Abstract: The present invention is directed to a process for producing a nanometer-sized metal compound. The process comprises forming a reverse micelle or reverse microemulsion system comprising a polar fluid in a non-polar or low-polarity fluid. A first reactant comprising a multi-component, water-soluble metal compound is introduced into the polar fluid in a non-polar or low-polarity fluid. This first reactant can be introduced into the reverse micelle or reverse microemulsion system during formation thereof or subsequent to the formation of the reverse micelle or microemulsion system. The water-soluble metal compound is then reacted in the reverse micelle or reverse microemulsion system to form the nanometer-sized metal compound. The nanometer-sized metal compound is then precipitated from the reverse micelle or reverse microemulsion system.

Abstract: Hematite particles for a non-magnetic undercoat layer for a magnetic recording medium, comprise: high-density acicular hematite particles having an average major axial diameter of not more than 0.3 .mu.m, a major axial diameter distribution in geometrical standard of not more than 1.50 and a BET specific surface area of not less than 35 m.sup.2 /g, showing a pH of not less than 8, and containing not more than 300 ppm of soluble sodium salt, calculated as Na, and not more than 150 ppm of soluble sulfate, calculated as SO.sub.4.

Abstract: The invention relates to the use of synthetically produced, bainite-rich iron raw materials to prepare iron oxide pigments.

Abstract: A method is provided of rapidly increasing the bulk density of an iron oxide powder by preventing the powder, processed by a roller consolidation machine, from flying up. The method consists of feeding an iron oxide powder, whose apparent bulk density is 0.4-0.6, into a sealed tank, depressurizing the tank to a vacuum of 100-200 torr, and revolving the rotating roller and rotating plow at a revolving speed of 1-2 m/sec.

Abstract: Embodiments of an apparatus and method for ferrite formation and the removal of heavy metal ions by ferrite co-precipitation from an aqueous solution at ambient temperature have been developed. Magnetically susceptible ferrite crystals can be continuously formed from aqueous solution and the heavy metal ion solution can be continuously treated by the ferrite co-precipitation process. The heavy metal ions are incorporated into the lattice points of the spinel ferrite structures. The precipitates of ferrite materials can then be magnetically separated. The main apparatus includes a ferrous sulfate mixing tank with a feeder assembly; a reaction tank or, alternatively, neutralization and oxidation tanks; settling and polishing tanks; and a magnetic separator. The reaction tank or oxidation tank includes an air distributor; a pH controller; and promoter feeding and ferrite product recirculating systems.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety of macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates of these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages of these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: Spindle-shaped goethite particles are produced by oxidizing a ferrous carbonate intermediate in the presence of a growth modifier, or alternatively by changing the flowrate of oxidizing gas during oxidation. The goethite particles thus produced have a narrow size distribution, high aspect ratio and are substantially dendrite-free. These properties make the inventive goethite particles suitable for use in preparation of high density magnetic recording media.

Abstract: This invention provides a method of producing goethite particles comprising the steps ofa) reacting, in aqueous solution, less than a stoichiometric amount of an alkali compound with an iron (II) salt to form a precipitated complex intermediate,b) oxidizing iron (II) in the complex intermediate to iron (III) at an average rate less than 10 g iron(III)/l/hr to form goethite seed particles until 20 to 70% of iron (II) in the precipitated complex intermediate has been converted to iron (III), andc) after 20 to 70% of iron (II) in the precipitated complex intermediate has been convened to iron (III), increasing the average oxidation rate to greater than 10 g iron(III)/l/hr.

Abstract: Disclosed herein is a process for producing fine metal oxide particles comprising the step of heat-treating an aqueous solution of a metal salt at a temperature of not lower than 200.degree. C. under a pressure of not less than 160 kg/cm.sup.2 for 1 second to 1 hour so as to bring into the decomposition reaction of said metal salt.

Abstract: The present invention relates to a process for the production of red, transparent iron oxide pigments of elevated chemical purity, to iron oxide pigments obtainable in this manner and to the use thereof to color lacquers and plastics.

