Showing papers on "Jet mill published in 2018"

Flow conditions inside spiral jet mills and impact on grinding performance

Abstract: Within the scope of comminution, spiral jet milling is still of great importance and even without alternatives in many fields of application. The number of parameters affecting the grinding process in the spiral jet mill is huge, while the general effects and coherences are most commonly unknown or discussed controversially. Insights about the flow conditions inside spiral jet mills are of particular importance for the exploration of the processes inside the mill, however these insights have a lack of transferability if they are considered individually. In this work, a substantial gain of knowledge of the processes and coherences is achieved due to the fact that the flow conditions inside the grinding chamber are investigated and correlated with corresponding investigations of the grinding performance. Since the purpose-built experimental spiral jet mill apparatus is constructed in an optically accessible way, the particle movement and net air flow inside the mill can be measured via the non-invasive particle image velocimetry (PIV) technique. Additionally, the apparatus is fully operative concerning the grinding ability, which enables the correlation of flow conditions and grinding performance. Further grinding investigations are conducted at an industrial spiral jet mill test facility and industrial spiral jet mill plant, which confirms the determined coherences and proves the practical transferability. The processes inside the grinding chamber are clearly revealed, resulting in a sharp segmentation in comminution zone and classifying zone via an abrupt loss of velocity and turbulent kinetic energy, with the location being dependent on the mill configuration. However, the comminution is mainly located in the nozzle jets and minorly at the front side of the jets. The velocity at the grinding nozzle jets and consequently the total size of the grinding nozzle jets are attributed as crucial factors of influence regarding the comminution and thus the product particle fineness. The particle velocity near the product outlet tube is characterized as essentially affecting the classifying and thus the width of the product particle size distribution and the mill parameters are investigated towards their influence on this process. All the investigations point out three main options for increasing the energy efficiency in spiral jet milling: i) decreasing the number of grinding nozzles, ii) deploying of Laval type instead of convergent grinding nozzles and iii) increasing the solid feed mass flow rate with simultaneous increase of the total gas mass flow rate. Due to the detailed description and correlation of the flow conditions and the impact on the grinding performance, this work can be considered as a guideline for further spiral jet mill research and development.

Prediction of particle size distribution of dronedarone hydrochloride in spiral jet mill using design of experiments

Abstract: In pharmaceutical industry, micronization is used to achieve solubility enhancement through the increase in specific surface area, and finally improving the dissolution rate of the drug. Industrial application of micronization is mostly based on experience and trial and error method. This research deals with the micronization of dronedarone hydrochloride and the path for evaluation of characteristics of micronized drug. Micronization was performed in laboratory spiral jet mill and the samples were analyzed to determine particle size distribution, span of distribution, sphericity, shape, and specific surface area. Results were analyzed using analysis of variance and in terms of specific energy consumption. Paths for evaluation of particle size and span of distribution were proposed and good correlation between experimental and model results was achieved.

Method of Modifying Portland Slag Cement with Ultrafine Component

Abstract: The paper presents the ways of modifying Portland slag cement with ultrafine substance for increasing its early strength. Blast-furnace granulated slag was used as ultrafine component having been preliminary ground in a laboratory airflow jet mill under restriction of upper limits of grinding to particle size of 1 μm. The obtained ultrafine slag was added into Portland slag cement in the dry state by dry blending and then in the suspension state instead of mixing water. Slag suspensions were prepared in water and water-polymer dispersion media. Plasticizer based on polycarboxylate resins was used as a stabilizer. Acoustic cavitation was used to stabilize water and water-polymer slag suspensions. The comparison of physical-and-mechanical and structural characteristics of modified samples detected that introducing slag suspension stabilized with plasticizer and acoustic cavitation instead of mixing water shows better efficiency. The effect of electrostatic factor is based on the formation of a double electric layer with the participation of functional groups of plasticizer at the surface of slag particles. The effect of structural-mechanical factor is conditioned by the formation of gelatinous films of main chain radicals on the surface of slag particles. Additionally, the stabilization of slag particles is provided by side branches of the plasticizer main chain, creating a spatial effect. Acoustic cavitation applied to water-polymer slag suspension results in the strengthening of electrostatic and structural-mechanical factors of aggregative stability and homogeneity of the suspension. The uniform distribution of stabilized slag particles in the hardening system leads to concentration of new formations on its surface and production of solid and firm structure of cement stone.

Method for grinding solids containing silicon

Abstract: The object of the invention are methods for the production of silicon particles by grinding silicon-containing solids in a jet mill using a grinding fluid containing water vapor.

