• Resources Recycling
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• v.29 no.6
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• pp.73-78
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• 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.%.

• Journal of Powder Materials
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• v.25 no.2
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• pp.104-108
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• 2018

Grain-growth behavior in the $95Na_{1/2}Bi_{1/2}TiO_3-5BaTiO_3$ (mole fraction, NBT-5BT) system has been investigated with the addition of $Na_2CO_3$. When $Na_2CO_3$ is added to NBT-5BT, the growth rate is higher than desired and grains are already impinging each other during the initial stage of sintering. The grain size decreases as the sintering temperature increases. With the addition of $Na_2CO_3$, a liquid phase infiltrates the interfaces between grains during sintering. The interface structure can be changed to be more faceted and the interface migration rate can increase due to fast material transport through the liquid phase. As the sintering temperature increases, the impingement of abnormal grains increases because the number of abnormal grains increases. Therefore, the average grain size of abnormal grains can be decreased as the temperature increases. The phenomenon can provide evidence that grain coarsening in NBT-5BT with addition of $Na_2CO_3$ is governed by the growth of facet planes, which would occur via mixed control.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.535-539
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• 2006

Effects of alkaline additives on the $CO_2$ removal reaction have been investigated by a thermogravimetric analyzer. $Li_2ZrO_3$ was synthesized by soild reaction of $ZrO_2$ with $Li_2CO_3$ and then alkali chemicals were added to the synthesized $Li_2ZrO_3$ and then heat treatment was carried out. Addition of alkali chemicals enhanced the reactivity of $Li_2ZrO_3$ with the following order; $K_2CO_3>NaCl>LiCl>Na_2CO_3$, which were resulted from the formation of partially melted $Li_2CO_3$. SEM photographs showed the presence of melted state and the XRD results showed that the chemical states of added salts were not changed. Addition of NaCl caused the induction time of about 60 min at the initial reaction stage and the addition of $Na_2CO_3$ inhibited the decomposition of $Li_2CO_3$ at about $700{\sim}750^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1025-1028
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• 2006

Dense $0.95(Na_{0.5}K_{0.5})NbO_3-0.05LiTaO_3$ (NKN-5LT) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding $Na_2CO_3$ as a sintering aid. The electrical properties of NKN-5LT ceramics were investigated as a function of $Na_2CO_3$ concentration. When the sample sintered at $1000^{\circ}C$ for 4 h with the addition of 1 mol% $Na_2CO_3$, electro-mechanical coupling factor $(k_p)$ and piezoelectric coefficient $(d_{33})$ of NKN-5LT ceramics were found to reach the highest values of 0.43 and 190 pC/N, respectively.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.132-139
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• 2018

A cost-effective preparation method is proposed to prepare nanoporous alumina (NA) using aluminum chloride as a precursor with a lower cost than aluminum butoxide. In addition, the surfactant template was replaced with magnesium stearate, which has a lower unit cost in stearate acid. The adsorption isotherm test for the CO gas was carried out to compare the adsorption performance of the NA adsorbents prepared using post-hydrolysis (NA) and cost-effective precipitation (C-NA). In addition, C-NA exhibited a similar uptake capacity as NA, and the maximum uptake capacity of Pd/C-NA increased 1.3 times via Pd nanodots loading.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.547-553
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• 2013

This paper investigates the effect of coal-fired fly ash on dry $CO_2$ sorbents as the supports and additives. For this purpose, various kinds of dry sorbent were manufactured by mixing fly-ash, the primary $CO_2$ absorption components (NaOH and CaO) and water with their different combination. Thereafter, their $CO_2$ absorption performance and the property were analyzed. As a result, variation of absorption efficiency and temperature as well as $CO_2$ desorption of the sorbents are confirmed, which may be primarily ascribed to fly-ash addition to the sorbents. Particularly, fly-ash effect is strongly measured in the sorbent manufactured by mixing all four components (named WNCF sorbents). Absorption efficiency of WNCF sorbents at $550^{\circ}C$ is 35.6% higher than that of flyash free sorbent and desorption is solely observed in WNCF sorbents. Fly-ash in WNCF sorbents leads to increase the dispersity of $CO_2$ absorption components and decrease their particle size in the sorbents. In addition, fly-ash is used as the supports and pozzolanic reaction is hindered by NaOH in WNCF sorbent. Furthermore, $CO_2$ desorption from the sorbents may be due to fly-ash. The interaction between fly-ash and $CO_2$ absorption components substantially attenuate the strength between captured $CO_2$ in CaO and NaOH.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.143-147
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• 2013

