Jet Pulverization Research Articles

High-quality ground tire rubber production from scrap tires by using supercritical carbon dioxide jet pulverization assisted with diphenyl disulfide

This study presents a high-quality ground tire rubber (GTR) production technology by using supercritical carbon dioxide jet pulverization. Diphenyl disulfide was incorporated as the devulcanization reagent during the pulverization process. The effects of rubber swelling on particle size distributions, shape characteristics, thermal degradation behaviors, and devulcanization behaviors of the acquired GTR were investigated. The results showed that fine pulverization of scrap tires can be achieved, along with a desired degree of rubber devulcanization. Rubber swelling or devulcanization was associated with the failure pattern of rubber under jet impact and was not beneficial for fine pulverization. Rubber devulcanization mechanisms included radical and oxidation-based reactions, both of which showed breakage selectivity of crosslinks. The excellent properties of the acquired GTR can help to achieve good dispersion and enhanced interfacial compatibility with the polymeric matrix. Therefore, supercritical carbon dioxide jet pulverization incorporated with diphenyl disulfide is a promising recycling technology for scrap tires.

Impact of jet pulverization and wet milling techniques on properties of aripiprazole long-acting injection and absorption mechanism research in vivo

This study aims to explore the influence of wet milling and jet pulverization on the aripiprazole microcrystalline long-acting injection. Crystal form and particle size distribution were taken as inspection indicators in vitro, and process parameters were optimized. The formulation prepared by wet milling (AMLAI-WM) was shown to undergo a slight conversion of crystal form by DSC, PXRD, TG, FT-IR and have a wider particle size distribution with D50 and Span values of 2.967 μm and 3.457 compared to the formulation fabricated by jet pulverization (AMLAI-JP) with 2.887 μm and 2.258 respectively. In addition, the in vitro release of AMLAI-WM was faster, whereby the pharmacokinetic data indicated that AMLAI-WM was absorbed more quickly within five days with AUC0-5d of 5243.7 μg·L-1·h and 4818.28 μg·L-1·h, respectively. Furthermore, no statistically significant differences in Cmax, tmax and AUC between AMLAI-JP and the commercial formulation (Abilify Maintena™) were found. The absorption mechanism was studied and showed a 1.4-fold later Tmax after depletion of macrophages and significantly lower Cmax and AUC after inhibiting angiogenesis, indicating inflammatory granuloma could facilitate drug plasma exposure. Overall, we demonstrated that jet pulverization was a good strategy for long-acting microcrystalline injection, and that the absorption behavior was affected by both particle size distribution and inflammatory granuloma.

Mechanochemical devulcanization of waste tire rubber in high pressure water jet pulverization

The resource reclamation of waste tire rubber (WTR) is regarded as the most suitable strategy for these solid wastes. Water jet pulverization (WJPul) is a sustainable reclamation technique for WTR, since both size reduction and rubber devulcanization can be achieved. Aiming at understanding the mechanisms related with pulverization and devulcanization of WTR, this work detailed the interactions between WTR and high pressure water jet (HPWJ). The results show that WJPul can be defined as a mechanochemical process for WTR. The compressive shear failure of rubber mainly induces rubber devulcanization and results in fine ground tire rubber (GTR) particles, HPWJ erosion mainly intensifies rubber depolymerization and results in coarse GTR particles. Chemical reactions can be detected between the devulcanized GTR from WJPul and asphalts, thus resulting in better modification performances of GTR from WJPul in asphalt. The results can help better understand the WJPul mechanisms and provide guidelines for WJPul application.

Research on the Increase of Mineral Dissociation Degree by High Pressure Water Jet

The traditional grinding technology of ball mill has many problems, such as high energy consumption, unable to maintain the original crystal shape, and it is difficult to obtain high quality and high purity ultrafine powder. The high-pressure water jet mineral dissociation technology is a new technology which is developed in response to these requirements. The experiment shows that the water jet technology has a strong ability of ultrafine grinding. With the increase of jet velocity, the crushing effect is more obvious. The high-pressure water jet pulverization is superior to ball milling for the separation of rare earth minerals, which has the characteristics of high dissociation degree and relatively uniform particle size. The water jet pulverization is more beneficial to the separation and recovery of rare earth minerals.

