Abstract: The present invention relates to a precursor of a hydrogenation catalyst of carbon dioxide, a method for preparing thereof, a hydrogenation catalyst of carbon dioxide, and a method for preparing thereof. An embodiment of the present invention provides a precursor of a hydrogenation catalyst of carbon dioxide comprising CuFeO2.

Abstract: A thin film structure including a dielectric material layer and an electronic device to which the thin film structure is applied are provided. The dielectric material layer includes a compound expressed by ABO3, wherein at least one of A and B in ABO3 is substituted and doped with another atom having a larger atom radius, and ABO3 becomes A1-xA?xB1-yB?yO3 (where x>=0, y>=0, at least one of x and y?0, a dopant A? has an atom radius greater than A and/or a dopant B? has an atom radius greater than B) through substitution and doping. A dielectric material property of the dielectric material layer varies according to a type of a substituted and doped dopant and a substitution doping concentration.

Abstract: The ferrite powder of the present invention is a ferrite powder containing a plurality of ferrite particles, wherein the ferrite particles each are a single crystal body having an average particle diameter of 1-2,000 nm, and have a polyhedron shape, and wherein the ferrite particles each contain 2.0-10.0 mass % of Sr, and 55.0-70.0 mass % of Fe.

Abstract: The present invention relates to the design and fabrication of a device able to efficiently convert broad-spectrum, microwave to X-ray, electromagnetic energy into electricity. Exciton Scavenger fabrication requires intercalation of rare earth ion containing crystallites, quantum-dots, or nanoparticles within a one-dimensional semiconducting material nanoarchitecture, such as arrays of nanowires or nanotubes.

Abstract: The invention relates to a method for starting up a fluidized bed boiler, such as a circulating fluidized bed (CFB) or a bubbling fluidized bed (BFB) boiler, for operation with a predetermined concentration of ilmenite particles in the bed material. The invention also relates to a method for pre-oxidizing ilmenite, to pre-oxidized ilmenite and to the use of pre-oxidized ilmenite in a fluidized bed boiler.

Abstract: In a zinc oxide powder of the present invention, a content of a water-soluble substance is 0.30% by mass or less, and a mass ratio between an alkali metal and an alkaline earth metal which are included in the water-soluble substance is in a range of 1:2 to 10:1.

Abstract: Catalyst systems and methods for making and using the same are provided. The catalyst system can include a catalyst support, wherein the catalyst support has an average particle size of about 2 microns to about 200 microns. Nanoparticles are adhered to the catalyst support, wherein the nanoparticles have an average particle size of about 2 to about 200 nanometers. A catalyst is supported on the catalyst support.

Abstract: The present invention relates to a process for modifying a layered double hydroxide (LDH), the process comprising, a. providing a water-wet layered double hydroxide of formula: [Mz+1-xM?y+x(OH)2]a+(Xn?)a/r.bH2O??(1) wherein M and M? are metal cations, z=1 or 2; y=3 or 4, x is 0.1 to 1, preferably x<1, more preferably x=0.1-0.9, b is 0 to 10, X is an anion, r is 1 to 3, n is the charge on the anion X and a is determined by x, y and z, preferably a=z(1?x)+xy?2; b. maintaining the layered double hydroxide water-wet, and c. contacting the water-wet layered double hydroxide with at least one solvent, the solvent being miscible with water and preferably having a solvent polarity (P?) in the range 3.8 to 9, as well as to a layered double hydroxide prepared according to that process.

Abstract: Disclosed are methods, systems and devices for operation of non-volatile memory devices. In one aspect, a non-volatile memory device may be placed in any one of multiple memory states in a write operation by controlling a current and a voltage applied to terminals of the non-volatile memory device. For example, a write operation may apply a programming signal across terminals of non-volatile memory device having a particular current and a particular voltage for placing the non-volatile memory device in a particular memory state.

Abstract: A battery capable of improving load characteristics, low-temperature characteristics and high-temperature cycle characteristics is provided. A cathode (13) includes a lithium cobalt complex oxide represented by LiaCoxMIyMIIzO2 (MI includes at least one kind selected from the group consisting of Al, Cr, V, Mn and Fe, MII includes at least one kind selected from the group consisting of Mg and Ca, 0.9?a?1.1, 0.9?x<1, 0.001?y?0.05, 0.001?z?0.05, x+y+z=1), and further includes Zr as a sub-component element. The content of Zr is within a range from 0.01 mol % to 10 mol % both inclusive as a ratio (Zr/Co) of Zr to Co in the lithium cobalt complex oxide.