A supersonic target jet mill based on the entrainment of annular supersonic flow.

Abstract: Jet mill is an apparatus that produces superfine powder and is widely used in various industries. In this work, a new supersonic target jet mill based on aerodynamic theory is presented according to the flow field of a traditional jet mill. An annular supersonic flow produced by an annular converging-diverging nozzle is used to entrain the central particle flow by the shear mechanism in this new supersonic target jet mill. Then, the particle beam concentrating in the flow center impacts the target with high kinetic energy after the entrainment of the supersonic flow. An apparatus of the annular supersonic target jet mill was created to validate the theoretical design. Two types of experiments were implemented to estimate its performance. The validation experiments confirmed that the gas speed in the collision chamber was approximately 600 m/s and the supersonic flow could deliver a kinetic energy of approximately 180 J/s to the particles. The particle size reduction of boroncarbide (B4C) and silica (Si) in the collision tests showed that the accelerated particles concentrated in the supersonic flow center collided on the targets precisely with high collision energy.

Preparation technology of printer needle head

Abstract: The invention discloses a preparation technology of a printer needle head. The technology comprises the following steps of smelting an alloy of which the nominal composition is Nd27Dy4.9M0.8FebalB1.05(M is Al, Co and Nb) by adopting 100 vacuum induction melting furnaces under the protection of 99.99% of Ar, completely smelting the alloy, refining the alloy for 3min, casting the alloy into a water-cooled ingot mold for 1.5h, taking out a product after the ingot mold is completely cooled and preparing powder of which the mean particle size is 4.7 microns by adopting a jaw crusher, an intermediate crusher and a jet mill; adding a thermosetting adhesive to the prepared powder, carrying out molding at intermediate pressure of 750Mpa, carrying out solidifying at 150-170 DEG C until the magneticpowder filling rate is 70% and then adding mineral oil; and fabricating a grain boundary phase alloy into an ingot alloy by adopting a casting process or a strip-casting sheet by adopting a strip-casting process or a rapid quenching tape by adopting a rapid quenching process, crushing the grain boundary phase alloy through a hydrogen blasting method or the crusher and then milling the material through the jet mill to prepare the grain boundary phase alloy powder of which the mean particle diameter is 2-10 microns.

Preparation method of titanium dioxide supported remediator for continuously-ploughed soil

Abstract: The invention discloses a preparation method of a titanium dioxide supported remediator for continuously-ploughed soil and belongs to the technical field of soil remediator. The preparation method comprises the following steps: milling straws to form particles with the particle sizes being smaller than 50mm; then, mixing the particles with nanometer titanium dioxide and titanate, and milling the mixture to form particles with the particle sizes being smaller than 1mm; next, milling the particles by using a jet mill to form particles with the particle sizes being smaller than 1mu m to obtain the titanium dioxide supported remediator for continuously-ploughed soil, wherein the mass ratio of nanometer titanium dioxide to titanate to the straws is controlled at (2-10):(0.2-1):(89-97.8). The preparation method disclosed by the invention is simple; and the prepared remediator for the soil has a relatively good effect on repairing the continuously-ploughed soil, better utilizes the straws, belongs to an energy-saving and emission-reducing item and has an environmental effect.

Method for preparing reaction-sintered grouting-formed silicon carbide ceramics

Abstract: The invention discloses a method for preparing reaction-sintered grouting-formed silicon carbide ceramics. Two kinds of silicon carbide micro-powders which are produced by a jet mill and which are saturated by particle shaping have a particle diameter of 50 [mu]m and 5 [mu]m, and the relative blending ratio ranges from 1:1 to 10:1, pigment carbon black or metallurgical carbon black with a particlesize of 20 nm to 100 nm is taken as a carbon source, the ratio of addition is 1% to 15%, novel high-efficiency binders are adopted and are multiple or all of a group consisting of acrylamide, polyvinylpyrrolidone, polycarboxylic acid, polyvinyl formal, amino ethanol, tetramethylammonium hydroxide, maleic anhydride and polyacrylic acid, and deionized water in a volume ratio of 10% to 40% is adopted. By controlling the suitable silicon carbide raw material particle size and particle size grading, the suitable proportion of carbon and the suitable binders, the carbide ceramics which are low in free silicon residue uniformly distributed, are basically free of free carbon and have high product density and product strength can be prepared, and the reaction-sintered grouting-formed silicon carbide ceramics can be applied to the fields such as lightweight armor, aerospace materials, and reactor vessels.

