Showing papers on "Jet mill published in 2008"

State of the Dispersant and Particle Surface During Wet-Jet Milling for Preparation of a Stable Slurry

Abstract: Wet-jet-milled alumina slurries exhibited distinctly different stability behavior compared with ball-milled ones in terms of reflocculent efficiency and rheological properties. The distinction was attributed to the different behavior of the same dispersant (NH4+ salt of poly(acrylic acid); PAA–NH4+) in ball milling and wet-jet milling. Alumina particles after the wet-jet milling retained the initial surface conditions, although ball-milled alumina particles yielded more hydroxyl groups on the surface. Furthermore, degradation of dispersant on milling was investigated qualitatively. Infra-red analysis and isoelectric point measurements suggested that degradation of the dispersant occurred during ball milling, indicating neutralization of the dispersant due to formation of monodentate COOX groups. On the other hand, in the case of wet-jet milling, COO− groups of PAA–NH4+ were not degraded at all, indicating maintenance of the structures of dispersant with electrostatic repulsion. Change in the polymer size of the dispersant by different milling methods was confirmed using high performance liquid chromatography (HPLC) measurements. The HPLC results of the wet-jet milled samples showed that a dispersant with a larger molecular size was generated. Force measurement on approach via the colloid probe method in the centrifuged supernatant of the milled slurries confirmed that the interaction distance between an α-alumina colloid probe and c-sapphire surface was about two times larger in the wet-jet-milled slurry supernatant compared with the ball milled one. Thus, it was found that wet-jet milling process led to a stable slurry because of the maintenance of not only steric repulsion but also electrostatic repulsion.

Micronization of dihydroartemisinin by rapid expansion of supercritical solutions.

Abstract: The purpose of this study was to prepare fine particles of antimalarial drug dihydroartemisinin (DHA) by rapid expansion of supercritical solutions (RESS) using carbon dioxide as supercritical fluid. The mechanical grinding by jet mill and additional vibration rod mill also was performed as a comparative method. In the RESS process, drug particles were prepared by varying processing conditions, including extraction condition, pre-expansion condition, nozzle diameter, nozzle temperature, and collecting distance. Particle size and morphology and physicochemical characteristics of the drug particles were investigated. The RESS process could produce the smaller drug particles (about 1–2 μm) when compared to mechanical grinding method (about 7 μm). All RESS processing parameters had an effect on size and morphology of drug particles. The particle size of drug was related to the solubility of drug in supercritical CO2 at each processing condition. The fine particles of DHA (about 1 μm) with narrow size distribu...

Fine copper powder and its manufacturing method

Abstract: PROBLEM TO BE SOLVED: To provide copper powder which has fine particle size, nearly spherical shape and high tap density and exhibits low resistance value when hardened with resin addition and can be suitably used for a conductive paste. SOLUTION: Dendritic electrolytic copper powder having 0.8 to 2.0 g/cm 3 bulk density is ground and densified using a jet mill of high-pressure jet stream swirling vortex type. The resultant fine copper powder has a spherical or granular shape of 1 to 6μm average particle size, and tap density after the surface is coated with fats and oils is ≥4.5 g/cm 3 . When resin is added to the fine copper powder to undergo hardening at 200°C, a specific resistance value ranging from 1×10 -5 to 1×10 -4 Ωcm can be obtained. COPYRIGHT: (C)2008,JPO&INPIT

Modified method for producing titanium dioxide

Abstract: The invention discloses an improved method for producing titanium dioxide. The invention includes materials wetly ground, enveloped, washed and dried after the production of the titanium dioxide, products achieved in a first stage separation in the processes of jet milling and organic substance enveloping, and a two-stage dry solid powder separation method is adopted, and inlet material returning to a jet mill is achieved in a second stage separation. The invention not only reduces the operation cost of consumption used in wet pulp returning and greatly enhances the product quality, but also strengthens the operation parameters of the jet mill, prolongs the service life of a bag filter and resolves the problems in purification and dispersion of product quality, etc. Therefore, the invention not only can improve the product quality of the titanium dioxide, but also has the advantages of energy conservation, low manufacturing cost and obvious economic profit, etc.

An investigation of carbon nanotube jet grinding

Abstract: The main challenges for the development of an industrial process for carbon nanotubes (CNTs) synthesis are the formation of agglomerates and the control of their size distribution. The project objective was to investigate the feasibility of CNT grinding with two arrangements. Experiments showed that a commercial jet mill can meet product quality requirements. However, in-situ grinding of CNTs, within the fluidized bed reactor, would improve both the productivity and quality of CNTs. A new, two-parameter grinding model shows that the primary grinding mechanism is fragmentation for the jet mill and erosion in the fluidized bed column.