Abstract: A Bi-substituted rare earth iron garnet single crystal has a composition of R3-xBixFe5-wAwO12 (wherein R denotes one or more rare earth elements among Tb, Y, Eu, Gd, Ho, Yb, Lu, Nd, Tm, La, Sm, Dy, Er, Ce, and Pr and inevitably include Tb; A denotes one or more elements among Ga, Al, In, Sc, Co, Ni, Cr, V, Ti, Si, Ge, Mg, Zn, Nb, Ta, Sn, Zr, Hf, Pt, Rh, Te, Os, Ce, and Lu, 0.7<x?1.5, and 0<w?1.5), contains Pt and does not contain Pb, and additionally contains Mn or at least one Group 2 element, wherein the coefficient ? is set at a value within a numerical range of 0.91±0.05 and ? (which means [M]?(?×[Pt])) is set from ?7.23 atppm to 1.64 atppm.

Abstract: Provided is a lead-free dielectric ceramics having a low leakage current value, and a bismuth iron oxide powder as a raw material thereof. The bismuth iron oxide powder includes at least: (A) grains including a bismuth iron oxide having a perovskite-type crystal structure; (B) grains including a bismuth iron oxide having a crystal structure classified to a space group Pbam; and (C) grains including a bismuth iron oxide or a bismuth oxide having a crystal structure that is classified to a space group I23. The dielectric ceramics are made of bismuth iron oxide in which the bismuth iron oxide crystals having the crystal structure classified to the space group Pbam are distributed at a grain boundary of crystal grains of the bismuth iron oxide crystals having the perovskite-type crystal structure.

Abstract: A set of paramagnetic particles synthesized by co-precipitation methods wherein an alkaline hydroxide solution is mixed with a metal salt solution. The alkaline hydroxide features ammonium hydroxide, potassium hydroxide, sodium hydroxide, or mixtures thereof. The metal salt solution features at least one ferrous salt and at least one tetravalent metal salt selected from Group 4 elements of the Periodic Table. The concentration of the ferrous salt is equal to or greater than the concentration of the tetravalent metal salt. The paramagnetic particles may be used for bioprocessing via magnetic fields. Bioprocessing, for example, may include purifying, concentrating, or detecting biomolecules of interest (e.g., nucleic acids, carbohydrates, peptides, proteins, other organic molecules, cells, organelles, microorganisms, viruses, etc.), or other magnetic field-based processes common to applications in separation science, diagnostics, molecular biology, protein chemistry, and clinical practice.

Abstract: An aspect of the present invention relates to ferromagnetic hexagonal ferrite powder, the average particle size of which is equal to or less than 20 nm, and which comprises, on a particle number basis, equal to or more than 50% of ellipsoid hexagonal ferrite powders satisfying relation (1): 1.2<major axis length/minor axis length<2.0 . . . (1).

Abstract: A composition is described that includes a perovskite of the formula LaMO3, where M is at least one element selected from among iron, aluminum or manganese, in the form of particles dispersed on an alumina or aluminum oxyhydroxide substrate, wherein after calcination at 700° C. for 4 hours, the perovskite is in the form of a pure crystallographic phase, and in that the size of the perovskite particles does not exceed 15 nm. The described composition can be used in the field of catalysis.

Abstract: In a device and a process for purifying water which is contaminated with sulphate ions and heavy metal ions, the water is collected in a water reservoir and a substance having basic activity in water is fed to the water reservoir in such a manner that a precipitant having heavy metal ions is precipitated from the water, wherein at least a subquantity of water is taken off from the water reservoir and is separated into pure water which is substantially freed from sulphate ions and heavy metal ions and dirty water which is enriched with sulphate ions and heavy metal ions. The dirty water is at least in part recirculated to the water reservoir, as a result of which a concentration of sulphate ions in the water reservoir is achieved such that a precipitant having sulphate ions is precipitated from the water.

Abstract: In at least one embodiment, a rechargeable battery is provided comprising an anode having an active material including MSb2O4 having a purity level of greater than 93 percent by weight, wherein M is a metal. The metal may have an oxidation state of 2+ and may include transition metals and/or alkali-earth metals. The anode active material may be synthesized using metal acetates or metal oxides. The synthesis may include heating at a first temperature to remove oxygen and water and reacting at a second temperature to form the MSb2O4 structure, which may be a spinel crystal structure.

