Jet Mill Research Articles

Jet Milling Effect on Functionality, Quality and In Vitro Digestibility of Whole Wheat Flour and Bread

Jet milling is an ultragrinding process in order to produce superfine powders with increased functionalities. The effect of milling pressure, feed rate, vibration rate of feeder, and feedback of jet milling on whole wheat flour functionality and the potential of those flours for breadmaking with the goal of improving bread quality and digestibility were investigated. Increasing milling pressure (from 4 to 8 bar), decreasing feed rate (from 0.67 to 5.18 kg/h), and/or using recirculation augmented the severity of the process and reduced flour particle size from 84.15 to 17.02 μm. Breakage of aleurone particle layer and the reduction of particle size in jet milled flours were detected using scanning electron microscopy (SEM). Ash and protein content did not change after jet milling. However, total fiber content and digestible starch increased from 13.01 to 14.72 % and from 33.80 to 43.23 mg/100 mg, respectively, when subjected to jet milling at 8-bar air pressure. Mixolab® data indicated that water absorption increased from 64.1 to 68.0 %, while pasting temperature decreased from 63.4 to 66.1 °C owing to the milling intensity. Referring to bread, jet milled flour addition reduced the specific volume from 2.50 to 1.90 cm3/g, luminosity from 60.48 to 55.87, and moisture content from 35.78 to 33.49 %, and increased crumb hardness from 707 to 1808 g. Jet milled breads presented a slight decrease in estimated glycemic index (eGI) (from 86 to 81), suggesting that jet milling treatment could also have nutritional benefits.

Carbon Diffusion within Periclase During Melting

Physicochemical possibilities are considered for entry of carbon into the structure of fuzed MgO during crystallization from a melt. It is established that fuzed periclase contains carbon, which during periclase grinding is concentrated at the surface of MgO crystals. With fine milling in a vibration mill carbon concentration is higher at the surface of MgO than with milling in a jet mill, and comprises 41.40 and 35.42 wt.% respectively. Melting MgO in an experimental electric arc furnace confirms the possibility of preparing periclase saturated with carbon.

Exploration of Straw Fiber as Reducing Agent Utilization in Rotary Hearth Furnace Process for Direct Reduced Iron Production

Straw fiber is a waste obtained by jet milling after extracting valuable substances form corn straw through steam explosion-washing-mechanical carding process. At the same time, it is also a clean and renewable reducing agent. In this study, physical and chemical characteristics of straw fiber were investigated firstly. The usage of straw fiber in rotary hearth furnace process for direct reduced iron production was then discussed. The results show that on one hand, fixed carbon content in straw fiber is low, which is unfavorable for the productivity of direct reduced iron; on the other hand, ash and sulfur content is also low, which improves the quality of direct reduced iron. Besides, the fibrous structure is conducive to improving the pelletizing performance of carbon-containing pellets, thus reducing an additional amount of binder. Compared with common reducing agents, straw fiber provides better reduction effect, and straw fiber carbon-containing pellets possess higher compressive strength and larger volumetric shrinkage, which is beneficial to increase the thickness of the whole material layer in rotary hearth furnace. In addition, these carbon-containing pellets also have advantages of lowering C/O ratio and shortening reduction time. The appropriate C/O and reduction time are 0.8 and 15 min, respectively, and the particle size of straw fiber below 0.15 mm has better reduction effect. This study aims to provide theoretical and technical basis for the utilization of straw fiber in rotary hearth furnace process.