Hydraulic jet mill

Abstract: An hydraulic jet mill is disclosed in which a high pressure line and a low pressure line are introduced into at least one jet (or nozzle). The jet is configured such that there is an orifice at the forward end of the jet and the cross sectional area of the interior of the rearward portion of the jet is significantly greater than the cross sectional area of the interior of the forward portion of the jet. There is an incompressible liquid such as water in the high pressure line and a material to be milled in a slurry with an incompressible liquid such as water in the low pressure line. The high pressure line is introduced into the rearward portion of the jet and the low pressure line is introduced through a venturi into the forward portion of the jet. The contents of the high pressure line and the low pressure line mix and are forced out of the orifice at high velocity. The material is milled when it strikes either an impingement plate or an opposed second jet.

The Study of Characteristics of Cosmetic Powder by Using Various Grinding mill

Abstract: By Using various grinding mill in powder cosmetics manufacturing process; screen milt and pin mill, jet mill, properties of the powder and grinding mills were studied; talc, mica, nylon powder, silica, titanium dioxide. Besides, the experiments fur evaluation of grinding were performed by using iron oxides those are tracers. In powders of plate shape, they were grinded more vertically than horizontally at the screen mill and pin mill, although were all grinded vertically and horizontally at the jet mill. The spheric powders became the primary particles or aggregation by electrostatic interaction at the screen mill and pin mill. But, at the jet mill, they resulted the agglomeration or transformation or damage up to 2bar. Titanium dioxides became the primary particles by all grinding mill. Pin mill has an excellent result in experiments which is a change of the tone of color by grinding. From these results, suggest that the jet mill is used to pre-treat of powders of plate shape in practical cosmetic manufacturing process, and the screen mill and pin mill are used to match the color of powder cosmetics. If industrial process condition is taken into consideration, suggest that 4times of grinding is excellent on grinding effect by the screen mill, and twice grinding by the pin mill and grind air pressure of 1bar by the jet mill.

Heat treating method for metal powder

Abstract: PROBLEM TO BE SOLVED: To provide a method where, in heat treatment for modifying metal powder, e.g., of increasing crystal grain diameters, metal powder in which the flocculation of each powder is prevented and dispersibility is maintained, and having a sharp grain size distribution can be obtained. SOLUTION: Metal powder as an object for modification is heat-treated using a jet mill apparatus where it is heated by a high pressure air flow at 240 to 800°C in a neutral or reducing atmosphere, and is pulverized (cracked) by collision and friction between metals in a pulverization chamber. As the objective metal powder, base metal powder is preferable, and further, Ni powder is more preferable. COPYRIGHT: (C)2009,JPO&INPIT

Manufacturing method of sintered rare-earth magnet

Abstract: PROBLEM TO BE SOLVED: To improve molded body strength by means of molding in a magnetic field by suppressing the degradation in magnetic characteristics. SOLUTION: This method comprises: a step of coarse crushing a raw material alloy of an Nd-Fe-B-based sintered magnet; a step of pulverizing the coarse-crushed powder obtained in the coarse crushing step by a jet mill; a step of pressure molding the pulverized powder obtained in the pulverizing step while applying a magnetic field to the powder; and a step of sintering the molded body obtained in the pressure molding step. In the pulverizing step, an impingement jet mill is used and the amount of oxygen of its pulverization atmosphere is specified to 8,000 to l5,000 ppm. The pulverized powder preferably satisfies the conditions of an average grain size D50=3.0 to 6.0 μm, D10/D50=0.35 to 0.55, D90/D50=1.80 to 2.05. COPYRIGHT: (C)2008,JPO&INPIT

Jet mill comprising a fluid jet for comminuting and/or separating a grinding material

Abstract: Disclosed is a jet mill comprising a fluid jet for comminuting and/or separating a grinding material in a grinding chamber (1) At least one intake element (4), especially an intake nozzle (3), which has at least one intake port (3) is provided for allowing the fluid jet to flow into the grinding chamber (1), a supply element (7) that has at least one supply port (5) is provided for supplying the grinding material into the grinding chamber (1), an outflow element (11) that has at least one outflow port (14) is provided for allowing the fluid jet to flow out of the grinding chamber (1), and a discharge element that has at least one discharge port (10) is provided for discharging the ground material from the grinding chamber (1) The grinding chamber (1) is fitted with at least one section (9) that is substantially designed as a truncated cone, the grinding chamber (1) having a larger internal cross-section in the top zone than in the bottom zone In order to obtain a particularly compact design, the fluid jet flows through the outflow port (14) and/or within the outflow element (11) in a substantially downward direction

