• Title/Summary/Keyword: $Na_2SiO_3$

Search Result 797, Processing Time 0.03 seconds

Preparation of Mesoporous Molecular Sieve by the Reaction of Na2SiO3 and H2SiF6 in the Presence of an Aqueous Nonionic Surfactant Solution (비이온성 계면활성제 수용액에서 Na2SiO3와 H2SiF6의 반응을 통한 메조포러스 실리카의 제조)

  • Kim, Jin-Yeong;Kwon, Oh-Yun
    • Applied Chemistry for Engineering
    • /
    • v.29 no.1
    • /
    • pp.122-126
    • /
    • 2018
  • Mesoporous molecular sieves were prepared by the reaction of $Na_2SiO_3$ and $H_2SiF_6$ using nonionic micelle templates in an aqueous solution. Well-crystalline mesoporous molecular sieves were obtained after several seconds at atmospheric conditions. Powder samples exhibited d-spacing of 3.8-5.1 nm with the sharpness of the d00l peak, showing well-crystalline mesoporous molecular sieves, pore size distributions of 2.5-3.1 nm and large specific surface areas of $290-1,018m^2/g$, depending on types of surfactants. SEM images of samples showed well-divided spherical particles with an uniform size of ${\sim}0.5{\mu}m$ and TEM images demonstrated uniform pores with a worm hole shape.

Phase Transformation of Coal Tailing of Beneficiation with the Addition of Na2CO3 at High Temperature (Na2CO3의 첨가에 따른 석탄 선탄 폐석의 소결 상변화 연구)

  • YOU, Kwangsuk
    • Resources Recycling
    • /
    • v.29 no.6
    • /
    • pp.73-78
    • /
    • 2020
  • To use a tailing obtained from coal beneficiation as a raw material for glass material, the behaviors of phase transformation of the tailing was investigated according to sintered temperature with the addition of Na2CO3. As a result of the experiment, mullite was formed at 700~1,100 ℃, and the mullite and the cristobalite just only existed at 1,450 ℃. The glassification ratio of the coal tailing was to be 97.9 wt.% at 1,450 ℃ with the addition of Na2CO3 to tailing weight ratios of 10 wt.%. However, in the case of sample of coal tailing with 20 wt.% Na2CO3 added, nepheline(Na2O·Al2O3·2SiO2) was produced during the re-sintering(2nd sintering) at 1,100 ℃. From the results, the suitable addition amount of Na2CO3 for glassification of coal tailing was found around 10 wt.%.

Synthesis of Gallosilicate(Ga-MFI} and Its Comparison with ZSM-5 (갈리실리케이트(Ga-MFI)의 합성 및 ZSM-5와의 비교)

  • Kim, Young-Kook;Hwang, Jae-Young;Kim, Myung-Soo;Park, Hong-Soo;Hahm, Hyun-Sik
    • Journal of the Korean Applied Science and Technology
    • /
    • v.21 no.3
    • /
    • pp.231-237
    • /
    • 2004
  • Ga-MFI was synthesized by a hydrothermal process at atmospheric pressure. The effect of mole ratios of reactants on crystallization was also investigated thoroughly. The characteristics of synthesized Ga-MFI was compared with ZSM-5. The synthesis of Ga-MFI was carried out with five different mole-compositions of $\underline{a}SiO_2-\underline{b}Ga_2O_3-\underline{c}Na_2O-\underline{d}TPA_2o-\underline{e}H_2O$. The synthesized Ga-MFI and ZSM-5 were characterized by XRD and FT-IR. The inorganic cation ($Na^+$) and water played an important role in crystallinity and the organic cation ($TPA^+$) as a template played a great influence on yields. With the increase in the amount of $Ga^{3+}$, crystallization time was increased. With a fixed $SiO_2/Ga_2O_3$ ratio of 400, the optimum reaction condition was obtained at $H_2O/SiO_2$=30${\sim}$35, $Na_2O/SiO_2$=0.5${\sim}$0.6, and $TPA_2O/Na_2O$=1${\sim}$1.25. In these cases, the crystallinity and yield were more than 95% and 90%, respectively. By comparing IR spectrum of Ga-MFI with those of ZSM-5 and silicalite, it was found that Ga-MFI showed a unique peak at 970 $cm^{-1}$, which may be used to identify Ga-MFI from ZSM-5 and silicalite.

