Natural Calcium Carbonate Research Articles

Pengaruh Suhu Kalsinasi Terhadap Nilai Rendemen CaO Cangkang Tiram (Crassostrea Gigas)

Oyster shell contained more than 60% of calcium carbonate.it can be used as natural calcium source. Calcium oxide (CaO) can be converted from natural calcium carbonate (CaCO3) at high temperature with decomposition reaction. The purpose of this research was to isolating calcium oxide and to know the yield of CaCO3 decomposition. Calcined samples oyster shells flour is at 500ºC, 700ºC, 900°C and 1100ºC for 2 hours. The sequential data yield of CaO obtained was 96.65%; 96.57%; 60.41% and 54.67%.

Experimental study of the adsorption of Zn2 + ions on Natural Calcium Carbonate

In this study, Natural Calcium Carbonate (NCC) that was characterised by X-ray diffraction has been used as an adsorbent in the removal of Zn2+, from aqueous solution by a batch adsorption technique. The effects of various experimental parameters such as solution PH, initial concentration of solution, contact time, adsorbent masses and stirring speed were investigated. The results showed that basic PH and the average stirring speed were favourable for the adsorption of Zn2+, and the adequate equilibrium time for the adsorption of Zn2+ onto Natural Calcium Carbonate was 80min. The experimental data were analysed by the linear form of Langmuir, Freundlich. Isotherm models and showed a good fit with the Langmuir isotherm model. Adsorption kinetic was studied using pseudo first order kinetic equation, second order kinetic equation. The adsorption kinetic followed the pseudo second order equation.Â

Epoxy Composites Filled with Natural Calcium Carbonate. 1. Epoxy Composites Obtained in the Presence of Monoperoxy Derivative of Epidian-6 Epoxy Resin

Epoxy Composites Filled with Natural Calcium Carbonate. 1. Epoxy Composites Obtained in the Presence of Monoperoxy Derivative of Epidian-6 Epoxy Resin

Natural rubber composites for solid tyre used for forklift tensile properties and morphological characteristics

The engineering of natural rubber and synthetic rubber into vulcanized solid tyres for forklifts has been carried out to obtain the optimum ratio of formula and process temperature according to the standards of solid tyre commercial forklifts. Composite formulated materials consist of natural rubber, synthetic rubber, carbon black, silica, calcium carbonate, and coal fly ash, while the temperature, time, and other process materials are fixed variables. The results of testing the mechanical properties of forklift solid tyres for formula C are as follows: specific gravity1.195 g/cm3 hardness78 Shore A, tensile strength 17.3 Mpa, tear strength 55.2 kN/m, abrasion resistance 160.8 mm3 modulus 300% is 6.6%, and ozone resistance at 50 pphm, 20% strain, 24 h, 40 °C is no cracks.

In situ calcium isotopic ratio determination in calcium carbonate materials and calcium phosphate materials using laser ablation-multiple collector-inductively coupled plasma mass spectrometry

This study presents a highly precise and accurate Ca isotope analysis method using laser ablation multiple collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) in calcium carbonates and calcium phosphates. High-sensitivity cones and nitrogen gas were used to improve the performance of the LA-MC-ICP-MS. The experiment results show that at the N2 mode, the signal intensity of 44Ca+ in the high-sensitivity cones (Jet + X cones) was 5-fold higher than that in the normal cones (S + H cones), while the polyatomic interferences of 40Ar1H1H+ and 40Ar16O+ in the high-sensitivity cones were suppressed by factors of 6.1 and 10.6, respectively, after the addition of 8 ml min−1 N2. The combination of high sensitivity cones and N2 addition did not increase the production of double charged ions. Additionally, the interference correction of doubly charged Sr ions was investigated in detail. The experiment results demonstrate that the concentration ratio of Sr to Ca (represented as I87Sr++/I44Ca+), the 87Sr/86Sr ratio and the mass fractionation factor of Sr (fSr) during the measurement process were key parameters for in situ Ca isotope ratios analysis. The threshold values of these key parameters were evaluated and are recommended to ensure an accurate correction of doubly charged Sr ions. Using the optimized instrumental conditions and correction strategies, an excellent within-run precision (<0.06‰, 2SE) and external reproducibility (<0.15‰, 2SD) for the microanalysis of δ44/42Ca915b were obtained in natural calcium carbonates and calcium phosphates. These precisions are better than the values previously reported in the literature regarding using LA-MC-ICP-MS. Matrix effects were observed during the in situ Ca isotope analysis among calcium carbonates, hydroxy calcium phosphates and igneous apatites. Using the matrix-matching standards, accurate δ44/42Ca915b values in natural materials with various matrices were achieved, confirming the availability of the proposed method to resolve the spatial variation of δ44/42Ca in natural materials.

