• Title, Summary, Keyword: $CaCO_3$ 제조

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Study on the Dispersion Stability of Precipitated Calcium Carbonate Suspensions (침강성 탄산칼슘 현탁액의 분산 안정성에 관한 연구)

  • Park, Myung-Jae;Ahn, Ji-Whan;Kim, Hwan
    • Journal of the Korean Ceramic Society
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    • v.38 no.4
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    • pp.343-350
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    • 2001
  • 본 연구에서는 탄산화법으로 침강성 CaCO$_3$분말을 제조하고 제조된 CaCO$_3$현탁액의 분산안정성을 연구하였다. CaCO$_3$현탁액의 pH 변화와 고분자전해질 PMAA와 PAA의 첨가에 따른 입자크기, 유동학적 특성(점도), zeta potential 및 현탁액의 침강속도 등을 측정하였다. 탄산화법에 의해 약 0.1$\mu\textrm{m}$ 크기와 비표면적이 23.57$m^2$/g인 단분단 calcite형 CaCO$_3$분말을 제조하였다. pH가 11인 CaCO$_3$현탁액에 0.01 wt% PMAA가 첨가된 경우에 우수한 분산안정성을 나타내었는데 이는 CaCO$_3$입자표면에 PMAA의 흡착에 의한 electrosteric 안정화기구와 CaCO$_3$입자들 사이의 정전기적 반발력에 의한 것으로 판단된다. PMAA와 PAA 첨가량 변화에 따른 pH 6, 9, 11의 CaCO$_3$현탁액의 침전높이를 측정한 결과 PMAA와 PAA의 농도가 0.15 wt% 부근에서 분산안정성을 보였는데 이는 CaCO$_3$입자들 사이간의 분산제에 의한 뚜렷한 경계를 갖는 흡착층이 형성되었기 때문으로 생각되며 따라서 CaCO$_3$현탁액의 최적 분산안정성을 위해서는 적절한 pH 조절과 PMAA 및 PAA의 첨가가 필요함을 알 수 있다.

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Study on $CaCO_3$ Preparation from MSWI Fly Ash (생활쓰레기 소각(燒却)비산재로부터 $CaCO_3$ 제조(製造)에 관한 연구(硏究))

  • Choi, Woo-Zin;Park, Eun-Kyu
    • Resources Recycling
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    • v.15 no.5
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    • pp.47-51
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    • 2006
  • The total amount of ash generated from the municipal solid waste incineration(MSWI) in Korea was approximately 420,000 tons in 2005 including 68,000 tons of fly ash. Fly ash from MSWI generally contains high amount of CaO (upto ${\sim}50%$) due to the treatment of flue gas by spraying CaO-base materials. Currently, most of fly ash generated is finally ended up with specially designed landfill sites and only less then 20% of fly ash is recycled. In the present work, preparation of $CaCO_3$ from the MSWI ny ash was studied to promote the fly ash recycling. Fly ash obtained from the dust collector in stoker-type MSWI is used to selectively dissolve CaO by using the sugar solution. Then, $CO_2$ gas was passed through the dissolved solution to pro- duce $CaCO_3$ powder. The optimum conditions for CaO dissolution were solid content 10%, reaction time 15 minutes, sugar concentration $10{\sim}15%\;and\;pH\;10.5{\sim}11.0$. The high grade $CaCO_3$ powder was obtained and the experimental conditions are also discussed.

Processing and Properties of Calcium Cobaltite Layer Structure Oxide Thermoelectrics (칼슘 코발트 층상 산화물계 열전반도체의 제조와 물성)