Optimal thermodynamic conditions for ternary system (CO2, DMSO, ampicillin) in supercritical CO2 antisolvent process

Pharmaceutical micronization increases the dissolution rate and bioavailability absorption and thus decreases the dosage used. Conventional methods of micronization such as jet milling, spray drying and freeze drying have some drawbacks. Alternative methods, pharmaceutical micronization with supercritical fluids have recently attracted interest to overcome the shortcomings of conventional micronization methods. But the precipitation of particles in the supercritical gas antisolvent (GAS) process does not occur at arbitrary operating conditions. Thus thermodynamic models (phase equilibrium) are necessary to evaluate the suitable operating conditions in order to obtain the feasible application of GAS process. In this work the volume expansion and process conditions for the binary system (carbon dioxide (CO2) and dimethyl sulfoxide (DMSO)) and ternary system (CO2, DMSO, and ampicillin) were determined. The Peng–Robinson equation of state with linear combination of Vidal and Michelsen mixing rules (PR-LCVM) was used to model the fluid phases. The minimum pressures for ternary system at 308, 313 and 319 K were 7.3, 8, 8.97 MPa, respectively. At these operating pressures, recrystallization of the dissolved ampicillin occurred.

Application of High Pressure Gas Jet Mill Process to Fabricate High Performance Harmonic Structure Designed Pure Titanium

Application of High Pressure Gas Jet Mill Process to Fabricate High Performance Harmonic Structure Designed Pure Titanium

Are There Generalizable Trends in the Release of Airborne Synthetic Clay Nanoparticles from a Jet Milling Process?

Despite recent efforts to assess the release of nanoparticles to the workplace during different nanotechnology activities, the existence of a generalizable trend in the particle release has yet to be identified. This study aimed to characterize the release of synthetic clay nanoparticles from a laboratory-based jet milling process by quantifying the variations arising from primary particle size and surface treatment of the material used, as well as the feed rate of the machine. A broad range of materials were used in this study, and the emitted particles mass (PM2.5) and number concentrations (PNC) were measured at the release source. Analysis of variance, followed by linear mixed-effects modeling, was applied to quantify the variations in PM2.5 and PNC of the released particles caused by the abovementioned factors. The results confirmed that using materials of different primary size and surface treatment affects the release of the particles from the same process by causing statistically-significant variations in PM2.5 and PNC. The interaction of these two factors should also be taken into account as it resulted in variations in the measured particles release properties. Furthermore, the feed rate of the milling machine was confirmed to be another influencing parameter. Although this research does not identify a specific pattern in the release of synthetic clay nanoparticles from the jet milling process generalizable to other similar settings, it emphasizes that each tested case should be handled individually in terms of exposure considerations.

Influence of jet milling process parameters on particle size, phase formation and magnetic properties of MnBi alloy

The effect of jet milling conditions on phase decomposition, particle size and magnetic properties of MnBi alloy were studied. It is observed that jet milling pressure plays a critical role in controlling the decomposition of MnBi phase, particle size and associated magnetic properties. As the jet pressure increases, more amount of MnBi phase decomposes into Bi and Mn phases. The weight fraction of MnBi phase decreases from 81%, for the starting powder, to 43% by increasing the milling pressure to a high value of 80psi. Particle size decreases rapidly to about 1μm on jet milling and even though the average particle size does not change noticeably with further increase of milling pressure, the particle size distribution appears to be different. Moderate milling pressure has resulted in powders with narrow particle size distribution, low decomposition of MnBi phase and smooth demagnetization curves. All the jet milled powders displayed high coercivity (Hc) values of about 18kOe with saturation magnetization in the range of 41–51emu/g.

Effects of Hydrogenation-Disproportionation-Desorption-Recombination Processing Parameters on the Particle Size of Ultrafine Jet-Milled Nd-Fe-B Powders

The effects of variations in the hydrogenation-disproportionation-desorption-recombination (HDDR) processing parameters on the size of Nd-Fe-B ultrafine powders were investigated. The ultrafine powders were fabricated by hydrogen decrepitation and jet milling of the HDDR alloys. Before pulverization, the crystal grain size of the HDDR alloys obtained by changing the HD processing temperature (THD) varied from 0.27 to 0.55µm, and decreased as THD was lowered. The ultrafine powder of the HDDR alloy became finer as THD decreased, with sizes in the range of 0.33 to 0.58µm. [doi:10.2320/matertrans.M2014273]

