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1
Babu, Numbury Surendra, and Didugu Jayaprakash. "Computational Study of the Stability of Tautomers and equilibrium constants of Cyanuric acid (CA) in Different solvents." JOURNAL OF ADVANCES IN CHEMISTRY 11, no. 2 (2015): 3485–97. http://dx.doi.org/10.24297/jac.v11i2.6691.
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In the present investigation, the tautomeric and equilibrium of Cyanuric acid has been studied using Hartifock (HF) method in the gas phase and different solvents using the PCM model. The relative energies of these tautomers have been calculated at the HF level of theory using 6-311++ G (d,p) basis set. Energetics and relative stabilities of the tautomers were compared and analyzed in both the gaseous and different solvents. The results indicate that the keto tautomer (CA1) is the most stable form in the gas phase and other solvents. The order of stability of isomers was found to be CA1 > CA3> CA11> CA2> CA6> CA10> CA7> CA4> CA5> CA9>CA8. Having the largest dipole moment the CA8 tautomer is expected to have the strongest interaction with polar solvents. The HF method calculated tautomeric equilibrium constants with respect to the most stable tautomer CA1 of Cyanuric acid both in the gas and in different solvents. The of the equilibrium constants calculated starting from the general outline of interconversion.
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Bian, K., and R. D. Bukoski. "Modulation of resistance artery force generation by extracellular Ca2+." American Journal of Physiology-Heart and Circulatory Physiology 269, no. 1 (1995): H230—H238. http://dx.doi.org/10.1152/ajpheart.1995.269.1.h230.
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We tested the hypothesis that increasing extracellular Ca2+ (Cao) over a physiological concentration range depresses vascular smooth muscle force generation by altering the intracellular Ca2+ (Cai)-force relationship. Mesenteric resistance arteries were isolated from Wistar rats; Cai and isometric force were measured using a fura-based method and wire myography. Vessels were depleted of releasable Cai by repeated contraction with norepinephrine; Cao was then cumulatively added back from 0.025-2.5 mM in the presence of an agonist. With norepinephrine, serotonin, prostaglandin F2 alpha, and K+, Cao from 0.025 to 0.8 mM induced a graded increase in Cai and active stress. With the receptor agonists but not K+ raising Cao from 0.8 to 1.6 mM and from 1.6 to 2.5 mM decreased active stress to 82 +/- 6 and 54 +/- 6% of maximum, respectively, P < 0.05. Although there was a transient decrease in Cai in response to both 1.6 and 2.5 mM Cao, steady-state Cai only decreased significantly in response to 2.5 mM Cao (85 +/- 3% of maximum). Inhibition of the sarcoplasmic reticulum Ca(2+)-adenosinetriphosphatase with 1 microM thapsigargin had no effect on the decrease in force induced by high Ca2+. The decrease in active stress induced by 1.6 and 2.5 mM Cao was inhibited by Ca2+ channel antagonists and by blockade of Ca(2+)-activated K+ channels with charybdotoxin (with 1.6 mM Cao, control tension = 67 +/- 10% of maximum vs. charybdotoxin = 99.2 +/- 1%, P < 0.05; n = 9).(ABSTRACT TRUNCATED AT 250 WORDS)
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Mahardika, Ida Bagus Putra, Wega Trisunaryanti, Triyono Triyono, Dwi Putra Wijaya, and Kumala Dewi. "Transesterification of Used Cooking Oil Using CaO/MCM-41 Catalyst Synthesized from Lapindo Mud by Sonochemical Method." Indonesian Journal of Chemistry 17, no. 3 (2017): 509. http://dx.doi.org/10.22146/ijc.26561.
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Transesterification of waste cooking oil using CaO/MCM-41 synthesized from Lapindo mud by the sonochemical method has been carried out. The silica was separated from the mud by reflux method used 6 M HCl and 6 M NaOH. The silica was then analyzed by XRF and used as silica source in MCM-41 synthesis. The synthesis of MCM-41 was carried out by the sonochemical method, then analyzed by XRD, Infrared spectrophotometer, SAA, and TEM. The Ca2+ was loaded onto the MCM-41 by wet impregnation method under variation of the Ca2+ content of 1.15, 1.29, 2.39, and 3.25 wt.% analyzed by ICP produced CaO(1), CaO(2), CaO(3), and CaO(4)/MCM-41 catalyst respectively. Transesterification of used cooking oil was carried out under methanol/oil mole ratio of 15/1, the temperature of 55, 65 and 75 °C, and catalyst/oil weight ratio of 5/100, 10/100 and 15/100 for 2 h by reflux method. The XRD analysis of the MCM-41 showed a characteristic peak at 2θ = 2-5°. The MCM-41 has a specific surface area of 1290 m2/g and pore diameter of 3.4 nm. The TEM images of MCM-41 showed ordered pore distribution with a hexagonal shape. The highest conversion of methyl ester was 78.17 wt.% obtained under the reaction conditions at 65 °C and catalyst/oil weight ratio of 15/100 using the CaO(4)/MCM-41. The lifetime CaO(4)/MCM-41 catalyst was 9.8 h.
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Li, Bingrong, Yaowu Wei, Nan Li, Tao Zhang, and Jinhu Wang. "Effect of Al(OH)3 and La2O3 on the sintering behavior of CaO granules via CaCo3 decomposition." Science of Sintering 52, no. 2 (2020): 195–206. http://dx.doi.org/10.2298/sos2002195l.
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Hydration resistance of CaO aggregates is the key to the successful application of lime-based refractories. Granulation technology on limestone with additives and one step calcination method was used in this study to investigate the effects of Al(OH)3 and La2O3 on the sintering behavior and the hydration resistance of CaO granules. The result showed that the hydration resistance of CaO granules was improved significantly by adding Al(OH)3 and La2O3. The shell of sintered CaO granules was relatively dense after calcination and the specific surface area of CaO granules decreased from 7.5?10-2 m2/g to 1.2?10-2 m2/g. The average pore size of CaO granular was decreased from 3.54 ?m to 0.83 ?m due to the liquid phase sintering when Al(OH)3 additive was used. La2O3 promoted the densification of CaO compact by the ion substitution and solution with CaO. La3+ approached into CaO lattices, which enlarged the vacancy concentration of Ca2+ and accelerated the diffusion of Ca2+.
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Yang, Shi Mei, Shao Yun Shan, Qing Ming Jia, Ting Wei Hu, Li Hong Jiang, and Ya Ming Wang. "Preparation of Fibrous CaO Sorbent by Hydrothermal Method." Advanced Materials Research 534 (June 2012): 86–88. http://dx.doi.org/10.4028/www.scientific.net/amr.534.86.
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Using urea and calcium chloride as precipitator and calcium source, fibrous CaCO3 precursors were prepared using hydrothermal method, then fibrous CaO sorbent was obtained by calcination. The influence of hydrothermal temperature on CO2 absorption properties was discussed. X-ray diffraction analysis showed that pure CaCO3 phase with aragonite and calcite crystal forms was obtained. Scanning electron microscopy analysis showed that the resultant CaO sorbent presented a fibrous microstructure, which inherited the morphologies of CaCO3. The absorption capacity of the resultant CaO sorbent reached 59.86%, being 76% of theoretical absorption capacity. In addition, compared with the CaO sorbent from analytical pure CaCO3, the obtained fibrous CaO-sorbent have the better cyclic absorption properties.
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Zeng, Wei Jin, Chao Zeng, and Wei He. "Quantitative Phase Analyses of a Slag Using X-Ray Powder Diffraction." Advanced Materials Research 881-883 (January 2014): 1241–44. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.1241.
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The quantitative phase analyses of a slag have been successfully carried out by using both of the full-profile Rietveld and RIR methods from X-ray powder diffraction data. The qualitative phase analysis indicates that the slag contains mayenite (CaO)12(Al2O3)7, olivine Ca2(SiO4), gehlenite Ca2Al (AlSiO7), lemite Ca2(SiO4) and hibonite CaO(Al2O3)6. The quantitative analysis from Rietveld refinement shows that the weight concentrations of mayenite, olivine, gehlenite, lemite and hibonite for the slag are 48.8(4) wt.%, 32.2(5) wt.%, 11.0(9) wt.%, 6.2(1.1) wt.% and 1.8 (1.2) wt.%, respectively. The quantitative phase analysis results obtained by Rietveld method are more precise then those by RIR method.
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Kuljanin, Tatjana A., Vladimir S. Filipović, Milica R. Nićetin, Biljana Lj Lončar, Bojana V. Filipčev, and Lato L. Pezo. "CaO&CaSO4 and CaO&Al2(SO4)3 as Pectin Precipitants–Model of Overlapping Diffuse Layers." Periodica Polytechnica Chemical Engineering 63, no. 1 (2018): 239–45. http://dx.doi.org/10.3311/ppch.12320.
