Particle Morphology via Change of Ground Particle for Various Experimental Conditions During a Grinding Process by Three Kinds of Media Mills

Author(s):  
Shiori Sakuragi ◽  
◽  
Amgalan Bor ◽  
Jehyun Lee ◽  
Heekyu Choi
Author(s):  
Amgalan Bor ◽  
Battsetseg Jargalsaikhan ◽  
Khulan Uranchimeg ◽  
Jehyun Lee ◽  
Heekyu Choi

Author(s):  
Ikram Ul Haq ◽  
Khalida Akhtar ◽  
Zia Ullah Khan

AbstractIn this study, micron size uniform particles of aluminum compounds were synthesized by the homogeneous precipitation method under reflux boiling, using aluminum nitrate, urea and potassium sulfate as starting materials. In this method, varying amounts of the reactants were heated in a Pyrex glass round bottom flask at the boiling temperature for various periods of time, which led to the production of precipitated particles in the reactant mixtures. Scanning electron microscopic (SEM) examination of the precipitated particles revealed that uniformity in particle morphology of the precipitated particles was dependent on the applied experimental conditions. As such, the latter were extensively optimized for obtaining particles of uniform morphology and size. Some of the batches of the precipitated particles were calcined at the elevated temperature (800 and 1000 °C) for transformation into crystalline solids. Similarly, the as prepared and calcined particles were characterized by SEM, XRD, TGA/DTA and FTIR. XRD results revealed that at 1000 °C of calcinations, the as prepared amorphous alumina transformed in to crystalline state, while below this temperature, i.e. at 800 °C calcination, the powder was amorphous in nature. The point of zero charge (PZC) of the desired sample was estimated by the salt addition method.


2014 ◽  
Vol 670-671 ◽  
pp. 526-528
Author(s):  
Li Hua ◽  
Xiang Jun Wang ◽  
Rui Zhou

Mirror grinding mainly depends on the precision of the machine tool, cutting and grinding amount and wheel selection and dressing. This paper mainly studies the MG1432 high-precision universal cylindrical grinder, exploring the impact on the workpiece roughness through selection and design of various process parameters in grinding, such as changing work table speed in dressing the grinding wheel and grinding, workpiece linear velocity and excessive feeding. The experimental conditions were: Using resin binder white corundum graphite grinding wheels, workpiece: GCr15 (HRC60); dressing tool: sharp single particle diamond correction pen, and ultimately achieving mirror grinding process results.


2006 ◽  
Vol 6 (3) ◽  
pp. 1-8
Author(s):  
M.S. López-Vigil ◽  
M.T. Orta de Velásquez ◽  
R.M. Ramírez Zamora

The aim of this work was to investigate the influence of the number of regeneration cycles on the removal of ammoniacal nitrogen from aqueous solutions with zeolite clinoptilolite (in its sodium or homo-ionic form). In addition, the obtained results were correlated with the physicochemical properties of regenerated homo-ionic zeolites. A unifactorial experimental design, balanced with permanent effects, was applied to assess the removal of ammoniacal nitrogen with homo-ionic zeolites presenting 0–10 sodium regeneration cycles (Z0–Z10). The experimental conditions of trials were as follows: pH 7, contact time was 30 min, stirring speed was 100 rpm, in completely mixed batch reactors. Samples of natural zeolite (ZN without sodium homo-ionization) and homo-ionic zeolites (Z0–Z10) were used to determine their surface properties by using the BET-N2 method (surface area (m2/g), pore volume (cm3/g) and pore diameter (Å)). Other determined properties were the zeta potential (by micro-electrophoresis), percentage of elements (by the X-ray disperse spectrometric method) and particle morphology by scanning electronic microscopy. The results have shown that homo-ionic zeolites had a high removal capacity of ammoniacal nitrogen; this and other properties did not change in a significant way, even after a number of regeneration cycles as high as 10.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 283
Author(s):  
Juntao Ma ◽  
Daguang Wang ◽  
Shunbo Zhao ◽  
Ping Duan ◽  
Shangtong Yang

The grinding process has become widely used to improve the fineness and performance of fly ash. However, most studies focus on the particle size distribution of ground fly ash, while the particle morphology is also an important factor to affect the performance of cement paste. This article aims at three different kinds of ground fly ash from the ball mill and vertical mill, and the particle morphology is observed by scanning electron microscopy (SEM) to calculate the spherical destruction (the ratio of spherical particles broken into irregular particles in the grinding process of fly ash), which provides a quantification of the morphology change in the grinding process. The fluidity of cement paste and the strength of cement mortar are tested to study the relation of spherical destruction and fluidity and strength. The results show that the spherical destruction of ground fly ash in a ball mill is more than 80% and that in a vertical mill with a separation system is only 11.9%. Spherical destruction shows a significant relation with the fluidity. To different addition of ground fly ash, the fluidity of cement paste decreases with the increase of spherical destruction. To the strength of cement paste, particle size distribution and spherical destruction are both the key factors. Therefore, spherical destruction is an important measurement index to evaluate the grinding effect of the fly ash mill.


Author(s):  
F. I. Grace ◽  
L. E. Murr

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.


Author(s):  
Nalin J. Unakar

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.


Author(s):  
N. J. Zaluzec

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation


Author(s):  
V. Annamalai ◽  
L.E. Murr

Economical recovery of copper metal from leach liquors has been carried out by the simple process of cementing copper onto a suitable substrate metal, such as scrap-iron, since the 16th century. The process has, however, a major drawback of consuming more iron than stoichiometrically needed by the reaction.Therefore, many research groups started looking into the process more closely. Though it is accepted that the structural characteristics of the resultant copper deposit cause changes in reaction rates for various experimental conditions, not many systems have been systematically investigated. This paper examines the deposit structures and the kinetic data, and explains the correlations between them.A simple cementation cell along with rotating discs of pure iron (99.9%) were employed in this study to obtain the kinetic results The resultant copper deposits were studied in a Hitachi Perkin-Elmer HHS-2R scanning electron microscope operated at 25kV in the secondary electron emission mode.


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