Separation of 44Sc from Natural Calcium Carbonate Targets for Synthesis of 44Sc-DOTATATE.

The rapid increase in applications of scandium isotopes in nuclear medicine requires new efficient production routes for these radioisotopes. Recently, irradiations of calcium in cyclotrons by α, deuteron, and proton beams have been used. Therefore, effective post-irradiation separation and preconcentration of the radioactive scandium from the calcium matrix are important to obtain the pure final product in a relatively small volume. Nobias resin was used as a sorbent for effective separation of 44Sc from calcium targets. Separation was performed at pH 3 using a column containing 10 mg of resin. Scandium was eluted with 100 μL of 2 mol L−1 HCl. Particular attention was paid to the reduction of calcium concentration, presence of metallic impurities, robustness and simple automation. 44Sc was separated with 94.9 ± 2.8% yield, with results in the range of 91.7–99.0%. Purity of the eluate was confirmed with ICP-OES determination of metallic impurities and >99% chelation efficiency with DOTATATE, followed by >36 h radiochemical stability of the complex. A wide range of optimal conditions and robustness to target variability and suspended matter facilitates the proposed method in automatic systems for scandium isotope separation and synthesis of scandium-labeled radiopharmaceuticals.

Influence of aqueous Mg concentration on the transformation of amorphous calcium carbonate

In natural aquatic environments amorphous calcium carbonate (ACC) shows a remarkable stability, which is assumed to arise from the incorporation of foreign ions as well as organic ligands. Such impurities, like Mg, are considered to be controlling the transformation of ACC and finally occurring CaCO3 polymorphs. Although transformation of ACC with different Mg contents is extensively studied, the role of the aqueous Mg on ACC transformation is still underexplored. Therefore, experiments on the transformation behaviour of additive-free ACC reacting with Mg-bearing solutions were carried out and monitored using highly time-resolved in-situ Raman spectroscopy. The results show that while ACC transformed instantly to calcite and vaterite in pure water, it exhibited a prolonged stability of up to 11.5 h at elevated Mg concentrations in the reactive solutions. During this process ACC incorporated up to 5 mol% of Mg. The subsequent, transformation pathway of the newly formed Mg-ACC changed from forming Mg-calcite and vaterite to precipitating aragonite with nesquehonite and monohydrocalcite as intermediate phases. This indicates that the distinct ACC transformation mechanisms and thus sequences of minerals formed are controlled by the aqueous Mg concentration of the reactive solution. Hence, the finally formed minerals are not determined by the pre-structuring of the original ACC.

Catalytic performance enhancement of CaO by hydration-dehydration process for biodiesel production at room temperature

This research presents an efficient technique to enhance the catalytic activity, surface area and total basicity of CaO with hydration-dehydration process to be the catalyst for the transesterification of palm oil to biodiesel. The catalytic performance of the resulted catalyst was tested via transesterification reaction of palm oil at room temperature (30 ± 2 °C) and was compared against commercial CaO and CaO derived from natural calcium carbonate sources. Under the optimal reaction conditions (catalyst loading of 5 wt%, methanol to oil molar ratio 12:1), FAME yields were approximately 94% for CaOHY and 60.5%, 55.3%, 49.5% and 51.4% for CaOcom, CaOegg, CaOgol and CaOriv as catalysts, respectively. Catalyst reusability and scaling up of biodiesel production from 50 mL to 1.5 L were also investigated. The obtained biodiesel product after purification and treatment process showed high quality fuel properties within the range of biodiesel standard and similar with high-speed diesel. Furthermore, the used CaOHY as a solid heterogeneous catalyst at room temperature was not only low-cost but also environmentally-friendly, showing a high potential in the biodiesel production.

