Jet Mill Research Articles

Study of the Preparation of Micronized Zinc Phosphate Dihydrate with Potential for Application in the Phosphating Process

The protection of metal parts against corrosion damage is one of the most comprehensive areas of industrial chemistry and a wide range of methods exists to protect the surface from corrosive stimulators, including phosphating. A key phosphating process, the tricationic phosphating, consists of baths containing zinc dihydrogen phosphate and other cations, such as Zn2+, Co2+, Ni2+ or Mg2+. However, cobalt and nickel ions are classified as environmentally harmful and they are being actively excluded from industrial processes. The use of sufficiently micronized zinc phosphate dihydrate (µ-Zn3(PO2)2 · 2H2O) is one the possible approaches to significantly reduce or eliminate heavy metals from the phosphating process. The micronized zinc phosphate dihydrate serves as a nucleus on the metal surface to form a sufficiently high-quality phosphate layer. The study aims to find a procedurally optimal dispersion methodology suitable for application in the Czech Republic. The use of progressive grinding methods such as the jet mills is emphasized and shows promising results.

Effects of Jet Milling Pretreatment and Esterification with Octenyl Succinic Anhydride on Physicochemical Properties of Corn Starch.

(1) Background: In this study, aiming at the problems of low efficiency and high energy consumption in the esterification reaction of OSA and starch, the jet milling technology was used to pretreat corn starch and starch raw materials with different pulverization strengths were obtained by controlling the speed of the classifier. (2) Methods: The starch obtained under different classification speeds was modified by esterification with OSA. Using CLSM, FTIR, XRD, NMR, FTIR, XPS, and other technologies, the modification effect was verified, and the physical and chemical properties of J-OSA-Starch such as DSC, RVA, transparency, and emulsifying properties were determined. (3) Results: Jet milling pretreatment significantly reduced the particle size of corn starch and improved the reaction efficiency and degree of substitution during esterification with OSA. After pretreatment, the corn starch granules were broken, and the relative crystallinity was significantly reduced. CLSM, FTIR, XPS, and NMR confirmed the esterification of corn starch with OSA, which increased with increasing crushing strength. The thermodynamic properties and viscosity of J-OSA-starch decreased with the increase in the classification speed. Jet milling pretreatment enhanced the clarity, emulsifying activity, and emulsifying stability of OSA-modified corn starch. (4) Conclusions: Jet milling pretreatment can effectively increase the esterification efficiency of starch and OSA. Therefore, jet milling can be used as a pretreatment to improve the esterification of starch OSA and produce modified starch for industrial applications.

All-Gas-Phase Synthesis of Heterolayered Two-Dimensional Nanohybrids Decorated with Metallic Nanocatalysts for Water Splitting.

Herein, a sequential gas-phase process involving air jet milling followed by chemical vapor deposition (CVD), is demonstrated to be an efficient strategy for the fabrication of heterolayered 2D nanohybrids (2DNHs) decorated with nanocatalysts. Tens of grams of the nanohybrids, which is a substantial quantity at the laboratory scale, are produced in the absence of solvents and water, and without the need for an extra purification procedure. Air jet milling enables the development of binary/ternary heterolayered structures consisting of graphene, WSe2 , and/or MoS2 via the gas-phase co-exfoliation of their bulk counterparts. Based on the X-ray photoelectron and Raman spectroscopy data, the heterolayers of the 2DNHs exert chemical and electronic effects on each other, while diminishing the interactions between same-component layers. Moreover, the electrochemically active surface area increases by >190% and the charge transfer resistance decreases by >35%. CVD is performed to introduce Pt and Ru nanoparticles with diameters of a few nanometers as additional electrocatalysts into the 2DNHs. The nanocatalyst-decorated 2DNHs show excellent performance for the production of hydrogen and oxygen gases in water-splitting cells. Notably, the proposed all-gas-phase processes allow for the large-scale production of functional 2DNHs with minimal negative environmental impact, which is crucial for the commercialization of nanomaterials.

Varied Bulk Powder Properties of Micro-Sized API within Size Specifications as a Result of Particle Engineering Methods.

