Determination of particle size distribution in an Fe2O3-based catalyst using magnetometry and x-ray diffraction

1992 ◽  
Vol 7 (7) ◽  
pp. 1856-1860 ◽  
Author(s):  
Manjula M. Ibrahim ◽  
Jianmin Zhao ◽  
Mohindar S. Seehra
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mössbauer Measurements ◽  
Log Normal ◽  
Log Normal Distribution

In this paper, the techniques of SQUID magnetometry and line broadening in x-ray diffraction are employed for determining an important parameter for catalysts, viz. the particle size distribution. Magnetization versus temperature (5 K–400 K) and magnetization versus field (up to 55 kOe) data are reported for an α–Fe2O3 based catalyst. After determining the region of superparamagnetism, the distribution function f(r) is determined assuming a log normal distribution and Langevin paramagnetism of superparamagnetic particles. The distribution is found to be fairly symmetric with center near 65 Å and range of 35 to 115 Å. From line-broadening of Bragg peaks in x-ray diffraction, particle radii varying between 75 Å and 110 Å are obtained. These results are compared with the reported Mössbauer measurements of Huffman et al. on the same sample.

Determination of Particle Size of a Dispersed Phase by Small-Angle X-ray Scattering

1989 ◽  
Vol 171 ◽  
Author(s):  
Frank C. Wilson
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Spherical Particles ◽  
Dispersed Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Resultant Data ◽  
Log Normal ◽  
Log Normal Distribution

ABSTRACTA method for determining particle diameters up to ca 500 rnm is described. X-ray data are obtained with an ultra-high resolution Bonse-Hart diffractometer and subsequently desmeared. The resultant data, viewed as the invariant argument h l(h), are interpreted as arising from a log-normal distribution of independent spherical particles. The distribution is characterized by its median value and breadth.

Synthesis of the Mümetal Magnetic Powders by Mechanical Alloying

2011 ◽  
Vol 672 ◽  
pp. 157-160
Author(s):  
Ionel Chicinaş ◽  
Viorel Pop ◽  
Florin Popa ◽  
Virgiliu Călin Prică ◽  
Traian Florin Marinca ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Mechanical Alloying ◽  
Size Distribution ◽  
Milling Time ◽  
Cast Alloy ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapid Formation

The formation of quaternary 76Ni17Fe5Cu2Cr (wt. %) alloy by mechanical alloying is investigated. The elemental powders of Ni, Fe, Cu and Cr where milled in argon atmosphere in a planetary ball mill for time up to 20 h. Formation of the alloy was checked by X-ray diffraction studies. It is found that the rapid formation of the alloy lead to the rapid establishment of an equilibrium between the welding and fracture process during milling, leading to a constant particle size distribution over a big range of milling time. The morphology of the powders, studied by scanning electron microscopy (SEM) confirms the rapid increase in size. The particle size distribution and the flowability of the powders are also analyzed as a function of milling time. Enhanced magnetization was found for the milled samples, compared to a cast alloy.

Using Lime Mud Waste from Pulp Mill as an Additive in Brick Clay

2014 ◽  
Vol 608 ◽  
pp. 3-7
Author(s):  
Srichalai Khunton ◽  
Siriphan Nilpairach ◽  
Supin Sangsuk
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Pulp Mill ◽  
Mineralogical Composition ◽  
X Ray Diffraction ◽  
Brick Clay ◽  
X Ray ◽  
Lime Mud ◽  
Firing Shrinkage

Lime mud from a pulp mill was used as an additive in brick clay from the southern part of Thailand. It was mixed with the clay from Cha-Aud district, Nakorn Sithammarat province. The chemical composition of lime mud and the clay was characterised by X-ray fluorescence (XRF), and the mineralogical composition was measured by X-ray diffraction (XRD). The particle size distribution was also measured. The main composition of lime mud is CaO, and Cha-Aud clay consists of SiO2 and Al2O3 as major oxides. The lime mud contains calcite as a major phase when Cha-Aud clay is constituted by quartz, kaolinite, illite and goethite. Particle size distribution of lime mud is in the range of 1-50 μm. After the lime mud was neutralized using hydrochloric acid, it was mixed with Cha-Aud clay at 10 wt%. Samples with and without lime mud were sintered at 700, 800, 900 and 1000°C for 1 hour. The results showed that lime mud can be used as an additive in brick clay. Both types of samples were similar in terms of physical properties when their linear firing shrinkage, water absorption and flexural strength were in the same range.

The Effects of Surfactants on the Granularity of the HA Powder Synthesized by Mechanochemistry

2009 ◽  
Vol 610-613 ◽  
pp. 1323-1326
Author(s):  
Tao Yu ◽  
Jian Dong Ye ◽  
Ying Jun Wang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fine Particles ◽  
Low Cost ◽  
Sodium Hexametaphosphate ◽  
X Ray Diffraction ◽  
Laser Scattering ◽  
X Ray ◽  
Batch Sizes

The hydroxyapatite (HA) was synthesized by wet mechanochemical method；the effects of surfactant, such as triethanolamine, polyethylene glycol (200000), sodium hexametaphosphate, polyvinylpyrrolidone (K30), on the particle size distribution of as-prepared HA powder were studied. Results were characterized by means of X-ray diffraction (XRD), Scanning electron microscopy (SEM), Laser Scattering Particle Size Distribution Analyzer. The results show that the addition of surfactants eliminated the agglomeration of the powder and the uniform, fine particles (D10=0.1149μm, D50=0.12551μm, D90=0.1481μm) were obtained with the Triethanolamine (6 wt %) and Sodium hexametaphosphate (4 wt %) respectively. Our work demonstrates applicability of the mechanosynthesis for reproducible and low-cost synthesis of uniform, fine HCA powder in large batch-sizes.

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