  • Kwak, Dong-Ha;Park, Jong-Won;Yoon, Sun-Ho;Choi, Jung-Chul;Choi, Seung-Chul
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.1
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    • pp.1-6
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    • 2008
  • Thermoelectric properties of calcium cobalt layer structure oxide system, $Ca_3Co_2O_6$ and $Ca_3Co_4O_9$ were investigated at the temperature range of 300 to 1000K for the application of thermoelectric generation. In the composition, the Ca site was partially substituted with Bi, Sr, La, K and the Co site was partially substituted with Mn, Fe, Ni, Cu, Zn. The thermoelectric properties of Bi substituted $Ca_3Co_4O_9$. $Ca_{2.7}Bi_{0.3}Co_4O_9$ for electrical conductivity, Seebeck coefficient and power factor were $85.4({\Omega}$cm)^{-l}, $176.2{\mu}V/K$ and $265.2{\mu}W/K^m$, respectively. The unit thermoelectric couple was fabricated with the p-type of $Ca_{2.7}Bi_{0.3}Co_4O_9$ and n-type ($Zn_{0.98}Al_{0.02}$)O thermoelectrics whose figure-of-merit(Z) were $0.87{\times}10^{-4}/K$ and $0.41{\times}10^4/K$, respectively. The generated thermoelectric power was about 30mV at the temperature difference of 120K in the unit thermoelectric couple.

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New approach on thin film synthesis with shape-controlled structure and application (미세 구조 패턴이 형상 제어 된 박막의 합성 및 응용기술)

  • Lee, Seungwoo;Jeon, Chiwan;Chae, Soochun;Jang, Youngnam
    • 한국신재생에너지학회:학술대회논문집
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    • pp.60.2-60.2
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    • 2010
  • 본 연구는 상온 상압하에서 미세구조 패턴을 갖는 대용량의 CaCO3 박막을 제조하고 여러 가지 첨가제를 이용하여 박막 표면의 형상제어를 수행하였다. 또한 형상 제어된 CaCO3 박막을 템플릿으로 이용하여 고분자 및 금속 박막 형상 제어 연구를 수행하였다. 본 연구를 통해 개발된 LACS(Large Area CaCO3 Stamping)법을 통해 흡착능과 소수성의 특성과 같은 다양한 기능성을 갖는 박막의 제조가 가능하였다. 기존의 박막제조 기술은 주로 저압조건에서 이루어지기 때문에 대면적화가 어렵고 형상을 제어 하는데 여러 가지 단점이 있었던 반면 LACS는 에너지의 소모가 적고 다양한 형상제어를 통해 기존의 박막제조 기술의 단점을 보완할 수 있을 것으로 판단된다.

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Preparation and Characterization of $CaCO_3$ Encapsulation by PMMA Core-Shell latex (PMMA와 캡슐화된 $CaCO_3$ Core-Shell 라텍스 제조와 물성연구)

  • Lim, Jong-Min;Seul, Soo-Duk
    • Elastomers and Composites
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    • v.38 no.4
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    • pp.303-315
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    • 2003
  • Inorganic/organic composite particles were also synthesized by changing an initiator an it's concentration, concentration of an adsorbed surfactant, reaction temperature, and agitation speed in the presence of $CaCO_3$ adsorbed SDBS. The polymerization conditions were optimized according to the conversion of the core-shell composite particles. In the inorganic/organic core-shell composite particle polymerization, $CaCO_3$ absorbed surfactant SDBS of 0.5 wt % was prepared first and then core $CaCO_3$ was encapsulated by sequential emulsion polymerization using MMA, concentration of APS $3.16{\times}10^{-3}mol/L$ to minimize the formation of new PMMA particle during MMA shell polymerization. The structure characterization of the inorganic/organic core-shell particles was verified by measuring the decomposition degree of $CaCO_3$ using HCl solution. It was found that $CaCO_3$ was encapsulated by shell PMMA due to having excellent dispersion in the epoxy resin, smooth surface distinctly from spindle shape, and broad particle distribution after the capsulation.

Fabrication of Mg Alloy Foam via Melting Foaming Method Using $CaCO_3$ as Blowing Agent ($CaCO_3$를 이용한 발포 마그네슘 합금의 제조)

  • Yang, Dong-Hui;Seo, Chang-Hwan;Wang, Xiao-Song;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.26 no.6
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    • pp.272-276
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    • 2006
  • For the first time AZ91 (MgAl9Zn1) and AM60 (MgAl6) Mg alloy foams with homogeneous pore structures were prepared successfully via melting foaming method by using $CaCO_3$ powder as blowing agent. The possible foaming mechanisms and pore structures of these Mg alloy foams were discussed and investigated. The results show that Mg alloy melt can affect $CaCO_3$ decomposition behavior and AZ91 Mg alloy is relative easy to be foamed into metal foam with high porosity and big pore size.