Charged powder for circuit formation and multilayer wiring board using the same

Abstract: PROBLEM TO BE SOLVED: To provide a charged powder for circuit formation capable of filling conductive metal particles densely in a wiring pattern, and a multilayer wiring board using the same SOLUTION: The charged powder 10 for circuit formation is composed in such a manner that a first conductive metal powder 11, a second conductive metal powder 12 of which average particle diameter is smaller than that of the first conductive metal powder 11, a charge control agent 13, and an adhesion enhancing agent 14 are uniformly dispersed in a hot-melt resin 15 Spherical copper particles which are the first conductive metal powder 11 having an average particle diameter of 08 μm, spherical copper particles which are the second conductive metal powder 12 having average particle diameter of 04 μm, azo-series metal dye which is the charge control agent 13, silica which is the adhesion enhancing agent 14, and a styrene-acryl copolymer which is the hot-melt resin 15 are mixed at the ratio of 30:50:1:1:18 by weight The mixture is then kneaded with a kneader by a hot-melt kneading, coarsely ground with a cutter mill, and finely ground with a jet mill The charged powder 10 for circuit formation having average particle diameter is 80 μm is acquired by air stream classification COPYRIGHT: (C)2008,JPO&INPIT

Method for preparing biological disinfectant

Abstract: The invention provides a preparation method of biological antibiotic, and relates to a preparation method of antibiotic purifying agent. The method is that: TiO2 with the weight ratio of 1:0.1 to 0.5:0.1to 0.5, heavy calcium carbonates and calcium phosphate are pumped in a jet mill at the same time, and are ground fine through the jet mill, and are mixed and processed into compound powder with grain size between 10 to 50 nanometer. The powder is the biological antibiotic. The product can be added into road surface materials, inner wall and outer wall decorative materials, architectural coating and glasses, and also can be applicable to treating industrial wastewater and waste gas, purifying automobile exhaust and tap water supply device, and also can be used in a sterile room, canteen, a swimming pool, daily tableware and so on in a hospital. The invention can kill the contacted bacteria and fungi under the action of light, and break down harmful gases which contain organic nitrogen, organophosphorus insecticide and so on into harmless small molecule substance.

Methods and device for particles making by means of spray drier and jet mill working together

Abstract: FIELD: technological processes. ^ SUBSTANCE: suggested method includes the following stages: (a) spraying of emulsion, solution or suspension, which contain dissolvent and basic material, through the sprayer into primary drying chamber for making of drops, which contain dissolvent and basic material; (b) evaporation in primary drying chamber, of at least some part of dissolvent into drying gas for solidification of drops and formation of particles, dispersed in drying gas; and (c) passage of particles and of at least part of drying gas through jet mill for deagglomeration and grinding of particles. Combination of spraying drier with parallel jet grinding provides for single-stage method with simultaneous equipment operation. ^ EFFECT: processing time is reduced as well as technology cost at the high quality of produced powders. ^ 42 cl, 3 dwg, 13 tbl ^ id8027583

Spraying jet mill

Abstract: PROBLEM TO BE SOLVED: To provide a spraying jet mill for grinding materials to be ground in a state of having a demanded particle size distribution. SOLUTION: The upper member 12 of a jet mill body 2 keeps air nozzles for jetting an air stream at a predetermined angle with respect to the center line 100 of a disk-like grinding chamber 8 disposed on a ring-shaped side wall. The upper member has supply ports 14a-14c for materials to be ground at a radial position according to the demanded particle size distribution of the materials to be ground from the outlet 6 provided nearly at the center of the lower member 10. Moreover, the jet mill body 2 is connected to a supply device 16 for materials to be ground with supply pipes 18a-18c having switching valves 20a-20c, and the respective supply pipes 18a-18c are connected to the supply ports 14a-14c. COPYRIGHT: (C)2008,JPO&INPIT

Production method of translucent alumina raw material fine powder

Abstract: PROBLEM TO BE SOLVED: To provide a production method of translucent alumina raw material fine powder, in which alumina fine powder having a small ratio of coarse particles is obtained in one continuous pulverizing process. SOLUTION: In the production method wherein alumina particles of a purity of more than 99.9% is pulverized in a jet mill 1, a flow channel 46 of a pulverizing nozzle 4 in the jet mill 1 is provided with a high pressure gas flow channel 41 formed roughly in a columnar shape, and a slit flow channel 42 communicated with the high pressure gas flow channel 41, with a cross section orthogonal to the jetting direction of the high pressure gas slit-likely formed along the radial direction of the flow channel 46. The end part of the slit flow channel 42 faces the outside as a jetting port 44 on the jetting face 43 of the pulverizing nozzle 4. Thus, the jetting port 44 faces a pulverizing chamber 14 in a state of the pulverizing nozzle 4 attached to a casing 2. COPYRIGHT: (C)2009,JPO&INPIT

