Thermoelectric materials based on tetrahedrite structures for thermoelectric devices and methods for producing thermoelectric materials and devices are disclosed. The thermoelectric device has a pair of conductors and a p-type thermoelectric material disposed between the conductors. The thermoelectric material is at least partially formed of a hot pressed high energy milled tetrahedrite formed of tetrahedrite ore and pure elements to form a tetrahedrite powder of Cu12-xMxSb4S13 disposed between the conductors, where M is at least one of Zn and Fe.

An iron-based oxide magnetic particle powder has a narrow particle size distribution a small content of fine particles that do not contribute to magnetic recording characteristics, and a narrow coercive force distribution, to enhance magnetic recording medium density. Neutralizing an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of the Fe sites by adding an alkali to make pH of 1.5 or more and 2.5 or less, adding a hydroxycarboxylic acid, and further neutralizing by adding an alkali to make pH of 8.0 or more and 9.0 or less are performed at 5 C. or more and 25 C. or less. A formed iron oxyhydroxide precipitate containing the substituting metal element is rinsed with water, then coated with silicon oxide, and then heated thereby providing e-type iron-based oxide magnetic particle powder. The rinsed precipitate may be subjected to a hydrothermal treatment.

Disclosed herein are compositions and methods of making a hard magnetic material from iron oxide fines, the hard magnetic material having a general formula MFe.sub.xO.sub.y. In one aspect, the method comprises a) providing an iron oxide fine; b) providing a metal carbonate of a general formula M.sub.x(CO.sub.3).sub.y; c) mixing the iron oxide fine and the metal carbonate to form a mixture; d) calcining the mixture of the iron oxide fine and the metal carbonate; wherein M is a divalent metal ion.

An object of the present invention is to provide ferrite particles for a filtering medium excellent in filtration ability having a small apparent density, capable of various properties maintained in the controllable state and filling a specified volume with a small amount, and a filtering medium made from the ferrite particles. In order to achieve the object, ferrite particles provided an outer shell structure containing Ti oxide for a filtering medium, and a filtering medium made from the ferrite particles are employed.

An object of the present invention is to provide ferrite particles for a filtering medium excellent in filtration ability having a small apparent density, capable of various properties maintained in the controllable state and filling a specified volume with a small amount, and a filtering medium made from the ferrite particles. In order to achieve the object, ferrite particles provided an outer shell structure containing Ti oxide for a filtering medium, and a filtering medium made from the ferrite particles are employed.

Disclosed herein are embodiments of composite hexagonal ferrite materials formed from a combination of Y phase and Z phase hexagonal ferrite materials. Advantageously, embodiments of the material can have a high resonant frequency as well as a high permeability. In some embodiments, the materials can be useful for magnetodielectric antennas.

The present invention relates to H.sub.2S removal that may be contained in biogas or industrial process gases in concentrations of 35-15000 ppm. By means of nanoparticles of manganese ferrite MnxFe.sub.3-xO.sub.4 with x=0%, 0.1%, 0.3% and 0.5%, obtained by means of chemical co-precipitation from solutions of chlorides and at a temperature below 100 C. With surface area of 142-240 m.sup.2/g and particle size of 7-9 nm. And that is done through a set of components such as: pressure regulating valve, a flow meter, a piston flow rector, a pressure gauge, a three-way valve, a biogas measuring device, a gas scrubber and a burner biogas.

An object is to provide the ferrite particles used as a magnetic filler or a raw material for a molded product excellent in dispersibility as a powder and excellent in uniformity after molding and result the surface with small unevenness; and a method of manufacturing the particles. To achieve the object, MnMg ferrite particles having an average particle size of 1 to 2000 nm and having a spherical shape are employed. It is preferable that the ferrite particles are produced by a method including subjecting of a ferrite raw material obtained through preparation of a ferrite composition to flame-spraying in air for ferritization followed by rapid cooling for solidifying of the ferrite.

A hydrothermal synthesis for LiFePO.sub.4 is provided. First, each raw material solution is prepared using a degassed water in advance, second, those solution are mixed by dripping in a fixed order, and then those materials are reacted in a hydrothermal synthesis, so that LiFePO.sub.4 is obtained in a predesigned form.

The present invention relates to method/process of synthesis for ferrate synthesis. More specifically, it includes method for producing a liquid ferrate solution of oxidation of plus 6 stage, and discusses the apparatus and the raw materials and an improved greener process for synthesizing stable, high purity ferrate (VI) used for treating wastewater. The synthesis method involves three stages, namely, oxidation of hematite ore, followed by ferrate with chlorine under alkaline conditions and addition of stabilizing agent to improve shelf life of liquid ferrate solution for minimum 6 weeks. The process results in the efficient and effective productions of ferrate with high yields and small amounts of waste production. The synthesized chemical ferrate (VI) through the present invention has resulted in the effective reduction of BOD, COD and TSS.