Abstract: An SiO.sub.2 coated iron oxide powder used for the preparation of an acicular metallic iron powder or an acicular magnetic iron oxide powder, is produced by forming a slurry of hydrated iron oxide as a starting material or a iron oxide powder having pH of 8 to 14; admixing a water soluble silicate at a ratio of 0.1 to 10 mol % as SiO.sub.2 based on Fe; hydrothermally reacting said mixed slurry at 100.degree. to 250.degree. C. for 5 minutes or longer in a closed reactor, and washing, filtering and drying the product.

Abstract: In a process for producing an iron oxide having magnetite as a main component by heating to reduce a powder of an oxide or a hydrated iron oxide comprising an iron oxide as a main component in an atmosphere for reduction, an improvement characterized in that said atmosphere for reduction is formed by passing an industrial liquefied nitrogen gas.

Abstract: High purity hexagonal plate-like .alpha.-Fe.sub.2 O.sub.3, commonly called micaceous iron oxide, is prepared by a hydrothermal treatment of either magnetite or an iron ore, or an iron oxide, of which principal component is magnetite together with an oxidizer in an aqueous alkali solution. Main advantage of this process is a great decrease in the consumption of alkali. Pure magnetite for use in this process can be prepared economically by a hydrothermal treatment of an iron ore, or an oxide, of which principal component is an oxide of trivalent iron in an aqueous alkali solution together with a compound of divalent iron and/or metallic iron.

Abstract: An alkali hydroxide is added to an aqueous solution of ferrous salt to form a precipitate and a part of the solution is separated to control a ratio of an anion to a ferrous component to less than 1 and the ferrous component is oxidized to acicular goethite with an alkali metal chlorate such as potassium chlorate.

Abstract: An alkali hydroxide is added to an aqueous solution of ferrous salt to form a precipitate and a part of the solution is separated to control a ratio of an anion to a ferrous component to less than 1 and the ferrous component is oxidized to acicular goethite by bubbling air through the supernatant and precipitate.

Abstract: A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe.sub.2 O.sub.3 containing a crystalline phase of Fe.sub.2 O.sub.3, Fe.sub.3 O.sub.4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected.

Abstract: Iron rich dusts created during steelmaking, as in the basic oxygen and open hearth processes, are useful for scavenging hydrogen sulfide. For example, basic oxygen furnace dusts, which are in more abundant supply, are found to consist of fine, nearly spherical particles of iron oxide whose crystalline composition comprises Fe.sub.3 O.sub.4 (major portion) and Fe.sub.2 O.sub.3 (minor portion) as seen by X-ray diffraction. Their great surface area makes them highly reactive to hydrogen sulfide gas. Their reaction yields unexpected products, namely, free sulfur and iron hydroxides. According to the present invention such iron rich dusts are used in water slurries through which sour hydrocarbon gas is bubbled, and in water based drilling muds to scavenge hydrogen sulfide encountered in well drilling.

Abstract: Transition metal hydroxides of the first transitional series are prepared by reacting a transition metal with water, a nitrogen-containing compound, one or more aliphatic or alicyclic monocarboxylic acids containing at least eight carbon atoms and a diluent in the presence of oxygen. Only small amounts of the acid and nitrogen-containing compound are required. The reaction mixture also can contain dispersants. The method of the invention avoids the corrosion and pollution problems which are present in some prior art processes. The transition metal hydroxides prepared in accordance with the invention are free of salt contamination.

Abstract: The present invention relates to a method of manufacturing molten iron oxide in which magnesite is first rammed between the furnace wall and in a mold of sheet iron to form a lining. The lining is sintered by inserting cast iron or steel into the mold and melting the cast iron or steel at 1600.degree.-1900.degree. C. The major amount of the thus-melted iron steel material is poured out of the furnace and the remaining melt is converted to iron oxide by adding a charge of iron oxide to the furnace and the temperature of the mixture is adjusted such that a solid and melted material is formed within the furnace by regulating the electrical power supply, the mixture is stirred sufficiently to render the temperature of the mixture uniform throughout and then a major amount of the iron oxide melt thus-formed is charged and melted and stirred according to the same porcedure outlined above until the lining has to be changed. According to this procedure, the lining can be used for a long time without deterioration.

