Showing papers on "Jet mill published in 1994"

Method for manufacturing high strength isotropic graphite piston components

Abstract: A method for manufacturing a high strength isotropic graphite including a kneading step to mix an aggregate consisting of carbonaceous fine powder with a pitch binder a molding step to mold the raw material prepared by re-pulverizing the kneaded mixture using rubber press method and a carbonizing and graphitizing step to fire carbonize and graphitize the molded product. The aggregate uses a fine mosaic coke powder as the aggregate, which mosaic coke powder is finely pulverized in a jet mill to an average particle size of 1 μm or less and a maximum particle size of 5 μm or less, and has a surface average electrostatic field intensity of 1.2×104 esu/cm2 or more. The invention provides a high strength isotropic graphite having a high bending strength of 120 MPa or more, which is suitable for piston components of gasoline engines and provides a method for manufacturing high strength isotropic graphite.

Apparatus for coating jet milled particulates onto a substrate by use of a rotatable applicator

Abstract: A film coating apparatus and feed system therefor which comprise: (a) a feeder for dispensing a particulate material at a substantially uniform rate; (b) a jet mill which receives the particulate material from the feeder, wherein the jet mill processes the particulate material by breaking up particle agglomerations and by dispersing substantially uniformly the particulate material into a carrier fluid to result in a processed particulate material; (c) a substrate coating assembly comprising a rotatable applicator; and (d) a tubing having a material receiving end to receive the processed particulate material from the jet mill and a material feeding end to dispense the processed particulate material to the substrate coating assembly, wherein the feeding end is adjacent the surface of the applicator.

Method and apparatus for solid material grinding

Abstract: The invention relates to a method and to an apparatus for crushing and fine grinding of solid particulate materials, e.g. clinkers used in cement, utilizing a conventional ball mill. More particularly, the invention involves use of such a ball mill in the primary crushing of the material (which use is advantageously limited to the preliminary crushing operation requiring minimum energy consumption), and of a jet mill in the final crushing (conventionally done in a ball mill also). The jet mill is incorporated in a secondary independent grinding circuit which grinds the material to the required fineness value. The method of usage of the high capacity jet mill in combination with the ball mill, which is operated in the preliminary crushing mode differing from the conventional mode, considerably decreases energy consumption for the grinding process and can be used during the modernization of existing ball mills in different fields of industry such as in cement production--for grinding of cement precursors such as raw material mixtures and clinker, slags, quartz sands, carbonate-containing raw material, in ceramic articles manufacturing--for fine dispersity powder production, compound materials and others.

Manufacturing for material of r-f-b-based permanent magnet

Abstract: PURPOSE: To provide magnetic powder with uniform grain distribution effectively, by forming ingot pieces with a given thickness from an R-Fe-B-based molten alloy in a strip-casting method, breaking the ingot naturally in hydrogen occlusion, stabilizing it in dehydrogen treatment, and milling the alloy powder with a given additive of lubrication in a jet mill. CONSTITUTION: R-Fe-B-based molten alloy is founded into fine pieces with separated construction of 5μm or below from a R-rich phase, along with plate thickness of 0.03 to 10m. By feeding H, gas of 200Torr to 50kg/cm , collapsed alloy powder is obtained, and dehydrized. A lubricant of 0.02 to 5.0wt.% is added to the raw powder of average grain size of 10 to 500μm, and the powder is finely ground. After, a mold is filled with the fine powder of average grain size of 1 to 10μm, along with bulk density of 1.4 to 3.5g/cm , a pulse magnetic field of 10kOe or above is applied instantaneously so that the powder has orientation. Then, molding, sintering and aging steps are carried out. In this way, fine grinding with efficiency is carried out and a magnet with high iHc can be obtained.