Investigation of the milling capabilities of the F10 Fine Grind mill using Box-Behnken designs

Size reduction or milling of the active is often the first processing step in the design of a dosage form. The ability of a mill to convert coarse crystals into the target size and size distribution efficiently is highly desirable as the quality of the final pharmaceutical product after processing is often still dependent on the dimensional attributes of its component constituents. The F10 Fine Grind mill is a mechanical impact mill designed to produce unimodal mid-size particles by utilizing a single-pass two-stage size reduction process for fine grinding of raw materials needed in secondary processing. Box–Behnken designs were used to investigate the effects of various mill variables (impeller, blower and feeder speeds and screen aperture size) on the milling of coarse crystals. Response variables included the particle size parameters (D10, D50and D90), span and milling rate. Milled particles in the size range of 5–200μm, with D50 ranging from 15 to 60μm, were produced. The impeller and feeder speeds were the most critical factors influencing the particle size and milling rate, respectively. Size distributions of milled particles were better described by their goodness-of-fit to a log-normal distribution (i.e. unimodality) rather than span. Milled particles with symmetrical unimodal distributions were obtained when the screen aperture size was close to the median diameter of coarse particles employed. The capacity for high throughput milling of particles to a mid-size range, which is intermediate between conventional mechanical impact mills and air jet mills, was demonstrated in the F10 mill. Prediction models from the Box–Behnken designs will aid in providing a better guide to the milling process and milled product characteristics.

Novel concepts for preparation of reference materials as whole water samples for priority substances at nanogram-per-liter level using model suspended particulate matter and humic acids.

One of the unresolved issues of the European Water Framework Directive is the unavailability of realistic water reference materials for the organic priority pollutants at low nanogram-per-liter concentrations. In the present study, three different types of ready-to-use water test materials were developed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and tributyltin (TBT) at nanogram-per-liter levels. The first type simulated the dissolved phase in the water and comprised of a solution of humic acids (HA) at 5 mg L−1 dissolved organic carbon (DOC) and a spike of the target compounds. The second type of water sample incorporated the particulate phase in water. To this end, model suspended particulate matter (SPM) with a realistic particle size was produced by jet milling soil and sediments containing known amounts of PAHs, PBDEs and TBT and added as slurry to mineral water. The most complex test materials mimicked “whole water” consequently containing both phases, the model SPM and the HA solution with the target analytes strongly bound to the SPM. In this paper, the development of concepts, processing of the starting materials, characterisation of the HA and model SPMs as well as results for homogeneity and stability testing of the ready-to-use test materials are described in detail. Graphical Vials containing 0.5 g of model SPM, black caps for TBT, silver caps for PAH and red caps for PBDEs, respectively. Graphical Petri dishes with dried model SPMs; to the left 95.7 ± 0.9 mg of SPM containing PBDEs; in the middle 95.8 ± 0.7 mg of SPM containing TBT and to the right 93.7 mg ± 0.7 mg of SPM containing PAHs

Highly transparent ceramics obtained from jet milled sesquioxide powders synthesized by co-precipitation method

High purity Yb3+ doped Lu2O3 powder has been synthesized by the co-precipitation method. The powders underwent a jet milling at various feed rate using a commercial jet mill machine. It is found that jet milling is very effective in breaking up of large agglomerates without cross-contamination. Median agglomerate size decreased from 8.74 μm to 1.06 μm when jet milled at a feed rate 0.75 lb/hr. There was no noticeable increase in impurities picked up during the jet milling process in the final powder obtained after a sacrificial run that was carried out for the purpose of conditioning the surface of the liner. Homogeneous, uniform, and highly transparent ceramic was obtained from the ceramic hot pressed with the final jet milled powder compared to the one made from as-produced powder where some defects and splotches are often observed. Transmission of the Yb3+:Lu2O3 ceramics obtained from the jet milled powder is very close to the theoretical limit, demonstrating the excellent quality of the transparent ceramic.