Abstract: A carrier core particle for an electrophotographic developer includes a composition expressed by a general formula: MnxFe3?xO4+y (0<x?1, 0<y), a full width at half maximum z of the most intense peak (311) plane in a powder X-ray diffraction pattern satisfying 0.16 (degree) ?z, and a magnetization of 50 emu/g or higher in an external magnetic field of 1000 Oe.

Abstract: The disclosure relates to the oxidation and immobilization of trivalent arsenic from arsenic-containing solutions. The process includes oxidation of trivalent arsenic (As3+) species to the pentavalent state (As5+). A carbon additive (e.g., activated carbon) and oxygen are used to promote the arsenic oxidation processes. After oxidation of arsenic to the pentavalent state, the arsenic can be removed by precipitation to ferric arsenate or calcium arsenate or other arsenic containing compounds known in the art. The oxidation of arsenic can also occur simultaneously with the production and precipitation of ferric arsenate (e.g., scorodite). Ferrous iron can be oxidized to ferric iron in the presence of activated carbon and oxygen.

Abstract: A template-free reverse micelle (RM) based method is used to synthesize pyrochlore nanostructures having photocatalytic activity. In one embodiment, the method includes separately mixing together a first acid stabilized aqueous solution including pyrochlore precursor A and a second acid stabilized aqueous solution including pyrochlore precursor B with an organic solution including a surfactant to form an oil-in-water emulsion. Next, equimolar solutions of the first and second acid stabilized oil-in-water emulsions are mixed together. Then, the mixture of the first and second acid stabilized oil-in-water emulsion is treated with a base to produce a precipitate including pyrochlore precursors A and B. After which, the precipitate is dried to remove volatiles. The precipitate is then calcined in the presence of oxygen to form a pyrochlore nanostructure, such as a bismuth titanate (Bi2Ti2O7) pyrochlore nanorod. The method of synthesizing the pyrochlore nanorod is template-free.

Abstract: A method of forming a Fischer-Tropsch catalyst by providing at least one metal nitrate solution, combining each of the at least one metal nitrate solutions with a precipitating agent whereby at least one catalyst precipitate is formed, and incorporating a strong base during precipitation, subsequent precipitation, or both during and subsequent precipitation. Catalysts produced via the disclosed method are also provided.

Abstract: A method of: dissolving salts of a first metal ion and a second metal ion in water to form a solution; heating the solution to a temperature of about 80-90° C.; and adding a base to the solution to precipitate nanoparticles of an oxide of the first metal ion and the second metal ion.

Abstract: The present invention provides an electrocatalytic material and a method for making an electrocatalytic material. There is also provided an electrocatalytic material comprising amorphous metal or mixed metal oxides. There is also provided methods of forming an electrocatalyst, comprising an amorphous metal oxide film.

Abstract: A composition comprising: a metal oxide of a first metal ions and second metal ions; an electrically conductive material; and a binder material. The second metal ions have a higher oxidation state than the first metal ions. The presence of the second metal ion increases the number of metal cation vacancies. A method of: dissolving salts of a first metal ion and a second metal ion in water to form a solution; heating the solution to a temperature of about 80-90° C.; and adding a base to the solution to precipitate nanoparticles of a metal oxide of the first metal ion and the second metal ion.

Abstract: Provided is a lead-free dielectric ceramics having a low leakage current value, and a bismuth iron oxide powder as a raw material thereof. The bismuth iron oxide powder includes at least: (A) grains including a bismuth iron oxide having a perovskite-type crystal structure; (B) grains including a bismuth iron oxide having a crystal structure classified to a space group Pbam; and (C) grains including a bismuth iron oxide or a bismuth oxide having a crystal structure that is classified to a space group I23. The dielectric ceramics are made of bismuth iron oxide in which the bismuth iron oxide crystals having the crystal structure classified to the space group Pbam are distributed at a grain boundary of crystal grains of the bismuth iron oxide crystals having the perovskite-type crystal structure.

Abstract: The present invention relates to a method for preparing a nickel ferrite nanoparticle composite having an inverse spinel structure obtained using a polyol process, a nickel ferrite nanoparticle composite prepared by the method, and a method for selectively binding, separating or purifying a specific protein using the nickel ferrite nanoparticle composite. The method for preparing a magnetic nanoparticle composite according to the present invention includes a one-step hydrothermal synthesis process, and thereby the magnetic nanoparticle composite can be prepared in a simple and economic manner. Also, the nickel ferrite nanoparticles synthesized by the method of the present invention can be strongly magnetic, and also exist in the form of Ni2+ in which Ni binds to a specific protein, thereby preventing loss of separability caused by additional oxidation and repeated recycling of the nanoparticles.