Abstract: In the production of iron oxide pigments and substantially iron-free sodium sulphate from iron sulphate by passing an oxygen-containing gas through an alkalized iron sulphate-containing solution at a temperature of about 40.degree. to 100.degree. C.

Abstract: A process for the manufacture of acicular ferrimagnetic iron oxide by reducing heat-treated acicular iron(III) oxide hydroxide with an organic compound which decomposes in the presence of iron oxide at from 450.degree. to 650.degree. C., followed by at least partial oxidation with an oxygen-containing gas at from 200.degree. to 500.degree. C., wherein the iron(III) oxide hydroxide employed is heat-treated at from 450.degree. to 700.degree. C. and has a surface area, measured by the BET method, of from 10 to 23 m.sup.2 /g.

Abstract: Low density, porous, metal oxide microspheres are prepared from metal salt solutions by sol-gel technique followed by ammonia treatment of the green microspheres, drying, impregnation with fugitive organic material and heat temperature under controlled conditions of temperature and atmosphere. The product metal oxide microspheres have a density of below 70% of their theoretical maximum density and a porosity of at least 0.04 cubic centimeters per gram as measured by mercury penetration technique. Microspheres of hematite, magnetite, and other metal oxides useful as catalysts or as purifying agents to remove contaminants from liquid or gaseous streams may be produced.

Abstract: Single crystalline, acicular ferric oxide particles are produced by maintaining an aqueous suspension of ferric hydroxide at an elevated temperature at an alkaline pH in the presence of an organic phosphonic acid compound or a hydroxycarboxylic acid compound as a growth-regulating agent.

Abstract: In the production of ferric oxide black pigments with the simultaneous recovery of sodium sulphate wherein ferrous sulphate is reacted with an alkaline sodium compound at a pH above about 6 and a temperature above about 50.degree. C., and the pigment formed is separated from the mother liquor containing sodium sulphate, the improvement which comprises conducting the reaction at a sodium sulphate concentration of at least about 20% by weight, after separation of the pigment cooling at least part of the sodium sulphate-containing mother liquor to a temperature of at most about 30.degree. C., thereby to crystallize sodium sulphate decahydrate, and separating the crystals. Air is preferably passed through the reaction solution to oxidize the precipitated pigment and, advantageously, make-up water is added to compensate for water carried off by the air. The end product mother liquor, containing an appreciable amount of sodium sulphate, is employed to dissolve ferrous sulphate for a subsequent cycle.

Abstract: A process for the recovery of sulfuric acid from waste sulfuric acid containing iron sulfate and from solid iron sulfate of high water content of crystallization which consists essentially of:A. concentrating waste sulfuric acid to an acid concentration of 25-55 weight percent, based upon the suspension, by removing water therefrom;B. mixing the concentrated acid of Step A with recycled concentrated sulfuric acid obtained from Step E to form a resultant acid mixture of acid concentration of 30-65 weight percent, based upon the suspension;C. adding said solid iron sulfate of high water content of crystallization to the acid mixture of Step B thereby obtaining iron sulfate of low water content of crystallization;D. separating the iron sulfate of low water content from the resultant sulfuric acid solution of Step C;E. concentrating the separated sulfuric acid solution of Step D to an acid concentration of 45-70 weight percent, based on salt-free acid, and recycling at least a portion thereof to Step B; andF.

Abstract: This invention describes the preparation of a red pigment of iron oxide from ferrous salts, by simultaneous reduction of organic nitro derivatives.

