scholarly journals Controlling CaCO3 Particle Size with {Ca2+}:{CO32–} Ratios in Aqueous Environments

2021 ◽  
Author(s):  
Sergěj Y. M. H. Seepma ◽  
Sergio E. Ruiz-Hernandez ◽  
Gernot Nehrke ◽  
Karline Soetaert ◽  
Albert P. Philipse ◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Environments ◽  
Caco3 Particle

scholarly journals Controlling CaCO3 particle size with {Ca2+}:{CO32-} ratios in aqueous environments

2021 ◽  
Author(s):  
Sergěj Seepma ◽  
Albert Philipse ◽  
Sergio Ruiz-Hernandez ◽  
Gernot Nehrke ◽  
Karline Soetaert ◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Environments ◽  
Caco3 Particle

Experimental Investigation of the SO2 Abatement Capacity of South African Calcium-Based Materials

2007 ◽  
Author(s):  
Zachary O. Siagi ◽  
Makame Mbarawa
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
South African ◽  
Efficient Operation ◽  
Shrinking Core ◽  
Caco3 Particle ◽  
Ph Stat ◽  
Kinetics Of ◽  
Different Sources ◽  
So2 Absorption

One of the most important steps in the wet limestone-gypsum flue gas desulphurization (WFGD) process is CaCO3 dissolution, which provides the dissolved alkalinity necessary for SO2 absorption. Accurately evaluating the CaCO3 dissolution rate is important in the design and efficient operation of WFGD plants. In the present work, the dissolution of limestone from different sources in South Africa has been studied in a pH-stat apparatus under conditions similar to those encountered in wet FGD processes. The influence of various parameters such as the reaction temperature (30 ≤ T ≤ 70°C), CaCO3 particle size (25 ≤ dp ≤ 63μm), solution acidity (4 ≤ pH ≤ 6), and chemical composition were studied in order to determine the kinetics of CaCO3 dissolution. The results obtained indicate that the dissolution rate increased with a decrease in particle size and an increase in temperature. The dissolution curves were evaluated in order to test the shrinking core model for fluid–solid systems. The analysis indicated that the dissolution of CaCO3 was controlled by chemical reaction, i.e. 1 − (1 − X)1/3 = kt.

scholarly journals Effect of Calcium Carbonate Particle Size on the Scratch Resistance of Rapid Alkyd-Based Wood Coatings

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 340
Author(s):  
Orkun Ersoy ◽  
Sinan Fidan ◽  
Harun Köse ◽  
Dilek Güler ◽  
Ömer Özdöver
Keyword(s):  
Particle Size ◽  
High Hardness ◽  
Polymer Coatings ◽  
Scratch Resistance ◽  
Wood Coatings ◽  
Caco3 Particle ◽  
External Conditions ◽  
Mohs Hardness ◽  
Identical Test ◽  
Mineral Fillers

Polymer-based wood coatings are used for aesthetic purposes as well as to protect wood surfaces, especially under external conditions. High-hardness mineral fillers are thought to enhance the resistance of these polymer coatings to wear and scratching. However, recent studies suggest that the relatively low-hardness mineral calcite (CaCO3, Mohs hardness of 3) performs similarly to harder minerals under external conditions. It can replace more expensive hard minerals, thus driving research interest in its use. In this study, CaCO3 powders with different grain sizes were applied to rapid alkyd-based coating formulations, and the effect of CaCO3 particle size on the scratch behavior of the coatings was investigated under identical test conditions. The scratch morphologies, scratch hardness, and roughness values of the scratched surfaces indicated that the surfaces of the rapid alkyd-based wood coatings including finer-grained CaCO3 experienced plastic plowing-type deformation in the form of regular, narrow, and shallow scratches, showing high scratch resistance. Coatings using coarser-grained CaCO3 experienced more extensive plastic deformation of the plowing–tearing type owing to the weaker filler–polymer interface and the breakage of larger coating pieces from the coating surface.

scholarly journals Analysis of Viscosity Change and Oil Leakage Characteristics According to CaCO3 Particle Size and Anti-Sedimentation Agent Content on Bituminous Emulsion Mastic

2022 ◽  
Vol 12 (2) ◽  
pp. 690
Author(s):  
Su-Young Choi ◽  
Dong-Bum Kim ◽  
Wan-Goo Park ◽  
Jin-Sang Park ◽  
Sang-Keun Oh
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Mixing Ratio ◽  
Viscosity Change ◽  
Melting Method ◽  
Oil Leakage ◽  
Caco3 Particle ◽  
Leakage Characteristics

This study analyzed the characteristics of viscosity change and oil leakage stability according to the average particle size and content of organic and mineral-based extenders such as CaCO3(CA) and anti-sedimentation (ASE) among materials consisting of bituminous emulsion mastic (BEM). The fabrication of samples for research was done using a melting method of 2L capacity with the production mixing ratio of BEM used in the actual manufacturing process as a standard mixing ratio. Each sample size was adjusted to 16 μm, 5 μm, 2 μm, 1.4 μm and 1 μm, the average particle size of CA as a variable, and the content of ASE for each particle size was set to increase from 1 to 6 times the standard mixing ratio. The analysis found that in all average particle sizes of CA, the viscosity increased as the content of anti-sedimentation increased, and the viscosity was highest at the CA average particle size of 16 μm. The viscosity increased as the average particle size decreased at 5 μm, 2 μm, 1.4 μm and 1 μm. In addition, it was confirmed that the oil leakage stability increased as the average particle size of CA decreased, and the content of ASE increased. The evaluation results showed that specimens that met both workability and oil leakage stability conditions were the specimens with 4 times and 5 times the ASE content at the CA average particle size of 2 μm, and those with twice the ASE content at the CA average particle size of 1.4 μm.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

Effect of particle size on erosion measurements and predictions in annular flow for an elbow

Wear ◽  
2020 ◽  
pp. 203579
Author(s):  
G. Haider ◽  
M. Othayq ◽  
J. Zhang ◽  
R.E. Vieira ◽  
S.A. Shirazi
Keyword(s):  
Particle Size ◽  
Annular Flow ◽  
Effect Of Particle Size
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