Micronized particles are commonly used to improve the content uniformity (CU), dissolution performance, and bioavailability of active pharmaceutical ingredients (API). Different particle engineering routes have been developed to prepare micron-sized API in a specific size range to deliver desirable biopharmaceutical performance. However, such API particles still risk varying bulk powder properties critical to successful manufacturing of quality drug products due to different particle shapes, size distribution, and surface energetics, arising from the anisotropy of API crystals. In this work, we systematically investigated key bulk properties of 10 different batches of Odanacatib prepared through either jet milling or fast precipitation, all of which meet the particle size specification established to ensure equivalent biopharmaceutical performance. However, they exhibited significantly different powder properties, solid-state properties, dissolution, and tablet CU. Among the 10 batches, a directly precipitated sample exhibited overall best performance, considering tabletability, dissolution, and CU. This work highlights the measurable impact of processing route on API properties and the importance of selecting a suitable processing route for preparing fine particles with optimal properties and performance.

Effects of Jet Milling on the Physicochemical Properties of Buckwheat Flour and the Quality Characteristics of Extruded Whole Buckwheat Noodles.

The effects of jet milling on the physicochemical properties of buckwheat flour and the quality characteristics of extruded whole buckwheat noodles (WBN) were investigated in this study. The results reveal that the application of jet milling significantly reduced the particle size of buckwheat flour. As a result, the damaged starch content, water solubility index, water absorption index and swelling power of buckwheat flour all increased. It was worth noting that moderately ground buckwheat flour powder (D50 = 65.86 μm) had the highest pasting viscosity and gel hardness. The breaking rate and cooking loss of extruded whole buckwheat noodles made from the above powder were reduced by 33% and 16%, respectively. Meanwhile, they possessed the highest lightness and firmest network structure. Jet milling increased the soluble dietary fiber (SDF) content from 3.45% to 4.39%, and SDF further increased to 5.28% after noodle extrusion. This study was expected to provide a reference for exploiting high-quality gluten-free noodles from the perspective of milling.

Realization of high-performance HRE-free Pr-Fe-B sintered magnet through microstructure regulation

Currently, the continued high prices of the heavy rare earth (HRE) elements Dy and Tb are prompting an exploration of the development of HRE-free high-performance 2:14:1-type permanent magnets. In this paper, a high maximum energy product of 44.04 MGOe at room temperature (RT) was obtained while maintaining a coercivity greater than 20 kOe in HRE-free Pr-Fe-B sintered magnets through microstructural regulation, which reached an equivalent to the commercially 45SH level. The Pr-Fe-B sintered magnet possesses excellent magnetic properties at low temperatures, and its remanence and coercivity increased to 14.75 kG and 75.01 kOe at −170 °C, respectively. Microstructure analysis indicated that the fine and uniform columnar crystals in the strip-casting (SC) alloys provided conditions for the preparation of fine-grained jet milling (JM) powders and sintered magnets. After annealing, the continuous grain boundary (GB) layers and the fine grain size of 2.80 μm ensured high coercivity. Meanwhile, the reduction of microcracking at the GB helps densification and the improvement of c-axis alignment ensured high remanence. The above exploration of microstructural regulation throughout the metallurgical process can provide meaningful guidance for the development of HRE-free Pr-Fe-B sintered magnets with high performance.

Influence of particle trap rings with different shapes and heights on the performance of spiral jet mills

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Comminution efficiency of spiral jet mills with different grinding nozzle types and shapes

Comminution efficiency of spiral jet mills with different grinding nozzle types and shapes

Modelling and experimental investigation of flat surface achieved by large rectangular electrochemical jet milling

Modelling and experimental investigation of flat surface achieved by large rectangular electrochemical jet milling

Enhancement of surface quality in the electrochemical milling of 316L using a novel cathode structure

In electrochemical jet milling (EJM), enhancing the current density at the trail edge of a workpiece can improve the surface quality. In this study, a novel rectangular cathode tool structure insulated at one side was designed to reinforce the current density at the trail edge of a workpiece to improve the machined surface quality. Numerical simulation was performed to analyse the current density distribution with respect to various parameters, and experiments were conducted to verify the simulation results. The simulation results showed that the current density could be strengthened by utilising the tool with an insulated frontal nozzle tip, which can improve the surface quality during the machining process. Meanwhile, the experimental results revealed that a mirror-like surface could be obtained when utilising the tool under favourable conditions. Compared to other tools, the surface machined by the tool with an insulated frontal nozzle tip had minimum roughness, defects, and overcut.

