPPER IN THE FORM OF RELATIVELY LARGE PARTICLES WHICH CAN BE RECOVERED BY CONVENTIONAL MINERAL-DRESSING OPERATIONS, FOR EXAMPLE, BY GRINDING AND FLOTATION.

The formation of pyrite from hydrated iron oxide in aqueous solution at 20°C

Abstract: Experiments are described in which pyrite is synthesized at room temperature and atmospheric pressure from hydrated iron oxides and hydrogen sulphide under conditions similar to those expected in the natural environment. This synthesis differs from earlier work in that oxygen was rigorously excluded from the system and the pH was 5.6. During a later ageing period a reaction appears to take place in which iron monosulphide is converted to pyrite at pH 5.85.