Abstract: The present invention relates to a process for preparing magnetite (Fe3O4) or derivatives thereof, comprising the steps: a) preparing an aqueous solution A of a Fe(III) salt, b) preparing an aqueous solution B of an iodide salt, c) mixing solutions A and B to obtain a first precipitate, d) separating the first precipitate to obtain a filtrate, e) hydrolyzing the filtrate obtained in step d) by adjusting the pH to about 8.5-9 or above, preferably 9, in order to obtain a second precipitate, and f) separating the second precipitate.

Abstract: It is an object of the present invention to provide a positive electrode material having a large ratio of the discharge capacity around 4 V to the total discharge capacity including the discharge capacity at 4V or lower while making the discharge capacity around 4 V sufficient, for the purpose of providing a lithium secondary battery using a lithium transition metal phosphate compound excellent in thermal stability, utilizing the discharge potential around 4V (vs. Li/Li+) that is higher than the discharge potential of LiFePO4, and being advantageous with respect to the detection of the end of discharge state, and a lithium secondary battery using the same. The present invention uses a positive active material for a lithium secondary battery containing a lithium transition metal phosphate compound represented by LiMn1-x-yFexCoyPO4(0.1?x?0.2, 0<y?0.2).

Abstract: A ferrite powder according to the present invention includes a laminar structure exhibiting a state where W-type ferrite phases are laminated in an easy direction of magnetization, the W-type ferrite phases including a compound expressed by AM2Fe16O27, where A, M, Fe, and O represent a first metal element (Sr, Ba, Ca, Pb, etc), a second metal element (Fe, Zn, Cu, Co, Mn, Ni, etc), iron, and oxygen, respectively. This ferrite particle is obtained through: a shape forming step that shapes a mixed powder in a magnetic field to obtain a compact, the mixed powder including for example an M-type ferrite particle including a compound expressed by AFe12O19 and a spinel-type ferrite particle (S-type ferrite particle) including a compound expressed by MFe2O4; a calcination step that calcines the compact to obtain a calcined substance; and a milling step that mills the calcined substance.

Abstract: Disclosed herein are a ferrite powder not including pores in a surface thereof, a method for preparing the same, and a common mode noise filter including the same as a material for a magnetic layer. The spherical ferrite powder in which the pores in the surface thereof are removed as a magnetic layer of the common mode noise filter has high density, such that dispersibility is improved, thereby making it possible to improve adhesive strength with a polymer binder to be mixed. In addition, the adhesive strength between the polymer binder and the ferrite powder is improved, such that at the time of manufacturing or mounting of a chip, a defect such as a crack generated by a thermal impact due to a lack of adhesive strength between the ferrite powder and the polymer binder may be suppressed, thereby securing the reliability with respect to the thermal impact.

Abstract: The present invention relates to the field of polymer chemistry and more particularly to multiblock copolymers and micelles comprising the same. Compositions herein are useful for drug-delivery applications.

Abstract: The invention is directed to a method for producing a film of porous carbon, the method comprising carbonizing a film of an ionic liquid, wherein the ionic liquid has the general formula (X+a)x(Y?b)y, wherein the variables a and b are, independently, non-zero integers, and the subscript variables x and y are, independently, non-zero integers, such that a·x=b·y, and at least one of X+ and Y? possesses at least one carbon-nitrogen unsaturated bond. The invention is also directed to a composition comprising a porous carbon film possessing a nitrogen content of at least 10 atom %.

Abstract: A biotemplated nanomaterial can include a crystalline perovskite.

Abstract: A catalyst for oxidative dehydrogenation of organic compounds is provided by forming a solution of catalyst precursor components comprised of Fe+3 and Zn+2 cations and at least one other modifier element cation in water to form an aqueous solution of the catalyst precursor components. The modifier element cation has a standard reduction potential of from greater than about ?2.87 E° (V) to less than about ?0.036 E° (V) with a valence of +2. A base is separately and simultaneously added to the aqueous solution in amounts to maintain the pH of the aqueous solution at a pH of from about 8.5 to about 9.5 as the catalyst precursor components. The catalyst precursor components are allowed to react and precipitate out of solution as a precipitate. The resulting precipitate is calcined to form a modified zinc ferrite catalyst compound.