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This work is concerned with the theoretical basis of novel sugar beet juice purification method using binary systems CaO&CaSO4 and CaO&Al2(SO4)3. The Gouy–Chapman–Stern (GCS) model of overlapping of diffuse layers of EDLs on pectin surface and that on Ca2+ and Al3+ ions, theoretically explains this method. The change of the zeta potential was used to quantitatively indicate overlapping of diffuse layers. For the experiment two model solutions of pectin (0.1 % w/w) were prepared, while the concentrations of CaO&CaSO4 and CaO&Al2(SO4)3 in the range of 50–500 g dm-3 were used. The greater decrease in the absolute value of zeta potential indicated greater overlapping of diffuse layers between pectin particles and Ca2+ and Al3+ ions and faster coagulation of pectin. The overlapping degree increased with increased concentration of these binary systems. Pectin with a greater surface charge and multivalent Al3+ from CaO&Al2(SO4), exerted a greater impact on the zeta potential. Optimal quantities of the applied binary mixtures were as follows: 256–640 mg g-1 pectin. This is much lower than CaO commonly used in the conventional process of sugar beet juice purification (about 9 g g-1 pectin).
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Simpen, I. Nengah, I. Nyoman Suprapta Winaya, I. Ketut Suarsana, and I. Ketut Gede Sugita. "Green nanocomposite of silica-supported CaO: synthesis by sol-gel method and characterization." EUREKA: Physics and Engineering, no. 6 (November 28, 2024): 151–61. http://dx.doi.org/10.21303/2461-4262.2024.003407.
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The sol-gel method offers several advantages over other techniques for synthesizing nanocomposites, including simplicity, cost-effectiveness, and low processing temperatures. In this study, a silica-supported CaO nanocomposite was synthesized using eggshells as the calcium source and rice husk ash as the silica support via the sol-gel method. The green silica-supported CaO nanocomposite was characterized using various techniques, including BET surface area and porosity analysis, FTIR for functional groups identification, XRD for crystallinity and crystallite size determination, SEM and TEM for surface morphology examination, as well as TGA for thermal stability assessment. The XRD and the FTIR analysis clearly demonstrated the successful synthesis of the silica-supported CaO nanocomposite. The silica-supported CaO composite had a crystalline structure combination of 55.45 % silica and 20.46 % CaO, as well as exhibited the stretching vibrations of Si-O-Si, Ca-O, Si-O-Ca, and Si-O functional groups and a bending vibration of Si-O functional group. The SEM and the TEM images revealed that the composite particles were irregularly shaped and evenly distributed compared to green-silica (G-silica) and green-CaO (G-CaO). The particle size of the composite was distributed in the range of 0.1–100 nm, with a more uniform distribution compared to G-silica (dominant in the range of 80.1–100 nm) and G-CaO (dominant in the range of 0.1–20 nm). TGA results showed that the thermal stability of the silica-supported CaO composite was enhanced by silica support compared to G-CaO. These findings demonstrate that CaO derived from eggshells and silica from rice husk ash are promising materials for the fabrication of multifunctional silica-supported CaO nanocomposite
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Wang, Haocheng, Haoming Ning, Zhenjun Fan, and Guangyao Liu. "Analysis of Phase Diagram of CaO-CoOx-ErOy and Crystal Structure of Perovskite (Ca3−xErx)Co2O6−z Solid Solution." Energies 16, no. 13 (2023): 4958. http://dx.doi.org/10.3390/en16134958.
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In this work, a series of compounds in the CaO-CoOx-ErOy ternary oxide system were synthesized in air at 885 °C, using a high temperature solid-phase synthesis method. The phase boundary of each solid solution region in the CaO-CoOx-ErOy system was determined by X-ray powder diffraction techniques. The phase diagram of the CaO-CoOx-ErOy system at 885 °C includes three series of ternary oxide solid solutions: (Ca3−xErx)Co4O9−z (0 ≤ x ≤ 0.9), (Ca3−xErx)Co2O6−z (0 ≤ x ≤ 1.25), and (Er1−xCax)CoO3−z (0 ≤ x ≤ 0.33). Four three-phase regions and five solid solution tie-line regions were obtained. The structure of the perovskite solid solution (Ca3−xErx)Co2O6−z has been analyzed by Rietveld refinements. With the increase of Er content, the cell parameters of (Ca3−xErx)Co2O6−z exhibit a decreasing trend in a and b directions and an increasing trend in c direction. A brief comparison of the phase diagrams of the CaO-CoOx-ROy (R = La, Dy, and Er) systems in air at 885 °C is provided.
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Guan, Wei, Fangying Ji, Yong Cheng, et al. "A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites." Journal of Nanomaterials 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/542109.
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This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH) based on the calcium oxide/polyethylene glycol (CaO/PEG2000) composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), and Fourier transformed infrared spectroscopy (FT-IR). The reactivity of silica materials (SiO2) enhanced by increasing pH value. Ca2+could not sustain release from CaO/PEG2000and reacted with caused by silica to form CSH until the hydrothermal temperature reached to 170°C, avoiding the hardly dissolved intermediates formation efficiently. The as-prepared CSH, due to the large specific surface areas, exhibited excellent release capability of Ca2+and OH−. This porous CSH has potential application in reducing the negative environmental effects of continual natural phosphate resource depletion.
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Wen, Tianpeng, Yao Jin, Chen Tian, Lei Yuan, and Jingkun Yu. "Synthesis of calcium aluminate powders by ethanol thermal decomposition method." Processing and Application of Ceramics 15, no. 4 (2021): 403–9. http://dx.doi.org/10.2298/pac2104403w.
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The aim of this work was the synthesis of calcium aluminate powders at a relatively low temperature via the ethanol thermal decomposition method. The effect of the cation concentration in the ethanol solution and CaO contents incorporated in calcium aluminate materials on the structure of the prepared calcium aluminate powders in terms of phase composition, particle size distribution and specific surface area were investigated. It was demonstrated that the prepared powders containing 40 wt.% of CaO were mainly composed of CaAl2O4 and CaAl4O7 phases, while Ca3Al2O6 and Ca12Al14O33 became the major phases accompanied with free CaO mesophase when the CaO content increased to 60wt.%. A decrease in the particle size was observed for both types of calcium aluminate powders with the decrease of the cation concentration and CaO contents, while the specific surface area increased. The research results provide an optional process for the preparation of calcium aluminate materials, playing an important role in simplifying the production process and shortening the production time.
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Widia, Lilik, Roniyus Marjunus, and Sudibyo Sudibyo. "Penggunaan Metode Taguchi untuk Menentukan Kondisi Parameter Optimum Pada Pembuatan CaO dari Batu Kapur (CaCO-3)." Journal of Energy, Material, and Instrumentation Technology 2, no. 1 (2021): 23–29. http://dx.doi.org/10.23960/jemit.v2i1.46.
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Research has been carried out to determine the optimum conditions for making quicklime (CaO) using the Taguchi Method. CaO is the burning result of limestone (CaCO_3) in calcination process by releasing of CO_2 gas until CaO solids occur. The limestone was calcined at 950^o c. The Taguchi Method is a quality improvement technique with the selection of the most influential parameters of the making of process CaO. The parameters are particle size, CaO mass, heating temperature and stirring time. The XRF results show that the levels of CaO after the Taguchi Method design has increased from 98.779% to 98.814%. The XRD results show that the CaO phase is amorphous. The phase which were formed by calcination are Lime (CaO), Quartz (SiO_2) and Hematite (〖Fe〗_2 O_3). Based on the SEM results, the morphology of CaCO_3 has an irregular particle size and tends to be a granular solid due to the presence of impurity. Meanwhile, the results of the EDS analysis show that the content of Calcium (Ca) is quite high. From the design results of the Taguchi Method, the optimum conditions is obtained at a particle size of 140 mesh, 75 gr CaO mass, heating temperature 70^o c and stirring time 0,5 hour.
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Küçük, Elvan, and Jale Naktiyok. "Investigation of catalytic pyrolysis of Erzurum-Umutbaca coal by using the thermal analysis method." Polish Journal of Chemical Technology 27, no. 1 (2025): 29–37. https://doi.org/10.2478/pjct-2025-0004.
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Abstract In the study, the catalytic pyrolysis behavior of low-rank Umutbaca coal with the addition of CaO was examined using thermal analysis methods. For this purpose, the effect of adding CaO to coal on both the pyrolysis temperatures of the coal and the composition of the gas and solid product (char) was investigated. Also, the kinetic analysis was carried out to characterize the catalytic pyrolysis process by adding CaO to coal. Using the data obtained in TGA at heating rates of 2.5, 5, and 10 °C/min, the activation energies required for the pyrolysis process of coal both with and without CaO were calculated by KAS and FWO methods. Thermodynamic parameters including ∆H, ∆G, and ∆S were calculated with activation energies obtained from the FWO method. The thermodynamic suitability of adding CaO to a low rank coal such as Umutbaca for the pyrolysis process was investigated.