Abstract: Ammonium jarosite is converted to hematite or magnetite and ammonium sulphate. The invention can be used for removing iron from a feed solution containing dissolved ferrous sulphate. The feed solution is treated with ammonium sulphate and oxygen to precipitate ammonium jarosite which is then separated from the treated solution to produce an ammonium jarosite slurry and a separated solution containing sulphate ions. The ammonium jarosite slurry is treated with ammonia to convert the ammonium jarosite to hematite or magnetite and ammonium sulphate solution. The ammonium sulphate solution is separated from the hematite or magnetite, and a portion of the separated ammonium sulphate solution is recycled to the ammonium jarosite precipitation step, the remaining portion of the separated ammonium sulphate solution being recovered.

Abstract: Aromatic amines and iron oxide pigment are produced by reacting a ferrous salt, a reduceable aromatic nitrogen compound chosen from nitroderivatives with a single nitro-group or with two nitro-groups and azoderivatives, and a basic compound, chosen from hydroxides and carbonates of ammonium, alkali metals and alkaline earth metals, operating at 25.degree.-200.degree. C. in an aqueous medium. The color of the pigment can be varied from yellow to black by increasing the reaction temperature and the molar ratio between ferrous salt and aromatic nitrogen compound.

Abstract: A multi-phase thermochemical circulating process for producing hydrogen and oxygen from water is described, using the system of iron and chlorine compounds. Hydrogen is released by the reaction of iron(II)-oxide with water vapor and the oxygen by the reaction of chlorine with water vapor, iron(II)-oxide or iron (II, III)-oxide. Intermediately-formed iron (II)-chloride is hydrolyzed with water vapor to iron(II)-oxide in a multi-stage reaction at a gradually raised temperature, whereby in the hydrolysis the formation of metallic iron or of iron(II, III)-oxide is avoided.

Abstract: Gypsum and magnetite which are both coarse and of good quality can simultaneously be produced by introducing calcium carbonate into an aqueous solution containing ferrous sulfate while an oxidizing gas is blown, and then carrying out a neutralizing and oxidizing operation at a pH of 5-6 and a temperature of 60-80.degree. C, and can be separately recovered by magnetic separation.

Abstract: In the production of acicular ferromagnetic iron oxide of highly uniform particle size by oxidizing an iron (II) hydroxide suspension at a pH of at least 11 with an oxygen-containing gas to form acicular iron (III) oxide hydroxide, reducing and optionally further reoxidizing this into ferromagnetic iron oxide, the improvement which comprises providing the iron (II) hydroxide suspension with a water-soluble silicate in an amount of less than 1.7% by atom based on the amount of the iron (II) hydroxide in the suspension and calculated as the ratio of Si to Fe (II) while prior to the oxidation of the suspension with the oxygen-containing gas.

Abstract: A metallic iron-containing starting material such as iron filings, iron powder or a reduced ore such as ilmenite is oxidized with air in the presence of 5 to 40% of iron oxide and/or iron oxide hydroxide nuclei and about 2.5 to 200% of an electrolyte, percentages being based on metallic iron by weight. The oxidation is effected in aqueous suspension at 75.degree. to 100.degree. C and a pH of 4 to 6.5. If the nuclei are magnetite-free, at least the first quarter of the oxidation should be at pH 5 to 6.5. Preferred electrolytes are transition metal salts. The pigments are more intense in color and have a more pronounced blue tinge.

Abstract: Synthetic rutile is made from ilmenite by pre-oxidizing it, reducing it in a fluid bed, thereafter aeration leaching it, optionally acid leaching, and drying.

Abstract: Process for the recovery of pigment-grade iron oxide and technical hydrochloric acid of predetermined molarity, from iron chloride solutions such as pickling solutions containing hydrochloric acid. The iron chloride solution is concentrated until the molarity of the chloride ion therein is the same as the molarity of the hydrochloric acid which it is desired to produce. Concentrated sulfuric acid in slight stoichiometric excess relative to the iron, is then added to the iron chloride solution, which solution is thereafter evaporated to dryness. The distillation from this evaporation is hydrochloric acid of the predetermined molarity, and the dry residue is iron sulfate. The iron sulfate is calcined to drive off sulfur dioxide and sulfur trioxide and to leave iron oxide which may contain sulfates; and to remove these latter, the iron oxide is leached with dilute hydrochloric acid and is thereafter washed with water. The washed iron oxide is dried and micropulverized to produce a red iron oxide pigment.

