Showing papers on "Jet mill published in 1998"

Method for fluidized bed jet mill grinding

Abstract: The method and apparatus for impact pulverization by directing at least one high-velocity gas or vapor jet exiting from a nozzle into a fluidized bed of milling material, wherein the gas or vapor jet is jointly accelerated with a portion of the milling material and thereafter directed into the fluidized bed of milling material.

Fluidized bed type jet mill

Abstract: PROBLEM TO BE SOLVED: To provide a jet mill excellent in grinding efficiency. SOLUTION: A fluidized bed type jet mill including at least a grinding chamber 3 having a center axis (m), the collision member 7 arranged in the grinding chamber and having the center on the center axis (m) of the grinding chamber 3 nozzles 5 ejecting a high speed gas to the center axis (m) of the grinding chamber and, in the nozzle axis (n) and the vertical cross section (p) including the center axis (m) of the grinding chamber, the angle α formed by the nozzle axis (n) and the collision member 7 is set to 25-80°. COPYRIGHT: (C)2000,JPO

Equipment and method for producing ultra fine dry powders by means of a high-energy power gas

Abstract: The invention concerns an equipment and a method for producing ultra fine dry powders by means of an energetic power gas using an opposed jet mill (2.3) and a classifier (3) and a device (5, 6) for separating gas and solids connected thereto. The invention is characterized in that the device for separating gas and solids from each other (5, 6) comprises at least one ion jet tube (5, 6) with a concentrically extending high voltage electrode (5.4) provided with a large number of radial ion jet tips (5, 6), whereby the solid particles of the gas solid suspension led at a low speed through the ion jet tube (5, 6) are attached to the inner walls of the tube (5, 6) at the influence of ion jets developed by the ion jet tips (5.6), from which walls the particles are easily recoverable in exactly limited fractions, and the purified power gas is arranged to discharge from the opposite end of the ion jet tube (5, 6), and that in order to control the operation of the equipment an on-line operating measuring and analysing device (4), coupled to a control unit of the equipment, is mounted into the discharge channel (3.5) for the fine fraction in order to determine the particle size and the fineness of the solid particles of the gas-solid suspension flowing through the discharge channel (3.5).

Preparation of dry chitin powder or dry chitosan powder

Abstract: PROBLEM TO BE SOLVED: To obtain a dry chitin or chitosan powder efficiently at a low cost by directly charging and griding hardly grindable chitin or chitosan in the state of contg. water into and with a grinder without drying the chitin or chitosan. SOLUTION: Water-contg. chitin or chitosan is ground with a grinder to give a dry chitin or chitosan powder. Drying is carried out simultaneously with the grinding with a grinder. A pneumatic jet mill is used as the grinder. Before the grinding, the water content is 20-80% and the average particle size, 300 μm-1 cm; and the powder obtd. by grinding has a water content of 10% or lower and an average particle size of 300 μm or lower. The degradation in physical properties due to grinding is usually such that the viscosity retention after the grinding with a pneumatic jet mill is about 15-35%; however, when the water content is 20-80%, the viscosity retention after the grinding with a pneumatic jet mill is 25-45%, thus exhibiting a decreased degradation in physical properties. COPYRIGHT: (C)2000,JPO

Production of ito sintered compact

Abstract: PROBLEM TO BE SOLVED: To provide an ultrahigh density ITO(indium oxide-tin oxide) sintered compact not generating a nodule during sputtering, suppressing the generation of foreign matter and having 7.08g/cm sintering density. SOLUTION: At least tin oxide powder is pulverized by collision with each other or with a colliding body in a flow of gas and it is mixed with indium oxide powder, compacted and sintered to produce the objective ITO sintered compact. After the pulverization, 2-90% of the tin oxide powder has 0.2-10μm particle diameter and a jet mill may be used for the pulverization.

Electrifying powder for formation of circuit and multilayered wiring board using that

Abstract: PROBLEM TO BE SOLVED: To obtain dense packing of conductive metal particles in a wiring pattern. SOLUTION: The electrifying powder 10 for the formation of a circuit has a structure of uniform dispersion of first conductive metal powder 11, second conductive metal powder 12 having a smaller average particle size than that of the first conductive metal powder, a charge control agent 13 and an adhesion enhance agent 14 in a hot-melt resin 15. First, spherical copper particles having 0.8 μm average particle size as the first conductive metal powder 11, spherical copper particles having 0.4 μm average particle size as the second conductive metal powder 12, an azo metal dye as the charge control agent 13, silica as the adhesion enhancing agent 14 and a styrene-acryl copolymer as the hot-melt resin 15 are mixed in the weight ratio of 30:50:1:1:18. Then the mixture is molten by heating while kneaded in a kneading machine, coarsely pulverized in a cutter mill and then finely pulverized in a jet mill. Then the pulverized material is subjected to winnowing to obtain the electrifying powder 10 for the formation of a circuit having 8.0 μm average particle size. COPYRIGHT: (C)1999,JPO

A method for homogeneously mixing a uranium/plutonium mixed oxide

Abstract: A method for homogeneously mixing a uranium/plutonium mixed oxide which is used for the preparation of a uranium/ plutonium mixed oxide fuel. The method comprises weighing a uranium oxide powder, a plutonium oxide powder, and a dry recovered powder prepared by grinding a uranium/plutonium mixed oxide sinter so as to give a predetermined plutonium enrichment; roughly mixing these powders together by means of a mixer; pulverizing and homogeneously mixing the roughly mixed powder by means of a jet mill (16); discharging the homogeneously mixed powder together with compressed air from the jet mill; and separating the mixed powder from the air by means of a first-stage cyclone (18) to recover at least 90% of the discharged powder.