Kneading and crushing of carbonous raw material

Abstract: PURPOSE:To enable to decrease the number of steps from 3 to 4 steps required in conventional processes to only one step by jetting in a binding agent from at least one of gas jetting inlets in the case of crushing a carbonous raw material in a jet mill crusher CONSTITUTION:In a horizontal cross section diagram of a jet-mill crusher a ceramic liner 2 is inserted in a mill frame 1 and a carbonous raw material (eg raw coke from coal tar pitch) is blown into a crushing zone 10 from a pressure nozzle 3 through a venturi nozzle by compressed air Compressed air is, as a jet stream making gas, blown into from griding nozzles 4, 5, 6, 7, 8 and 9 A binding agent (eg a molten liquid binder pitch) having 90-95 degC softening point is fed from the nozzle 4 at 30-120 ptswt ratio based on 100 ptswt carbonous raw material In the crushing zone 10 raw materials collide themselves to crush and binder coated micro-particles having <=30mum average size are obtained from a central outlet

Synthesis of fine particle-YBCO superconductor by wet-type jet mill with methyl-ethyl-ketone

Abstract: Fine particle-YBCO was produced from the high quality superconductor YBCO powders by wet-type jet mill in which YBCO particles collided in a high pressure flow of MEK (methyl-ethyl-ketone:CH3COCH2CH3). In order to obtain fine and highly homogeneous particles of YBCO superconductor, YBCO powders were produced by crushing Y1Ba2Cu3Ox pellets with a pulverizer first, and then YBCO powders were pulverized by the wet-type jet mill in which maximum processing pressure is 1300 kgf/cm2 and maximum running speed in the orifice is 300 m/sec. As a result, when the mill is operated at a pressure of 1300 kg/cm2, the average particle size of ∼ 0.5 μm is obtained in 10 passes.

Process for the production of high-strength isotropic graphite and of piston components for Otto engines which are made of high-strength isotropic graphite

Abstract: Process for producing a high-strength isotropic graphite, comprising a kneading step for mixing an aggregate comprising fine, carbon-containing powder and a pitch binder, a shaping step for shaping the raw material which has been prepared by repulverising the kneaded mixture using the rubber pressing method and a carbonisation and graphitisation step for firing to carbonise and graphitise the shaped product. The aggregate uses a fine mosaic-like coke powder as aggregate, whose mosaic-like coke powder is very finely milled in a jet mill to an average particle size of 1 mu m or less and a maximum particle size of 5 mu m or less and has an average electrostatic field strength at the surface of 1.2 x 10 esE/cm or more. The invention provides a high-strength isotropic graphite which has a high flexural strength of 120 MPa or more and is suitable for piston components for Otto engines (spark ignition engines), and provides a process for producing high-strength isotropic graphite.

Preparation of particle wherein surface is coated with superfine particle

Abstract: PURPOSE:To obtain a whetstone with uniform strength by grinding an aggregate formed with particles made of an inorg. material or a metal material the surface of which is coated with an superfine particle and dispersing it. CONSTITUTION:In a flow contg. an superfine particle of an inorg. material or a metal material formed by a vapor phase method, this superfine particle is brought into contact with a particle of the inorg. material or the metal material in a fluid state. An aggeregate formed with particles of the inorg. material or the metal material the surface of which is coated with the superfine particle is obtd. thereby. This aggregate is introduced into a raw material powder feeding part of a jet mill and it reaches a grinding zone and after grinding, fine particles are taken out at a classification zone and rough particles are returned to a rough powder return as they are carried by a gas introduced from a compressed air intake and they reach the grinding zone again. The aggregate is dispersed.

Water-based pigment ink composition for writing utensil

Abstract: PURPOSE:To obtain a compsn. which is excellent in dispersion stability an hiding power and does not require operations such as stirring before the use by fixing fine titanium oxide particles on the surfaces of resin particles to form composite particles with specified particle sizes. CONSTITUTION:The compsn. contains, as a coloring matter, composite particle having a mean particle size of 0.2-2mum and obtd. by fixing fine titanium oxide particles having a mean particle size of 0.1mum or lower on the surfaces of resin particles. The resin particle reduces the apparent density of the oxide particles, improving the dispersion stability of the latter particles, and increases the apparent particle size of the latter, improving the whiteness and hiding power of the latter. The composite particles are obtd. by mixing the resin and the oxide particles and fixing the oxide particles on the surfaces of the resin particles by causing the oxide particles to be adsorbed by the surface or to be forced into the resin particles, e.g. by mixing and grinding with an automatic mortar, a jet mill, etc., and/or giving a mechanical impact with a hammer mill, etc.

