• Title/Summary/Keyword: $CaSO_4$

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Effect of Limestone Powder on Hydration of C3A-CaSO4·2H2O System (C3A-CaSO4·2H2O 계의 수화반응에 미치는 석회석 미분말의 영향)

  • Lee, Jong-Kyu;Chu, Yong-Sik;Song, Hun
    • Journal of the Korean Ceramic Society
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    • v.48 no.6
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    • pp.584-588
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    • 2011
  • In this work, effects of limestone powder on hydration of $C_3A-CaSO_4{\cdot}2H_2O$ system was discussed based on the XRD Quantitative analysis, and the possibility of Delayed Ettringite Formation was also discussed. The early hydration of $C_3A$ was delayed by addition of $CaCO_3$ powder. The delay effect was enhanced by increasing of $CaCO_3$ content and finer powder of $CaCO_3$ addition. After consumption of $CaSO_4{\cdot}2H_2O$, the reaction of $CaCO_3$ is started. Delayed Ettringite Formation would take place because monosulfoaluminate is not stable in presence of $CaCO_3$. In order to prevent the delayed ettringite formation in $C_3A-CaSO_4{\cdot}2H_2O-CaCO_3$ system, the reduction of monosulfoaluminate formation is important. Therefore, by increasing the amount of $CaCO_3$ addition and finer $CaCO_3$ powder addition, the delayed ettringite formation can be prevented.

Textural Properties of Soygel with Added Alginate and Pectin (Alginate와 pectin 첨가에 의한 콩묵의 텍스쳐 특성)

  • Choi, Hee-Sook;Park, Hye-Jeen;Kim, Woo-Jung
    • Korean Journal of Food Science and Technology
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    • v.27 no.3
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    • pp.336-341
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    • 1995
  • Effect on alginate, pectin and Ca salts on textural properties of whole soybean gel(soygel) was investigated. The soygel was prepared by addition of sodium alginate, pectin and Ca salts into whole soy flour(300 mesh, WSF) suspension followed by through mixing. Addition of sodium alginate or pectin into WSF suspension significantly increased the hardness, adhesiveness and cohesiveness of the gel. The most uniform gel was obtained by $12{\sim}15%$ addition of sodium alginate or pectin, while their mixture rather decreased the textural properties. Sensory evaluation by ranking test for the gels showed that 12% sodium alginate and 0.125g $CaSO_4/g$ WSF produced the most desirable gel in terms of elasticity, uniformity, smoothness and total acceptability, followed by 12% sodium alginate and 0.12g Ca $gluconate-CaSO_4$(50 : 50). From the results, the optimal preparative conditions for soygel were suspension of WSF in 10 times of water(v/w), addition of 12% sodium alginate(w/w of WSF) and 12.5% $CaSO_4$ or Ca $gluconate-CaSO_4$(50 : 50) into WSF suspension followed by gel formation at $4^{\circ}C$.

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Effect of $SO_3$ on Calciumsilicate Formation(III) (Calciumsilicate의 생성반응에 미치는 $SO_3$ 영향(III))

  • 임은극;박병철
    • Journal of the Korean Ceramic Society
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    • v.21 no.3
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    • pp.221-230
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    • 1984
  • In this study an investigation was made to determine optimum ratio between $SO_3$, MgO and $K_2O$ that maximizes $C_2S$ formation in Clinkering reaction Using response surface analysis method. It was proved that 1) Residual $K_2O$ int he clinker should be converted to $K_2SO_4$ because $K_2SO_4$ has less effect on the burnability than $K_2O$, 2) Optimum ratio if $SO_3$/K2O is 1.5, 3) Optimun balance between $CaSO_4$ and MgO is to be adjusted to such a level that w/o SO3=0.7(w/o MgO-2).4) In case of lack of $K_2O$ free CaO was minimized when $K_2SO_4$=2.3w/o and MgO=1.5w/o but if remaining $K_2O$ was 2w/o free CaI was minimized in the level that $K_2SO_4$=2.3w/o and MgO =1.5 w/o but if remaining $K_2O$ was 2 w/o free CaO was minimized in the level that $K_2SO_4$=4.5w/o and MgO =3.0 w/o.

