• Title/Summary/Keyword: 염산용액

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Production of High purity $Mn_3O_4$Powder by Precipitation of Calcium fluoride in the Manganese Leaching Solution (망간침출액에서 불화칼슘화에 의한 高純度 망간酸化物의 製造)

  • 한기천;이계승;최재석;신강호;조동성
    • Resources Recycling
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    • v.11 no.1
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    • pp.3-8
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    • 2002
  • In order to make the high purity Mn$_3$O$_4$powder for the raw material of soft ferrite, Mn is extracted from the dust and the extracted solution is refined. The dust is generated in producing a medium-low carbon ferromanganese and contains 90% Mn$_3$O$_4$. Mn$_3$O$_4$in the dust was reduced into MnO by roasting with charcoal. Injection of the 180g/L of the reduced dust into 4N HCI solution increased pH of the leaching solution higher than 5 and then a ferric hydroxide was precipitated. Because the ferric hydroxide co-precipitates with Si ion etc, Fe and Si ion was removed from the solution and the about 10% Mn solution was obtained. The solution was diluted with water to Mn-15000 ppm and $NH_4$F was injected into the diluted solution at $70^{\circ}C$ to the F-3000 ppm. As a result, Ca ion is precipitated as $CaF_2$and the residual concentration of Ca was 14 ppm. Injection of the equivalent (NH$1.5M_4$)$_2$$CO_3$solution as 2 L/min at $25^{\circ}C$ into the above solution precipitated a fine and high purity $MnCO_3$powder. The deposition was filtrated and roasted at $1000^{\circ}C$ for 2 hours. As a result, $MnCO_3$powder is converted into $Mn_3$$O_4$powder and it had $8.2\mu$m of median size. The final production is above 99% $Mn_3$$O_4$powder and it satisfied the requirement of high purity $Mn_3$$O_4$powder for a raw material of soft ferrite.

Anti-oxidative Activities of Angelica dahurica Radix Ethanol Extract (백지 에탄올추출물의 항산화 활성에 관한 연구)

  • Kim, Pil-Sun;Lee, Tae-Jong;Kim, Yang-Hee;Kim, Jung-Si
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4378-4384
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    • 2011
  • In order to evaluate the anti-oxidative capabilities of Angelica dahurica Radix ethanol extract (ADEE), we analyzed the contents of polyphenol and flavonoid compounds and the electron donating ability from ADEE. For animal experimentation, the test agent was topically applied to the artificial tanning spots which were induced by 1,500 mJ/$cm^2$ of ultraviolet B radiation on the backs of brown guinea pigs weighing approximately 450~500g. The test agent of $30{\mu}{\ell}$ was applied (6areas per group) twice a day, five days a week, for five weeks. On completion of the experiment, the animals were sacrificed under anesthetization, and the artificial tanning spots were obtained by biopsy punch and stained with H&E to observe the histological change in the epidermis and dermis. As a result, the contents of polyphenol and flavonoid compounds in ADEE were 20.7mg/g and 19.5mg/g respectively. As the for electron-donating capability of ADEE, it was observed that ADEE displays a dose-dependent antioxidative capacity of 14.8% and 19.8% at the concentration of 500 and 1000 ${\mu}g/m{\ell}$ respectively. Tissue staining with H&E revealed that the epidermis of the control group was slightly thicker than that of the other groups. However no inflammation or any other undesirable effect on the skin tissue due to ADEE was observed. These results indicate that ADEE is of value as a natural antioxidant.

Synthesis, Stability Constants, X-ray Structure and Electrochemical Studies of Copper (II) 1, 14-Bis (2-hydroxybenzyl)-2, 6, 9, 12-tetraazatetradecane.tetrahydrochloride Complex (1, 14-Bis(2-hydroxybenzyl)-2, 6, 9, 12-tetraazatetradecane.tetrahydro-chloride 구리착물의 합성, 안정도상수, X-ray 구조 및 전기화학적 연구)