Preparation method of tyre reclaimed rubber

Abstract: The invention discloses a preparation method of reclaimed rubber and especially a preparation method of tyre reclaimed rubber. The method includes steps of: rubber cutting, crushing, desulfuration, secondary pulverization, hot-mixing, batch-off and packaging. In the preparation method, through initial crushing, the tyre is crushed into pieces with small outer diameter; then through the secondary pulverization, the pieces are pulverized into particles having smaller outer diameter being about 60 [mu]m. The preparation method is higher in production quality of the reclaimed rubber. The secondarypulverization is carried out with a jet mill, so that the rubber pieces are pulverized uniformly and completely.

Fluidized bed jet mill

Abstract: The utility model provides a fluidized bed jet mill, belongs to dry powder materials crushing apparatus technical field, and complicated just easy introduction of current fluidized bed jet mill feeding structure is polluted, the utility model provides a modified fluidized bed jet mill which comprises the base and the rubbing crusher body, the rubbing crusher body is provided with annular wind chamber by lower supreme air inlet housing, crushing room, classifying chamber and the cover of divideing into on the lateral wall of crushing room, and through the U -shaped union coupling, the wind chamber is passed through the intake stack and is connected with outside air supply between air inlet housing and the wind chamber, be provided with the barometer on the intake stack, the feed inlet of crushing room be connected with the feeding chamber, the other end in feeding chamber is connected with the wind chamber, the feeding chamber still is connected with the powder raw material storehouse through corrugated pipe, classifying chamber inside be provided with horizontal minute driving cone, the other end and the induced draft pipe connected of horizontal minute driving cone were connectedwith the motor of outside to driving cone one end in horizontal minute, the bottom of air inlet housing set up row cinder notch, the utility model discloses simple structure and non -staining powder.

Jet mill unit

Abstract: The invention discloses a jet mill unit, which comprises a jet mill, a material feeder, a vortex gas pump, an operation table and a material pipeline, wherein the material pipeline is sequentially provided with a separator, a capture device, a pressure gauge pressure adjustment valve and a gas storage bag, the separator, the capture device, the pressure gauge pressure adjustment valve and the gasstorage bag are communicated through the material pipeline, the jet mill is connected to the material inlet of the material pipeline through a connection device, the capture device is connected to thevortex gas pump through a conduction pipe, the operation table comprises a first table layer, a second table layer and support vertical columns, the jet mill, the material feeder, the separator, thecapture device and the gas storage bag are respectively and fixedly connected to the first table layer, the vortex gas pump is arranged on the upper side of the second table layer, the bottom sides ofthe separator and the capture device are respectively connected to a material receiving barrel through connection devices, the upper side of the gas storage bag is provided with a pressure gauge, a first pressure adjustment valve, a second pressure adjustment valve and a third pressure adjustment valve, the first pressure adjustment valve and the second pressure adjustment valve are connected tothe jet mill, and the third pressure adjustment valve is connected to the material feeder.

Method for preparing superfine uniform yttrium oxide

Abstract: The invention discloses a method for preparing superfine uniform yttrium oxide and relates to the technical field of preparation of chemical products. The preparation method comprises the following specific steps: weighing yttrium oxide powder, putting the yttrium oxide powder into a reaction kettle, adding pure water, then performing uniform mixing and stirring, adding a surfactant and a stabilizing agent, and performing stirring at a uniform speed to obtain a completely-soaked mixture; firstly adding zirconium beads to a sand mill, then adding the soaked mixture to the sand mill, and performing milling to obtain uniformly-dispersed slurry; containing the uniformly-dispersed slurry in a charging basket container, connecting one end of a peristaltic pump with the charging basket container,and connecting the other end of the peristaltic pump with a drying machine; spraying vaporous slurry into the drying machine through the peristaltic pump; drying the sprayed slurry in the drying machine; and dispersing the dried product collected from the drying machine through a jet mill to obtain a product, namely the superfine uniform yttrium oxide. The method disclosed by the invention is simple in preparation process, free of wastewater, friendly to environment and low in cost and can be used for large-scale production.

Horizontal fluidized bed jet mill

Abstract: The invention discloses a horizontal fluidized bed jet mill which comprises a crushing chamber, a transition chamber, a grading chamber as well as a separation plate and a backflow plate, wherein a grading wheel is arranged inside the grading chamber; the crushing chamber, the transition chamber and the grading chamber are communicated in a horizontal direction; the separation plate is positionedbetween the crushing chamber and the transition chamber and is used for partitioning the crushing chamber from the transition chamber; and the separation plate is of a porous structure. The inventionaims to improve equipment efficiency and solve the problems that a conventional fluidized bed jet mill is cumbersome and hard to operate.