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Development of Technology for Recovering Valuable Metals in Detoxified Waste Asbestos-Containing Waste (무해화된 폐석면에 함유된 유가금속 회수 기술 개발)

  • Kim, Dong Nyeon;Yang, Dong Hyeon;Kim, Seok Chan
    • Applied Chemistry for Engineering
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    • v.31 no.4
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    • pp.438-442
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    • 2020
  • Studies on the recovery conditions and optimization process for valuable metal recovery through chemical treatment from detoxified asbestos-containing waste composed of calcium silicate, larnite, merwinite, and akermanite were conducted. The main components, Si, Ca, and Mg, of detoxified asbestos-containing waste (DACW) were separated and recovered in the form of SiO2, CaSO4, and Mg(OH)2 compounds, respectively. Each separated component was confirmed through X-ray diffraction (XRD) and inductively coupled plasma spectrometer (ICP) analysis. The recovery conditions for each component were first treating them with an acid to separate SiO2 and subsequently with H2SO4 to recover Ca in the form of sulfate, CaSO4. The remaining Mg was recovered by precipitation with Mg(OH)2 under strong basic conditions. This study suggested that it is possible to convert existing treatment process of asbestos waste by landfill through recovering the components into a resource-recycling green technology.

Fabrication of $CaSO_4:Eu$ TLD and Its Physical Characteristics ($CaSO_4:Eu$ TLD의 제작과 물리적 특성)

  • Kim, Do-Sung;Park, Myeong-Hwan
    • Journal of Sensor Science and Technology
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    • v.8 no.5
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    • pp.388-393
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    • 1999
  • In this study, the $CaSO_4:Eu$ TLDs are fabricated and their trap parameters are determined. The optimum concentration of Eu for fabrication of the $CaSO_4:Eu$ TLD is 0.5 mol% and optimum temperature is $600^{\circ}C$ for 2 hours sintering in air. The glow curve of $CaSO_4:Eu$ consists of two glow peaks and these peaks are isolated by thermal bleaching method. Trap parameters of two glow peaks are measured using the initial rise, the peak shape, the heating rate and the least square curve fitting methods. The activation energies of the glow peak I and II are 1.00 eV and 1.09 eV, and the frequency factors are $7.04{\times}10^{11}\;s^{-1}$ and $5.12{\times}10^{11}\;s^{-1}$ and the kinetic orders are 1.11 and 1.33, respectively.

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Effect of Mixed Coagulant on the Rheological Properties of Soybean Curd (이성분 혼합응고제에 의한 두부의 물성 변화)

  • 홍정화;김진우;이재권
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.6
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    • pp.1096-1101
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    • 1997
  • Soy curd was prepared using imported soybean(U.S.grade A) and changes in quality were evaluated using different types and mixtures of coagulants(CaCl$_2$, CaSO$_4$, MgCl$_2$, MgSO$_4$, and glucono-$\delta$-lactone). Quality of soy curd was determined by rheological properties, yield, and color. Based upon the characteristics of each coagulant, mixtures of two coagulants were prepared in various ratios. The mixture of CaSO$_4$or MgCl$_2$with glucono-$\delta$-lactone(GDL), and that of CaSO$_4$or MgCl$_2$with MgSO$_4$resulted in soy curd of good quality in terms of rheological properties and yield.

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Studies on the Chemical Compositions and Distributions of Ambient Sumicron Aerosols (Submicron 부유분진의 화학적 조성 및 분포에 관한 연구)