Abstract: A process for reducing the residual chloride present in iron oxides, particularly in regenerated iron oxides produced from hydrochloric acid waste liquid generated from steel pickling, by post-synthesis treatment of the iron oxides with yellow iron oxide, and subsequently heating the mixture at a temperature sufficient to release at least a part of the crystalline water contained in the yellow iron oxide to facilitate the removal of residual chloride present in iron oxides. The purified regenerated iron oxides are particular suitable for making high-grade ferrites.

Abstract: Alkali-metal bisulfate is employed in a non-polluting and economically-feasible system for producing titanium dioxide pigment from titanium mineral or slag with recycling of alkali-metal bisulfate and ammonia.

Abstract: Disclosed herein is fine acicular .alpha.-ferric oxide which has the crystallite diameter (D.sub.1014) in the direction perpendicular to the (1014) plane and the crystallite diameter (D.sub.1120) in the direction perpendicular to the (1120) plane such that their ratio D.sub.1014 /D.sub.1120 is in the range of 1-2, and also has a specific surface area of 40-50 m.sup.2 g. Disclosed also herein is fine acicular .alpha.-ferric oxide which has the crystallite diameter (D.sub.1014) in the direction perpendicular to the (1014) plane and the crystallite diameter (D.sub.1120) in the direction perpendicular to the (1120) plane such that their ratio D.sub.1014 /D.sub.1120 is the range of 1-2, and also has an average aspect ratio of 10-15 and a specific surface area of 20-40 m.sup.2 /g. They are produced by wet process including the step of hydrothermal reaction.

Abstract: A process for the preparation of acicular .alpha.-iron oxide hydrate which comprises oxidizing a slurry of ferrous hydroxide having an excessive alkali concentration of 1.0 mol/l or above with an oxygen-containing gas, interrupting oxidation, adding an excessive quantity of an aqueous solution of a salt of aluminate, homogenizing and stirring the resulting mixture, again oxidizing it with an oxygen-containing gas to obtain a slurry containing free aluminate ion and .alpha.-iron oxide hydrate, homogenizing and stirring the slurry, then neutralizing and aging it, and washing and drying it.

Abstract: The non-acicular modified maghemite and magnetite have high coercivity of, for the maghemite, up to 2200 Oe, saturation and residual magnetization of 63-85 emu/g and 43-52 emu/g, respectively; for the magnetite, the corresponding values are 800-1600 Oe, 82-87 emu/g, and 44-51 emu/g, respectively; while retaining same squareness ratio and same chemistry with conventional iron oxides, fine particle size of around 50 nm, easier dispersion and coating, invaried properties after curing, and low value of temperature coefficient of coercivity (0.24-0.37%/.degree. C. for the maghemite and 0.20-0.33%/.degree. C. for the magnetite), have been invented. They are thus especially suitable for high density recording. The modified maghemite and magnetite are prepared by precipitating from aqueous solution containing Fe, Mn, Co and Zn ions at proper ratio using an organic alkali as precipitant, followed by specific heat treatment sequences.

Abstract: Disclosed herein are a process for producing acicular goethite particles comprising the step off: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution, an aqueous alkali carbonate solution, or an aqueous alkali hydroxide and alkali carbonate solution based on Fe.sup.

Abstract: The present invention relates to a process for the preparation of finely divided metal and/or ceramic powders by reacting appropriate metal compounds and appropriate reagents in the gas phase (CVR) chemical vapor reaction, wherein the metal compound(s) and the further reagents are brought to reaction in the gaseous state in a reactor and are subsequently homogeneously condensed directly out of the gas phase, with exclusion of any wall reaction, and are subsequently separated from the reaction medium.

Abstract: A process for preparing transparent yellow iron oxide pigments by the precipitation of iron (II) hydroxide by adding an inorganic base to an iron (II) salt solution and subsequent oxidation to FeOOH.

Abstract: Disclosed herein are magnetic composite iron oxide particles comprising spinel-type Fe.sub.3 O.sub.4 particles as core particles and spinel-type CoFe.sub.2 O.sub.4 outerlayer of the composite iron oxide particles, a process for producing the same, and a magnetic recording medium comprising a substrate and a magnetic recording layer containing the said magnetic iron oxide particles.

