Papers by Keyword: Calcium Carbonate

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Authors: Rong Zhang, Peng Fei Yin, Qian Liu, Ting Zhou, Jiang Chang Hu, Yi Bing Li
Abstract: A new method to prepare micro-nanopowder with incorporating jet milling and electrostatic dispersion was presented in this study. The dispersivity of the powder could be improved during the process of jet milling by having the particles charged with identical charge. Both micro-nanopowders with high dispersion, calcium carbonate (CaCO3) and magnesium zinc ferrite (MgZnF) were prepared respectively. The theoretic studies on this method and the analyses on the effects of preparation parameters on dispersivity, showed that jet milling /electrostatic dispersion (J/E) method to prepare micro-nanopowder in the air without any additive is achievable. The charge voltage and air current pressure would strongly affect the characters of the powder. The charge to mass ratio (q/m) of both powders reached its peak under the charge voltage at 50 kV and air current pressure at 0.3MPa.
Authors: Hui Yan Zeng, Zi Ling Yan, Meng Ran Jiao, Dong Dong Xu, Jiu Xin Jiang
Abstract: An entirely novel preparation method of calcium carbonate (CaCO3) from calcium hydrogen carbonate (Ca (HCO3)2) solution was presented and named as thermal decomposition. The variation of the polymorphs and morphologies of CaCO3 particles with reaction temperature was investigated. XRD result indicates that high temperature favors the formation of calcite. Cubic or rhombohedra calcite crystals, lamellar and spherical vaterite crystals and rod– and needle–like aragonite crystals are found in powder synthesized at different temperatures. The reaction process was also discussed in the present work.
Authors: Januarti Jaya Ekaputri, Fahmi Firdaus Alrizal, Iqbal Husein, Triwulan, Mohd Mustafa Al Bakri Abdullah
Abstract: Self-healing cement is a novel topic in concrete technology. Concrete is created to have its own ability to heal cracks. Crack closure is due to the material deposition of the gap so causing the crack closed. Materials used in this paper is mortar composition with ordinary portland cement replaced by calcium carbonate (CaCO3) and rice husk ash. There are three testing presented in this paper. The first is compressive test to determine the compression applied to mortar for initial cracks. The second is an ultrasonic pulse velocity (UPV) test to observe the depth of cracks and density of each composition. The third is macroscopic investigation to observe cracks wide in each mixture. The maximum compressive strength of 22.46 MPa shown by specimens made with 10% rice husk ash and 10% calcium carbonate cement. By the end of healing process, it reached 23.18 MPa. It was also shown that in crack depth decreased from 38 mm to 16 mm. From this analysis, it can be concluded that rice husk ash (RHA) and calcium carbonate (CaCO3) can be utilized as self-healing concrete materials.
Authors: Xue Ying Zhang, Xiao Xiang Zhou, Xue Feng Dong
Abstract: In this paper, the problem of high calcium carbonate content of desulfurization gypsum using limestone - gypsum wet desulphurization technology in coal-fired power plants questions, recommendations in running process from the control of absorption tower pH, lime stone powder, lime powder fineness activity to solve the above problems.
Authors: Hirotaka Maeda, Toshihiro Kasuga
Abstract: A new type of poly(lactic acid) (PLA)/calcium carbonates hybrid membrane incorporated with silicon, which is suggested to stimulate the formation of bones, was prepared using aminopropyltriethoxysilane (APTES) for bone repair materials. Carboxyl groups in PLA made a chemical bond with amino groups in APTES, resulting in the formation of the hybrid membrane. The membrane formed hydroxycarbonate apatite (HCA) on its surface after 3 days of soaking in simulated body fluid (SBF). X-ray energy dispersive spectroscopy showed the HCA layer includes Si with Ca and P. A result of osteoblast-like cellular proliferation on the substrates that the membrane coated with silicon-containing HCA had much higher cell-proliferation ability than the membrane.
Authors: Daiki Honda, Akari Takeuchi, Ishikawa Kunio
Abstract: Feasibility of starfish bone to be a source material for apatite bone substitute was investigated in the present study because starfish bone is known to be porous calcium carbonate. Starfish bone was assembly of Mg containing calcite granules. And the calcite granules had fully interconnected porous structure with approximately 20 µm of pore size. After the hydrothermal treatment of the calcite granules in Na2HPO4 aqueous solution, the granules were gradually transformed to apatite. Therefore, starfish derived calcium carbonate would be a candidate of a source material for carbonate apatite bone substitute.
Authors: Yang Xu, Cheng Yu Wang, Jian Li
Abstract: The hydrophobic CaCO3 nanoparticles were synthesized in situ by mimicking the essential functions of biomineralization. Using this method, CaCO3 nanoparticles were synthesized and were surface modified at the same time in the system of aqueous solution. The organic substrate of dodecanoic acid used here not only induces the nucleation and growth of calcium carbonate but also make the surface of calcium carbonate hydrophobic. The contact angle of the modified CaCO3 nanoparticles reached 110o.
Authors: Jin Sang Cho, Sung Min Joo, Sang Hwan Cho, Young Hwan Yu, Im Ho Kim, Hwan Kim, Choon Han
Abstract: 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.
Authors: Xiao Kai Xing, Rui Yan Sun, Shi Gang Wang
Abstract: Various non-chemical water treatment methods have been utilized to solve fouling problems. All of these methods have never been scientifically proven to be a valid tool for controlling scales, and one of reasons could be the lack of understanding of the operational principle and treatment mechanisms. The present study focuses on characteristics of calcium carbonate crystal size distribution in solution and crystal structure on the surface under the electromagnetic field in order to comprehend the mechanisms of the Electromagnetic treatment device (ETD). An electromagnetic treatment setup was built for treating scaling water, and a series of fouling tests were carried out with and without ETD, analyzing the particles size distribution in solution by Dynamics Light Scattering (DLS) technology and making Scanning Electron Microscope (SEM) photos. The main results were as follows:The number of precipitate nucleation in solution was few and the particle growth was slow without ETD. In opposition to the case untreated, a rapid particle growth was observed and the number of nucleation was expected to be more, due to the ETD effectively increasing the ions and crystals collision frequency and effectiveness by utilizing the induced electric field. It was implied that the particle growth was promoted mainly by coagulation process but not nucleation growth in all the experimental temperature range. In the high temperature, the crystal phase of calcium carbonate could be changed from aragonite type without ETD to calcite with ETD. In the lower temperature, all the precipitated crystals in solution were calcite and there were little differences between with ETD and without ETD.
Authors: Wimonlak Sutapun, Yupaporn Ruksakulpiwat, Nitinat Suppakarn, Rachasit Jeencham, Ajcharaporn Aontee
Abstract: In this work, PCC was prepared from chicken eggshell powder (ESP) by dissolving 100 g ESP in 1 M hydrochloric acid at room temperature. Under vigorous stirring, PCC was precipitated from the ESP-dissolved solution using 1 M sodium carbonate solution. The dried PESP (precipitated eggshell powder) was then characterized by particle size analyzer, X-ray diffractometer, Brunauer-Emmett-Teller surface analyzer and thermogravimetric analyzer. The particle shape of the PESP was revealed using scanning electron microscope. It was found that PESP was a binary mixer of calcite and vaterite. The particles were in cubic and spherical shape. In addition, PESP had a volume average diameter of 8.16 μm, D[V, 0.5] of 7.22 μm, D[V,0.9] of 16.57 μm, and the specific surface area of 4.38 m2/g. The average particle size was lower than and the specific surface area was higher than that of ESP. The decomposition process of PESP occured in a single step between 610 and 770 °C, with 44.43% weight loss.
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