Abstract: In a two-stage process for producing black iron oxide pigments wherein an iron salt solution is alkalized in a first stage to precipitate about 55 to 70% of the iron, the solution is oxidized to convert the precipitate to goethite, the solution is further alkalized in a second stage to precipitate the balance of the iron, the precipitated iron II hydroxide is allowed to react with goethite to form magnetite, the improvement which comprises effecting the second stage in the presence of an inorganic ionic compound of at least one metal selected from the group consisting of copper, nickel, aluminum, chromium, titanium, zirconium and vanadium in about 0.05 to 5% calculated as metal based on the weight of the final pigment. The resulting pigment is of high color intensity, narrow grain distribution range and pronounced magnetite structure.

Abstract: A soil modifier comprising from 80 to 95% by weight of a mixture of ferric oxide and ferric sulphate in an oxide/sulphate weight ratio of from 0.25:1 to 1:1, is prepared by calcining at 500.degree.-600.degree. C in an oxidizing atmosphere a blend of by-product obtained in the manufacture of titanium oxide by the sulphate process, with at least 20% by weight with respect to said by-product, of a material based on ferric sulphate and/or ferric oxide. Calcining is then continued under the same conditions, replacing said material in the blend continuously fed in by a recycle fraction of the product continuously discharged.

Abstract: Endothermic processes are carried out in a fluidized-bed reactor which is connected to a holding reactor, solids being recirculated between the two reactors. The primary fluidized-bed reactor uses a fast-fluidized bed system in which the solids concentration decreases continuously from the bottom to the top of the reactor. After the necessary residence time in the holding reactor, solids are discharged. Solids are entrained with the gas stream from the primary reactor and are separated therefrom to be delivered to the holding reactor. The reaction is controlled by regulating the rate of recirculation of solids from the holding reactor to the fast fluidized bed reactor.

Abstract: A process for the production of hydrogen and oxygen from water comprising the steps of forming ferric chloride from ferriferrous oxide by reaction with a chloride ion yielding substance, thermally reducing the ferric chloride to produce ferrous chloride, reducing the ferrous chloride to metallic iron, then oxidizing the metallic iron with water so as to produce hydrogen. The metallic iron may be formed by reducing the ferrous compound with hydrogen. Two specific reactant regenerative closed cycle systems are disclosed utilizing the process of this invention for the production of hydrogen and oxygen.

Abstract: Novel compositions for use in agriculture as soil improvers and fertilizers comprising as essential components ammonium sulfate and ferric oxide hydrate. By-products obtained in the production of titanium dioxide from ilmenite or ilmenite slag in the sulfate process and substantially consisting of ferrous sulfate heptahydrate are reacted with ammonia and that the reaction product obtained, consisting substantially of ammonium sulfate and ferrous hydrate, is subsequently oxidized until a composition is obtained which substantially consists of ammonium sulfate and ferric oxide hydrate.

Abstract: A soil modifying composition and a concentrated solution of ammonium sulphate with a high purity degree are obtained from by-products consisting essentially of ferrous sulphate heptahydrate, obtained in the production of titanium dioxide from ilmenites by the sulphate process, by contacting solid particles of said by-products with gaseous ammonia, lixiviating the resulting product with water, thereby to recover said concentrated solution of ammonium sulphate, the dried residual solid yielding said soil modifying composition.

Abstract: A process is disclosed for preparing magnetite having an equiaxial morphology and a narrow particle size dispersion by precipitation from a ferrous sulphate solution, characterized in that:A. during a first step, at a temperature between 15.degree. and 40.degree. C, alkali is added to the ferrous sulphate solution, in a stoichiometric amount adapted to precipitate, in the form of ferrous hydroxide, 2/3 of the Fe.sup.+.sup.+ ion, and then, at the conclusion of said precipitation, air is blown thereinto thus oxidizing ferrous hydroxide to goethite .alpha.FeO(OH); andB. during a second step, alkali is added to the slurry obtained in the first step, the remaining Fe.sup.+.sup.+ is precipitated in the form of ferrous hydroxide, and the slurry is heated to a temperature between 70.degree. and 100.degree. C, thus causing the formation of magnetite which is then separated from the solution.

