• Title/Summary/Keyword: Calcium Carbonate

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Preparation of Needle like Aragonite Precipitated Calcium Carbonate (PCC) from Dolomite by Carbonation Method

  • Ramakrishna, Chilakala;Thenepalli, Thriveni;Huh, Jae-Hoon;Ahn, Ji Whan
    • Journal of the Korean Ceramic Society
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    • v.53 no.1
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    • pp.7-12
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    • 2016
  • In this paper, we have developed a simple, new and economical carbonation method to synthesize a pure form of aragonite needles using dolomite raw materials. The obtained aragonite Precipitated Calcium Carbonate (PCC) was characterized by XRD and SEM, for the measurement of morphology, particle size, and aspect ratio (ratio of length to diameter of the particles). The synthesis of aragonite PCC involves two steps. At first, after calcinated dolomite fine powder was dissolved in water for hydration, the hydrated solution was mixed with aqueous solution of magnesium chloride at $80^{\circ}C$, and then $CO_2$ was bubbled into the suspension for 3 h to produce aragonite PCC. Finally, aragonite type precipitated calcium carbonate can be synthesized from natural dolomite via a simple carbonation process, yielding product with average particle size of $30-40{\mu}m$.

Effect of RPM and Temperature on the CSD in the CMSMPR Calcium Carbonate Crystallizer (연속식 탄산칼슘 결정화기에서 교반속도와 온도가 입도분포에 미치는 영향)

  • Han, Hyun Kak;Jeong, Ok Hee;Lim, Mi Hee;Kim, Jin A
    • Korean Chemical Engineering Research
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    • v.44 no.3
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    • pp.289-293
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    • 2006
  • In the CMSMPR (continuous mixed suspension mixed product removal)system, the effect of temperature and RPM on the CSD (crystal size distribution) in the calcium carbonate process was investigated. In the steady state operation, the change of solution pH was small. At the low temperature and below 300 RPM, volume mean size change of calcium carbonate was stable and CSD was narrow. In the SEM view, calcite and aragonite was obtained.

Synthesis of amorphous calcium carbonate by gas-liquid reaction and its crystallization

  • Ahn Ji-Whan;Kim Hyung-Seok;Park Jin-Koo;Kim Ka-Yeon;Yim Going;Joo Sung-Min
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.654-657
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    • 2003
  • We obtained amorphous calcium carbonate through the carbonation reaction of $Ca(OH)_2$, and through this reaction, observed changes in particle shape and phase by electric conductivity, XRD and TEM analysis. According to the result of the analysis, in the first declining stage of electric conductivity, amorphous calcium carbonate that has formed is coated on the surface of $Ca(OH)_2$ and obstructs its dissolution, and in the first recovery stage of electric conductivity, amorphous calcium carbonate is dissolved and re-precipitated and forms chains of fine calcite particles linearly joined. In the second decline of conductivity, viscosity increases due to the growth of chains of calcite particles, and finally the calcite particles are dissolved and separated into colloidal crystalline calcite, thereby increasing electric conductivity again.

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Quality Characteristics and Antioxidant Activities of Green Tea Garlic Paste added Calcium (칼슘첨가 녹차마늘 페이스트의 품질 특성 및 항산화성)

  • Son, Chan-Wok;Jeon, Mi-Ra;Kim, Min-Hee;Kim, Mee-Ree
    • Korean journal of food and cookery science
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    • v.24 no.6
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    • pp.876-881
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    • 2008
  • The aim of this study was to evaluate the quality characteristics and antioxidant activities of green tea garlic paste added calcium. Garlic was heated with green tea and charcoal at high temperature ($120^{\circ}C$) and high pressure ($1.5\;kgf/cm^2$) for 20 min, and then added several calcium sources (calcium carbonate, calcium citrate, calcium lactate, mixed calcium, calcium powder). Calcium carbonate, mixed calcium or calcium powder significantly increased pH of green tea garlic paste (p<0.05). All kinds of calcium sources significantly increased the viscosity of green tea garlic paste (p<0.05). Solid soluble content of green tea garlic paste was increased only in calcium citrate and calcium powder groups. Lightness, redness and yellowness of green tea garlic paste with calcium were increased, compared with control group (green tea garlic paste without calcium). The antioxidant activities by DPPH and hydroxyl radical scavenging activity of green tea garlic paste added calcium citrate, calcium lactate or calcium carbonate group were much higher than those of the other control groups. The garlic odor and garlic taste by sensory test were significantly weaker in calcium carbonate or calcium citrate group (p<0.05). Based on these results, it was suggested that calcium carbonate or calcium citrate is appropriate material for deodorizing and fortifying agent for green tea garlic paste.