Remdesivir powders manufactured by jet milling for potential pulmonary treatment of COVID-19

Remdesivir is one of the effective drugs proposed for the treatment of coronavirus disease 2019 (COVID-19). However, the study on inhalable regimen is currently limited though COVID-19 is respiratory diseases and infects lung area. This work aims to prepare inhalable remdesivir formulations and verify their effectiveness through in vitro evaluations. Formulations containing different ratios of jet-milled inhalable remdesivir (5, 10, 20,40, and 70%) with excipients were produced and characterized in terms of the particle size distribution, particle morphology, flowability, water content, crystallinity, the water sorption and desorption capabilities, and the aerodynamic performance. Results indicating that drug loading are a vital factor in facilitating the dispersion of remdesivir dry powder, and the ternary excipient plays a negligible role in improving aerosol performance. Besides, the 70% remdesivir with lactose carrier (70% RD-Lac) was physically stable and retain high aerosol performance after conditioned at 40 °C and 75% RH for a month. Therefore, formulation 70% RD-Lac might be recommended as a candidate product for the potential treatment of COVID-19.

Ultrafine biosorbent from waste oyster shell: A comparative study of Congo red and Methylene blue adsorption

High value utilizations of waste oyster shell and industrial waste heat play the crucial roles in field of environmental protection. Crushed shell powder has expended specific surface and exposed chitin and the character makes it suitable for adsorption. Industrial waste heat can be used as energy resource of steam jet mill to produce shell powder with different particle sizes. And this method has relatively great potential in cleaner production since it avoids extra contamination. Average particle size of products decreases sharply from 27.75 μm to 8.15 μm. Specific surface and exposed chitin increase with the decreasing particle size. The results of adsorption experiments indicate powder with smaller diameters has relatively high adsorption capacity of Congo red (CR) increased by 48.3% and Methylene blue (MB) by 62.5% compared with pristine shell powder. Meanwhile, the adsorption capacity of CR is higher than that of MB due to cationic chitin.

Fabrication of Silver Nanoparticles / Chitosan Nanofibers Composite Material Using a High-Pressure Wet-Type Jet Mill and their Antibacterial Properties

Fabrication of Silver Nanoparticles / Chitosan Nanofibers Composite Material Using a High-Pressure Wet-Type Jet Mill and their Antibacterial Properties

A novel uncoupled quasi-3D Euler-Euler model to study the spiral jet mill micronization of pharmaceutical substances at process scale: model development and validation

In this work we present a novel approach to model the micronization of pharmaceutical ingredients at process scales and times. 3D single-phase fluid-dynamics simulations are used to compute the gas velocity field within a spiral jet mill which are provided as input in a 1D compartmentalized model to calculate solid velocities along the radial direction. The particles size reduction is taken into account through a breakage kernel that is function of gas energy and local solid hold-up. Simulation results are validated against micronization experiments for lactose and paracetamol, comparing the model predictions with D10, D50 and D90 diameters values coming from Design of Experiments isosurfaces.The developed model allows for a fair estimation of the outlet particle size distribution in a short computational time, with very good predictions especially for D90 values.

Mechanical Characterization of Pharmaceutical Powders by Nanoindentation and Correlation with Their Behavior during Grinding.

Controlling the size of powder particles is pivotal in the design of many pharmaceutical forms and the related manufacturing processes and plants. One of the most common techniques for particle size reduction in the process industry is powder milling, whose efficiency relates to the mechanical properties of the powder particles themselves. In this work, we first characterize the elastic and plastic responses of different pharmaceutical powders by measuring their Young modulus, the hardness, and the brittleness index via nano-indentation. Subsequently, we analyze the behavior of those powder samples during comminution via jet mill in different process conditions. Finally, the correlation between the single particle mechanical properties and the milling process results is illustrated; the possibility to build a predictive model for powder grindability, based on nano-indentation data, is critically discussed.