Method of milling; Jet mill

Abstract: Particulate material is fed from a holding vessel 1 to be entrained by a gas supplied through a jet nozzle 10, the holding vessel having an ullage which is maintained at a pressure of at least 0.05 MPa but less than the pressure at which gas is introduced to the jet nozzle 10. The method is particularly usefully employed in an impact jet mill in which the entrained particles impinge upon a surface 12, are reflected into another jet and passed into a cylindrical separation chamber 17. The holding vessel 3 has a supply pipe 4 for supplying a compressed gas and the material is supplied to vessel 3 from a hopper 5 mounted above a rotable air lock 6.

Production of chocolate

Abstract: PURPOSE:To obtain chocolate with smooth and thick touch feel by decreasing the size of the particles in the chocolate. CONSTITUTION:The solid particles in a chocolate stock are made into those <=1mum (a majority thereof being <=10mum in diameter by a method using a jet mill or ultra-high-pressure impact, and, for the purpose of improving the workability of the resultant particles, an emulsifier (esp. sucrose erucic ester or polyglycerin-condensed ricinoleic ester) is added to the above particles to produce the objective chocolate.

Production of material powder for rare earth magnet

Abstract: PURPOSE: To enhance the crushing efficiency significantly by a method wherein a specified liquid lubricant is admixed to a coarsely crushed powder having required composition and subjected to jet mill crushing and to produce a material powder for rare earth magnet excellent in press filling performance and orientation. CONSTITUTION: The material powder for rare earth magnet comprises 10-30at.% of at least one kind of rare earth element, 1-28at.% rot B, and 42-89at.% of Fe. 0.02-5wt.% of a lubricant, where at least one kind of fatty acid ester is liquefied, is then admixed to a coarsely crushed material powder for rare earth magnet having average particle size of 10-500μm. The mixture is subjected to jet mill crushing using an inert gas to produce a fine powder having average particle size of 1.5-5μm. Since the surface of fine powdery particle can be coated uniformly with the lubricant, a finely crushed material powder for press having required average particle size can be produced with significantly enhanced efficiency. Furthermore, fluidity of the powder is also enhanced thus enhancing the press filling performance significantly.

Production of raw material alloy for rare earth magnet

Abstract: PURPOSE:To prevent the flocculation of magnetic powders to each other or the adhesion of the magnetic powders to the inside walls of a jet mill and to improve pulverization efficiency by incorporating a specific ratio of gaseous nitrogen oxide into an inert gas to be used as a pulverizing gas. CONSTITUTION:The raw material alloy for a rare earth magnet of an R-T-B (R is at least >=1 kinds of the rare earth elements selected from Y, Sc and lanthanoids, T is at least >=1 kinds of transition metal elements, B is boron) system is pulverized by using the jet mill. Gaseous nitrogen oxide is incorporated at 50 to 8000ppm into an inert gas to be used as a pulverizing gas at this time. As a result, the magnetic powder surfaces are oxidized by a slow speed. The pulverizing power of the jet mill and the adequate average grain size and powder yield after the pulverization are improved. The raw material alloy is preferably embrittled by incorporating hydrogen into the alloy prior to the pulverization thereof.

Electrostatic particle for circuit printing

Abstract: PURPOSE:To realize fineness of a circuit pattern after burning and to improve adhesion between a circuit pattern and an insulation substrate by dispersing conductive metal powder, glass powder and a static control agent in thermal fusing resin. CONSTITUTION:A material formed by mixing flake-like silver powder of an average particle diameter of 0.6mum and spherical paradium powder of an average particle diameter of 0.3mum at a ratio of 85 to 15 is used as conductive metal powder 1, boro-silicate glass is used as glass powder 2, azo metal complex is used as a static control agent 3 and a material formed by mixing styrene acrylic copolymer and low molecular weight polypropylene is used as thermal fusing resin 4. They are mixed at a weight ratio of 80:4:1:15, respectively and particle of an average particle diameter of 10 to 15mum is acquired by performing processes for them including thermal fusing kneading by a kneader, rough grinding by a cutter mill, fine grinding by a jet mill and air flow type classification.