Histomorphometric evaluation of bone healing with natural calcium carbonate-derived bone substitutes in rat calvarial defect (백서두개골 결손부에서 천연물유래 탄산칼슘염 골대체의 골치유에 관한 조직계측학적 평가)

  • Lee, Chung-Ho;Jang, Je-Hee;Lee, Jae-Mok;Suh, Jo-Young;Park, Jin-Woo
    • Journal of Periodontal and Implant Science
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    • v.38 no.1
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    • pp.83-90
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    • 2008
  • Purpose: This study investigated the osteoconductivity of natural calcium carbonate-derived bone substitutes, hen eggshell (ES), and compared with those of commercial bone substitutes. Materials and Methods: Osseous defects created in the rat calvaria were filled with particulated ES(ES-1), ES with calcium-deficient hydroxyapatite surface layer (ES-2), Biocoral(Inoteb, France), and Bio-Oss(Geistlich Pharma, Wolhusen, Switzerland). After 4 and 8 weeks of healing, histomorphometic analysis was performed to evaluate the amount of newly formed mineralized bone area (NB%). Results: Histologic and histomorphometric analysis showed new bone formation and direct bony contact with the grafted materials in all groups. At 4 weeks, Biocoral group showed greater NB% compared to Bio-Oss and ES-1 groups (P<0.05). At 8 weeks, Biocoral and ES-2 groups showed significantly greater NB% compared to Bio-Oss group (P<0.05). Conclusion: These results indicate that natural calcium carbonate-derived bone substitutes with microporous calcium-deficient hydroxyapatite surface layer may be an effective materials treating osseous defects.

Calcium Carbonate Precipitation by Bacillus and Sporosarcina Strains Isolated from Concrete and Analysis of the Bacterial Community of Concrete

  • Kim, Hyun Jung;Eom, Hyo Jung;Park, Chulwoo;Jung, Jaejoon;Shin, Bora;Kim, Wook;Chung, Namhyun;Choi, In-Geol;Park, Woojun
    • Journal of Microbiology and Biotechnology
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    • v.26 no.3
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    • pp.540-548
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    • 2016
  • Microbially induced calcium carbonate precipitation (CCP) is a long-standing but re-emerging environmental engineering process for production of self-healing concrete, bioremediation, and long-term storage of CO2. CCP-capable bacteria, two Bacillus strains (JH3 and JH7) and one Sporosarcina strain (HYO08), were isolated from two samples of concrete and characterized phylogenetically. Calcium carbonate crystals precipitated by the three strains were morphologically distinct according to field emission scanning electron microscopy. Energy dispersive X-ray spectrometry mapping confirmed biomineralization via extracellular calcium carbonate production. The three strains differed in their physiological characteristics: growth at alkali pH and high NaCl concentrations, and urease activity. Sporosarcina sp. HYO08 and Bacillus sp. JH7 were more alkali- and halotolerant, respectively. Analysis of the community from the same concrete samples using barcoded pyrosequencing revealed that the relative abundance of Bacillus and Sporosarcina species was low, which indicated low culturability of other dominant bacteria. This study suggests that calcium carbonate crystals with different properties can be produced by various CCP-capable strains, and other novel isolates await discovery.

Effect of Metal Ionic Crosslinking Agents on the Water Resistance and Mechancial Properties of EVA Emulsion (EVA 에멀젼의 내수성 및 기계적 특성에 미치는 금속 이온 가교제의 효과)

  • Lee, Eun-Kyoung;Choi, Sei-Young
    • Journal of Adhesion and Interface
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    • v.9 no.2
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    • pp.24-31
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    • 2008
  • In this work, calcium hydroxide and magnesium carbonate as metal ionic crosslinking agents were used to introduce ionic crosslinking points to the ethylene vinylacetate (EVA) emulsions for the enhancement of water resistance and mechanical properties of emulsion films. The properties of EVA emulsion film were investigated in crosslinking density, thermal features, surface energy, and mechanical properties, such as tensile strength, elongation at break and tear strength. With the increasing content of metal ionic crosslinking agent, the crosslinking density of the EVA emulsion film increases, resulting into the improvement of water resistance. The surface energy and mechanical properties of the EVA emulsion film, however, showed somewhat different behaviors. The highest surface energy, tensile strength, and tear strength were observed when 0.4% for calcium hydroxide and 0.5% for magnesium carbonate was added respectively, because the EVA emulsion containing carboxylic acid forms strong carboxylate-metal bond of ionically-crosslinked system. Therefore, it can be concluded that metal ionic crosslinking agents, such as magnesium carbonate and calcium hydroxide are considered to improve water resistance and mechanical properties of the EVA emulsion.