Single-Step Synthesis of Silver Nanoparticles Supported on Cellulose Nanofibers Using a High-Pressure Wet-Type Jet Mill and Their Catalytic Activities

Single-Step Synthesis of Silver Nanoparticles Supported on Cellulose Nanofibers Using a High-Pressure Wet-Type Jet Mill and Their Catalytic Activities

Laser powder bed fusion of a Nb-based refractory alloy: Microstructure and tensile properties

In this study, Nb521 (Nb–5W–2Mo–1Zr) parts were successfully fabricated by laser powder bed fusion (LPBF) using quasi-spherical hydride-dehydride (HDH) powders modified by jet milling. The relative density of the LPBF made (LPBFed) Nb521 parts is 98.8 ± 0.2%, which were subsequently subjected to hot isostatic pressing (HIP) to achieve almost full densification. Nanoscale ZrO2 precipitates were found in the LPBFed parts and those after HIP (HIPed), showing semi-coherent with the matrix. The precipitation behavior is strongly related to the melt pool solidification process during LPBF in terms of thermal distribution and solidification rate. The LPBFed Nb521 parts after HIP presented sound tensile properties with the fracture strength of 678.7 ± 1.1 MPa and elongation of 5.91 ± 0.32%. The precipitated nanoscale ZrO2 underwent plastic deformation after tension, exhibiting the stress-induced tetragonal-to-monoclinic phase transformation and shearing by dislocations. This work presents the LPBFed Nb521 alloy with promising performance by employing low-cost jet-milled HDH powders.

A comprehensive study of tantalum powder preparation for additive manufacturing

In this study, sodium reduced tantalum (Ta) powders were processed by fluidization, jet milling and plasma spheroidization respectively to improve processing performance for additive manufacturing (AM). The morphologies, flowability, chemical compositions, and microstructural evolution of as-processed Ta powders were systematically studied. The flowability of raw Ta powder can be significantly improved by both jet milling (JMed) and plasma spheroidization (PSed). The impurities contents of powders in each process did not significantly change. The homogeneous oxide film and bimodal particle size distribution of PSed powder led to a higher laser absorption and wide printing parameters range as compared to JMed powder. The as-printed Ta components exhibited a good part precision and low hardness due to low oxygen content of both JMed and PSed powders.

Influence of different pretreatments on the quality of wheat bran-germ powder, reconstituted whole wheat flour and Chinese steamed bread

This paper studied the influences of low-temperature (temp) extrusion (nonexpanded), high-temp extrusion (expansion), explosion puffing and high-temp jet milling on the modification of wheat bran-germ powder (WBGP) and on the dough properties, storage stability and Chinese steamed bread (CSB) quality in relation to reconstituted whole wheat flour (WWF). The four pretreatments significantly increased the soluble dietary fiber content of WBGP by 79.0%, 72.8%, 47.6% and 70.9%, respectively, and the lipase and lipoxygenase activities were inactivated to varying degrees. The extrusion technologies did not cause significant changes in the gluten indexes and pasting properties of WWF, while the low-temp extrusion had better thermal stability and anti-retrogradation. The gas retention coefficients of WWFs were pretreated by extrusion was higher than the other WWFs. The specific volume of CSB pretreated by low-temp extrusion was slightly larger than that of control, and the cell diameters and coarse cell volumes were smaller. Pretreatment can obviously inhibit the increase in fatty acid contents of WWF during storage and inhibit enzyme activity. The storage stability of extrusion technologies was better than that of wheat flour. Altogether, low-temp extrusion was more suitable for pretreating WBGP.

Fabrication and analysis of mischmetal MM-Fe-B magnetic alloy

Mischmetal (MM30Nd70)30.4Fe68.2Al0.4Cu0.2B0.8 bulk magnets have been prepared with strip casting method followed by hydrogen decrepitating, jet milling, sintering and annealing. Process conditions to achieve optimum magnetic properties have been established through experimentations. XRD studies revealed main tetragonal RE2Fe14B phase and less RE-rich and CeFe2 phases. Microscopic examinations elucidated that magnet microstructure composed of main magnetically MM2Fe14B hard phase, RE-rich intergranular phase and magnetically soft CeFe2 phase. Henkel plot demonstrated the existence of exchange coupling between magnetic phase grains. Thermal studies showed Curie temperature of 278 °C for the Mischmetal (MM30Nd70)30.4Fe68.2Al0.4Cu0.2B0.8 magnet. Magnetic evaluations provoked coercivity Hcj of 619kA/m, remanenec Br of 1.15 T and maximum energy product density of 241 kJ/m3 for the (MM30Nd70)30.4Fe68.2Al0.4Cu0.2B0.8 magnetic alloy.