Showing papers on "Jet mill published in 1990"

Method and apparatus for coating fine powder

Abstract: PURPOSE:To firmly and uniformly coat fine powder of a metal, ceramics, etc., with various materials by dispersing the fine powder carried by a flow of gas, heating the dispersed powder under reduced pressure and coating the heated powder by sputtering. CONSTITUTION:Fine powder of a metal, ceramics or plastics is dispersed as primary particles in an inert atmosphere by treatment with a fluid jet mill 3. The dispersed fine powder is heated in an inert atmosphere under reduced pressure in a heating chamber 1. The heated fine powder 8 is charged into a rotating vessel 2 and this vessel 2 is rotated to form a fluidized bed 18. The powder in the bed 18 is coated by sputtering and the coated powder is recovered from the vessel 2 through a filter 4.

Powder for metal injection-molding and manufacture thereof

Abstract: PURPOSE:To make spheroidal and minute metal fine powder by accelerating raw material powder having irregular shape with gas injection flow and colliding these powders in the air to execute pulverization. CONSTITUTION:By using fluidized bed type counter jet mill, etc., the fluidized layer of gas and the raw material powder, having irregular shape with high pressure water atomizing method to molten metal, is formed with the gas injection flow and the particles of the raw material powder accelerated in this fluidized layer are collided mutually in the air to execute the pulverization. By this method, as the metal fine powder subjected to spheroidal and minute working can be obtd., the fluidity of kneaded material with organic binder, is made good and sintered material having excellent formability, sinterability and high density can be obtd.

Pulverization of poly-beta-alanine copolymer

Abstract: PURPOSE:To easily obtain the subject uniform copolymer having small average particle diameter and narrow particle size distribution at a low cost by carrying coarse particles of poly-beta-alanine copolymer on a jet stream and subjecting the particles to collision and pulverization. CONSTITUTION:Coarse particles of a poly-beta-alanine copolymer having a reduced viscosity (etaSP/C) of 0.2-15dl/g are pulverized in a jet mill pulverizer, etc., using a dehumidified air, inert gas, etc., having a water content of 1,000 to 500ppm or less at a jet stream velocity of Mach 0.5 to 5.0 (preferably Mach 1 to 3) and classified with a classifier to obtain the objective copolymer having an average particle diameter of 1.0 to 10.0mum. The pulverization and classification are repeated until the particle size reaches the target level.

Manufacture of composition for injection molding powder metallurgy

Abstract: PURPOSE:To obtain composition for injection molding powder metallurgy, which can be injection-molded to a product having excellent dimensional accuracy, by spheroidizing shape of irregular shaped metal powder made by the water atomizing method, etc., with mechanical treatment and kneading with the specific ratio of binder. CONSTITUTION:The molten metal is pulverized with the water atomizing method, etc., and the metal particles having irregular shape and <=50mum particle diameter are spheroidized with the mechanical means of impact type pulverizing machine, etc., such as jet mill, hammer mill. To 11 vol. parts of the spheroidized metal powders, 9 vol. parts of thermoplastic binder, such as ethylene polymer, wax, are added and sufficiently kneaded. This kneaded composition is injection- molded with an injection molding machine and by executing sintering after debinder treating, the injection-molded powder metallurgy product having excellent dimensional accuracy can be produced.

Molten fine spherical silica and production thereof

Abstract: PURPOSE:To obtain spherical silica having a prescribed particle size and a prescribed specific surface area and especially useful in the case of determining the particle size structure of a filler for a semiconductor sealant by forming powdery silica by pulverizing with a jet mill and by melting the silica with a gas flame. CONSTITUTION:High purity silica as starting material is pulverized to 2-5mum mean particle size with a jet mill. The resulting powdery silica is melted and sphered by dispersion in an oxygen-inflammagle gas flame to obtain molten fine spherical silica having 2-8mum mean particle size and 0.5-7m /g specific surface area. This spherical silica has high purity, contains <=1ppb uranium and thorium and is especially useful in the case of determining the particle size structure of a filler for a semiconductor sealant.

Comminution of Fe80B20 metallic glass

Abstract: Fe80B20 (Metglas 2605) in an unrelaxed state was comminuted by vibratory milling, cryomilling and jet milling. Surface area, particle size and morphology were examined as a function of comminution parameters. After comminuting the as-received glassy ribbon for 20 min, a surface area of 2.48 m2/g was obtained by cryomilling compared with 0.97 m2/g by vibratory milling. A maximum surface area of 3.46 m2/g was obtained by cryomilling for 150 min. The maximum surface obtained by vibratory milling was 1.01 m2/g after 60 min. Little deformation was observed by SEM or optical microscopy for products produced by cryomilling or vibratory milling. Jet milling was not effective in increasing the surface area or reducing particle size and appears to have no effect on the morphology of the feed material. No structural changes were observed either by XRD or by TEM diffraction for any comminution product. Also, no change in the crystallization temperature or enthalpy of crystallization, as measured by differential scanning calorimetry (DSC), of the comminuted products, as compared with the as-quenched glass, was observed for any of the comminution methods utilized. Thus, both the vibratory milling and cryomilling of Fe80B20 increased the surface area with no effect on the glass structure or stability. The effectiveness of the cryomilling appears to come from comminution below the ductile to brittle transition temperature.

Method and apparatus for processing and using the seeds of leguminous plants at a feed-production factory

Abstract: The invention relates to a method and apparatus integrated in a feed-production factory for processing and using the seeds of field pea-type leguminous plants. The seed of a pea-type plant is dehulled in a hulling device, crushed in a crusher, and finely ground in a pregrinder and in a jet mill. The flour is air separated in air classifiers into two or more fractions so that the starch granules originating from cotyledon cells are substantially included in coarse fractions and the protein granules substantially in fine fractions. For facilitating the fractionation, there is used a predetermined, selected variety of the pea-type leguminous plant. By effecting the grinding with a jet mill grinding technique it may be economically feasible to reach a sufficiently small particle size without subjecting the product to thermal injuries. The process is integrated as a part of the feed production of a feed factory in a manner that at least some of the flour fractions are administered into a mixed feed being prepared. The invention includes proteinaceous pea feeds including at least 35% pea protein.