scholarly journals Effect of Operational Factors on the Particle Size Distribution and Particle Shape of Precipitated Calcium Carbonate Synthesized. Effect of Initial Concentration of Calcium Hydroxide.

2000 ◽  
Vol 37 (9) ◽  
pp. 649-657 ◽  
Author(s):  
Tae Sup SO ◽  
Woo Sik CHOI
2006 ◽  
Vol 510-511 ◽  
pp. 1026-1029
Author(s):  
Jin Sang Cho ◽  
Sung Min Joo ◽  
Sang Hwan Cho ◽  
Young Hwan Yu ◽  
Im Ho Kim ◽  
...  

The effect of the impurity ions Al3+, Fe3+ and Mg2+ on the formation yield and crystal properties of precipitated calcium carbonate(PCC) produced by the carbonation process was investigated in Ca(OH)2-H2O-CO2 system. The effect of the impurity ions Al3+, Fe3+ and Mg2+ on the formation yield using particle size distribution and morphology of PCC were discussed. The particle size distribution of PCC was increased with increase of impurity ions. The morphology was transformed in order of spheroidal, scalenohedral, rhombohedral calcite for Al3+, Fe3+ and rhombospheroidal, spherical, scalenohedral for Mg2+ with increase of impurity ions.


1992 ◽  
Vol 266 ◽  
Author(s):  
June D. Passaretti ◽  
Trudy D. Young ◽  
Mick J. Herman ◽  
D. Bruce Evans

AbstractThis paper discusses the use of a new rhombohedral precipitated calcium carbonate (PCC) morphology and existing PCC morphologies in wood free, wood containing, and recycled paper. The new material has properties that mimic TiO2 with respect to morphology, particle size, particle size distribution, and surface area. TiO2 is widely used by the paper industry as a functional filler for opacity and brightness. The new PCC rhombohedral morphology can be used in place of TiO2 for many applications greatly reducing the cost of production.The physical properties of the new PCC morphology as well as application as a paper filling pigment will be discussed.


2021 ◽  
Vol 15 (1) ◽  
pp. 75-82
Author(s):  
Mingzi Xu ◽  
Changdong Sheng

The present work aims to develop a simple model for describing the particle size distribution (PSD) of residual fly ash from pulverized biomass combustion. The residual ash formation was modelled considering the mechanism of fragmentation and coalescence. The influences of particle shape and stochastic fragmentation on model description of the PSD of the fly ash were investigated. The results showed that biomass particle shape has a great influence on the model prediction, and a larger fragmentation number is required for cylindrical particles than that for spherical particles to get the same PSD of fly ash, and the fragment number of the particles increases with the shape factor increasing. For pulverized biomass with a wide size distribution, the model predicted ash PSD considering the stochastic fragmentation is very similar to that assuming uniform fragmentation. It implies that the simple model assuming uniform fragmentation is applicable for predicting fly ash size distribution in practical processes where biomass particles have a wide range of sizes. For the fuel with a narrower initial PSD, the stochastic fragmentation model generally predicts a coarser PSD of the residual ash than assuming uniform fragmentation. It means the stochastic fragmentation is of great influence to be considered for accurate description of ash formation from the fuel with a narrow PSD.


2007 ◽  
Vol 534-536 ◽  
pp. 1621-1624
Author(s):  
Yuto Amano ◽  
Takashi Itoh ◽  
Hoshiaki Terao ◽  
Naoyuki Kanetake

For precise property control of sintered products, it is important to know the powder characteristics, especially the packing density of the powder. In a previous work, we developed a packing simulation program that could make a packed bed of spherical particles having particle size distribution. In order to predict the packing density of the actual powder that consisted of nonspherical particles, we combined the packing simulation with a particle shape analysis. We investigated the influence of the particle size distribution of the powder on the packing density by executing the packing simulation based on particle size distributions of the actual milled chromium powders. In addition, the influence of the particle shape of the actual powder on the packing density was quantitatively analyzed. A prediction of the packing density of the milled powder was attempted with an analytical expression between the particle shape of the powder and the packing simulation. The predicted packing densities were in good agreement with the actual data.


2020 ◽  
Vol 11 (11) ◽  
pp. 9547-9559
Author(s):  
Annika Feichtinger ◽  
Elke Scholten ◽  
Guido Sala

Particle size distribution and particle size ratio have an important effect on rheological properties of model chocolate samples, but also other factors like particle shape, surface roughness and hydrophilicity should be taken into account.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Mahinroosta ◽  
Vahid Oshtaghi

AbstractThis paper investigates the effect of particle shape on the stress reduction and collapse deformation of gravelly soil using a medium-scale direct shear test apparatus under different relative densities, normal stress, and shear stress levels. A new method based on the Micro-Deval test was introduced to produce sub-angular particles from angular particles. Therefore, two series of soil specimens were obtained with the same rock origin, particle size distribution, and relative density but different particle shapes. In addition to traditional direct shear tests on dry and wet specimens, a specific test procedure was applied to explore the stress reduction and collapse of soil specimens due to wetting. The results of the tests, including shear stress–shear displacement and vertical displacement-shear displacement, were compared. The results showed that the stress reduction and settlement due to wetting increased with vertical and shear stress levels in both types of particle shapes, with higher values in angular particle shapes. The particle breakage of the soil specimens was also studied quantitatively using the change in the particle size distribution before and after the test. It was shown that the wetting of the samples had more impact on the particle breakage in angular gravel than sub-angular gravel, which increased linearly with the normal stress.


1982 ◽  
Vol 62 (4) ◽  
pp. 631-639 ◽  
Author(s):  
G. T. PATTERSON ◽  
G. J. WALL

Replicate soil samples (2–20) from the A, B and C horizons of 41 pedons were collected to measure within-pedon variability of particle size distribution, organic matter content, calcium carbonate equivalent and pH. Variability in soil properties was examined in relation to the mode of origin of the soil material, soil horizonation and soil drainage. Variance in particle size distribution was significantly influenced by mode of deposition as well as by soil horizons, while soil drainage had no significant influence on the variation in particle size distribution. Variance in calcium carbonate equivalent and organic matter content was not influenced by soil drainage or mode of deposition. The number of replicate samples required for statistically reliable evaluation of a pedon at given confidence limits was determined for the soil properties studied. The results of these calculations indicate the need for up to five replicate samples to achieve satisfactory levels of accuracy at the 95% confidence level for some of the soil properties studied.


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