Preparation of devulcanized ground tire rubber with supercritical carbon dioxide jet pulverization

This work presents a novel waste tire rubber reclamation method using supercritical carbon dioxide (ScCO2) jet pulverization. The particle size distributions of the acquired ground tire rubber were analyzed and the rubber devulcanization behaviors were investigated. Results show that devulcanized ground tire rubber with fine particle size and coarse surfaces can be acquired in ScCO2 jet pulverization. The rubber swelling in ScCO2 significantly impedes fine pulverization. The jet impact mainly results in main chain scission, while long reaction time and low jet pressure are beneficial for the selective breakage of crosslinks. It indicates that ScCO2 jet pulverization can be an excellent choice for WTR reclamation concerning both size reduction and rubber devulcanization.

Simulation and experimental study on the air jet pulverization of TiC-containing slag

Process of “high temperature carbonization and low temperature chlorination”, which was considered to be one of the most promising technologies, could extracte more than 70% titanium from the furnace slag containing TiO2 10% - 30%. TiC-containing slag was the product of high temperature carbonization, and to meet the requirement of the following chlorination process, it needs to be crushed and grounded to a suitable size distribution. The air jet pulverization of TiC-containing slag was studied in this paper. On the one hand, By CFD numerical simulation, the distribution regularity of nozzle flow field about the main crushing equipment was obtained with different throat diameters and crushing gas pressures. On the other hand, the influences of nozzle throat diameter, crushing pressure, and collision angles on the particle size of the powder were studied by experiment. With the better parameters, the particle size distribution of the product powder was uniform.

CO2 capturing performances of millimeter scale beads made by tetraethylenepentamine loaded ultra-fine palygorskite powders from jet pulverization

Millimeter-sized spheres were prepared in this work as potential solid sorbents for industrial-scale CO2 capture due to their low cost, excellent adsorption capacity and reusability characters. The naturally abundant palygorskite was smashed with jet pulverization, and then acid treated to increase its surface area from 148 to 390 m2/g. Then the tetraethylenepentamine (TEPA) functionalized acid-modified palygorskite (MPA) was synthesized via chemical impregnation. In addition, MPA spheres (MPAS) with average size of ∼3.6 mm were produced by a pellet machine. The prepared solid sorbents were characterized using X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and N2 adsorption–desorption isotherms treated by BET (Brunauer-Emmett-Teller) analysis. The thermogravimetric analysis indicated that the CO2 adsorption capacity of nature palygorskite (0.63 mmol/g) could be enhanced through amine modification. The MPAS-50 had the best CO2 adsorption capacity (2.63 mmol/g) and excellent repeatable adsorption ability, according to the CO2 adsorption tests. The results indicated that the TEPA-functionalized palygorskite sphere is a promising solid sorbent for CO2 capture in industrial green house gases controlling fields.

Multiresponse optimization of process parameters in water jet pulverization via response surface methodology

Water jet pulverization (WJP) is a recently proposed strategy in the reclamation of waste tire rubber (WTR). Aiming at improving the quality of the produced ground tire rubber (GTR), along with increasing the yield and efficiency of WJP, the present study focused on the multiresponse optimization of process parameters as working pressure of water jet (219.5-320.5 MPa), standoff distance between the jet orifice and WTR (98.9-351.1d) and transverse velocity of the orifice (597.7-1102.3 mm/min) in WJP using response surface methodology (RSM). A five-level three-factor central composite rotatable design by RSM was employed to statistically describe the main and interaction effects of process variables on the selective five responses. The predicted results by the regression models showed good agreements with the experimental data. In addition, an optimization was successfully carried out by a desirability function, in order to define the combination of process parameters that optimizes the quality evaluation of the produced GTR and minimizes the specific energy consumption in WJP.