Board -like supersonic speed jet mill of vertically collide

Abstract: The utility model discloses a board -like supersonic speed jet mill of vertically collide, including rubbing crusher cavity, the vertical setting of rubbing crusher cavity, the utility model disclosesthe injection pipe and the collision plate of the supersonic nozzle of ingenious design realize smashing a lot of of high rigidity material is high -efficient, at first are that the gas -solid mixescollision many times, then hit the impact plate to special design together, powerful smashing, efficient, kibbling powder particle size range is narrow, and key components is longe -lived, has solvedtraditional fluidized bed airflow pulverizer, only utilizes gas material to mix, inefficiency, disadvantage that output is low, in addition the utility model discloses avoided the horizontal to smash,the gas -solid compound body receives effect of gravity in the motion process, produces the skew of collision, causes wearing and tearing asymmetric, the fast disadvantage that became invalid, and kibbling powder particle size range is narrower simultaneously, the utility model discloses the range of application is wide, is applicable to to smash like high rigidity powders such as silicon monoxide powder, silica powder industry ceramic powder, electron ceramic powder, various silicon powder.

Fluidized bed jet mill

Abstract: The utility model relates to a fluidized bed jet mill, including feed inlet, crushing room, discharge gate and nozzle main part, the nozzle main part movable mounting be in smash on the grinder shellof room lateral wall lower extreme, the nozzle main part is stretched into smash indoor piecemeal activity and adjust, through adjusting the radial interval of air flow nozzle to make this fluidized bed jet mill can adapt to material of different nature, and then increase substantially fluidized bed jet mill's crushing efficiency and application range.

Automatic butt joint device for jet mill and receiving tank

Abstract: The invention discloses an automatic butt joint device for a jet mill and a receiving tank. The device comprises at least three driving mechanisms and alignment blocks correspondingly connected with the driving mechanisms, wherein the driving mechanisms drive the alignment blocks to move in the radial direction of a pipe of the jet mill, and the cross section of the pipe of the jet mill is equallydivided by the projection of the shortest connecting line between the plurality of alignment blocks and the central axis of the pipe of the jet mill on the cross section of the pipe of the jet mill in the vertical direction; top surfaces of the alignment blocks are higher than a discharge port of the pipe of the jet mill; bottom surfaces of the alignment blocks are lower than a feed port, in buttjoint with the discharge port of the pipe of the jet mill, of the receiving tank. The device has the beneficial effects that butt joint quality and butt joint efficiency are high, safe production isensured, and the labor cost is reduced.

Process for producing fine, morphologically optimized particles using jet mill

Abstract: The present invention relates to a process for producing fine particles with a high aspect ratio and/or a low specific surface area by means of jet mills, wherein an alkaline grinding aid is added to the grinding gas before it is fed into the grinding chamber of the jet mill. The invention relates to the micronisation of particles of layered structure material having an interplanar distance ranging from 0.30 to 0.40 nm as measured by X-ray diffraction method.

Whole coffee&whole coffee-based process and product

Abstract: A process for preserving the organoleptic characteristics of coffee-based products and extending their shelf lives, comprising the steps of roasting the green coffee beans and placing it in a chamber with an inert gas atmosphere, first milling of the roasted coffee beans under inert gas conditions to a size between seventy five (75) and five hundred (500), second milling the previously milled roasted coffee beans under refrigerated conditions to ensure that the size of the bean particles fall between ten (10) and thirty (30) microns and jet milling the first and second milled coffee beans using a closed, or semi-closed, loop of inert gas jet mill to bring the bean particles' size between one tenth (0.1) and less than ten (10) microns resulting in an ultrafine powder. Micro-encapsulating or agglomerating the ultrafine powder by spraying the ultra-fine powder with food ingredients in a closed or semi-closed loop fluid bed drier (or cooler) within a refrigerated inert gas environment, resulting in coated roasted whole coffee granules.