Abstract: The present invention relates to a complex oxide catalyst of Bi/Mo/Fe and an oxidative dehydrogenation of 1-butene in the presence of a catalyst herein. A catalyst of the present invention is superior to the conventional Bi/Mo catalyst in thermal and mechanical stabilities, conversion and selectivity toward 1,3-butadiene, while showing a long-term catalytic activity.

Abstract: The present invention refers to a method for the synthesis of an adsorbing material consisting of a single-phase tetravalent manganese feroxyhite (?-Fe(1-x)MnxOOH), in which a percentage of 0.05 to 25% of iron atoms has been isomorphically substituted by Mn(IV) atoms. Its production takes place in a continuous two-stage flow reactor at weakly acidic conditions (pH 4-7) and high redox (300-800 mV). The material can be used for the removal of both pentavalent and trivalent arsenic as well as other heavy metals form water. More specifically, its adsorption capacity and selectivity depending on the trivalent and pentavalent arsenic water content, are determined by the manganese percentage and the compact or hollow morphology of its structural unit which can be both controlled by the parameters of the synthesis procedure.

Abstract: The invention provides for a sorbent composition comprising Fe(IV), Fe(V), Fe(VI), and/or a mixture of thereof. (“the ferrate compound”), wherein upon exposure to CO2 and moisture, the sorbent composition absorbs CO2 and co-generates O2, and materials, systems and methods of using this sorbent composition.

Abstract: Provided is an arsenic-containing solid comprising 100 parts by mass of a scorodite-type iron-arsenic compound and at least 1 part by mass of an iron oxide compound added thereto, in which the scorodite-type iron-arsenic compound is produced by adding an oxidizing agent to an aqueous acidic solution that contains a 5-valent arsenic (V) ion and a 2-valent iron (II) ion, then promoting the precipitation of an iron-arsenic compound with stirring the liquid, and finishing the precipitation thereof within a range where the pH of the liquid is at most 1.2. The iron oxide compound includes goethite, hematite and their mixture, preferably having a BET specific surface area of at least 3 m2/g, more preferably at least 20 m2/g.

Abstract: A composition comprising: a metal oxide of a first metal ions and second metal ions; an electrically conductive material; and a binder material. The second metal ions have a higher oxidation state than the first metal ions. The presence of the second metal ion increases the number of metal cation vacancies. A method of: dissolving salts of a first metal ion and a second metal ion in water to form a solution; heating the solution to a temperature of about 80-90° C.; and adding a base to the solution to precipitate nanoparticles of a metal oxide of the first metal ion and the second metal ion.

Abstract: The present invention is to provide a cathode catalyst capable of increasing the initial capacity, decreasing the charging voltage and improving the capacity retention of a rechargeable metal-air battery, and a rechargeable metal-air battery having high initial capacity, excellent charge-discharge efficiency, and excellent capacity retention. A cathode catalyst for a rechargeable metal-air battery comprising NiFe2O4, and a rechargeable metal-air battery comprising an air cathode containing at least NiFe2O4, an anode containing at least a negative-electrode active material and an electrolyte interposed between the air cathode and the anode.

Abstract: A Fe—Ni compound oxide is used as an oxygen carrier for chemical looping combustion process, wherein the structure of the Fe—Ni compound oxide is a single-phase spinel structure. The method for manufacturing the Fe—Ni compound oxide of the invention includes the following steps: mixing Fe2O3 and NiO to obtain a mixing solution and ball milling the mixing solution by the solid state ball milling method; drying the mixing solution to obtain a precipitate; granulating the precipitate and then calcining the granulated precipitate to obtain the Fe—Ni compound oxide. Accordingly, the Fe—Ni compound oxide manufactured by the method of the invention is provided with high oxidation rate and high reduction rate, and capable of keeping loops and producing hydrogen gas.

Abstract: Disclosed is a superconducting compound which has a structure obtained by partially substituting oxygen ions of a compound, which is represented by the following chemical formula; LnTMOPh [wherein Ln represents at least one element selected from Y and rare earth metal elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu), TM represents at least one element selected from transition metal elements (Fe, Ru, Os, Ni, Pd and Pt), and Pn represents at least one element selected from pnictide elements (N, P, As and Sb)] and has a ZrCuSiAs-type crystal structure (space group P4/nmm), with at least one kind of monovalent anion (F?, Cl? or Br?). The superconducting compound alternatively has a structure obtained by partially substituting Ln ions of the compound with at least one kind of tetravalent metal ion (Ti4+, Zr4+, Hf4+, C4+, Si4+, Ge4+, Sn4+ or Pb4+) or a structure obtained by partially substituting Ln ions of the compound with at least one kind of divalent metal ion (Mg2+, Ca2+, Sr2+ or Ba2+).