The Study and Preparation of Petroleum Coke Oil Slurry for Diesel Engine

An amount of 1.8 μm of ultra-fine petroleum coke was prepared by air jet mill and used to prepare the petroleum coke oil slurry for a diesel engine. The results indicated that the viscosity of the slurry decreased from 587 to 305 mPa·S, when the amount of additive NDZ-105 increased from 0 to 2 wt%. The coke oil slurry was used in the modified R180 diesel engine, and the results showed that the engine maximum power reduced by 19% compared with burning diesel fuel, and the smoke emission was 2–5 times higher than burning diesel fuel.

Modeling of continuous self‐classifying spiral jet mills part 2: Powder‐dependent parameters from characterization experiments

The milling model described in Part 1 has been expanded to a three‐level model with the addition of powder‐dependent parameter function models with simple material characterization measurements as inputs. This allows the determination of these parameters with minimal consumption of powder. Specifically, the powder‐dependent parameters are related to material hardness from microindentation or to a breakage measure from single‐impact milling. Three crystalline powders, sodium bicarbonate, lactose monohydrate, and sucrose, have been used to test the described material characterization techniques and expanded milling model. © 2014 American Institute of Chemical Engineers AIChE J 60: 4096–4103, 2014

Modeling of continuous self‐classifying spiral jet mills part 1: Model structure and validation using mill experiments

The objective of this work is to develop a milling model for a continuous self‐classifying spiral air jet mill. Its foundation is a population balance model with selection and breakage distribution functions that have been related to a minimal number of mill‐dependent and powder‐dependent parameters. Initially, experimentation is required to determine the mill‐dependent parameters for a specific mill, by milling a “base” powder at multiple operating conditions. Powder‐dependent parameters can be determined from either mill experiments or from material characterization measurements that require small amounts of powder (presented in Part 2). Ultimately, the milling model presented successfully predicts the product particle size using as inputs the feed particle‐size distribution and mill operating conditions. Three crystalline powders, sodium bicarbonate, lactose monohydrate, and sucrose, have been used to test the proposed milling model. © 2014 American Institute of Chemical Engineers AIChE J 60: 4086–4095, 2014

Effect of wet jet milling of carbon nanotube on electrical properties of polymer nanocomposites

Wet-type jet milling (WJM) was used as a pre-treatment procedure for carbon nanotube (CNT) which was utilized as electrical conductive filler for polymer nanocomposites. Nanocomposites were prepared by dispersing WJM treated CNT (WJM-CNT) or as-received CNT (AR-CNT) in isotactic polypropylene matrix, and the effect of WJM pre-treatment on nanocomposite properties was investigated. Dispersion structure of CNT was observed by SEM and electrical property was studied by impedance spectroscopy. DC conductivities (σDC) showed different CNT concentration dependences, which were characterized by the percolation critical exponents. At 0.5 wt% of CNT, σDC increased two-fold by using WJM-CNT. Analysis of imaginary part of impedance spectra and complex dielectric permittivity suggested the WJM-CNT nanocomposites had much complicated local structure as compared to the AR-CNT counterparts. These electrical properties were discussed in relation to the dispersion structure of CNT.

Flue Gas Desulfurization by Mechanically and Thermally Activated Sodium Bicarbonate

Abstract This paper presents the results of study on structural parameters (particle size, surface area, pore volume) and the sorption ability of mechanically and thermally activated sodium bicarbonate. The sorption ability of the modified sorbent was evaluated by: partial and overall SO2 removal efficiency, conversion rate, normalized stoichiometric ratio (NSR). Sodium bicarbonate was mechanically activated by various grinding techniques, using three types of mills: fluid bed opposed jet mill, fine impact mill and electromagnetic mill, differing in grinding technology. Grounded sorbent was thermally activated, what caused a significant development of surface area. During the studies of SO2 sorption, a model gas with a temperature of 300°C, of composition: sulfur dioxide at a concentration of 6292 mg/mn 3, oxygen, carbon dioxide and nitrogen as a carrier gas, was used. The best development of surface area and the highest SO2 removal efficiency was obtained for the sorbent treated by electromagnetic grinding, with simultaneous high conversion rate.

