Showing papers on "Jet mill published in 2000"

The Influence of Comminution method to Particle Shape

Abstract: The different applications of fine powders need different physical characteristics of the solids. This study presents the influence of the comminution method to the shape of the product particles. The types of mill were a ball mill, an attrition bead mill and a jet mill. The test minerals were limestone, FGD (Flue Gas Desulfurisation) gypsum and waste gypsum from phosphoric acid plant. The size and the shape of the ground particles were measured with an image analyzer. The relevant shape features of the ground products were extracted by self-organizing maps (SOM) and then the particles were clustered with the SOM. The different mill products were clustered differently showing that the fraction of concave particles is a relevant shape feature.

Method, device and system for fluidised-bed jet mill

Abstract: The pulverizing process involves breaking down particles in a fluidized bed by means of a fluid jet (6, 7). The application of centrifugal force to the particles in the region of the fluid jet or jets causes more energy to be used on the particles in the fluidized bed, particularly in the vicinity of the fluid jet entrance.

Fluidized bed type ultra fine jet mill

Abstract: The utility model relates to a fluidized bed type ultra fine jet mill and is a processing device which is applicable to carrying out ultra minuteness pulverizing towards medicine, foodstuff, chemical material and other metal and nonmetal. The utility model is composed of a pulverizing chamber, a grading chamber and a screw feeder. The utility model is characterized in that a nozzle arranged in the middle part of the pulverizing chamber forms a definite included angle with a horizontal plane. In addition, the bottom of the pulverizing chamber is additionally provided with a nozzle which is upward, and all nozzles form focusing ejection. Furthermore, the front side of the nozzle is provided with a mixing pipe. The utility model can increase the collision opportunity of the supersonic airflow of the introducing nozzle towards carrying of powder body and the space of the powder body, consequently improving pulverizing efficacy.

Flat shaped fine copper powder and its production

Abstract: PROBLEM TO BE SOLVED: To inexpensively and easily obtain copper powder having good electric conductivity and sagging preventing effect by specifying the average major axis diameter and flattening ratio therein. SOLUTION: Granular fine copper powder of 3 to 5 μm average grain size obtd. by subjecting dendrite electrolytic copper powder obtd. by an electrolytic method to crushing and pulverizing by a collision board system jet mill is dispersed in water to form into copper slurry. The inside of this copper slurry is added with a lubricant such as fatty acid salt (sodium oleate or the like), a dispersant or the like, which is introduced into a medium type stirring mill, and the fine copper powder is flattened. At this time, the feeding rate of the copper slurry desirably controlled to about 0.5 to 1.0 l/min in the case the volume is 1.4 l, as the medium type stirring mill, a bead mill is used, the diameter of the beads is controlled to about 0.3 to 1.0 mm and the operating time of the flattening is controlled to 30 min to 2 hr. In this way, the flat shaped fine copper powder having 4 to 10 μm average major axis diameter and 2 to 20 flattening ratio is obtd. Desirably, the bulk density therein is 2 to 4 g/cm3, and the BET specific surface area is 0.4 to 1.5 m2/g.

Production of fine copper powder

Abstract: PROBLEM TO BE SOLVED: To inexpensively and easily obtain copper powder showing good electric conductivity by adding and mixing dendrite electrolytic copper powder having specified average particle size and bulk density with oils and fats, coating the surface of the electrolytic copper powder with the oils and fats and executing crushing and pulverizing with a collision board system jet mill. SOLUTION: A compositional soln. of about 5 to 50 g/l CuSO4.5H2O and 50 to 150 g/l H2SO4 is subjected to electrolytic treatment at 5 to 10 A/dm2 electrolytic density and at 20 to 60 deg.C soln. temp. to directly precipitate dendrite electrolytic copper powder having 20 to 35 μm average particle size and 0.5 to 0.8 g/cm3 bulk density into the cathode. This dendrite electrolytic copper powder is added and mixed with oils and fats (lauric acid, oleic acid or the like) by 0.1 to 5 wt.%, and the surface of the electrolytic copper powder is coated with the oils and fats. Next, this electrolytic copper powder is fed to a collision board system jet mill, is collided against a collision board in a crushing chamber by compressed air, is crushed and pulverized and is classified by a classifier to recover the objective fine copper powder by a cyclone and a bag filter.

Production of fine particle dispersion, and fine particle dispersion

Abstract: PROBLEM TO BE SOLVED: To disperse a dispersion to a primary particle size or a particle size close to the primary particle size and to make producible a uniform a fine particle dispersion stably when the dispersion of barium titanate is produced by treating a barium titanate suspension with a wet jet mill. SOLUTION: As the wet jet mill used in the production of a fine particle dispersion, a type in which raw liquid is supplied to a closed nozzle arranged in a pressure container at a high pressure, and a dispersed substance in the liquid is emulsified, dispersed, or crushed by forming a spiral jet flow in the nozzle, is preferable. The preferable concentration of a barium titanate suspension (dispersion) is about 10-80%, more practically 30-60%. The medium of the dispersion is not restricted particularly, and various organic solvents and water or their mixtures can be used corresponding to use. In this way, the dispersion can be dispersed finely and uniformly in a primary particle state.