Abstract: A process for producing nickel oxide and other products in which percentages of metal powder, particularly nickel powder, and water are blended, the blend being subjected to a heat treatment to form the desired product. In the case of nickel oxide, the blend is exposed to air and temperature sufficient to form an oxide shell substantially about the powder particles, this treatment being followed by a final firing heat treatment.

Abstract: Soil modifiers comprising from 80 to 95% by weight of a mixture of ferric oxide and ferric sulphate in an oxide/sulphate weight ratio of from 0.2:1 to 2:1 are prepared by calcining at 500.degree.-600.degree. C in the presence of an oxidizing gas a material consisting essentially of ferrous sulphate with an average number of molecules of crystallization of from 1 to 5 obtained by partial dehydration of the waste materials, consisting essentially of ferrous sulphate heptahydrate, obtained in the manufacture of titanium dioxide from ilmenites or ilmenite slags by the sulphate process. These modifiers are particularly suitable for clay soils.

Abstract: A process is disclosed for producing magnetite having an equiaxial morphology in the state of a hyperfine powder, starting from a solution of a bivalent iron solution, characterized in that:A. an aqueous suspension of Fe(OH).sub.2 is prepared by reacting an aqueous solution of a ferrous salt with alkali;B. said aqueous suspension of Fe(OH).sub.2 is fed into an autoclave into which is also introduced a quantity of air corresponding to 4-15 normal liters per 100 g of bivalent Fe; andC. the autoclave is then brought to a temperature between 150.degree. and 200.degree. C and maintained at this temperature until the inside pressure has stabilized itself at a constant level, thereby bringing about the formation of the desired magnetite which, once discharged from the autoclave, is washed and dried. The aqueous suspension of Fe(OH).sub.2 subjected to thermal decomposition in the autoclave may have present therein Cu.sup.+.sup.+ion, in a quantity between 0.3 and 1.4% by weight of the bivalent Fe. When Cu.sup.+.sup.

Abstract: A method is disclosed for controlling the particle size of equiaxial magnetite obtained by a process for preparing same starting from ferrous sulphate solutions, characterized in that the reaction forming the magnetite is conducted in a suspension to which .gamma. FeO(OH) has been added in such an amount that Fe of the .gamma. FeO(OH) is 0.1-10% of the Fe.sup.+.sup.+ initially present in the solution.

Abstract: Ammonium hydroxide is added to a mixture of high-temperature, high-pressure geothermal steam and brine to raise the pH of the brine to between 6.0 and 7.0 and precipitate out a gelatinous sludge of aluminum and iron hydroxides. The hydroxide sludge is suspended in the brine and sweeps out enough dissolved silica so that the temperature and pressure of the brine can be reduced with little, if any, formation of silica scale. Various metals and ammonium hydroxide may then be recovered from the brine, the ammonium hydroxide being recycled in the process.

Abstract: Elongated, polycrystalline particles of alpha iron oxide, characterized by an open, porous structure and consisting of hematite microcrystallites containing from 2 to 4 percent of sulfate are prepared by the reaction of lithium hydroxide and ferric sulfate in weakly acidic to neutral aqueous solution under at least autogenous pressures at temperatures in the range of 150.degree.-350.degree. C. The particles are readily converted to gamma iron oxide of good magnetic properites and also have utility as pigments and catalysts.

Abstract: A process for the extraction and recovery of hydrated stannic oxide and alkali metal ferrocyanide from the sludge formed in a halogen tin electrodeposition bath is described. The process comprises dissolving the ferrocyanide compounds and the tetravalent tin compounds present in the sludge in an alkaline medium, removing any insoluble materials, precipitating hydrated stannic oxide from the solution by neutralization of the solution, and separating the hydrated stannic oxide from the solution which then contains ferrocyanide ion together with acid and base counterions.