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Maeda, Hirotaka, Yuki Nakano, and Toshihiro Kasuga. "Preparation of CaO-SiO2Glass-Ceramic Spheres by Electrospraying Combined with Sol-Gel Method." Journal of Nanomaterials 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/463048.
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CaO-SiO2glass-ceramic spheres were prepared by an electrospray method using hydrolyzed silicon alkoxide containing calcium nitrate. Crystalline calcium silicates, such as Ca2SiO4andβ-CaSiO3, formed around the surface of the spheres after heat treatment. The dissolution of the crystal phase of the spheres caused the release of Ca2+and Si4+ions during the initial stage of soaking in Tris-buffer solution, leading to the formation of nanosized pores at the sphere surface. The incorporation of Ca2+ions into the glassy phase of the spheres suppressed the rapid pH increase during the initial stage of soaking in Tris-buffer solution.
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Munawaroh, Fatimatul, Yoga Masdya, Malik Anjelh Baqiya, and Triwikantoro Triwikantoro. "SYNTHESIS AND CHARACTERIZATION OF CaO PREPARED FROM LIMESTONE USING SOL-GEL METHOD." Indonesian Physical Review 7, no. 2 (2024): 249–58. http://dx.doi.org/10.29303/ipr.v7i2.313.
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The sol-gel method has been successfully applied to the synthesis and characterization of calcium oxide (CaO) derived from calcite-based natural limestone from Pamekasan, Madura, East Java Indonesia. Controlled dissolution, titration, gel formation, and subsequent calcination at temperatures 650°C and 900°C were the steps involved in the synthesis. X-ray diffraction was used for characterization to identify the phase that had formed. Supporting software, MATCH! used to analyze the phases and structures and Rietica for refinement using the Rietveld method. The Ca(OH)2 phase formed was 59.65 ± 2.45 %wt before the calcination process, according to the XRD results. 23.71 ± 0.61 %wt CaO was produced by the calcination process at 650°C, and 64.52 ± 1.85 %wt was produced at 900°C. Meanwhile, after calcination at 900°C, crystal size analysis using MAUD software produced CaO with a size of 534 ± 74 nm. K CaO powder synthesized using the sol-gel method is calcined at 900°C to get a higher percentage than at 600°C. The CaO powder can be used for CO2 capture applications because it comes from natural resources and is environmentally friendly.
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Prodjosantoso, A. K., Y. Febriadi, A. R. P. Utami, and M. P. Utomo. "The Stabilization of Copper and Cadmium in The Hydrated CaO-CuO-SiO2 and CaO-CdO-SiO2 Composites." Nature Environment and Pollution Technology 23, no. 2 (2024): 947–57. http://dx.doi.org/10.46488/nept.2024.v23i02.029.
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The stabilization of toxic metals in the stable matrices is quite well-known. Research on copper and cadmium stabilization in the CaO-CuO-SiO2 and CaO-CdO-SiO2 composites was conducted to study the characteristics of CaO-CuO-SiO2 and CaO-CdO-SiO2 composites as well as the Cu and Cd metals stabilization in the hydrated composites. The composites of CaO-CuO-SiO2 and CaO-CdO-SiO2 were synthesized by the solid-state reaction method. A stoichiometric amount of CaO, SiO2, Cu(NO3)2, and CdO were calcined at 1050°C for 4 hours. The synthesized compounds were further hydrated in a soaking time of 30, 60, and 90 days. The hydration produced calcium silicate hydrate that can stabilize metals. The Cu and Cd stability in CaO-CuO-SiO2 and CaO-CdO-SiO2, respectively, were tested using the Toxicity Leaching Procedure (TCLP) method. The hydrated and hydrated composite characterizations were performed using X-ray diffraction (XRD), Fourier Transform Infra-Red Spectrophotometer (FTIR), and Scanning Energy Mocroscopy-Energy Dispersive X-ray analyzer (SEM-EDX) and the Atomic Absorption Spectroscopy (AAS) methods. The composites mainly consist of Ca3SiO5, Ca2SiO4, Ca(OH)2, SiO2, and metal oxide of CuO, Cu2O, and CdO. The composites were able to stabilize ~100% of the heavy metals of Cu and Cd.
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Li, Shijian, Guoyu Qian, Yiwei Sun, Sheng Pang, Dong Wang, and Zhi Wang. "Innovative separation model for boron removal from silicon during slag refining based on ion and molecule coexistence theory." Metallurgical Research & Technology 119, no. 3 (2022): 304. http://dx.doi.org/10.1051/metal/2022024.
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How to reduce boron concentration to an extremely low level has become a major obstacle during silicon waste recycling. As a simple and efficient method of removing impurities, slag refining plays an increasingly important role for industrial silicon waste recovery. The deboration ability of slag is usually evaluated by boron distribution ratio LB. However, the development of a separation prediction model is challenged by the limitations on the recognition of impurity structure in slag and complexity of slag-silicon reactions. Herein, a novel thermodynamic model for predicting boron distribution ratio between CaO-SiO2 based slags and molten silicon has been developed based on ion and molecule coexistence theory (IMCT), i.e., IMCT-LB model. The reaction abilities of structural units are represented by the calculated mass action concentration. The predictive boron distribution ratio between CaO-SiO2, CaO-Al2O3-SiO2, CaF2-CaO-SiO2 slags and silicon correspond well with experimental data, reflecting the reasonability of IMCT-LB model. According to IMCT, deboration reactions between slags and silicon can be represented by ion couples (Ca2+ + O2–), simple molecule Al2O3 with SiO2 to form eight deboration products as B2O3, 3CaO · B2O3, 2CaO · B2O3, CaO · B2O3, CaO · 2B2O3, 2Al2O3 · B2O3, 9Al2O3 · B2O3, CaO · 2SiO2 · B2O3. With the developed IMCT-LB model, the respective boron distribution ratio LB,i of the eight deboration products can be determined quantitatively. Furthermore, the effect of temperature, mass ratio of CaO to SiO2 (%CaO/%SiO2), Al2O3 and CaF2 content of CaO-SiO2 based slags on LB are fully discussed.
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Widyarini, Widyarini, Muhammad Djoni Bustan, and Sri Haryati. "Synthesis and Characterization of CaO-Zeolite Catalyst by Sonochemical Engineering Method." Indonesian Journal of Fundamental and Applied Chemistry 7, no. 3 (2022): 113–21. http://dx.doi.org/10.24845/ijfac.v7.i3.113.
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Calcium Oxide (CaO) loaded on zeolite was categorized as a heterogeneous catalyst. The utilization of CaO catalyst could be implemented in catalytic pyrolysis enhance gaseous production. In this paper, CaSO4.2H2O is an active site embedded in natural zeolite, and the activity of the CaO-Zeolite catalyst is synthesized by a sonochemical impregnation-assisted drying process and calcination. The stirrer impregnation method was used as a control. CaO-Zeolite catalyst characterization and properties were identified via Scanning Electron Microscopy- Energy Dispersive X-Ray (SEM-EDX).The activation experiments were performed at an oven temperature of 120oC for 5 h and a calcination temperature of 300oC for 2 h. The synthesized catalysts of sonochemical were performed at 20 minutes, 20 kHz, and 1200 Watt, and the synthesized catalyst of stirrer were performed at 120 minutes, 1500 rpm, and 1000 watts. The experimental results revealed that the characterization of the catalysts prepared by the sonochemical method was better than that of the stirrer. Specifically, obtained CaO-Zeolite catalyst with Ca wt % increased from 0.86 wt% NZ (natural zeolite) to (11.3 wt%, 14.15 wt% and 23.48 wt%) of sonochemical and (11.82wt%, 13.95 wt% and 20.64wt%) of stirrer. The results demonstrated that Ca wt% by sonochemical in 20 minutes dispersed at support surface (zeolite) more effective than stirrer in 120 minutes. These results were impacted by acoustic cavitation and shockwave of ultrasonic on solid-liquid transport and distribution. On the other side, sonochemical assisted the activation technique to minimize particle size and allowed metal oxide (CaSO4.2H2O) to be dispersed uniformly into the pores structure of the zeolite. The utilization of sonochemical in CaO-Zeolite synthesizing enhanced catalyst activity.
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Suprapto, Suprapto, Tikha Reskiani Fauziah, Meiske S. Sangi, Titie Prapti Oetami, Imroatul Qoniah, and Didik Prasetyoko. "Calcium Oxide from Limestone as Solid Base Catalyst in Transesterification of Reutealis trisperma Oil." Indonesian Journal of Chemistry 16, no. 2 (2018): 208. http://dx.doi.org/10.22146/ijc.21165.