Abstract: The present invention provides acicular particles (A) containing an iron carbide, which have (a) a free carbon content of at most 20 wt. %, and (b) and Fe.sub.5 C.sub.2 ratio(x) of at least 70% and a coercive force of 3.times.+300 to 7.times.+270 Oe, the ratio(x) being expressed by ##EQU1## where S1 is the X-ray diffraction strength of Fe.sub.5 C.sub.2, and S2 is the X-ray diffraction strength of Fe.sub.3 O.sub.4.The invention further provides particles (B) containing nickel and an iron carbide.The invention further provides acicular particles containing an iron carbide which are obtained by heating an aqueous dispersion of ferric hydroxide in an alkaline system in the presence of a water-soluble compound capable of coordinating to iron to obtain acicular .alpha.-ferric oxide and contacting the product with a carbon-containing reducing-and-carburizing agent or with a mixture of the agent and a carbon-free reducing agent, with or without contacting the product with the carbon-free reducing agent.

Abstract: This invention relates to new pure-colored iron oxide direct red pigments, to a process for their production and to their use for pigmenting lacquers, plastics, building materials and ceramics.

Abstract: Superparamagnetic particles are provided for medical applications including hyperthermia techniques, localized heating and tissue-specific release of therapeutic agents, and magnetic resonance imaging contrast enhancement, comprising superparamagnetic iron oxide and a polymer such as dextran at a ratio of about 0.5 to 0.1 w/w of polymer to iron. The particles display at least one of the following magnetic properties: (a) specific power absorption rate greater than 300 w/g Fe; (b) initial magnetic susceptibility greater than 0.7 EMU/g Fe/Gauss; and (c) magnetic moment greater than 10.sup.-15 erg/Gauss.

Abstract: Disclosed herein are a process for producing poreless plate-like magnetite particles which have as large a plate ratio (average particle diameter/thickness) as possible and which are discrete each other, the process comprising the step of: obtained by oxidizing a suspension containing FeCO.sub.3 obtained by reacting an aqueous ferrous salt solution and an aqueous alkali carbonate solution by passing an oxygen-containing gas therethrough, wherein the suspension is obtained by reacting a ferrous salt solution containing 0.2 to 5.0 mol % of a ferric salt, calculated as Fe(III), based on Fe(II) and an aqueous alkali carbonate the amount of which is so controlled that the equivalent ratio of an alkali carbonate to the Fe(II) and Fe(III) in the aqueous ferrous salt solution is not less than 1 and the following general formula is satisfied: ##EQU1## and if necessary, 0.01 to 8.

Abstract: Method for recovering cadmium (Cd), nickel (Ni) and iron (Fe) from batteries containing the steps of: (a) reducing the size of the batteries to small pieces and separating the pieces into a coarse fraction and a fine fraction with the coarse fraction further separated into a magnetic and a non-magnetic fraction; (b) leaching out the fraction at approximately 90.degree. C.; (c) removing the Cd; (d) stripping the extractant and separating metallic Cd therefrom; (e) converting Fe-ions into (solid) Fe hydroxide and filtering; (f) recovering Ni from the filtrate.

Abstract: A process for reducing the residual chloride present in iron oxides, particularly in regenerated iron oxides produced from hydrochloric acid waste liquid generated from steel pickling, by post-synthesis treatment of the iron oxides with sulfuric acid optionally followed by drying and calcining. The purified regenerated iron oxides are particular suitable for making iron oxide based catalysts such as ethylbenzene dehydrogenation catalysts and high-grade ferrites.

Abstract: Disclosed herein are a process for producing acicular goethite particles comprising the steps of: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution and/or an aqueous alkali carbonate solution based on Fe.sup.2 + in said aqueous ferrous salt solution so as to oxidize said colloidal ferrous hydroxide or iron-containing colloidal precipitates and to produce acicular goethite nucleus particles, adding to the resultant aqueous ferrous salt reaction solution containing said acicular goethite nucleus particles not less than one equivalent of an aqueous alkali carbonate solution based on Fe.sup.