The influence of carrageenan addition on the gelatinization of salt-based surimi gels was investigated by measuring compressive properties and Hunter color scale values. Hydrocolloid kappa (${\kappa}$)-carrageenan at 0%, 0.2%, and 1.0% and NaCl (2% w/w), KCl (1.5% w/w), and a mixture of NaCl (2% w/w) and KCl (1.5% w/w), were added to Alaska pollock surimi. Gel compressive properties were assessed by measuring the breaking force and gel strength. The gelling property of ${\kappa}$-carrageenan-induced surimi gel was significantly increased by the incorporation of KCl rather than NaCl. The addition of ${\kappa}$-carrageenan increased the breaking force and gel strength of surimi gels. Gels with 1% ${\kappa}$-carrageenan and KCl had the highest breaking force and gel strength. The addition of ${\kappa}$-carrageenan caused an increase in the whiteness values of the surimi gels.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.230.1-230.1
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• 2010

조촉매(Promotor)인 Na은 수성가스전이(Water Gas Shift, WGS) 반응 시 생성된 포름산염의 C-H결합을 쉽게 분해하는 역할을 한다. 본 연구에서는 $Pt/CeO_2$ 촉매의 성능 향상을 위해 Na의 담지량을 변화시켜 촉매적 활성을 비교하여 보았다. 제조된 담체는 침전법(Precipitation)을 사용하여 제조하였으며 $500^{\circ}C$에서 6시간 소성하였다. Pt 담지량은 1wt%로 고정하였고 Na 담지량은 1 wt%~5 wt%로 변화를 주어 동시(공)-함침법(Co-incipient wetness method)으로 담지 시켰다. 반응 실험은 공간속도(Gas Hourly Space Velocity, GHSV) $45,385h^{-1}$에서 수행하였다. WGS 반응 결과 3 wt%의 Na이 담지된 $Pt/CeO_2$ 촉매의 경우를 제외하고 나머지 Na이 담지된 촉매들은 비교적 높은 CO의 전환율을 나타내었다. 특히 2 wt%의 Na이 담지된 $Pt/CeO_2$ 촉매는 가장 높은 CO의 전환율을 나타내었다. 따라서 Na 담지량의 변화가 포름산염의 C-H결합 분해에 영향을 미친다는 것을 알 수 있다.

• Journal of the Korean Chemical Society
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• v.21 no.1
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• pp.53-59
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• 1977

A method of synthesizing $NaAlCO_3(OH)_2$ (Dawsonite) and $KAlCO_3(OH)_2$, was investigated by blowing $CO_2$ gas into sodium and potassium aluminate solutions. The reactions were accomplished at a temperature of 80 to $90^{\circ}C$, while $CO_2$ gas was blowing into the solutions which the molar ratios of $Na_2O/Al_2O_3,\;and\;K_2O/Al_2O_3$ were 6 to 8 and 8 to 10, respectively. It was observed that highly purified Dawsonite and $KAlCO_3(OH)_2$ are produced when Alumina is present in Boehmite at an equilibrium solid phase with a large amount of $HCO_3^-$ in the solutions. The rational formulas of Dawsonite and $KAlCO_3(OH)_2$synthesized under the conditions should be expressed as $NaAlO(OH)HCO_3\;and\;KAlO(OH)HCO_3$, respectively, by IR analysis. In addition, electron microscopic observation also indicated that Dawsonite in a fibrous crystal and $KAlCO_3(OH)_2$ in a needleshaped crystal.

• The Korean Journal of Ecology
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• v.7 no.2
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• pp.85-90
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• 1983

There was a decrease in nitrate reductase activity (NRA) measured in vivo in rice roots (Oryza sativa cv. Tongil) grown in anaerobic culture solution. But it was reversed by addition of malonate to the in vivo nitrate reduction assay medium. Malonate increased the in vivo NRA during 2-5 hours incubation and decreased it in longer incubation hours. In vivo NRA was stimulated by addition of NaHCO3 to the assay medium, but not by Na2CO3. The stimulation of NRA by NaHCO3 was not observed in shoot removed rice roots. It is suggested that CO2 from NaHCO3 is carboxylated by phosphoenol pyruvate carboxylase, results in increasing the malate contents in the roots, and stimulates the in vivo NRA. NADH needed in nitrate reduction is supported by malate oxidation. In rice roots, it seems probable that malate oxidation in the mitochondria is more important to nitrate reduction than malae oxidation in cytoplasm.