Surface treating method for magnetic material powder

Abstract: PROBLEM TO BE SOLVED: To attain sufficient oxidation resistance conveniently in safety by coating the surface of rear earth magnet material powder with at least one kind of metal selected from Al, Si, Fe, Co, Ni, Cu, Ni, In and Sn using laser ablation. SOLUTION: Rear earth magnet material powder crushed finely to have mean grain size of 1-10 by means of a ball mill or a jet mill is collected in a stainless steel pot and added with stainless steel balls for stirring. It is fixed into the film deposition chamber of laser ablation and the material powder is coated by irradiating an Zn target with a laser beam while turning the pot. A film is deposited efficiently by adjusting positional relationship of the target, the pot and the laser light source. A coating material powder thus obtained is admixed with an epoxy resin and applied with an orientation field and then it is molded and cured to produce a bond magnet.

Production of liquid toner and liquid toner

Abstract: PROBLEM TO BE SOLVED: To enhance productivity and quality by dry-comminuting specified colored chips and carrying out further wet comminution in a nonaqueous solvent. SOLUTION: A colorant, a resin and ionomer are heated and kneaded at a temperature above the softening point of the resin, the kneaded material is coarsely comminuted and the resulting colored chips are dry-comminuted and further wet-comminuted in a nonaqueous solvent. A pigment effective in prolonging the life of an interim transfer body as well as an ordinarily used pigment or dye may be used as the colorant. An acrylic resin such as a polyacrylic ester, a polyethylene type resin such as polyethylene or a mixture of such resins may be used as the resin. The ionomer is obtained, e.g. by neutralizing an ethylene-acrylic acid copolymer with a metal. A hummer mill, a jet mill or the like is used for the dry comminution. A media crusher such as an attriter, a sand mill or a mill can be used for the wet comminution without causing any trouble.

Method for crushing and reducing slag containing metal oxide

Abstract: not available for EP1017646Abstract of corresponding document: WO9967182The invention relates to a method for crushing and reducing slag containing metal oxide for producing latently hydraulic binders, clinker or cement additives. According to said method the slag containing metal oxide is introduced into a jet mill together with reducing agents, notably carbon carriers, and the jet mill (1) is operated with hot waste gases.

XRD Study on Ultrafine Wollastonite Pulverized by A Jet Mill

Abstract: Ultra fine wollastonite was pulverized by a jet mill.The result of XRD shows:Most of XRD intensity peaks of the ultrafine wollastonite decrease but the peak of d =0.298nm increases from 834 cps to 2139 cps. On the basis of XRD theory of Bragg Bretano,it is regarded as a result of transforming from triclinic system wollastonite to monoclinic system one.

Grinding of Hard Fine Materials by Jet Mill

Abstract: The grinding rate characteristics of hard fine materials was investigated with a laboratory scale jet mill. The variations of product size distributions of synthetic diamond, alumina and quartz sand with the number of passes were described by using a grinding kinetics approach for various values of the grinding air pressure and the feeding rate. As a result, the grinding rate was found to decrease with increase in the hardness of comminuted materials from quartz to alumina and then to increase slightly for synthetic diamond due to its low impact strength. This trend is more pronounced for all materials with higher gas pressure and lower material feed rate. Thus, it is proved experimentally that the grinding characteristics of very hard materials even around 1, μm with the jet mill still fits the rate equation of comminution but the effect of operational conditions becomes low.

New particles technology for oxide-superconductor using dry- and wet-type jet mill

Abstract: Superconducting YBCO particles with an average size of 1-2 /spl mu/m were prepared by dry-type jet mill. It is found from the measurements of critical currents (Ic) that the superconducting transition temperature (Tc) at 91-92 K is obtained for the YBCO particles which have oriented and elongated grains align parallel to [003] [005] and [006]-plane. On the other hand, fine YBCO particles were prepared from high quality superconducting YBCO powders by wet-type jet mill in a high pressure now of MEK (methyl-ethyl-ketone:CH3COCH2CH3) or toluene (C6H5CH3). As a result, the resulting particles are homogenius in MEK and fine YBCO particles show oriented and polycrystal structures with an average particle size of 164 nm in diameter and with the lattice parameter of a=3.9 A, b=3.5 A in [001]-orientation from TEM (Transmission Electron Microscopy)-studies.