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CaO catalysts were synthesized from limestone by thermal decomposition and coprecipitation methods. The CaO and MgO reference catalysts were also synthesized for comparison. The catalysts were characterized by X-ray diffractometer (XRD) and the analysis result was refined by Rietica software. CaO catalyst obtained by coprecipitation method has higher purity of CaO and lower MgO content than those of calcined CaO. The catalysts were also characterized by Fourier Transform Infrared (FTIR) spectroscopy. FTIR spectra showed that the catalysts can be easily hydrated and carbonated in air. The catalytic activity of the catalyst was studied in transesterification reaction of Reutealis trisperma (Kemiri Sunan) oil with methanol. Transesterification reaction was carried out at oil to methanol molar ratio 1:1 and 1% of catalyst at 60 °C for 2 h. Catalytic activity of CaO catalyst obtained by coprecipitation was higher than calcined CaO. The methyl ester yield obtained from synthesized CaO, CaO from coprecipitation, calcined CaO, and synthesized MgO catalysts were 56.13; 37.74; 15.97; and 3.61%, respectively.
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Pintana, Pakamon, and Nakorn Tippayawong. "Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content." Scientific World Journal 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/216975.
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Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higherEvalues were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal.
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Oko, Syarifuddin, and Andri Kurniawan. "Modification of CaO Catalyst with Impregnation Method Using KoH in Biodiesel Synthesis from Waste Cooking Oil." Logic : Jurnal Rancang Bangun dan Teknologi 19, no. 2 (2019): 62. http://dx.doi.org/10.31940/logic.v19i2.1318.
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Chicken eggshells can be used as raw material in the manufacture of CaO catalysts. Increased CaO catalyst activity can be done by the impregnation method. The purpose of this study was to determine the effect of %K on the wet impregnation of CaO catalyst using KOH and to find out the impregnation catalyst (CaO / K2O) on the biodiesel yield. Prepared chicken egg shells were calcined at 900oC for 3 hours. Then the CaO obtained was impregnated using KOH with a variation of % K (5%, 7%, 9% and 12% (w / w)) while heated at 85oC. The impregnation product was calcined at 600oC for 5 hours. The impregnation catalyst (CaO K2O) was applied to the biodiesel synthesis through a transesterification reaction with a mole ratio of 1:12 waste cooking oil: methanol, the amount of catalyst was 1.5% at a reaction temperature of 70°C for 2.5 hours. Based on the results of SEM-EDS analysis, the highest K2O at 7% K was 21.99%), while the highest CaO content was at 9% K by 81.53%. For the highest surface area analysis at 7% K with a surface area of 71.22 m2 / g, alkalinity was 2.59 mmol / g. The best biodiesel was obtained with a yield of 87.17%, kinematic viscosity of 2.89 cSt, water content of 0.032%, density of 0.819 g/ml, methyl ester level of 99.39%.
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Sabir, Asmeati, Hammada Abbas, Ahmad Yusran Aminy, and Sapta Asmal. "Analysis of duck eggshells as hydroxyapatite with heat treatment method." EUREKA: Physics and Engineering, no. 4 (July 30, 2022): 16–24. http://dx.doi.org/10.21303/2461-4262.2022.002017.
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Duck eggshell contains very high calcium, making it a raw material for hydroxyapatite (HA) biomedical applications. The aim of this study was to synthesize natural HA from duck eggshell waste using cleaning, drying, smoothing with a smoothness level of passing is 200 meshes and heat treatment with temperature variations of 850 ºC, 900 ºC, and 950 ºC for one hour. The resulting HA material was characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results of the physical characteristics of raw duck eggshells without heat treatment are white, slightly bluish in color, the smell and level of smoothness is smooth. However, heated powdered duck eggshells which are heated 950 °C are whiter than the samples which are heated at 850 ºC and 900 ºC, they have no odor and their smoothness is the smoothest. The small peaks of HA from the non-heat duck eggshell powder were 64.89 % with a CaCO3 of 23.50 %, then the peak of CaO increased along with the increasing of heat treatment temperature of 900 °C that result HA in 69.31 % and reduce CaCO3 in 19.44 %. Duck egg shell powder achieved the highest diffraction with the increasing formation of HA at a heat 950 ºC by 91.87 % with a very significant decrease of CaCO3 in 2.25 %. The XRF test results of duck eggshell powder showed that the chemical composition of CaO was 99.50 %, with elemental calcium (Ca) of 99.71 %. The FTIR test results on mesh 200 observed a reduction in the intensity of CaCO3 absorption, while the intensity of CaO at 364.55 cm-1 was getting stronger, which indicated the formation of CaO at 950 °C. This showed that the CaO formation at a temperature of 950 ºC was much more than the formation at a lower temperature. The deformation from the CaO to HA phase was close to perfect with 91.87 % hydroxylapatite
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Sabir, Asmeati, Hammada Abbas, Ahmad Yusran Aminy, and Sapta Asmal. "Analysis of duck eggshells as hydroxyapatite with heat treatment method." EUREKA: Physics and Engineering, no. 4 (July 30, 2022): 16–24. https://doi.org/10.21303/2461-4262.2022.002017.
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Duck eggshell contains very high calcium, making it a raw material for hydroxyapatite (HA) biomedical applications. The aim of this study was to synthesize natural HA from duck eggshell waste using cleaning, drying, smoothing with a smoothness level of passing is 200 meshes and heat treatment with temperature variations of 850 ºC, 900 ºC, and 950 ºC for one hour. The resulting HA material was characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results of the physical characteristics of raw duck eggshells without heat treatment are white, slightly bluish in color, the smell and level of smoothness is smooth. However, heated powdered duck eggshells which are heated 950 °C are whiter than the samples which are heated at 850 ºC and 900 ºC, they have no odor and their smoothness is the smoothest. The small peaks of HA from the non-heat duck eggshell powder were 64.89 % with a CaCO3 of 23.50 %, then the peak of CaO increased along with the increasing of heat treatment temperature of 900 °C that result HA in 69.31 % and reduce CaCO3 in 19.44 %. Duck egg shell powder achieved the highest diffraction with the increasing formation of HA at a heat 950 ºC by 91.87 % with a very significant decrease of CaCO3 in 2.25 %. The XRF test results of duck eggshell powder showed that the chemical composition of CaO was 99.50 %, with elemental calcium (Ca) of 99.71 %. The FTIR test results on mesh 200 observed a reduction in the intensity of CaCO3 absorption, while the intensity of CaO at 364.55 cm-1 was getting stronger, which indicated the formation of CaO at 950 °C. This showed that the CaO formation at a temperature of 950 ºC was much more than the formation at a lower temperature. The deformation from the CaO to HA phase was close to perfect with 91.87 % hydroxylapatite
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Hu, Qizhi, Wei Yao, and Gaoliang Tao. "Research on Alkali-Activated Slag Stabilization of Dredged Silt Based on a Response Surface Method." Materials 17, no. 17 (2024): 4410. http://dx.doi.org/10.3390/ma17174410.
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To improve the resource utilization of dredged silt and industrial waste, this study explores the efficacy of using ground granulated blast furnace slag (GGBS), active calcium oxide (CaO), and sodium silicate (Na2O·nSiO2) as alkali activators for silt stabilization. Through a combination of addition tests, response surface method experiments, and microscopic analyses, we identified key factors influencing the unconfined compressive strength (UCS) of stabilized silt, optimized material ratios, and elucidated stabilization mechanisms. The results revealed the following: (1) CaO exhibited the most pronounced stabilization effect, succeeded by Na2O·nSiO2, whereas GGBS alone displayed marginal efficacy. CaO-stabilized silt demonstrated rapid strength augmentation within the initial 7 d, while Na2O·nSiO2-stabilized silt demonstrated a more gradual strength enhancement over time, attributable to the delayed hydration of GGBS in non-alkaline conditions, with strength increments noticeably during later curing phases. (2) Response surface analysis demonstrated substantial interactions among GGBS-CaO and GGBS-Na2O·nSiO2, with the optimal dosages identified as 11.5% for GGBS, 4.1% for CaO, and 5.9% for Na2O·nSiO2. (3) X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses clarified that the hydration reactions within the GGBS-Na2O·nSiO2 composite cementitious system synergistically enhanced one another, with hydration products wrapping, filling, and binding the silt particles, thereby rendering the microstructure denser and more stable. Based on these experimental outcomes, we propose a microstructural mechanism model for the stabilization of dredged silt employing GGBS-CaO-Na2O·nSiO2.