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The Effects of the Combination of Calcium Carbonate and Fibrin Adhesive on the Periodontal Regeneration of Class II Furcation Defect in Dogs (Calcium carbonate와 fibrin adhesive의 병용이 성견 2급 치근 분지부 치주조직 재생에 미치는 영향)

  • Seo, Eun-Pyo;Chung, Hyun-Ju;Kim, Young-Jun
    • Journal of Periodontal and Implant Science
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    • v.30 no.2
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    • pp.229-242
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    • 2000
  • The purpose of this study was to evaluate the effect of fibrin tissue adhesive and porous resorbable calcium carbonate on the periodontal regeneration of the class II furcation defect in dogs. Class II furcation defect was surgically created on the second, third, and fourth premolars bilaterally in the mandibles of six mongrel dogs. The experimental sites were divided into four groups according to the treatment modalities: Control-surgical debridement only; Group I-calcium carbonate grafting; Group II-application of fibrin adhesive only; Group III-application of fibrin adhesive after calcium carbonate grafting. The animals were sacrificed at the 2, 4, and 12 weeks after periodontal surgery and the decalcified specimens were prepared for histological and histometrical examination. The results are as follows : Clinically, there were no inflammatory response in all groups after 2, 4, 12 weeks. In the Control group, junctional epithelium was grown downward to the reference notch. In Group I, graft materials were exfoliated from the defect throughout the experimenta periods andnew bone was seen in the notch area at 4 and 12 week specimens. In Group II, fibrin adhesive was absorbed at 2 week specimens, and connective tissue attachment increased than that of control group. New cementum and new bone were seen above the notch area. In Group III, the graft material was maintained in the defect throughout the experimental period and inducing the amount of periodontal tissue regeneration was higher than other groups. These results suggest that the use of fibrin tissue adhesive in conjunction with porous resorbable calcium carbonate would improves the stability of graft material and inhibit the epithelial down growth and make it be a feasible method for periodontal regeneration.

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Single Particle Characterization of Aerosol Particles Collected During "Asian Dust" Storm Events in the Spring of 2000 and 2001, Using Low-Z Electron Probe X-ray Microanalysis (단일입자분석 (Low-Z Electron Probe X-ray Microanalysis)을 이용한 2000년, 2001년에 발생한 황사 입자의 특성분석)

  • 황희진;김혜경;노철언
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.4
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    • pp.415-425
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    • 2003
  • A single particle analysis, called low-Z electron probe X-ray microanalysis was applied to characterize the atmospheric aerosols collected during Asian Dust storm events in the year of 2000 and 2001. Most frequently encountered chemical species were the soil-originated species such as aluminosilicates, silicon dioxide, and calcium carbonate. Also various species such as carbon -rich, organics, sea salts, and some reacted calcium carbonate were identified. The observation of internally mixed particles oi calcium carbonate, calcium nitrate and/or calcium sulfate shows the occurrence of the heterogeneous reaction between Asian Dust particles and NO$_{x}$ and/or SO$_{x}$ species in the atmosphere.ere.

Rapid Volumetric Assay of Fluorspar Concentrate (고품위 형석의 신속 용량법)

  • Q. Won Choi;Joon-Suk Oh;Kwang-Woo Lee
    • Journal of the Korean Chemical Society
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    • v.8 no.3
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    • pp.109-112
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    • 1964
  • A volumetric method of the determination of calcium carbonate and calcium fluoride in fluorspar concentrate is described. The carbonate is converted into solution by treatment of the sample in HNO$_3$-acetone (l% by volume) mixture, and the fluoride by treating the residue with H$_3BO_3$-HCl mixture. The calcium in the solution is determined volumetrically using EDTA standard solution. The selective dissolution of calcium carbonate by HNO$_3$-acetone mixture is superior to Bidtel's acetic method and little correction for the dissolution of calcium fluoride is needed. Triethanolamine is found to be superior to KCN in masking heavy metal ions.

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