Abstract: A process for the production of hydrogen and oxygen from water comprising the steps of forming ferric chloride from ferriferrous oxide by reaction with a chloride ion yielding substance, reducing the ferric chloride produced with a reducing agent to produce ferrous chloride, thermally reducing the ferric chloride to produce ferrous chloride, then oxidizing either the ferrous compound or metallic iron with water so as to produce hydrogen. The metallic iron may be formed by reducing the ferrous compound with hydrogen. Four specific reactant regenerative closed cycle systems are disclosed utilizing the process of this invention for the production of hydrogen with high energy efficiencies.

Abstract: A continuous process is provided which has the primary purpose of removing NH.sub.3, H.sub.2 S, HCN, and (CN).sub.2 from the subject gas mixtures and the secondary purpose of producing (NH.sub.4).sub.2 SO.sub.4 and iron oxide for industrial uses. The gas mixture which contains tar and other condensible vapors, NH.sub.3, H.sub.2 S, HCN, and (CN).sub.2 together with small volumes of gas from the ammonia still of the system, and gas from a system H.sub.2 SO.sub.4 plant, is contacted in a single three-stage reaction chamber in the presence, if need be, of a tar solvent, additional NH.sub.3, and the reagent Fe(OH).sub.2, which itself is a product of a concurrent reaction between NH.sub.3 and FeSO.sub.4. The unpurified gas mixture's condensible vapors are largely prevented from condensing by maintaining a steady, elevated temperature, while the mixture is essentially freed of HCN, (CN).sub.2, NH.sub.3, and H.sub.2 S in the reactor before the gas mixture passes through a primary gas cooler.

Abstract: A dilute aqueous slurry of hydrated zinc oxide is subjected to heat and pressure to obtain solids having improved filtering characteristics. The process is especially useful in the treatment of neutralized waste liquor from the viscose rayon system to provide a more economical method for the recovery of zinc sulfate.

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.

Abstract: Process for the production of a finely divided oxide of a metal or silicon by the hydrolytic conversion of a volatile corresponding metal halide or silicon halide in a flame, said process comprising feeding the volatile halide in a mixture with a combustible hydrogen-containing gas and air or oxygen to a burner provided with a mouth emitting a flame, burning the mixture in a fire tube to form a first portion of water vapor, said burner surrounded by an annular chamber forming a nozzle through which hydrogen is passed to keep the mouth of the burner free of attachments of solid substances, the quantity of oxygen or air being sufficient for the practically complete combustion of the combustible gas, and the quantities of oxygen or air and combustible gas being sufficient to produce the first portion of water vapor which will at least suffice for the hydrolysis of the volatile halides, and further wherein said flame is allowed to burn in an atmosphere consisting of gases containing a second portion of water vapo

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 SiO.sub.2 in the form of a sol or soluble salt, the resulting iron (III) oxide hydroxide having SiO.sub.2 deposited thereon.

Abstract: A process for the production of hydrogen and oxygen from water comprising the steps of forming ferric chloride from ferriferrous oxide by reaction with a chloride ion yielding substance, reducing the ferric chloride produced with a reducing agent to produce ferrous chloride, and then oxidizing the ferrous compound with water so as to produce hydrogen. Suitable reducing agents include cuprous chloride, chromous chloride and platinum. Several reactant regenerative closed cycle systems are disclosed utilizing the process of this invention for the production of hydrogen with high energy efficiences.

Abstract: Compositions useful in agriculture as soil modifiers and fertilizers are prepared by contacting the waste materials, obtained in the manufacture of titanium dioxide from ilmenites by the sulphate process, and which consist essentially of ferrous sulphate, with oxides, hydroxides or carbonates of alkali metals or alkaline earth metals or ammonium carbonate, and then submitting the reaction product to oxidation to convert the ferrous hydroxide into ferric hydroxide. Ferric hydroxide is further converted to ferric sulphate by treatment with sulphuric acid.