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Chang, Ren-Wei, Chin-Jung Lin, and Ya-Hsuan Liou. "Multicycle Performance of CaTiO3 Decorated CaO-Based CO2 Adsorbent Prepared by a Versatile Aerosol Assisted Self-Assembly Method." Nanomaterials 11, no. 12 (2021): 3188. http://dx.doi.org/10.3390/nano11123188.
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Calcium oxide (CaO) is a promising adsorbent to separate CO2 from flue gas. However, with cycling of carbonation/decarbonation at high temperature, the serious sintering problem causes its capture capacity to decrease dramatically. A CaTiO3-decorated CaO-based CO2 adsorbent was prepared by a continuous and simple aerosol-assisted self-assembly process in this work. Results indicated that CaTiO3 and CaO formed in the adsorbent, whereas CaO gradually showed a good crystalline structure with increased calcium loading. Owing to the high thermal stability of CaTiO3, it played a role in suppressing the sintering effect and maintaining repeated high-temperature carbonation and decarbonation processes. When the calcium and titanium ratio was 3, the CO2 capture capacity was as large as 7 mmol/g with fast kinetics. After 20 cycles under mild regeneration conditions (700 °C, N2), the performance of CO2 capture of CaTiO3-decorated CaO-based adsorbent nearly unchanged. Even after 10 cycles under severe regeneration conditions (920 °C, CO2), the performance of CO2 capture still remained nearly 70% compared to the first cycle. The addition of CaTiO3 induced good and firm CaO dispersion on its surface. Excellent kinetics and stability were evident.
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Han, Jianxun, Ruixue Sun, Xiuying Zeng, et al. "Rapid Classification and Quantification of Camellia (Camellia oleifera Abel.) Oil Blended with Rapeseed Oil Using FTIR-ATR Spectroscopy." Molecules 25, no. 9 (2020): 2036. http://dx.doi.org/10.3390/molecules25092036.
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Currently, the authentication of camellia oil (CAO) has become very important due to the possible adulteration of CAO with cheaper vegetable oils such as rapeseed oil (RSO). Therefore, we report a Fourier transform infrared (FTIR) spectroscopic method for detecting the authenticity of CAO and quantifying the blended levels of RSO. In this study, two characteristic spectral bands (1119 cm−1 and 1096 cm−1) were selected and used for monitoring the purity of CAO. In combination with principal component analysis (PCA), linear discriminant analysis (LDA), and partial least squares regression (PLSR) analysis, qualitative and quantitative methods for the detection of camellia oil adulteration were proposed. The results showed that the calculated I1119/I1096 intensity ratio facilitated an initial check for pure CAO and six other edible oils. PCA was used on the optimized spectral region of 1800–650 cm−1. We observed the classification of CAO and RSO as well as discrimination of CAO with RSO adulterants. LDA was utilized to classify CAO from RSO. We could differentiate and classify RSO adulterants up to 1% v/v. In the quantitative PLSR models, the plots of actual values versus predicted values exhibited high linearity. Root mean square error of calibration (RMSEC) and root mean square error of cross validation (RMSECV) values of the PLSR models were 1.4518–3.3164% v/v and 1.7196–3.8136% v/v, respectively. This method was successfully applied in the classification and quantification of CAO adulteration with RSO.
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Firnanelty, Firnanelty, Andi Nur Fitriani Abubakar, Anas Qurniawan, and M. A. Syam. "Comparison of Air Contact And Distilled Water Distribution Method in The Conversion of Cao to Ca(OH)2 As A Precursor Hydroxyapatite Synthesis." JKPK (Jurnal Kimia dan Pendidikan Kimia) 8, no. 3 (2023): 423. http://dx.doi.org/10.20961/jkpk.v8i3.78348.
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<p>Eggshells containing CaCO<sub>3</sub> have potential as bioceramics for several tissue engineering applications. The content of CaCO<sub>3</sub> converted into Ca(OH)<sub>2</sub> can be used as a precursor to implant material. The purpose of the study was to compare two methods of converting CaO into Ca(OH)<sub>2</sub> as the primary material for making hydroxyapatite. The method used is direct contact with air and dissolution with water. Hydroxyapatite synthesis using Ca(OH)<sub>2</sub> is calcined from CaCO<sub>3 </sub>with <em>a sintering</em> temperature of 900 °C. The result of calcination is in the form of CaO. The stages of obtaining Ca(OH)<sub>2</sub> by converting CaO using two methods, namely direct contact with air and dissolution with water. The XRD characterization results obtained that Ca(OH)<sub>2</sub> results from direct contact with air show the formation of phase (<em>portlandite</em>), which is characterized by its presence at the highest typical 2θ angles = 18.18°, 28.68°, 34.30°, 47.40°, 50.92°, 54.16°, and 62.62°. The XRD Ca(OH)<sub>2</sub> pattern with the distilled water distribution process shows the formation of a phase (<em>portlandite</em>) characterized by its presence at angles of 2θ = 18.18°, 28.68°, 34.30°, 47.40°, 50.92°, 54.16°, and 62.62 °. The results of FTIR Ca(OH)<sub>2</sub> characterization of air contact and water dissolution showed strong O-H functional groups at wave numbers 3643 cm<sup>-1</sup> and 3642 cm<sup>-1</sup>, C-O groups at 1487 cm<sup>-1</sup> and 1483 cm<sup>-1</sup>. This suggests that both methods can convert CaO to Ca(OH)<sub>2</sub>, which synthesizes hydroxyapatite. The hydroxyapatite characterization results obtained have met the standard.</p>
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Zhang, Qi, Yaowu Wei, Tao Zhang, Bingqiang Han, Kui Liu, and Bo Chen. "Preparation of CaO granules using the granulation method." Advances in Applied Ceramics 117, no. 6 (2018): 334–39. http://dx.doi.org/10.1080/17436753.2017.1422333.
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Tang, Zhen-Xing, David Claveau, Ronan Corcuff, Khaled Belkacemi, and Joseph Arul. "Preparation of nano-CaO using thermal-decomposition method." Materials Letters 62, no. 14 (2008): 2096–98. http://dx.doi.org/10.1016/j.matlet.2007.11.053.
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Akatobi, K. N., B. I. Okolo, O. Adeyi, et al. "Synthesis and characterisation of CaO nanoparticle from oyster shell using sol-gel method." LAUTECH Journal of Engineering and Technology 8, no. 2 (2024): 101–9. http://dx.doi.org/10.36108/laujet/4202.81.0290.
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Because human activity is constantly increasing the content of heavy metals, heavy metal removal becomes a major challenge in wastewater treatment. In an attempt to provide an innovative and sustainable option for addressing the said challenge, this study is aimed at the synthesis and characterization of nano-based CaO biosorbent from oyster shell. The sol- gel method was used to synthesize the biosorbent, characterized using FTIR, XRD, SEM and BET respectively. From the analysis conducted, the developed CaO nanoadsorbent has a point of zero charge of 5.6, indicating stable charge balance. The biosorbent was chemically characterized by the presence of a number of functional groups, most notably the –OH and C-H. The CaO nanoadsorbent was found to be crystalline in nature as revealed by XRD analysis. Findings from the BET indicated the material has a surface area of 344.528 m2/g, specific pore volume of 0.170cc/g and pore diameter of 2.118nm, indicating that it is mesoporous structurally. The results of the characterization reveal that the CaO nanoadsorbent present a suitable option for treatment of wastewater based on its associated attributes.
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Zhang, Bo, Chengjun Liu, and Maofa Jiang. "A new method of red mud recycling in the process of hot metal pretreatment." Metallurgical Research & Technology 117, no. 1 (2020): 115. http://dx.doi.org/10.1051/metal/2020010.
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To realize a large-scale consumption of red mud in the steelmaking industry, a new recycling method was investigated through the pre-reduction roasting experiment and the slag-metal interaction experiment simulating the hot metal pretreatment process in the steelmaking industry. In virtue of the sensible heating of the hot metal and the reducibility of [C] and [Si], the iron could be separated and recovered from the pre-reduced red mud pellets into the hot metal directly with a recovery rate exceeding 75%. With the composition adjustment of the residual oxides in the pre-reduced red mud (PRRD) using CaO and Al2O3 or aluminium dross (AD), a slag having a low melting point (below 1300 °C) and a high sulfide capacity (lgCS = −2.3) was formed, and more than 94% of [S] in the hot metal could be removed into this slag through the slag-metal interaction. The desulfurization efficiency of the flux (PRRD-CaO–Al2O3; PRRD-CaO–AD) is approximate to the traditional desulfurizing flux (CaO–CaF2). The advantages of this method are summarized as the low energy cost and the slag valorization.