Modular spiral jet mill: an innovative tool for targeted micronization of pharmaceutical products

Abstract: Approximately 70% of new chemical entities fall into the BCS Class II category [1], hence requiring application of appropriate pharmaceutical technologies during dosage-form development to achieve an improved biopharmaceutical profile. For this class of drugs, the dissolution rate is the key parameter for the in-vitro evaluation of delivery systems. In fact, increasing the dissolution rate could lead to an enhancement in bioavailability and therapeutic effect [2]. Micronization is one of the most popular, robust and reliable process in the pharmaceutical field for improving the bioavailability of poorly soluble APIs by increasing particle surface area through particle size reduction. The effect of the spiral jet mill on the powder to be milled is related to many geometric and process parameters; in fact, each powder is characterized by a particular physico-mechanical profile and therefore requires a specific mill configuration. According to literature [3-6] and based on practical experience in using jet-milling equipment, 18 parameters (i.e., 15 geometrical and 3 process parameters) have been identified as critical for their impact on the micronization performance and on the subsequent powder classification capabilities. This work deals with the development and the testing of a modular spiral jet mill that could be used to generate, theoretically, 215 different jet-mill configurations. This modular mill will represent a tool to be used for the micronization and classification performances investigation and optimization.

Method for producing ezetimibe-containing pharmaceutical composition

Abstract: PROBLEM TO BE SOLVED: To provide a method for producing an ezetimibe-containing pharmaceutical composition having excellent elution properties.SOLUTION: A method for producing an ezetimibe-containing pharmaceutical composition has (a) a first pulverizing step for pulverizing ezetimibe with a pin mill or jet mill, (b) a second pulverizing step for supplying the pulverized matter obtained by the step (a) as raw material, to pulverize it with a pin mill or jet mill, and (c) wet granulating the pulverized ezetimibe obtained by the step (b).SELECTED DRAWING: None

An experimental method to measure APIs residence time distribution in the jet mill micronization process

Abstract: Micronization by jet mill technology is a method of improving the bioavailability of poorly soluble APIs (Active Pharmaceutical Ingredient). The particle’s residence time distribution (RTD) is a key factor on which the number of particle impacts depends, hence, the achievable particle size reduction and the amorphization state, the so called mechano-chemical activation (MCA). To date, just a few attempts have been made to quantify the particles RTD in jet mill micronization processes, the most relevant are: • Direct measurement by radioactive tracers, method developed by Muller F. et al. [1] in 1996; • Indirect measurement by means of RT’s particle size dependence with probability functions, study performed by Gommeren H.J.C. et al. [2] in 1996. The state of the art of the existent methods present some limitations, the first because of technological complexity, the second being inaccurate (based on probability functions and assumptions). This work deals with the development and testing of a robust, safe and affordable experimental measuring technique suitable to quantify the particles mean residence time (MRT) in micronization processes. The developed method, based on phosphorescent tracer particles emitting green afterglow light, is a partial adaptation of the method developed by Harris et al. [3]. The application of the measurement system is thought for spiral jet mills, however it is applicable to any other solid-gas multi-phase flow process.

Counter-impact jet milling mechanism and jet mill using the same

Abstract: The invention provides a counter-impact jet milling mechanism. The counter-impact jet milling mechanism comprises rotating members capable of rotating around an axis, and is characterized in that at least 4 circumferentially distributed grinding areas are arranged in the rotating members, a through path is formed between the outer edge of each of the grinding areas and the inner wall of each of the rotating members, and negative pressure blades, positive pressure blades and material diverters are arranged in each of the grinding areas. The invention further provides a counter-impact jet mill. The counter-impact jet mill comprises a motor, and is characterized in that the milling mechanism is coaxially installed on an output shaft of the motor, the milling mechanism is arranged in a shell, a feed port and a discharge port are respectively arranged on the shell, the feed port is communicated with the material inlet of the milling mechanism through a feed channel, and the discharge port is communicated with the material outlet of the milling mechanism through a discharge channel. The invention has the advantages of low energy consumption, conforming to environmental protection requirements, suitable for large-scale industrial production, and capable of producing fine powder to superfine powder having different requirements with no need for sectionalizers and induced draft fans.

Method and formulation

Abstract: Methods are disclosed for simultaneously jet milling and conditioning particulate glycopyrrolate and magnesium stearate using a milling gas having humidity between 5% and 30% Relative Humidity in the grinding chamber of a jet mill, the jet mill is configured with a humidifier arranged to supply humidity into the grinding chamber. A composition and formulation comprising physically stable micronized composite glycopyrrolate particles made by this method is also disclosed.

Method for producing wax-coated silicic acid

Abstract: The invention relates to a method for coating silicic acids with wax by introducing the wax in a solid or liquid form into the milling chamber of a fluidized-bed counter-jet mill or a dense-bed jet mill and simultaneously injecting steam as milling gas into the milling chamber at a pressure exceeding the pressure inside the mill by 0.05 to 0.8 bar.