Recycling waste tire rubber by water jet pulverization: powder characteristics and reinforcing performance in natural rubber composites

Abstract Pulverization is a general strategy used prior to any practical application of recycled waste tire rubber (WTR). Mechanical grinding, in use currently, is an inefficient technique due to low-quality rubber powder production and certain indispensable additional pretreatments. The aim of this study is to propose a novel pulverization technique of WTR by ultrahigh pressure water jet. Efficient pulverization of WTR was accomplished by water jet without any pretreatment. Powder characteristics, including particle size distribution (PSD), surface area, thermal behavior and chemical structure changes, were investigated. The curing, mechanical and morphological properties of natural rubber (NR) vulcanizates filled with ground tire rubber (GTR) from water jet pulverization (WJPULV) were evaluated. The results indicate that GTR granules from WJPULV possess a quite fine PSD and large surface area, show similar thermal degradation behaviors to the original WTR and have been partially devulcanized. The improvement of tensile and tear strength of the composites reveals that GTR from WJPULV can be added up to 40 phr without adverse effect. The morphological analysis corroborates the homogeneity of GTR in the NR matrix. All findings confirm that water jet can be an excellent choice for pulverization of WTR.

High efficient fabrication of chitosan micropowder by combination of gamma radiation and jet pulverization

We describe here a novel approach to the high efficient fabrication of chitosan micropowder by combining radiation technique and jet pulverization. The radiation dose is at 100–300 kGy. Size of microparticles in ethanol dispersion determined by dynamic laser scattering (DLS) is in the range of 5–20 μm, depending on the radiation dose and degree of deacetylation (DD). However, Scanning electron micrography (SEM) measurement shows a size range of 0.1–10 μm. FTIR spectra indicate that chemical structure of the micropowder is retained, while the decomposition temperature measured decreases slightly as compared to the control.

Application of water jet pulverization technology

Application of water jet pulverization technology

Effects of feed particle shapes on jet pulverization.

On etudie les effets de la forme des particules sur la distribution granulometrique et l'aire specifique du produit, particulierement pour des particules de moins de 10 μm, a l'aide de particules de verre et de quartz de diverses formes

Jet pulverization of hard or solid particles in fluidized beds

Jet pulverization of hard or solid particles in fluidized beds

On the Limiting Fineness of Powders Ground by Circulating Type Jet pulverizer

The limiting fineness of powders in jet pulverization was investigated with a circulating type jet pulverizer, Jet-O-Mizer 102. Sizes of pulverized powders decrease with the decrease of feeding rate of material into the jet pulverizer.At the point of zero feeding rate, pulverized ultra fine powder might be circulated in the mill for an infinitely long time and might accordingly attain the limiting fineness.From this preliminary experiment, it is observed that the limiting fineness is affected neither by feed size nor by nozzle air pressure but by grindability and also density of materials.

A note on some aspects of jet pulverization

The velocity required for the impact destruction of small particles is determined. It is established that energy is exchanged between particles accelerated in a gas stream. The particle density distribution when two dust-laden streams meet is found.

On the Mechanism of Jet Pulverization

Pneumatic pulverizers have come to be used widely in chemical industries for ultra fine pulverization, but it is very hard to analyze their characteristics quantitatively. We tried, by experiment, to analyze the mechanism of a jet pulverizer, which is expected to be one of the most efficient pneumatic finepulverizers.Thinking that in the mechanism of jet pulverization, suction of particles by jet was essential, we used a simple jet-suction pulverizer shown in Fig. (2-1), and found the relation between the suction of particles and the nozzle pressure relative to other factors, as given by Eq. (3·1). As to grinding, the relation between the rate of pulverization and the nozzle pressure was discovered as presented by Eq. (4·4), which is closely related to Eq. (3·1).Constant kj was defined to be grindability of pneumatic pulverization, which is completely independent of sizes of particles fed, and it was found that kj was closely related to the size distribution pattern of the pulverized material and that such characteristic of the material was clearly indicated by coefficient n, which represents the degree of surface grinding. When n=2.0, the mechanism of pulverization was defined as surface grinding, and when n=0, as bulk crushing (See Fig. 4-3). We believe that this analysis of mechanism will be widely applicable to the other sorts of grinding as well.Further, we experimented in impact jet pulverization by a couple of jets crossing each other (Fig. (7-1)) and obtained the results as shown in Fig. (7-2, 7-3). Another experiment led us to make clear the effects of secondary air on the suction of particles and on pulverization as shown in Fig. (6-2).