Recovering method for resin for recycling

Abstract: PURPOSE:To recover a recycling resin so as not to damage the mechanical physical properties or appearance of a molded product after remolding by grinding a resin molded product subjected to surface coating processing and classifying the ground matter by a screen having a specific mesh size CONSTITUTION:A resin molded product such as a car part, especially, a bamper, a fender or a trim is ground and the ground product is classified using a classifying screen having a mesh size of 1000mum or less In the recovery of a resin molded product whose surface is subjected to surface coating processing by painting, printing, bonding, vapor deposition or sputtering, a ground product is classified by a screen having a mesh size of 198mm or less according to a specific gravity difference separation method using a hydrocyclone As a grinding means, a hammer mill, a turbo mill or a jet mill is used and a freezing grinding system is employed with respect to polyethylene or polypropylene especially hard to grind at room temp

Manufacture of raw material powder for rare-earth magnet

Abstract: PURPOSE:To provide a method of pulverizing raw powder for Fe-B-R and R-Co rare- earth magnet, which improves a grinding efficiency, reduces a pulverizing cost and in particular, is capable of improving significantly the grinding efficiency in a jet mill grinding. CONSTITUTION:Coarsely crushed powder of a necessary magnet composition obtained by an ingot grinding method or a Ca reduction method is subjected to jet mill grinding by an ultrasonic inert gas air flow of zero point-20 deg.C to -40 deg.C in a state that the interior of the total system ranging from a raw material hopper to the delivery of the crushed powder via a grinding chamber is isolated from the outside air by inert gas and is pulverized into fine powder of a mean granularity of 1.5 to 5mum. Thereby, the mean glanularity of the pulverized powder is microminiaturized much finer and at the same time, the fluidity of the power is improved, an efficiency for obtaining the coarsely crushed powder having a necessary mean granularity as press raw powder is significantly improved, each particle of the obtained coarsely crushed powder is easily orientated in the direction of a magnetic field in a press molding in the magnetic field and an anisotropic sintered magnet having superior magnet characteristics is obtained.

Method of pulverizing particulate substance

Abstract: PURPOSE: To provide a method for milling a particulate material in a more effective form in terms of energy by maintaining the pressure of the gas in an ullage formed within a holding vessel at a value above the atmosphere pressure and lower than the pressure under which the gas is introduced into a jet nozzle CONSTITUTION: This method for milling the particulate material is constituted to supply the particulate material from the holding vessel 1 housing the particulate material via an inlet 3 so as to be entrained by the gas while supplying the gas via the jet nozzle 10 of a jet mill and to pass the mixture composed of the gas and entrained particles formed in such a manner through the jet mill The amount of the particulate material in the holding vessel 1 is smaller than the amount to fill the vessel 1, by which the ullage is formed and the gas is maintained under the pressure higher than the atmosphere pressure in the ullage The pressure of the gas in the ullage is maintained at least at 005 MPa above the atmosphere pressure and is set at the value lower than the pressure under which the gas is introduced to the jet nozzle 10

Method of milling in a jet mill

Abstract: An improved method of milling a particulate material in a jet mill is described. The material is fed from a holding vessel (1) to be entrained by a gas, the holding vessel (1) having an ullage which is maintained at a pressure of at least 0.05 MPa but less than the pressure at which gas is introduced to the jet mill. The method is particularly usefully employed in an impact jet mill in which the entrained particles impinge upon a surface (12), are reflected into another jet (13) and passed into a cylindrical separation chamber (17). The method enables such an impact mill to be operated under more energy-efficient conditions.