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Mohd Daud, Farah Diana, Muhammad Mirza Mohamad Azir, Mudrikah Sofia Mahmud, Norshahida Sarifuddin, and Hafizah Hanim Mohd Zaki. "PREPARATION OF CaO-BASED PELLET USING RICE HUSK ASH VIA GRANULATION METHOD FOR POTENTIAL CO2 CAPTURE." IIUM Engineering Journal 22, no. 1 (2021): 234–44. http://dx.doi.org/10.31436/iiumej.v22i1.1544.
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CO2 capturing has become very significant option to reduce the emission of CO2 in the atmosphere and hence, minimizing environmental issues.Among solid CO2 sorbent, calcium oxide (CaO) is an attractive regenerable sorbent for CO2 capturing because of their reactivity and high CO2 absorption capacity. CaO alone suffers from rapid decay of CO2 adsorption during multiple carbonation/calcination reaction cycles. The stability of CaO sorbents during cyclic runs can be achieved via the incorporation of additive support materials. The silica (SiO2) from natural sources such as rice husk is the best candidate to be used as an additive in the sorbents. However, the CaO-based sorbent in finely generated powders are prone to severe attrition problems. Therefore, this research focuses on preparation of CaO-based pellets by using rice husk ash (RHA) via granulation method. The result of the raw materials confirmed that Ca(OH)2 have crystalline structure with finely distributed grains and RHA exhibit amorphous structure with randomly oriented size grains. Based on the XRD, it is confirmed that the insertion of RHA does not alter the phase structure of the pellets. Each ratio yield different intensity value and has formation of new peaks after sintering. Meanwhile, the microstructures of the pellets show that the pores reduced as the calcination temperature increased while the incorporation of RHA caused the pores size increased with randomly oriented shape. These findings indicate that the optimum value for the pellets is with the Ca(OH)2:RHA ratio of 80:20 and calcination temperature of 750 °C. ABSTRAK: Penangkapan CO2 telah menjadi pilihan yang sangat penting untuk mengurangkan pelepasan CO2 di atmosfer serta kesan alam sekitar. Antara penjerap CO2 pepejal, kalsium oksida (CaO) adalah penyerapan yang menarik untuk CO2 yang ditangkap kerana kereaktifan dan kapasiti penyerapan CO2 yang tinggi. CaO sahaja menderita daripada pelepasan cepat penjerapan CO2 semasa kitaran tindakbalas karbonasi / kalsinasi. Kestabilan CaO penjerap semasa berlaku kitaran boleh dicapai melalui penggabungan bahan sokongan tambahan. Silika (SiO2) dari sumber semula jadi seperti sekam padi (RHA) adalah calon terbaik untuk digunakan sebagai aditif dalam penjerap. Walau bagaimanapun, penjerap berasaskan CaO dalam bentuk serbuk halus yang dihasilkan adalah terdedah kepada masalah pergeseran yang teruk. Oleh itu, kajian ini memberi tumpuan kepada penyediaan pelet berasaskan CaO dengan menggunakan abu sekam beras melalui kaedah granulasi. Hasil bahan mentah mengesahkan bahawa Ca(OH)2 mempunyai struktur kristalografi dengan bijirin halus dan RHA yang mempamerkan struktur bukan kristal dengan butiran saiz berorientasikan secara rawak. Berdasarkan XRD, ia disahkan bahawa penyisipan RHA tidak mengubah struktur kristalografi pelet. Setiap nisbah menghasilkan nilai intensiti yang berbeza dan mempunyai pembentukan puncak baru selepas pensinteran. Sementara itu, mikrostruktur pelet menunjukkan bahawa pori-pori berkurangan apabila suhu kalsinasi meningkat sementara pembentukan RHA menyebabkan saiz pori meningkat dengan bentuk berorientasikan rawak. Penemuan ini menunjukkan bahawa nilai optimum bagi pelet adalah dengan nisbah Ca(OH)2:RHA 80:20 dan suhu kalsinasi 750 °C.
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Avram, Daniela, Dan Ungureanu, Nicolae Angelescu, and José Barroso de Aguiar. "A Comparative Study on the Properties of Potentially Bioactive Glasses Obtained by Sol-Gel Technique and by Melting Mixtures of Oxides." Scientific Bulletin of Valahia University - Materials and Mechanics 15, no. 13 (2017): 18–24. http://dx.doi.org/10.1515/bsmm-2017-0013.
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AbstractPhosphocalcic glasses, based on ternary system SiO2 - CaO- P2O5 and those doped with copper (SiO2 – CaO - P2O5 - Cu2O) can be obtained by the traditional method of sub-cooling melts or modern methods such as process that uses mechanical energy, neutrons action, deposition in thin layers or by sol-gel technique. This paper shows the experimental results of three compositional phosphocalcic glasses: 50% SiO2 - 43% CaO - 7% P2O5, 50% SiO2 - 38% CaO - 7% P2O5 - 5% Cu2O obtained through sol-gel method and 45% SiO2 - 22.5% CaO - 22.5 Na2O - 5% P2O5 - 5% Cu2O obtained by melting. In order to study their bioactivity, the three compositions were structural analyzed by X-ray diffraction method. In this case the apatite formation was highlighted after soaked in simulated body fluid, but also other compounds (CaCO3 and CuO) resulting from the same process were observed. In case of the melting glass apatite formation has not been highlighted. The functional groups present in the structure of glasses before and after soaking (PO43−, CO32− and HO−) were highlighted by the Fourier Transform Infrared Spectroscopy (FTIR). The elemental chemical composition was confirmed by elemental analysis WD-XRF. The morphology of sol-gel glass powders was revealed by SEM analysis. All glass compositions were tested in terms of antibacterial activity in vitro.
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Aziz, Hidayah Mohd, Noor Idayu Masrom, Nur Fatin Sulaiman, Mohd Khairul Asyraf Amat Mustajab, and Abdul Rahim Yacob. "Effect of Hydration-Dehydration Activation on the Basic Strength of Nano Structured Alkaline Earth Metal Calcium Oxide." Advanced Materials Research 383-390 (November 2011): 3835–39. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.3835.
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The study of physicochemical properties such as surface area, particle size and basicity of heterogeneous catalysts is in great interest nowadays. CaO yield a number of surface defects centers and these were important especially for heterogeneous catalyst. In this study, nano structured CaO was synthesized via hydration-dehydration method. The basic strength of the prepared CaO was also studied using simple back titration method with respect to the activation temperature. This result revealed that, the basic strength increases with the increasing of activation temperature. As the nano structured CaO were prepared, more surface cavity and defect were expected to be present and thus, exposing more O2- sites, which influences the basic strength. Finally it was found that nano structured CaO was successfully prepared, while compared to the commercial CaO have a better chemical properties for catalytic chemical reactions.
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Dudek, Magdalena, and Alicja Rapacz-Kmita. "CaZrO3-based powders suitable for manufacturing electrochemical oxygen probes." Open Chemistry 11, no. 12 (2013): 2088–97. http://dx.doi.org/10.2478/s11532-013-0332-2.
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AbstractCalcium zirconate powders doped with a small amount of CaO were synthesised using the Pechini method. X-ray analysis revealed that solid solution was formed in the concentration up to 51.5% mol CaO. For synthesis of stoichiometric CaZrO3, the highest temperature was required (1150°C), but introduction of excess CaO from 50.5 to 51.5% mol enabled us to lower the synthesis temperature to 800°C. The sintering behaviour of such samples under non-isothermal conditions was studied by dilatometric methods. Deviations were found in stoichiometry; by increasing the CaO concentration in CaZrO3 sinterability improved in comparison to CaZrO3 with stoichiometric composition. The presence of CaO as second phase caused deterioration of the sinterability of the CaZrO3-based samples. Pellets sintered at 1500°C for 2 h reached 96–98% of theoretical density. SEM and TEM observations were used to characterise the microstructure of the prepared samples. The electrical properties of CaZrO3-based samples were investigated by the AC-impedance spectroscopy method. It was found that introduction of excess CaO into the CaZrO3 structure caused an increase in ionic conductivity up to the solubility limit. The possibility of using CaZrO3-based samples for constructing prototype electrochemical oxygen probes to determine activity of oxygen dissolved in molten copper is also demonstrated.
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Yacob, Abdul Rahim, Nur Fatin Sulaiman, and Maimoonah Khalid Qasim. "Surface Modified Nano Calcium Oxide for Base Heterogeneous Transesterification of Kappaphycus Alvarezii Seaweed to Biofuel." Advanced Materials Research 974 (June 2014): 262–66. http://dx.doi.org/10.4028/www.scientific.net/amr.974.262.