The effects of refractory zirconium-based ceramic dopants on the stability performance of synthetic Ca-based sorbents prepared by co-precipitation method in cyclic CO2 capture operations

Calcium (Ca) based sorbents utilized in the carbon dioxide (CO2) capture process at high temperatures have displayed considerable activity loss during extended use, due to sintering. Refractory zirconium-based ceramics, however, have shown excellent performances as thermal barrier coatings in many high-tech applications; and, the recent doping of zirconia in Ca-based sorbents has exhibited excellent sustainability in the activity stability in cyclic CO2 capture operations. In this work, we doped sorbents, at loadings of 10 wt%, with a few zirconium-based ceramics, such as alkaline earth metal zirconate (calcium zirconate, CaZrO3), which has the chemical structure of perovskite, and rare earth metal zirconates, which have the chemical structure of pyrochlore. These materials were prepared through the wet co-precipitation method, in order to achieve the optimal uptake capacity and stability in cyclic CO2 capture operations. Among the sorbents tested, the CaZrO3-doped sorbents exhibited excellent performance, remarkable thermal stability and sintering resistant. Therefore, the sorbents were stable though 30 carbonation–calcination cycles. The sorbent showed a CO2 capture capacity of 12 mol CO2/kg sorbent, with an activity loss of 19.6% through carbonation at 675 °C for 10 min and calcination at 850 °C for 10 min. Among the rare earth metal zirconate ceramics, samarium zirconate (Sm2Zr2O7) exhibited the best stability with an activity loss of 23.4% loss, but at a lower uptake of 7.2 mol CO2/kg sorbent at the same carbonation–calcination conditions. In comparison, Cadomin (a natural calcium carbonate) at the same conditions resulted in a capture capacity of 13.5 mol CO2/kg sorbent and an activity loss of 69%. Surface area characterizations showed that incorporation of the ceramics to the calcium based sorbents significantly improved the surface morphology and textural properties of the sorbents. X-ray diffraction results indicated that the improved resistance of the sorbent could be due to forming of ceramic structures such perovskite-type CaZrO3 at a relatively low temperature (around 850 °C compared to higher temperatures required for pyrochlore-type ceramic formation), which made a stable sorbent structure for the carbonation process.

Исследование термического разложения природных карбонатов кальция методом температурно-программированной масс-спектрометрии

Исследование термического разложения природных карбонатов кальция методом температурно-программированной масс-спектрометрии

Utilization of Chicken Eggshell Waste as a Bio-Filler for Thermoplastic Polymers: Thermal and Mechanical Characterization of Polypropylene Filled with Naturally Derived CaCo3

The processing and characterization of polypropylene/eggshell composites was the main objective of this study. Natural source-derived calcium carbonate (CaCO3) was extracted from waste chicken eggshell and compounded with polypropylene polymer. The compound was molded using the Extrusion Compression Molding (ECM) process. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis were conducted on the eggshell to characterize its constituents. The effects of filler loading, 30 wt.% eggshell and 30 wt.% eggshell with 5 wt.% of maleic anhydride grafted polypropylene (MAPP) on the mechanical and thermal properties were studied. The addition of a small amount of MAPP during melt extrusion improved the dispersion and bonding of CaCO3 particles in polypropylene. 7.49% decrease in tensile strength, 35.51% enhancement in flexural modulus and 66.05% increase in notched Izod impact energy were obtained by adding 30 wt.% eggshell with 5 wt.% MAPP to polypropylene. Adding 30-wt % of eggshell filler and 5 wt.% MAPP to polypropylene delayed the flame propagation time by 99 seconds.

Modification of Green Calcium Oxide and Characteristics for Clean Energy Catalysts

The additional calcium oxide was designated at 10% by wt in copper-based catalysts. Prior to the catalyst preparation, calcium oxide was prepared by firing natural calcium carbonate (calcite structure) at 850 oC according to the decomposition temperature obtained from thermogravimetric analysis. The modification of basic strength was accomplished by additional Ti(OC2H5)4 or KMnO4 at 1% by wt to obtain CaO_Ti and CaO_KMn, and then they were calcinated at same temperature (850 oC). CO2 Temperature Programmed Desorption (CO2-TPD) was carried out to investigate the ability to adsorb CO2 molecules representing the number of basic sites for all calcium oxide. The copper-based catalysts were prepared with 10% weight CaO or modified CaO. The H2 temperature programmed reduction (H2-TPR) was carried out by thermogravimetric analysis under inert gas atmosphere in comparison with the result obtained under 5% H2 in inert. Addition of calcium oxide into copper-based catalyst gave significant effect on the reduction behaviour.