  • Kim, Sun-Deuk;Kim, Jun-Kwang;Kim, Seong-Yun
    • Analytical Science and Technology
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    • v.13 no.2
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    • pp.173-178
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    • 2000
  • A new open-chain ligand containing two phenol groups, 1, 14-Bis (2-hydroxybenzyl)-2, 6, 9, 12-tetraazatetradecane(bsated) was synthesized as its tetrahydrochloride salt and characterized by elemental analysis, mass, infrared and NMR. Its proton dissociation constants ($logK^n{_H}$) and stability constants ($logK_{ML}$) toward $Co^{2+}$, $Ni^{2+}$, $Cu^{2+}$ and $Zn^{2+}$ were determined at $25^{\circ}C$ and 0.10M($KNO_3$) ionic strength in aqueous solution by potentiometry. The X-ray structure of its copper (II) complex [Cu(bsated)]$(ClO_4)_2$ was reported: Monoclinic space group $P2_1/n$, $a=17.856(4){\AA}$, $b=17.709(1){\AA}$, $c=8.539(2){\AA}$, $V=2700(2){\AA}$ with Z=4. Electrochemical studies of [Cu(bsated)]$(ClO_4)_2$ complex in dimethyl sulfoxide (DMSO) solution containing tetrabutylammonium perchlorate (supporting electrolyte) were carried out by cyclic voltammograms (CV) and normal pulse voltammetry (NPV).

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Structure Analysis of Water-soluble Polysaccharides Extracted from The Unripe Fruit of Cudrania tricuspidata (꾸지뽕나무 열매에서 추출한 수용성 다당류의 구조분석)

  • Kim, Seok Ju;Lee, Kyung-Tae;Youe, Won-Jae;Lee, Sung-Suk;Kim, Yong Sik
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.6
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    • pp.740-746
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    • 2014
  • The unripe fruit of cudrania tricuspidata was extracted with 50% ethanol. The crude water-soluble extracts were separated by liquid-liquid separation with n-hexane, ethyl acetate and butanol followed by precipitation with ethanol, and then the water-soluble polysaccharide (F1) was isolated by the fractionation through gel permeation chromatography using preparative PLaquagel-OH column with water. The structure was characterized by monosaccharide composition with HPAEC-PAD, methylation analysis with GC-MS, FT-IR and HPLC. According to the data, F1 was com posed of glucose (22.84 mM), galactose (13.75 mM), arabinose (45.87 mM), xylose (7.49 mM). It was revealed which uronic acid and acetyl group were not attached in F1. And it is constituted of 1-linked arabinose, 1,4-linked arabinose, 1,3-linked glucose, 1,4-linked galactose, 1,4-linked glucose, 1,3,6-linked galactose, 1,3,6-linked glucose and the ratio was showed 1.1 : 1.0 : 4.9 : 7.5 : 3.0 : 3.1 : 1.4 : 1.5.