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The study of physicochemical properties of solid catalyst such as particle size, surface area and basicity are significant today since their reactivity depend on these properties. The number of defect sites in CaO, an alkaline metal oxide is important in heterogeneous catalysis. In this research work, nanostructured CaO was synthesized from commercial CaO via hydration-dehydration method. The surface modified CaO was calcined at various temperatures from 300°C to 800°C respectively under vacuum atmosphere of 10-3mbar. The prepared nanostructured CaO was then characterized using Thermogravimetric Analysis (TGA) and Fourier Transform Infrared (FTIR). The basicity then determined by back titration method. This research found that when activation temperature increased, the basicity also increases. For optimization, the prepared nanostructured CaO-600 was selected and applied for base transesterification reaction using algae species, Kappaphycusalvarezii to produce biodiesel. The latter reaction was then confirmed by Nuclear Magnetic Resonance (NMR) spectroscopy.
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Mohd Daud, Farah Diana, Nur Asyikin Kosen, Mudrikah Sofia Mahmud, Norshahida Sariffudin, and Hafizah Hanim Mohd Zaki. "Preparation of CaO-SiO2 Adsorbent for Potential CO2 Capture via Dry Mixing Method." Materials Science Forum 1025 (March 2021): 343–48. http://dx.doi.org/10.4028/www.scientific.net/msf.1025.343.
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Calcium-looping technology is defined as one of the most desirable methods of carbon capture, utilization and storage (CCUS). However, because of sintering, rapid deactivation of CaO-sorbents is currently a major barrier to this technology. The stability of calcium based sorbent may be enhance by incorporating them with inert support materials such as MgO, Al2O2, ZrO2 and SiO2. For this study, calcium based sorbent has been incorporate with silica obtained from rice husk ash. CaO-SiO2 sorbents are prepared using physical dry mixing method which is much simpler compared to other available methods. The prepared CaO-SiO2 sorbents were then characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). New crystalline phase, larnite (Ca2SiO4) was detected in XRD patterns and this phase possess good chemical durability and may help to prevent sintering effect of calcium based sorbents and enhance their cyclic capability. CaO-SiO2 sorbent calcined at 700 oC with different grinding times have highest intensity of XRD peak at (104) with element of calcite. Sorbents with different weight composition of CaCO3-RHA were observed to have different surface morphology. SEM images of the sorbent (90wt% CaCO3-RHA) before calcination showed bigger particle size with irregular shape and more porosity. Then, SEM analysis was conducted for samples with different grinding times after calcination. CaO-SiO2 sorbents with 20minutes grinding time exhibited small size of particles with some porosity. Besides that, the particles are well distributed without agglomeration occured. The CaO-SiO2 sorbent calcined at 700 oC sorbents were tested for 20 consecutive carbonation and calcination cycles using Thermogravimetric Analysis (TGA). CaO-SiO2 sorbent treated with 700 oC calcination temperature and 20 minutes of grinding shows better cyclic CO2 sorption capacity.
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Kou, Luyao, Junjing Tang, Tu Hu, Baocheng Zhou, and Li Yang. "Effect of CaO on catalytic combustion of semi-coke." Green Processing and Synthesis 10, no. 1 (2021): 011–20. http://dx.doi.org/10.1515/gps-2021-0002.
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Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.
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Imtiaz, Ayesha, Muhammad Akhyar Farrukh, Muhammad Khaleeq-ur-rahman, and Rohana Adnan. "Micelle-Assisted Synthesis of Al2O3·CaO Nanocatalyst: Optical Properties and Their Applications in Photodegradation of 2,4,6-Trinitrophenol." Scientific World Journal 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/641420.
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Calcium oxide (CaO) nanoparticles are known to exhibit unique property due to their high adsorption capacity and good catalytic activity. In this work the CaO nanocatalysts were prepared by hydrothermal method using anionic surfactant, sodium dodecyl sulphate (SDS), as a templating agent. The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO. The Al2O3·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques. The catalytic efficiencies of these nanocatalysts were studied for the photodegradation of 2,4,6-trinitrophenol (2,4,6-TNP), which is an industrial pollutant, spectrophotometrically. The effect of surfactant and temperature on size of nanocatalysts was also studied. The smallest particle size and highest percentage of degradation were observed at critical micelle concentration of the surfactant. The direct optical band gap of the Al2O3·CaO nanocatalyst was found as 3.3 eV.
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Tahya, Candra Yulius, Wahyu Irawati, Karnelasatri Karnelasatri, and Friska Juliana Purba. "Synthesis and Characterization of TiO2-CaO and TiO2-CaO-Fe2O3 Photocatalyst for Removal of Catechol." Molekul 14, no. 2 (2019): 140. http://dx.doi.org/10.20884/1.jm.2019.14.2.570.
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TiO2-CaO and TiO2-CaO-Fe2O3 photocatalysts have been synthesized through the surfactant-assisted sol-gel method. The catalysts were characterized using XRD, FTIR, SEM-ED Sand BET surface area. XRD pattern showed the formation of anatase TiO2 crystal phase both in TiO2-CaO and TiO2-CaO-Fe2O3. The TiO2-CaO has higher crystallinity than TiO2-CaO-Fe2O3. Based on the peak refinement using Rietveld, there are two peaks identified as Fe2O3 hematite in the sample TiO2-CaO-Fe2O3. BET surface area analysis showed that the average pore size of TiO2-CaO and TiO2-CaO-Fe2O3 catalysts are 8.04 and 8.41 nm respectively, indicating both catalysts are mesoporous.FTIR spectra show that the vibration of Ti-O, Ca-O, and Ca-TiO2 were observed in both catalysts. SEM images confirm that both catalysts are porous material. The catechol removal using TiO2-CaO and TiO2-CaO-Fe2O3 improved with the increase of catalyst concentration. After 360 minutes of UV radiation, the removal of catechol using TiO2-CaO-Fe2O3 reached 46.0%, 48.3%, and 69.2%, while when using TiO2-CaO, it reached 22.1%, 36.8%, and 57.0% for 0.1 g, 0.15 g, and 0.2 g of catalysts, respectively. The photocatalytic activity of TiO2-CaO-Fe2O3 is not so strong compared to TiO2-CaO catalyst but the catechol adsorption property of TiO2-CaO-Fe2O3 is higher than that of TiO2-CaO catalyst.
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Li, Z. S., P. T. Liang, and N. S. Cai. "A rate equation theory for the pore size distribution of calcined CaCO3 in calcium looping." Faraday Discussions 192 (2016): 197–216. http://dx.doi.org/10.1039/c6fd00019c.
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CaCO<sub>3</sub> calcination is an important step in calcium looping, and the formed pore structure of porous CaO is critical for subsequent carbonation towards carbon dioxide. Therefore, it is necessary to investigate the evolution of the pore structure of the sorbent in the calcination step. A mathematical model describing the pore size distribution during the calcination of the CaCO<sub>3</sub> particle was developed. CaCO<sub>3</sub> calcination is calculated following a shrinking core model at the CaO–CaCO<sub>3</sub> interface, and CO<sub>2</sub> diffuses through the porous CaO layers. During the decomposition of CaCO<sub>3</sub>, after the departure of the CO<sub>2</sub> molecule from its original lattice, a vacancy will be formed that will diffuse inside the solid, and the collision and coagulation of the vacancy results in pore formation. A rate equation theory was proposed to describe the vacancy coagulation and pore evolution inside the solid, with rate expressions derived for the pore size distribution function with time evolution. To validate the developed model, the evolution of the pore size distribution during CaCO<sub>3</sub> calcination was experimentally measured in a high-temperature furnace combined with the nitrogen adsorption method. It was found that there is a characteristic bimodal distribution for the pore structure of calcined CaCO<sub>3</sub>, with average pore sizes of ∼2.8 nm and ∼50 nm. The calculated results agree well with the experimental data, and the relative importance of growth and coagulation was discussed.
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Pantic, Jelena, Volker Kahlenberg, Vesna Poharc-Logar, and Aleksandar Kremenovic. "Natural CaO-TiO2-SiO2 based ceramics." Processing and Application of Ceramics 5, no. 2 (2011): 79–84. http://dx.doi.org/10.2298/pac1102079p.
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Lesnica river deposits consist of a large number of minerals of different grain sizes including sphene. Since it is very difficult to obtain pure monophase titanite by different synthetic routes (sol-gel, coprecipitation, combustion, spray pyrolysis and hydrothermal method), the aim of this work was to study the structure of the sphene from the Lesnica river deposits and possibility of using it as a natural precursor for CaO-TiO2-SiO2 based ceramics. The sphene from Lesnica was analyzed by different methods: tristimulus colorimetry, infrared spectroscopy, electron microprobe and X-ray single crystal diffraction. It was confirmed that Al, Fe, Mn and P are present in the sphene structure and proposed that corresponding structural formula could be: (Ca2+1.008 Mn2+0.002)1.010(Ti4+0.901 Fe3+0.033 Al3+0.060 P5+0.001)0.995 Si4+1.024 O2-5.