Buckwheat flour for cakes and method for producing the same

Abstract: PROBLEM TO BE SOLVED: To provide buckwheat flour for cakes, which can form the cakes even in a purity of 100 mass%, and to provide a cake produced from the buckwheat flour for cakes and excellent in the flavor of buckwheat. SOLUTION: This buckwheat flour for the cakes is made by adjusting the protein content and average particle diameter of the buckwheat flour to ≤7 mass% and a range of 10-50 μm, respectively, preferably to ≤3.5 mass% and ≤30 μm, respectively. The buckwheat flour can be used as a raw material flour to make cakes in a purity of 100 mass%. The protein content of the buckwheat flour can be prepared by milling buckwheat with an ordinary flour mill (roll type mill, stone mill, or the like) and using a technique such as a sieving technique or a classification technique. The average particle diameter of the buckwheat flour can be adjusted with a high speed grinder, a fine grinder or the like. Concretely, a pin mill, a hummer mill, a ball mill, a jet mill or the like can be adjusted. COPYRIGHT: (C)2008,JPO&INPIT

Changes in the structure of talc by continuous jet milling in relation to imposed specific kinetic energy.

Abstract: Ultra fine talc is used in many industries such as paper, paints, polymers, cosmetics and pharmaceutical. Emerging demand with stringent specification from these industries has marked jet mill as one of the essential grinding mill to produce ultra fine talc. Ultra fine grinding testwork of talc was carried out in opposed fluidized bed jet mill by varying the feed rate, classifier rotational speed and grinding pressure at three levels. In this jet mill, grinding and classification took place simultaneously. The ground products were characterized in terms of particle size distribution and mechanochemical effect via X-ray diffraction. The ground product exhibited poly-modal distribution and the minimum size obtained was 4.28 µm at 4 kg/h, 13000 rpm and 4 bar. Besides size reduction in micron range, mechanochemical effect was exhibited by the product ground in jet mill as jet mill is classified as high-energy mill. Reduction in peak intensity and peak base broadening was observed which indicates fine grinding process in jet mill induced mechanochemical effect. Furthermore preferential distortion of (00l) planes was observed as well. The degree of crystallinity of ground sample, which ranged from 26.5% to 85.3% reduces as the specific kinetic energy increase and its reduction gradient varies according to the classifier rotational speed. The crystallite size and lattice strain of talc ranged from 147.69 nm to 353.72 nm and 0.08 to 0.2 respectively.

Grinding method and ground product

Abstract: The milling process for the production of finely grounded powder from coarse-grained or crystalline materials such as food and/or food additives, by an impact crushing mill, comprises supplying a milling material in a milling chamber of the mill via a milling chamber inlet, and discharging the obtained milled product by a discharge pipe of the milling chamber. The milling process is carried out under conditions, in which the temperature in the milling chamber is >= 60[deg] C. The relative air humidity in the milling chamber is required less for conditioning the obtained milled product. The milling process for the production of finely grounded powder from coarse-grained or crystalline materials such as food and/or food additives, by an impact crushing mill, comprises supplying a milling material in a milling chamber of the mill via a milling chamber inlet, and discharging the obtained milled product by a discharge pipe of the milling chamber. The milling process is carried out under conditions, in which the temperature in the milling chamber is >= 60[deg] C. The relative air humidity in the milling chamber is required less for conditioning the obtained milled product. The inlet air in the milling chamber is warmed, so that a temperature of >= 65[deg] C adjusts itself in the milling chamber and/or in the discharge pipe and/or a temperature of = 160-180[deg] C adjusts itself in the milling chamber and/or in the discharge pipe. The humidity of the milling chamber atmosphere is increased against the standard conditions. The temperature and/or humidity are adjusted in the milling chamber, so that a reduction of the specific milling energy of the milling process is carried out around >= 10-20% against the standard conditions and otherwise identical process conditions. The relative humidity in the milling chamber and/or in the discharge pipe is 2-15%. The humidity load of the milling chamber atmosphere and/or in the discharge pipe is = 30 g/kg related to dry air. The conditioning of the milled product is carried out subsequently to the milling process by subjecting the atmosphere with other temperature and/or humidity load as the values in the milling chamber and by adding conditioning agents. The mill is a classifier mill or a jet mill. The milling material is sugar or milk powder. The relative humidity in the milling chamber is 3-12%. The milling material is milled to a grain size (d 5 0) of 20-25 mu m. An independent claim is included for a milled product in finely grounded form.

Fluidized‐Bed Jet Milling of Ceramics

Abstract: Many abrasive ceramic powders require milling and/or classification to achieve a required particle-size distribution. A solution for processing fine powder carbides, nitrides, borides, alumina, and other ceramics is a jet-mill.