Scientific analysis of the glass from Hwangnam-daech'ong Tomb No. 98 (황남대총(皇南大塚) 98호분 출토 유리(琉璃)의 과학적(科學的) 분석(分析))

  • Jo, Kyung-mi;Yu, Hei-sun;Kang, Hyung-tae
    • Conservation Science in Museum
    • /
    • v.1
    • /
    • pp.61-74
    • /
    • 1999
  • Elemental analysis of 40 glass samples from the Northern Tomb and the Southern Tomb of Hwangnam-daech'ong No. 98 was performed. Fourteen compositions of each sample were analyzed quantitatively by SEM-EDS and glass samples were classified by multivariate analysis such as PCA. All of 40 samples were confirmed to be Na2O-CaO-SiO2 system with about 20% of Na2O. Samples were classified into two groups by doing PCA on concentrations of 5 major elements(SiO2, Al2O3, Na2O, CaO and K2O). Samples included in group I showed the concentration of Al2O3 is about 9.7% and that of CaO, about 2.2%. In group II, concentration of Al2O3 is about 3.2% and that of CaO, about 4.9%. Especially yellow grains embedded in sample No. 12 were shown to be PbSnO3 by micro XRD, which was the first coloring material ever found in Korea. Lead isotope ratios of samples No. 12 and No. 17 which contained lead were measured by TIMS. The origin of lead was traced by means of multivariate analysis such as SLDA. The result showed that lead from southern China and southern Korea had been used for making glass.

Single-crystal Structure of Fully Dehydrated and Largely NH4+-exchanged Zeolite Y (FAU, Si/Al = 1.70), │(NH4)60Na11│[Si121Al71O384]-FAU

  • Seo, Sung-Man;Kim, Ghyung-Hwa;Kim, Young-Hun;Wang, Lian-Zhou;Lu, Gao-Qing;Lim, Woo-Taik
    • Bulletin of the Korean Chemical Society
    • /
    • v.30 no.3
    • /
    • pp.543-550
    • /
    • 2009
  • The single-crystal structure of largely ammonium-exchanged zeolite Y dehydrated at room temperature (293 K) and 1 ${\times}\;10^{-6}$ Torr. has been determined using synchrotron X-radiation in the cubic space group $Fd\overline{3}m\;(a=24.9639(2)\AA)$ at 294 K. The structure was refined to the final error index $R_1$ = 0.0429 with 926 reflections where $F_o>4\sigma(F_o)$; the composition (best integers) was identified as |$(NH_4)_{60}Na_{11}$|[$Si_{121}Al_{71}O_{384}$]-FAU. The 11 $Na^{+}$ ions per unit cell were found at three different crystallographic sites and 60 ${NH_4}^{+}$ ions were distributed over three sites. The 3 $Na^{+}$ ions were located at site I, the center of the hexagonal prism ($Na-O\;=\;2.842(5)\;\AA\;and\;O-Na-O\;=\;85.98(12)^{\circ}$). The 4 $Na^{+}$ and 22 ${NH_4}^{+}$ ions were found at site I' in the sodalite cavity opposite the double 6-rings, respectively ($Na-O\;=\;2.53(13)\;\AA,\;O-Na-O\;=\;99.9(7)^{\circ},\;N-O\;=\;2.762(11)\;\AA,\;and\;O-N-O =\;89.1(5)^{\circ}$). About 4 $Na^{+}$ ions occupied site II ($(Na-O\;=\;2.40(4)\;\AA\;and\;O-Na-O\;=\;108.9(3)^{\circ}$) and 29 ${NH_4}^{+}$ ions occupy site II ($N-O\;=\;2.824(9)\;\AA\;and\;O-N-O\;=\;87.3(3)^{\circ}$) opposite to the single 6-rings in the supercage. The remaining 9 ${NH_4}^{+}$ ions were distributed over site III' ($N-O\;=\;2.55(3),\;2.725(13)\;\AA\;and\;O-N-O\;=\;94.1(13),\;62.16(15),\;155.7(14)^{\circ}$).

Dry Media Reaction Procedure for Synthesis of α,β-Unsaturated Acids, α-Cyanoacrylonitriles and α-Cyanoacrylates via Knoevenagel Condensation Using NaHSO4·SiO2 Catalyst (NaHSO4·SiO2 촉매를 이용한 Knoevenagel 축합을 거친α,β의 불포화산, α-Cyanoacrylonitriles와 α-Cyanoacrylates의 합성을 위한 무수조건하의 반응 절차)

  • Gopalakrishnan, M.;Sureshkumar, P.;Kanagarajan, V.;Thanusu, J.;Thirunavukkarasu, S.
    • Journal of the Korean Chemical Society
    • /
    • v.51 no.4
    • /
    • pp.346-351
    • /
    • 2007
  • Efficient stereoselective synthesis of α,β-Unsaturated acids, α-Cyanoacrylonitriles and α-Cyanoacrylates has been carried out in the presence of NaHSO4·SiO2 under solvent?free conditions with an E-geometry.

Hydration of Granulated Blast Furnace Slag in the Presence of NaOH (NaOH 자극에 의한 고노수쇄 슬래그의 수화반응)

  • 송종택;대문정기(大門正機);근등련일(近藤連一)
    • Journal of the Korean Ceramic Society
    • /
    • v.17 no.3
    • /
    • pp.158-162
    • /
    • 1980
  • The experiments of suspension hydration were performed in the mixtures of slag and water or NaOH solutions which were made up with a liquid/solid ratio of 10. The liquid phase of the suspension was chemically analysed and discussed. When slag was in contact with water, CaO component was released from slag grains into the solution. The amounts of $SiO_2$ and $Al_2O_3$ liberated in the solution were very low as compared with CaO, for the impermeable coating of $SiO_2$, $Al_2O_3$-rich gel was formed on the surface of slag grains. The hydration was considered to be inhibited by this impermeable coating. The weak hydraulic property of slag was based on slowly released CaO and dissolved Na, K components which increased pH in the solution.