Evaluation of the Biocompatibility of Cuttlebone in Mouse

Bone grafting is widely used to bridge major bone defects or to promote bone union. Natural calcium carbonate (CC) has been used as a bone substitute material and used to scaffold for bone morphogenetic protein (BMP). The aims of this study is to evaluate the biocompatibility of cuttlebone (CB) and hydroxyapatite from CB (CBHA). Each material was shaped into disks (5 mm in diameter and 2 mm in thickness). To test biocompatibility, the disks were implanted into the dorsal subcutaneous tissue in mice. Fibrous capsule thickness around each disk was evaluated histologically at 2 and 4 weeks after implantation. Concerning biocompatibility, fibrous capsule thickness of CBHA was significantly thinner than that of CB and CHA (p < 0.05) at 2 and 4 weeks after implantation. Based on the clinical and histological results, CBHA would be a safe material for use inside the body and has more effective osteoconduction than CB.

Eggshells as natural calcium carbonate source in combination with hyaluronan as beneficial additives for bone graft materials, an in vitro study.

IntroductionIn bone metabolism and the formation especially in bone substitution, calcium as basic module is of high importance. Different studies have shown that the use of eggshells as a bone substitute material is a promising and inexpensive alternative. In this in vitro study, the effects of eggshell granulate and calcium carbonate towards primary bovine osteoblasts were investigated. Hyaluronan (HA) was used as artificial extracellular matrix (ECM) for the used cells to facilitate proliferation and differentiation and to mimic the physiological requirements given by the egg in vivo.MethodsHyaluronan, eggshells, a combination of hyaluronan and eggshells and CaCO3 were applied to the cells as additive to the used standard medium (modified High Growth Enhancement Medium) in a concentration of 0,1 g/l. The effect of the additives in the culture medium was examined by proliferation tests, immunohistochemical staining (anti-collagen type I, anti-osteopontin, anti-osteonectin and anti-osteocalcin) and kinetic oxygen measurements.ResultsOur investigations revealed that all investigated additives show beneficial effect on osteoblast activity. Cell proliferation, differentiation and the metabolic activity of the differentiated cells could be influenced positively. Especially in the case cell cultures treated with eggshells the strongest effects were detected, while for the hyaluronan compared with eggshells, a weaker increase in cell activity was observed.ConclusionIn summary, it can be stated that the investigated components come into consideration as beneficial supplements for bone graft materials especially for maxillo facial surgery application.

Composition, Luminescence, and Color of a Natural Blue Calcium Carbonate from Madagascar

Concerning the transparent blue calcite crystals of blue marble from Madagascar, this work suggests that their cavities, accessorial quartz, and marble stress textures do not provide unambiguous characterization of the blue color compared to other white marbles. It is suggested that the presence of stronium (∼850 ppm), barium (∼18 ppm), vanadium (∼10 ppm), and nickel (∼2 ppm) might be considered influential chromophores for the blue color. Blue marble aliquots were characterized to determine their mineralogical, textural, and chemical composition to elucidate luminescence spectra and the causes of the blue color by use of different techniques.

Porous apatites as novel high temperature sorbents for carbon dioxide

Synthetic hydroxy-apatite was tested as a potential new material for CO2 capture at high temperature, over the operation limit of CaO-based sorbents. Some porous granules of hydroxy-apatite were prepared ad hoc. They were shown to absorb CO2 upon dehydroxylation in the very high temperature range of 900–1200 °C, resulting in A-type carbonated apatite. No appreciable decay of the absorbing capacity was observed with a higher number of absorbing–desorbing cycles, differently from what happens in a conventional chemical sorbent, e.g. calcined natural calcium carbonate. The CO2 carrying capacity was maximum at 1000–1100 °C and very close to the theoretical limit of 2.6% by mass. The macro-granule porosity network appeared to be effective in making the sites available for CO2 capture. At first glance, the process appeared to be chemically controlled. The pre-treatment temperature of the porous granules also had an impact on the sorption capacity. As a first proof of concept, the results obtained by thermogravimetric analysis, and supported by FTIR and XRD analysis, were confirmed by tests carried out in a laboratory-scale reactor, operated as a fixed bed.