Assessment of Applicability of a Calcium Carbonate-Alginate Beads as Neutralizer for the High Cell Density Cultivation of Isolated Sourdough Lactic Acid Bacteria (Sourdough에서 분리된 유산균의 고농도 배양을 위한 중화제로서 Calcium Carbonate-Alginate Bead의 이용가능성 평가)

  • Jung, Seung-Won;Lee, Kwang-Geun;Kim, Cheol Woo;Lee, Su Han
    • Food Engineering Progress
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    • v.14 no.3
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    • pp.208-216
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    • 2010
  • Lab scale experiments were conducted in order to assess the applicability of $CaCO_{3}$-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of $CaCO_{3}$-alginate bead became higher. In batch process with $CaCO_{3}$-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, $CaCO_{3}$-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

CaO Manufacture for $CO_2$ Adsorption at a High Temperature (고온에서의 이산화탄소 흡착을 위한 흡착제 CaO 제조)

  • Lee Tae-Jong;Kim Gil-Soo;Baek Il-Hyun;Kim Bu-Ung
    • Journal of the Korean Institute of Gas
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    • v.5 no.4
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    • pp.27-32
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    • 2001
  • It is desired that carbon dioxide causing a greenhouse effect be removed at a high temperature and high pressure in a steam reforming reaction. In this research, a pellet form of adsorbent CaO is employed to capture $CO_2$. The adsorbent was manufactured using a high pressure molding on powdered $CaCO_3$ followed by calcination. Then its properties were analyzed and the adsorption experiments were carried out in a batch adsorption chamber. The pore area was found to be dependent on a molding pressure and the pore distribution showed two peaks. It is examined that $CO_2$ binds to CaO by means of chemisorption and its maximum conversion is nearly $80\%$ at $700^{\circ}C$.

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Oxygen Reduction Reaction of La1-xCaxCoO3 of Gas Diffusion Electrode in Alkaline Fuel Cell (알칼리형 연료전지용 La1-xCaxCoO3 기체확산전극의 산소환원반응)

  • Shim, Joong-Pyo;Park, Yong-Suk;Lee, Hong-Ki;Park, Soo-Gil;Lee, Ju-Seong
    • Applied Chemistry for Engineering
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    • v.7 no.5
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    • pp.992-998
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    • 1996
  • The $La_{0.8}Ca_{0.2}CoO_3$ prepared by a citrate process was shown to have higher oxygen reduction current density and specific activity than $LaCoO_3$, $La_{0.6}Ca_{0.4}CoO_3$. In the cyclic voltammogram, an oxygen desorption peak of a $La_{0.8}Ca_{0.2}CoO_3$+carbon electrode was larger than that of a only carbon electrode. $La_{0.8}Ca_{0.2}CoO_3$ sintered at $900^{\circ}C$ for 5 hours was shown high oxygen reduction current density because of the particle size distribution and sintering effect.

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Ca-Alginate에 고정화된 Calcium Carbonate를 완충제로 사용한 Bifidobacterium longum의 배양 증대와 저장 안정성

  • Lee, Gi-Yong;Yu, Won-Gyu;Kim, Ji-Yeon;Heo, Tae-Ryeon
    • 한국생물공학회:학술대회논문집
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    • pp.203-206
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    • 2000
  • Calcium carbonate $(CaCO_3)$ bead immobilized with alginate were developed as buffer system to enhance the cultivation efficiency of bifidobacteria. When Bifidobacteriuim longum KCTC 3128 and HLC 3742 were independently cultivated in 2.5-liter fermenter buffered the $CaCO_3$ bead, NaOH, $Na_2CO_3$, and $NH_4OH$. The proliferation of bifidobacteria and their storage stability were higher in culture broth buffered $CaCO_3$ beads than in culture broth buffered with NaOH, $Na_2CO_3$, and $NH_4OH$. Therefore, $CaCO_3$ bead may be useful as a buffer to enhance of the cultivation efficiency and viability of bifidobacteria.

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