Abstract: The use of superparamagnetic particles and of paramagnetic materials (such as lanthanide chelates) as contrast agents in magnetometric analysis, especially imaging, and in particular structural and functional, diagnosis or imaging is described.

Abstract: Disclosed herein are a process for producing acicular goethite particles comprising the step of: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution, an aqueous alkali carbonate solution, or an aqueous alkali hydroxide and alkali carbonate solution based on Fe.sup.

Abstract: A process for producing stable, high purity ferrate (VI) employing beta-ferric oxide (beta-Fe.sub.2 O.sub.3), and preferably monohydrated beta-ferric oxide (beta-Fe.sub.2 O.sub.3.H.sub.2 O) as the iron source. An improved process for producing stable, high purity beta-ferric oxide is also disclosed. The process results in the efficient and effective productions of ferrate with high yields and small amounts of waste production. A large portion of the unused product stream can be recycled to the ferrate reactor for the production of additional ferrate.

Abstract: The invention relates to transparent iron oxide pigments having an average particle size, based on the longest needle axis, of less than 0.1 .mu.m, to processes for their production and to their use for pigmenting lacquers and plastics.

Abstract: Disclosed herein is superparamagnetic fine particles of iron oxide having an unsaturated fatty acid adsorbed on the surface of superparamagnetic fine particles and having a magnetization of not less than 50 emu/g, the rate of change of the magnetization of not more than 10%, and an Fe.sup.2+ content (calculated as Fe.sup.2+ /Fe.sup.3+ molar ratio) of 0.16-0.5.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages or these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: Fine particle coal is beneficiated in specially designed dense medium cyclones to improve particle acceleration and enhance separation efficiency. Raw coal feed is first sized to remove fine coal particles. The coarse fraction is then separated into clean coal, middlings, and refuse. Middlings are comminuted for beneficiation with the fine fraction. The fine fraction is deslimed in a countercurrent cyclone circuit and then separated as multiple fractions of different size specifications in dense medium cyclones. The dense medium contains ultra-fine magnetite particles of a narrow size distribution which aid separation and improves magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water from one fraction diluting feed to a smaller-size fraction, and improving both overall coal and magnetite recovery.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety of macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates of these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages of these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: The present invention relates to a method of preparing Si-containing goethite (.alpha.-FeOOH) by the precipitation of Fe(II) salts with an excess of base, and subsequent oxidation in the presence of a silicate solution.

Abstract: A composition containing magnetic metal oxide ultrafine particles, which comprises an aqueous sol of a complex of the magnetic metal oxide ultrafine particles with a polysaccharide, a polysaccharide derivative and/or a protein; and an organic monocarboxylic acid. The composition is free of side effects such as platelet aggregation, is safe for use with living bodies, and, in the case of intravascular administration, has no harmful effects on living bodies, and is useful in fields such as medicine and diagnostic drugs.

Abstract: A method for producing high-purity iron oxide which comprises pulverizing iron ore into powder having an average particle diameter of 20-150 .mu.m, removing fine particles from the powder, and subjecting the powder to wet magnetic separation in a magnetic field of 1000-15000 gauss for the removal of impurities. The iron oxide powder may undergo the secondary steps of pulverization and classification, which are performed by the combination of a wet grinding means and a wet cyclone, and drying and calcination.

Abstract: Disclosed herein are magnetic iron oxide particles which have a spindle shape and a substantially uniform particle size and shape, and are substantially free of dendrites and have a large axial ratio (major axial diameter/minor axial diameter) and an excellent print-through characteristic, and a method of producing the same.

Abstract: Fine particle coal is beneficiated in specially designed dense medium cyclones to improve particle acceleration and enhance separation efficiency. Raw coal feed is first sized to remove fine coal particles. The coarse fraction is then separated into clean coal, middlings, and refuse. Middlings are comminuted for beneficiation with the fine fraction. The fine fraction is deslimed in a countercurrent cyclone circuit and then separated as multiple fractions of different size specifications in dense medium cyclones. The dense medium contains ultra-fine magnetite particles of a narrow size distribution which aid separation and improves magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water from one fraction diluting feed to a smaller-size fraction, and improving both overall coal and magnetite recovery.