Characterization of Hericium erinaceum powders prepared by conventional roll milling and jet milling

Four types of powder were prepared from freeze-dried fruiting bodies of the edible mushroom Hericium erinaceum by 2 different methods-conventional roll milling and the superfine grinding method of jet milling-at 3 different speeds, to compare their physicochemical properties and extraction of proteins and polysaccharides. Jet-milled powders prepared at 16,000rpm (JMP1), 9000rpm (JMP2), and 5000rpm (JMP3), and roll-milled powder (RMP) had an average particle size of 5.5, 12.9, 25.2, and 243.6μm, respectively. The reduction of particle size resulted in increased specific surface area, porosity, and bulk density. Among the 4 powders, JMP1 showed the highest bulk density (0.17g/ml). The water solubility index of H. erinaceum powder increased from 35.2% in RMP to 53.1% in JMP1. Similarly, the swelling capacity of JMP1, JMP2, JMP3, and RMP was 11.28ml/g, 7.36ml/g, 6.26ml/g, and 5.9ml/g, respectively. The extractions of proteins and polysaccharides from H. erinaceum powders were also improved by the application of jet milling. These results suggest that the superfine grinding method of jet milling could provide more opportunities for mushroom powders to be incorporated in a wider variety of functional food applications.

Dry Fine Grinding with Jet Mills: Potentials of Energy Optimization

AbstractThe interest in finer, dry products has led to the development of more efficient jet milling processes. The first part of the paper describes the thermodynamic basic principles for generation and application of steam, and compressed gases. Practical experience has shown that in the aspired fineness range stabilization during grinding provides an enormous potential for improvement. Some selected examples demonstrate that the energy requirement can be reduced by a factor of more than two by suitable choice of stabilizers.

Dissolution and oral absorption of pranlukast nanosuspensions stabilized by hydroxypropylmethyl cellulose

The objective of this study was to investigate the effect of particle size on the dissolution and oral absorption of pranlukast microsuspensions and nanosuspensions stabilized by hydroxypropylmethyl cellulose. Four pranlukast suspensions with different mean particle sizes (0.16, 0.89, 3.13, and 18.21μm) were prepared by various top-down processes such as jet milling, high pressure homogenization, and bead milling. The dissolution rate and oral absorption of pranlukast suspensions were significantly affected by the particle size. The in vivo pharmacokinetic parameters of pranlukast suspensions were increased with decreasing mean particle size of suspensions. Especially, the AUC0→24h and Cmax values of pranlukast nanosuspension with a particle size of 0.16μm were approximately 3.5- and 6.3-fold greater, respectively, than that of pranlukast microsuspension with a particle size of 18.21μm. Therefore, the preliminary results from our study suggest that a pranlukast nanosuspension with a mean particle size of about 0.16μm may have significant potential for clinical application.

Coercivity enhancement of sintered Nd-Fe-B magnets by chemical bath deposition of TbCl3

The chemical bath deposition (CBD) and the grain boundary diffusion method were combined to diffuse the heavy rare earth for obtain the thick magnets with high coercivity and low heavy rare earth. The jet mill powders were soaked into the alcohol solution of 0.2 wt. % TbCl3. A thin layer of TbCl3 was wrapped to the surface of (PrNd)2Fe14B powder particles. The coercivity of magnet is increased from 11.89 kOe to 14.72 kOe without significant reduction of remanence after grain boundary diffusion in the sintering and the annealing processes. The temperature coefficients of the remanence and the coercivity are improved by the substitution of PrNd by Tb in the surface of grains. The highly accelerated temperature/humidity stress test (HAST) results indicate that the CBD magnet has poor corrosion resistance, attributing to the present of Cl atoms in the grain boundaries.