  • PDF

The Effect of Co2+-Ion Exchange Time into Zeolite Y (FAU, Si/Al = 1.56): Their Single-Crystal Structures

  • Seo, Sung Man;Kim, Hu Sik;Chung, Dong Yong;Suh, Jeong Min;Lim, Woo Taik
    • Bulletin of the Korean Chemical Society
    • /
    • v.35 no.1
    • /
    • pp.243-249
    • /
    • 2014
  • Three single crystals of fully dehydrated $Co^{2+}$-exchanged zeolite Y (Si/Al = 1.56) were prepared by the exchange of $Na_{75}$-Y ($|Na_{75}|[Si_{117}Al_{75}O_{384}]$-FAU) with aqueous streams 0.05 M in $Co(NO_3)_2$, pH = 5.1, at 294 K for 6 h, 12 h, and 18 h, respectively, followed by vacuum dehydration at 673 K. Their single-crystal structures were determined by synchrotron X-ray diffraction techniques in the cubic space group Fd3m at 100(1) K. They were refined to the final error indices $R_1/wR_2$ = 0.0437/0.1165, 0.0450/0.1228, and 0.0469/0.1278, respectively. Their unit-cell formulas are $|Co_{29.1}Na_{11.8}H_{5.0}|[Si_{117}Al_{75}O_{384}]$-FAU, $|Co_{29.8}Na_{11.0}H_{4.4}|[Si_{117}Al_{75}O_{384}]$-FAU, and $|Co_{30.3}Na_{9.5}H_{4.9}|[Si_{117}Al_{75}O_{384}]$-FAU, respectively. In all three crystals, $Co^{2+}$ ions occupy sites I, I' and II; $Na^+$ ions are also at site II. The tendency of $Co^{2+}$ exchange slightly increases with increasing contact time as $Na^+$ content and the unit cell constant of the zeolite framework decrease.

The Study on the CEC Increase and Granulation of Natural Zeolite -The Effect of NaOH Concentration and Na2O/Al2O3 Ratio (천연(天然) Zeolite의 CEC 증가(增加)와 입단화(粒團化)에 관(關)한 연구(硏究) -1. NaOH농도(濃度)와 조반비(曺礬比)(Na2O/Al2O3)의 영향(影響))

  • Choi, Jyung;Hur, Nam-Ho
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.26 no.2
    • /
    • pp.67-71
    • /
    • 1993
  • This study was carried out to develop the soil conditioner and/or the absorbent of high CEC with the natural zeolite poeder whose price was very low. The $SiO_2/Al_2O_3$ ratio & CEC of the natural zeolite were 6.78 and 67.5me/100g respectively. The CEC of the post-reaction product which was treated with 3N-NaOH and $Na_2O/Al_2O_3$ ratio. 9.5 for 8hours was about 200me/100g, which was the highest value than any other treatments. The dominant clay minerals were clinoptilolite, mordenite and smectite in natural zeolite, while phillipsite in the post-reaction product.

  • PDF

Effect of Additives on the Refractive Index of B2O3-SiO2-Al2O3 Glasses for Photolithographic Process in Electronic Micro Devices

  • Won, Ju-Yeon;Hwang, Seong-Jin;Lee, Jung-Ki;Kim, Hyung-Sun
    • Korean Journal of Materials Research
    • /
    • v.20 no.7
    • /
    • pp.370-373
    • /
    • 2010
  • In fabricating plasma display panels, the photolithographic process is used to form patterns of barrier ribs with high accuracy and high aspect ratio. It is important in the photolithographic process to control the refractive index of the photosensitive paste. The composition of this paste for photolithography is based on the $B_2O_3-SiO_2-Al_2O_3$ glass system, including additives of alkali oxides and rare earth oxides. In this work, we investigated the density, structure and refractive index of glasses based on the $B_2O_3-SiO_2-Al_2O_3$ system with the addition of $Li_2O$, $K_2O$, $Na_2O$, CaO, SrO, and MgO. The refractive index of the glasses containing K2O, Na2O and CaO was similar to that of the [BO3] fraction while that of the SrO, MgO and Li2O containing glasses were not correlated with the coordination fraction. The coordination number of the boron atoms was measured by MAS NMR. The refractive index increased with a decrease of molar volume due to the increase in the number of non-bridging oxygen atoms and the polarizability. The lowest refractive index (1.485) in this study was that of the $B_2O_3-SiO_2-Al_2O_3-K_2O$ glass system due to the larger ionic radius of $K^+$. Based on our results, it has been determined that the refractive index of the $B_2O_3-SiO_2-Al_2O_3$ system should be controlled by the addition of alkali oxides and alkali earth oxides for proper formation of the photosensitive paste.