Abstract: A method is described for purifying iron oxide, for example, in the form of magnetite or hematite slime, which preferably contains quartz as the impurity. The method comprises calcinating the iron oxide together with alkali carbonate and thereafter leaching with a weak aqueous solution of an acid or a mixture of acids.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety of macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates of these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages of these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: Fine particle coal is beneficiated in specially designed dense medium cyclones to improve particle acceleration and enhance separation efficiency. Raw coal feed is first sized to remove fine coal particles. The coarse fraction is then separated into clean coal, middlings, and refuse. Middlings are comminuted for beneficiation with the fine fraction. The fine fraction is deslimed in a countercurrent cyclone circuit and then separated as multiple fractions of different size specifications in dense medium cyclones. The dense medium contains ultra-fine magnetite particles of a narrow size distribution which aid separation and improves magnetite recovery. Magnetite is recovered from each separated fraction independently, with non-magnetic effluent water from one fraction diluting feed to a smaller-size fraction, and improving both overall coal and magnetite recovery.

Abstract: Iron oxides in the form of platelets are produced by hydrothermal treatment of aqueous suspensions containing iron(III) hydroxide or oxide hydrates in the presence of alkali metal hydroxides and of aluminum and/or silicon compounds in two stages. The normality of the alkali is from 0 2 to 2 N in the first stage and is increased by from 0.2 to 2.5 in the second stage.The two-stage process according to the invention makes it possible to produce hematite pigments which are in the form of platelets, have increased luster, larger particle diameter, improved dispersibility and color hues which can be adjusted as desired.

Abstract: Disclosed herein is superparamagnetic fine particles of iron oxide having an unsaturated fatty acid adsorbed on the surface of superparamagnetic fine particles, and having a magnetization of not less than 50 emu/g, the rate of change of the magnetization of not more than 10%, and an Fe.sup.2+ content (calculated as Fe.sup.2+ /Fe.sup.3+ molar ratio) of 0.16-0.5.

Abstract: The present invention discloses a novel injector for the introduction of iron-containing vapor into a stream of heated oxidized gas wherein the injector has a least two passageways, one for the passage of the iron compound containing vapor and the other for the passage of an insulating gas.

Abstract: A process for producing stable, high purity ferrate (VI) employing beta-ferric oxide (beta-Fe.sub.2 O.sub.3) and as the iron source. The process results in the efficient and effective productions of ferrate with high yields and small amounts of waste production.

Abstract: A process for producing stable, high purity ferrate (VI) employing beta-ferric oxide (beta-Fe.sub.2 O.sub.3), and preferably monohydrated beta-ferric oxide (beta-Fe.sub.2 O.sub.3 .multidot.H.sub.2 O) as the iron source. An improved process for producing stable, high purity beta-ferric oxide is also disclosed. The process results in the efficient and effective productions of ferrate with high yields and small amounts of waste production. A large portion of the unused product stream can be recycled to the ferrate reactor for the production of additional ferrate.

Abstract: Low-silking iron oxide yellow pigments having improved color qualities are produced by a novel method which utilizes both precipitation process and the Penniman process. Pigments are nucleated and grown by precipitation to achieve multiplication factor of 2.5 to 7 and additional pigment growth is carried out by the Penniman process.

Abstract: An improved method of manufacturing superfine iron oxide particles by introducing a gas mixture of a non-oxidizing gas and an iron-containing compound into a stream of heated oxidizing gas, wherein the improvement resides in the use of an insulated injector to introduce the gas mixtures into the heated oxidizing gas stream.

Abstract: A black manganese/iron oxide pigment having a spinel structure and having the composition Mn.sub.x Fe.sub.3-x O.sub.4 wherein x has a value from 0.1 to 0.9, is prepared by the steps:a) oxidizing iron(II) salts or mixtures of iron(II) salts and manganese(II) salts, in solution or after reaction with alkaline precipitants, with manganese dioxide or other compounds containing manganese in high valency,b) additionally oxidizing the salts of (a) to establish an Fe(III) content therein with another oxidizing agent, andc) filtering, washing, drying and grinding the pigment;and the pigment is useful for pigmenting building materials to a black color.