Far infrared (THz) absorption spectra for the quantitative differentiation of calcium carbonate crystal structures: Exemplified in mixtures and in paper coatings

In this paper, far-infrared (FIR) spectroscopic techniques have been employed to detect different calcium carbonate crystal concentrations in powder mixtures. We have compared absorption spectral features of both pure and mixtures of natural ground calcium carbonate (GCC) and synthetic precipitated calcium carbonate (PCC). It is evident that the absorbance data differentiate clearly and unequivocally between calcite and aragonite in the spectral range of 2–18 THz. Also, from the absorbance measurement of two sets of mixtures, we have revealed a linear relationship between the ratio of some selected absorbance peaks of the mixtures and concentration of a particular pigment within the mixture. This innovative technique could be a novel, practicable technique for quality control or for analyzing coating and/or filler pigments and extenders in the paper making and printing industries. Finally, we have proven in the case of paper that, surface roughness and print color play no role as far as the locations and magnitudes of the absorbance spectral features are concerned.

Flow Micro‐Calorimetry and FTIR Spectroscopy Study of Interfacial Interactions in Uncoated and Coated Calcium Carbonate Filled Polyurethane Adhesives

SummaryThermoplastic polyurethane (TPU) ‐ calcium carbonate interactions were studied using flow micro‐calorimetry (FMC) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). FMC enabled the determination of adsorption and desorption energies; in this study a model compound approach was used to acquire insight in to the effect of calcium carbonate type and presence of stearate coating on polymer – filler interactions. It was anticipated that this data will assist in the understanding of differing responses obtained from parallel plate rheometry and viscoelastic measurements of the filled polyurethanes. Three calcium carbonates (coated and uncoated precipitated calcium carbonate, and natural ultramicronized uncoated calcium carbonate) were used. A stronger TPU‐filler interaction was shown in the uncoated precipitated calcium carbonate due to the fact that more of the surface was available for interaction.

Effects of biochar on air and water permeability and colloid and phosphorus leaching in soils from a natural calcium carbonate gradient.

Application of biochar to agricultural fields to improve soil quality has increased in popularity in recent years, but limited attention is generally paid to existing field conditions before biochar application. This study examined the short-term physicochemical effects of biochar amendment in an agricultural field in Denmark with a calcium carbonate (CaCO) gradient. The field comprised four reference plots and four plots to which biochar (birch wood pyrolyzed at 500°C) was applied at a rate of 20 t ha. Five undisturbed soil columns (10 cm diam., 8 cm height) were sampled from each plot 7 mo after biochar application, and a series of leaching experiments was conducted. The leachate was analyzed for tritium (used as a tracer), colloids, and phosphorus concentration. The results revealed that the presence of CaCO has resulted in marked changes in soil structure (bulk density) and soil chemical properties (e.g., pH and ionic strength), which significantly affected air and water transport and colloid and phosphorous leaching. In denser soils (bulk density, 1.57-1.69 g cm) preferential flow dominated the transport and caused an enhanced movement of air and water, whereas in less dense soils (bulk density, 1.38-1.52 g cm) matrix flow predominated the transport. Compared with reference soils, biochar-amended soils showed slightly lower air permeability and a shorter travel time for 5% of the applied tracer (tritium) to leach through the soil columns. Colloid and phosphorus leaching was observed to be time dependent in soils with low CaCO. Biochar-amended soils showed higher colloid and P release than reference soils. Field-scale variations in total colloid and P leaching reflected clear effects of changes in pH and ionic strength due to the presence of CaCO. There was a linear relationship between colloid and P concentrations in the leachate, suggesting that colloid-facilitated P leaching was the dominant P transport mechanism.

Evaluation of Mechanical Properties and Morphological Studies of Bagasse Fibre (Chemically Treated/Untreated)-CaCO3 Epoxy Hybrid Composites

In past few years natural fibre composites have become very important part of research as potential structural material. The present study deals with a new class of chemically treated/untreated natural fibre and calcium carbonate reinforced composites. In the present investigation composites of bagasse fibre (10 % w/w) and calcium carbonate powder of size ≤30 μm (2 and 4 % w/w) with epoxy resin have been examined. The lengths of bagasse fibre have been varied from 1 to 5 mm. The fibres were chemically treated with NaOH (5 % w/v). Morphological changes of the fibres were observed under the scanning electron microscope. Addition of calcium carbonate showed increased mechanical properties of the developed composites like, flexural strength, compression strength. The composites reinforced with chemically treated fibres show better mechanical properties as compared to the composites reinforced with untreated fibres.