Abstract: A perovskite oxide represented by a general expression, (Aa, Bb)(Cc, Dd, Xx)O3. (where, A: an A-site element, A=Bi, 0<a, B: one or more types of A-site elements, 0?b<1.0, C: an B-site element, C=Fe, 0 <c<1.0, D: one or more types of B-site elements, 0?d<1.0, 0<b+d, X: one or more types of B-site elements, the average valence of which is greater than the average valence of C and D in chemical formula, 0<x<1.0, (average valence of A-site in chemical formula) +(average valence of B-site in chemical formula)>6.0, O: oxygen, and standard molar ratio among A-site elements, B-site elements, and oxygen is 1:1:3, but it may deviate from the standard within a range in which a perovskite structure is possible.

Abstract: The invention relates to the use of a novel type of active mass in looping redox processes. Said mass contains a spinel of formula Cu1?xFe1+xAlO4 with 0?x?0.1. The active mass according to the invention has a high oxygen transfer capacity and improved oxidation and reduction rates.

Abstract: Embodiments of the present disclosure provide for nanoparticles, methods of making nanoparticles, methods of using the nanoparticles, and the like. Nanoparticles of the present disclosure can have a variety of morphologies, which may lead to their use in a variety of technologies and processes. Nanoparticles of the present may be used in sensors, optics, mechanics, circuits, and the like. In addition, nanoparticles of the present disclosure may be used in catalytic reactions, for CO oxidation, as super-capacitors, in hydrogen storage, and the like.

Abstract: A negative-electrode active material includes a compound that has a pseudobrookite structure.

Abstract: Provided is a Bi-substituted rare earth iron garnet single crystal which has a composition of R3-xBixFe5-wAwO12, wherein R denotes one or more rare earth elements among Y, Eu, Gd, Ho, Yb, Lu, Nd, Tm, La, Sm, Dy, Er, Ce, and Pr while definitely including Gd, A denotes one or more elements among Ga, Al, In, Sc, Co, Ni, Cr, V, Ti, Si, Ge, Mg, Zn, Nb, Ta, Sn, Zr, Hf, Pt, Rh, Te, Os, Ce, and Lu, 0.7<x?1.5, and 0<w?1.5, does not contain Pb and contains Pt, and additionally contains M which denotes Mn or at least one Group 2 element, wherein a coefficient ? is set to any value within a numerical range of 0.815±0.035 and ? (which means (?×[M])?[Pt]) is set from ?0.40 atppm to 3.18 atppm.

Abstract: 1-100 nm metal ferrite spinel coatings are provided on substrates, preferably by using an atomic layer deposition process. The coatings are able to store energy such as solar energy, and to release that stored energy, via a redox reaction. The coating is first thermally or chemically reduced. The reduced coating is then oxidized in a second step to release energy and/or hydrogen, carbon monoxide or other reduced species.

Abstract: Scorodite-type iron-arsenic compound particles in which the particle surface layer part comprise an iron-rich layer having an Fe/As molar ratio of at least 1.24. The particles can be obtained in a reaction process of feeding an oxygen-containing gas to an aqueous solution containing an arsenic(V) ion and an iron(II) ion to precipitate a scorodite-type iron-arsenic compound crystal at a pH of at most 2, in which an oxidizing agent is further added to the liquid before the end of the reaction (treatment A). The particles may also be obtained by a method comprising keeping a scorodite-type iron-arsenic compound particle of good crystallinity in contact with an iron ion-containing aqueous solution having a controlled pH of from 2 to 9 at 0 to 90° C. (treatment B). The scorodite-type iron-arsenic particles have good filterability and excellent arsenic release-preventing effect.

Abstract: To provide a method for improving a coercive force of epsilon-type iron oxide particles, and an epsilon-type iron oxide. Specifically, to provide a method for improving the coercive force of an epsilon-type iron oxide comprising: substituting Fe-site of the epsilon-type iron oxide with other element, while not substituting Fe of D-site in the epsilon-type iron oxide with other element, and the epsilon type iron oxide.