  • 황인조;김동술
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.1
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    • pp.11-23
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    • 1998
  • The purpose of this study was to survey chemical distribution of inorganic elements and ions in the submicron particles, to characterize qualitatively emitting sources by factor analysis, and finally to reveal existing patterns in terms of chemical compounds by a stepwise multiple regression analysis. Total of 141 samples were collected by a cascade impactor from 1989 to1996. Fifteen chemical species (Al, Ba, Cd, K, Pb, Cu, Fe, Ni, $Cl^-, NO_3^-, SO_4^{2-}, K^+, Mg^{2+}, Ca^{2+}, and Na^+$) were characterized by AAS and IC. The study showed that average seasonal levels of submicron particulate matters $(d_p<0.43 \mum)$ were 18.7 $\mug/m^3$ in spring, 15.5 $\mug/m^3$ in summer, 15.7 $\mug/m^3$ in fall, and 24.5 $\mug/m^3$ in winter, respectively. All of the anion concentrations in the particle were highest in the winter season. By applying a factor analysis, 5 source patterns were qualitatively obtained, such as sulfate related source, nitrate related source, oil burning source, calcium related source, and coal combustion source. Finally, when applying a stepwise multiple regression analysis, the results clearly showed that $Na^+ and Ca^{2+}, K^+ and Ca^{2+}, NO_3^-$ and relative humidity, $Cl^-$ and ambient temperature, $Ca^{2+} and Cl^-, Mg^{2+} and SO_4^{2-}, Na^+ and NO_3^-, and Ca^{2+} and NO_3^-$, respectively, are negatively contributed to each other. As a result of those statistical analysis, we could suggest that some chemical compounds in the submicron particles such as$NaNO_3, MgSO_4, Ca(NO_3)_2, and CaCl_2$ may not exist on the filter as final composing products; however, other compounds may possibly exist in the form of $Mg(NO_3)_2, CaSO_4, Na_2SO_4, K_2SO_4, MgCl_2, NaCl, and KCl$. Thus, it must be necessary to identify differences between the results of above statistical analysis and of the real world by laboratory experiments.

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Effect if $SO_3$ on Clciumsilicate Formation (I) (Calciumsilicate의 생성반응에 미치는 $SO_3$ 의 영향(I))

  • 임응극;박병철
    • Journal of the Korean Ceramic Society
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    • v.20 no.4
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    • pp.297-304
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    • 1983
  • In this study a Comparative investigation of the effect of $K_2SO_4$ and $CaSO_4$ on the formation of calcium silicate was made. $K_2SO_4$ had little effect on C3S formation. More than 4.0wt% of CaSO4 hindered the reaction of $C_2S$ and CaO so $C_3S$ formation was restrained by forming the reaction rim around $C_2S$ Particles. And activation energy for $C_3S$ formation was calculated around to be 40kcal/mol irespective of the amount of $K_2SO_4$.

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Manufacture of 11CaOㆍ$7Al_2O_3$$CaCl_2$Clinker Using the Bottom Ash of Municipal Solid Waste Incinerator Ash (생활폐기물 소각재중 바닥재를 이용한 11CaOㆍ$7Al_2O_3$$CaCl_2$클링커의 제조)

  • Ahn Ji-Whan;Kim Hyung-Seok;Han Gi-Ckun;Cho Jin-Sang;Han Ki-Suk
    • Resources Recycling
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    • v.11 no.4
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    • pp.27-36
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    • 2002
  • The clinker of which main component was calcium-chloroaluminate ($l1CaOㆍ7Al_2$$O_3$$CaCl_2$), was synthesized with the bottom ash of municipal solid waste incinerator ash. The hydration mechanism and synthesis temperature of calcium-chloro-aluminate were investigated. The synthesized clinker was blended with a cement. It was substituted with 3~13 wt.% for clinker and $CaSO_4$ of ordinary portland cement. The compressive strength and the content of leached heavy metals of its mortar were measured. Calcium-chloroaluminate was synthesized above $800^{\circ}C$ and its main hydrate was ettringite ($3CaOㆍAl_2$$O_3$$3CaSO_4$$32H_2$O). The calcium-chloroaluminate was also synthesized above $800^{\circ}C$ with the bottom ash of which size fraction was below 30 mesh mainly. The compressive strength of the blended cement mortar was increased as the additive content of the clinker synthesized from the bottom ash was increased by 11 wt.%. The concentration of heavy metals leached from each mortar was satisfied with the value of the environmental standards and regulations.