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Tan, Hong Bo, Kai Ke, Bao Guo Ma, and Jun Xiao. "Effect and Solid Solution Mechanism of Co2O3 during C3S Formation." Advanced Materials Research 146-147 (October 2010): 1587–92. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1587.
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C3S is one of the most important mineral phases in silicate cement clinker; alternative ions could be solidified into C3S crystal lattice. Therefore, the research on solid solution mechanism was studied, which was about C3S doped with ions, Meanwhile, the achievement of this paper could be taken as a guidance for cement clinker industry. The effect and solid solution mechanism of Co2O3 during C3S formation were studied by means of chemical analysis, XRD and phase diagram analysis. The results show that when Co2O3 additive was less than 1.5% in mass, the content of f-CaO increased with the increase of Co2O3, and the formation rate of C3S was accelerated by Co2O3; when Co2O3 addition exceeded 1.5%, the content of f-CaO decreased with the increase of Co2O3.By the least square method and defined f-CaO, the molecular formula that Co2O3 solidified in C3S could be deduced: (Ca3-0.86x Co0.86x) (Si1-0.14xCo0.14x) O5 (x=0.0209).
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Thanakkasaranee, Sarinthip, Pornchai Rachtanapun, Chitsiri Rachtanapun, et al. "Bio-Composite Films Based on Carboxymethyl Chitosan Incorporated with Calcium Oxide: Synthesis and Antimicrobial Activity." Polymers 16, no. 17 (2024): 2393. http://dx.doi.org/10.3390/polym16172393.
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The utilization of biopolymers incorporated with antimicrobial agents is extremely interesting in the development of environmentally friendly functional materials for food packaging and other applications. In this study, the effect of calcium oxide (CaO) on the morphological, mechanical, thermal, and hydrophilic properties as well as the antimicrobial activity of carboxymethyl chitosan (CMCH) bio-composite films was investigated. The CMCH was synthesized from shrimp chitosan through carboxymethylation, whereas the CaO was synthesized via a co-precipitation method with polyethylene glycol as a stabilizer. The CMCH-CaO bio-composite films were prepared by the addition of synthesized CaO into the synthesized CMCH using a facile solution casting method. As confirmed by XRD and SEM, the synthesized CaO has a cubic shape, with an average crystalline size of 25.84 nm. The synthesized CaO exhibited excellent antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (>99.9% R). The addition of CaO into CMCH improved the mechanical and hydrophobic properties of the CMCH-CaO films. However, it resulted in a slight decrease in thermal stability. Notably, the CMCH-CaO10% films exhibited exceptional antimicrobial activity against E. coli (98.8% R) and S. aureus (91.8% R). As a result, such bio-composite films can be applied as an active packaging material for fruit, vegetable, or meat products.
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Băbuţă, R., I. Lazău, and C. Păcurariu. "Study of CaO·2Al2O3 formation by polymeric precursor method." Journal of Thermal Analysis and Calorimetry 112, no. 1 (2012): 339–44. http://dx.doi.org/10.1007/s10973-012-2656-0.
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Katayama, I., N. Kemori, and W. T. Denholm. "Thermodynamic study of CaO-Sb2O3 system by emf method." Berichte der Bunsengesellschaft für physikalische Chemie 102, no. 9 (1998): 1272–74. http://dx.doi.org/10.1002/bbpc.19981020935.
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Li, Hua, Jia Ping Liu, Qian Tian, and Shou Zhi Zhang. "Hydration Kinetics and Microscopic Analysis of Calcium Oxide Expansion Clinker." Applied Mechanics and Materials 477-478 (December 2013): 908–14. http://dx.doi.org/10.4028/www.scientific.net/amm.477-478.908.
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Hydrating and calcining method combined with the kinetic equation were adopted to describe the hydration kinetics process of the laboratory-calcined CaO expansion clinker, XRD and SEM were used to test and analysis its mineral compo-sition and microstructure as well. The results show that, hydration reaction process in pure water of f-CaO contained in the CaO expansion clinker meets the Avrami isothermal crystallization kinetics model, and the hydration degree increases with temperature, with the relation between reaction rate constant and temperature conforming to Arrhenius law; the CaO expansion clinker powder contains a large number of particles in which f-CaO, CaSO4, Ca4Al6O12SO4 (partly still containing calcium silicates) phases existing at the same time, by the impact of the presence of impurity phases and the difference of calcining conditions, the hydration activity of f-CaO contained in CaO expansion clinker was different from that of pure CaO and that of f-CaO wrapped in cement clinker or high-calcium fly ash.
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Pujiastuti, Caecilia, Srie Muljani, and Ketut Sumada. "Precipitated calcium oxide nanosize from limestone and blood clam shells." Journal of Natural Sciences and Mathematics Research 9, no. 1 (2023): 12–18. http://dx.doi.org/10.21580/jnsmr.2023.9.1.13209.
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Calcium oxide (CaO) is a product that is needed by various types of industries such as the pharmaceutical, chemical, agricultural and health industries. CaO is generally produced by the calcination method of CaCO3 materials such as calcium carbonate rocks or from various types of shells. The calcination method requires a large amount of energy because the operating temperature is above 1000 C and the resulting calcium oxide product is still micrometer size. This study developed nanosize precipitated CaO from two calcium sources, namely blood clam shells and limestone. For clam shells using hydrochloric acid as a solvent and sodium hydroxide as a precipitating agent, while for limestone using phosphoric acid as a solvent and potassium hydroxide as a precipitating agent. The effect of acidity (pH) and calcination temperature on the characteristics of the precipitated CaO was observed. The blood calm shell produces precipitated CaO 85-92 % with a particle size of 200-250 Nm and the limestone produces precipitated CaO 42-66% with a particle size of 250-300 Nm
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Pujiastuti, Caecilia, Srie Muljani, and Ketut Sumada. "Precipitated calcium oxide nanosize from limestone and blood clam shells." Journal of Natural Sciences and Mathematics Research 9, no. 1 (2023): 12–18. http://dx.doi.org/10.21580/jnsmr.2023.9.1.13209.
Full textAbstract:
Calcium oxide (CaO) is a product that is needed by various types of industries such as the pharmaceutical, chemical, agricultural and health industries. CaO is generally produced by the calcination method of CaCO3 materials such as calcium carbonate rocks or from various types of shells. The calcination method requires a large amount of energy because the operating temperature is above 1000 C and the resulting calcium oxide product is still micrometer size. This study developed nanosize precipitated CaO from two calcium sources, namely blood clam shells and limestone. For clam shells using hydrochloric acid as a solvent and sodium hydroxide as a precipitating agent, while for limestone using phosphoric acid as a solvent and potassium hydroxide as a precipitating agent. The effect of acidity (pH) and calcination temperature on the characteristics of the precipitated CaO was observed. The blood calm shell produces precipitated CaO 85-92 % with a particle size of 200-250 Nm and the limestone produces precipitated CaO 42-66% with a particle size of 250-300 Nm
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Patricia Ese Umoru, Patricia Ese Umoru, Yusuf Sahabi Yusuf Sahabi, Abdullahi Isah Abdullahi Isah, Aminu Aliyu Aminu Aliyu, and and Ibrahim Dankane Bafarawa and Ibrahim Dankane Bafarawa. "Synthesis of Calcium Oxide Nanoparticles, its Characterization, Effect on Soil pH and Kinetic Evaluation in Acidic Solution." Journal of the chemical society of pakistan 47, no. 1 (2025): 01. https://doi.org/10.52568/001627/jcsp/47.01.2025.
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Synthesis of calcium oxide nanoparticles (CaO NPs), its characterization and kinetic evaluation with phosphite ion and soil sample in acidic solution was evaluated. CaO NPs was synthesized by thermal decomposition method at 850 0C for 6 hours using calcium carbonate (CaCO3) as the raw material. The CaO nanoparticle was characterized by the use of X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The sharp peak of CaO NPs was found to be between 17.98o and 71.7o with average crystallized particle sizes of 27.43 and#177; 0.1. The morphology was found to be a flower shape with agglomeration. The pace of the reaction was explored under specific concentration of hydrogen ion [H+], ionic strenght (I), and λmax of 460 nm using spectrophotometric method. The stoichiometry of the reaction gave a mole ratio of 2:3 for PO33- to CaO NPs. The reaction is 1st - order in favour of CaO and 1st – order in favour of PO33-. Alteration of acid content decreased the pace of reaction. Addition of CaO NPs on the soil sample changed the pH from acidic to alkaline values ranging from 6.67 – 7.81. The administration of CaO NPs on acidic compound like soil will therefore improve the soil pH thereby boost the fertility of the soil. The experimental data showed that the reaction advanced via outer-sphere process.