A method for homogeneous mixing uranium / plutonium mixed oxide

Abstract: A method for homogeneously mixing a uranium/plutonium mixed oxide which is used for the preparation of a uranium/plutonium mixed oxide fuel. The method comprises weighing a uranium oxide powder, a plutonium oxide powder, and a dry recovered powder prepared by grinding a uranium/plutonium mixed oxide sinter so as to give a predetermined plutonium enrichment; roughly mixing these powders together by means of a mixer; pulverizing and homogeneously mixing the roughly mixed powder by means of a jet mill; discharging the homogeneously mixed powder together with compressed air from the jet mill; and separating the mixed powder from the air by means of a first-stage cyclone to recover at least 90% of the discharged powder.

Boron nitride powder and its production

Abstract: PROBLEM TO BE SOLVED: To improve dispersibility of boron nitride powder in a resin by allowing the boron nitride powder to include specific amount of coagulated particles having a prescribed size and specifying the average particle diameter SOLUTION: This boron nitride powder includes >=60wt%, preferably >=70wt% particles having =30wt%, preferably >=40wt% particles having /g, more preferably 2-15m /g The boron nitride powder is produced by milling using a jet mill A film formed out of a resin (eg a polyimide) dispersing the powder has no formation of a foreign substance and is excellent in strength

Production of mixed inorganic filler

Abstract: PROBLEM TO BE SOLVED: To produce a mixed inorganic filler with a high density in a short time by a simple process by previously mixing two or more kinds of inorganic substances with different particle sizes, pulverizing the mixture with high speed air flow, and then sorting the pulverized mixture in the case of producing the mixed inorganic filler from two or more kinds of inorganic substances with different particle sizes. SOLUTION: Common fillers such as silica, alumina, zirconia, aluminum hydroxide, etc., are among the inorganic particles to be used. Two or more kinds of such inorganic particles are use. In this case, one of the particle preferably has 0.01-1μm particle size. At the time of mixing these inorganic particles, the particles are previously mixed by using a mixing apparatus in a dry and batch manner and the pre-mixed coarse powder mixture is pulverized by high speed air flow. The apparatus to be used for mixing and pulverizing the powder is preferably a jet mill. After that, in the sorting process, the sorting is carried out by using a centrifugal mixing type sorting apparatus, especially mesh type sorting apparatus, and consequently, a uniform mixture is produced.

Manufacture of material powder for fesi2 thermoelectric conversion element

Abstract: PROBLEM TO BE SOLVED: To restrain oxidation of material alloy powder and enable inexpensive manufacture of material fine powder, by roughly crushing a dissolution ingot of iron silicon containing a specified quantity of silicon in an inert gas atmosphere, then carrying out jet mill crushing using an inert gas, and adding and mixing a specified quantity of transition metal powder. SOLUTION: After a dissolution ingot of iron silicon containing 50% by weight or more of silicon is roughly crushed in an inert gas atmosphere, jet mill crushing is carried out using an inert gas. Then, transition metal powder is added and mixed at an atomic ratio of the powder transition metal element to silicon being 1:2. For example, in addition to a mixing method using a V- cone, a method for stirring in an inert gas atmosphere using a universal mixer, a planetary mixer or a speed mixer is effective. In addition, in order to improve the fluidity of the powder at the time of press molding, reduce the simplex unevenness, and improve the dimensional accuracy and sintering density, it is effective to form grains by a spray drier unit.

Process for the concentration of dilute sulfuric acid in a vacuum evaporating system making use of process heat

Abstract: Dilute sulfuric acid circulating in a titanium dioxide manufacturing plant is concentrated using a heat exchanger heated by gases exhausted from the steam jet mill used in TiO2 manufacture. The dilute acids are passed through a forced circulation evaporating plant consisting of the tubular heat exchanger and an evaporation vessel. The hot exhaust gases from the steam jet mill are passed through a dust filter on their way to the heat exchanger. The H2SO4 is concentrated to about 42-52 wt.%.

Manufacturing method of rare earth-iron-nitrogen magnetic material

Abstract: PROBLEM TO BE SOLVED: To relax the shock acting on magnetic powder at the time of collision of the powder and restrain the stress acting on a crystal structure at the time of pulverization, by adding and mixing a lubricant to a magnetic material and then pulverizing the mixture. SOLUTION: Magnetic powder of a magnetic material expressed by a formula RaFe(100-a-b-c)MbNc is prepared (with R contains at least one type of rare earth element including Y and Sm as an essential element at approximately 50at% or more, and M is at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, while a, b and c represent atomic percentages having the relations of 5<=a<=20, 0<=b<=5 and 3<=c<=30, with the remaining portion being Fe). Then, fatty acid as a lubricant is added to and mixed with the magnetic powder. The mixture is then pulverized by using a jet mill, more preferably, an airstream jet mill. Thus, the fatty acid film is caused to exist between colliding substances at the time of collision, thereby providing good lubricity. Thus, the shock acting on the magnetic powder at the time of collision is relaxed, thereby reducing the quantity of defects introduced by pulverization and exhibiting excellent magnetic property.