1,3-bisdicyanovinylindane 색소를 이용한 선택적 $Hg^{2+}$ 감지 특성

  • Kim, Su-Ho;Kim, Young-Sung;Kim, Sung-Hoon;Son, Young-A
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 2009.11a
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    • pp.19-20
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    • 2009
  • 최근 화학, 물리, 생명과학, 전기, 전자등의 다양한 분야에 활발하게 연구가 이루어지고 있는 초분자 화학은 선택적 분자인지를 위한 효율적인 골격구조와 나아가 다양한 계에 응용할 수 있다. 초분자 화학의 분자인지 과정의 특징은 일반적으로 수용체 (receptor 혹은 host)가 목표가 되는 기질 (substrate, analyte, 혹은 guest)에 대하여 선택적으로 식별하고 반응하는 것이다. 비공유 결합성 상호작용에 의하여 이루어지는 초분자 화학의 분자 인지 과정의 특징은 일반적으로 수용체 (receptor 혹은 host)가 목표가 되는 기질 (substrate, analyte, 혹은 guest)에 대하여 선택적으로 식별하고 반응하는 것이다. 이는 공유결합을 이용하는 분자화학과는 차별화 된 것이다. 수용체는 간단한 구조의 화합물 및 금속 이온들과 같은 기질과 가역적으로 상호 작용할 수 있는 착물을 형성한다. 최근들어 급격한 산업화가 진행되어 환경문제가 심각하게 대두 되어져 왔고, 그 중에서 특히 수은이나 카드뮴에 의한 질병, 납에 의한 중독 등 중금속에 의한 오염이 크게 나타남에도 불구하고, 현재 그러한 중금속을 검출함에 있어 많은 비용과 시간이 드는 문제점이 있다. 또한 우리에게 이로운 금속은 효율적 분석을 통해 환경계와 의료계에 많은 도움을 줄 것으로 사례되므로 화학센서 기술의 개발은 절실히 요구되어지고 있다. 이에 새로운 1,3-bisdicyanovinylindane 을 통해 $Hg^{2+}$ 금속의 감지 여부 알아보고, 그 특성을 파악하고자 한다. 1,3-indandion (2.18g, 14.9mmol), malononitrile (2.95g, 44.7mmol), ethanol 50ml를 20분간 상온에서 용해시킨다. 후에 sodium trihydrate acetate(3.05g)을 첨가한 후 5시간 동안 환류반응 시킨다. 이 과정에서 얻어진 용액을 필터과정을 통하여 에서 합성 반응 중에 생성된 불순물(1,3-dicyanovinylindane-1-one, monocondensation)을 제거한다. 필터과정을 통해 걸러진 미 반응 물질을 제�G 용반응욕액을 증류수(100ml)를 이용하여 희석시키고 난 후 염산을 이용, 산성화 시켜 고체 생성물을 얻어낸다. 이렇게 생성된 고체 생성물은 다시 필터 및 건조를 통하여 회색의 고체 화합물을 얻어낸다. 1,3-bisdicyanovinylindane과 금속이온에 대한 감응도를 확인하기 위하여 metanol/water(1:2)을 용매로 하여 금속이온의 농도를 변화시켜 발색특성을 살펴보았다. 본 색소화합물과 Hg2+에 대한 UV 흡광도 변화 적정결과와 그 화합물의 상태 살펴본 결과 금속이온이 0.2ml씩 더 참가되면서 색의 변화를 뚜렷하게 나타내었다. 반면 그 밖에 이온($Fe^{3+}$, $Ag^{2+}$, $Pd^{2+}$, $Zn^2$, $Fe^{2+}$, $Cu^{2+}$, $Pb^{2+}$)은 UV 흡광도 변화가 적거나 변화 자체가 없었다. 하지만 과량의 $Fe^{3+}$, $Ag^{2+}$, $Pd^{2+}$는 색상 변화를 나타내었으며,이와 같은 흡광도 변화는 금속에 따라 약간의 차이가 있지만, 420nm를 등흡수점으로 하여, 580nm의 파장 영역에 있는 흡수 밴드의 세기는 감소하는 반면 400nm 파장 영역에 있는 흡수 밴드의 세기가 증가하였다. 1,3-bisdicyanovinylindane 화합물은 다양한 생물계 및 환경계에서 요구되는 micro mol에서 milli mol 농도 영역의 $Hg^{2+}$ 이온의 선택적이고 민감한 검출과 정량적인 분석에 유용하게 사용될 수 있을 것이다.

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A Study on the Dissolution and Separation for the Quantitative Analysis of Iodide in Spent Nuclear Fuel (사용후핵연료중의 미량 요오드 정량을 위한 용해 및 분리 연구)

  • Choi, Ke Chon;Lee, Chang Heon;Song, Byang Chol;Park, Yang Soon;Jee, Kwang Yong;Kim, Won Ho
    • Analytical Science and Technology
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    • v.13 no.6
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    • pp.751-758
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    • 2000
  • A study was carried out on the dissolution of spent PWR fuels and performed on the fuels and the separation of iodide for the quantitative analysis using SIMFUEL which has chemical composition of a simulated spent PWR fuel (burn-up; 35,000 MWd/MTU and cooling time; 10 years). To dissolve the SIMFUEL effectively and to minimize the formation of volatile iodine through dissolution process, the optimum ratio of mixed acid ($HNO_3/HCl$ 80: 20 mol%) was established and ozone gas was purged. In the separation step of iodine with $CCl_4$, $NH_2OH{\cdot}HCl$ was used for reducing ${IO_3}^-$ to $I_2$.The optimum acidity of the dissolved solution and the added of $NH_2OH{\cdot}HCl$ were 2.5 M and more than $1.5{\times}10^{-3}mole$, respectively. The recovery of iodide by ion chromatography was $82.8{\pm}4.1%$ and the total yield was corrected by gamma spectrometery using $^{131}I$ as a tracer.

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Problem Analysis and Improvement of an Experiment on Reactivityof Metals in ChemistryⅠ (화학Ⅰ 금속의 반응성 실험의 문제점 분석 및 개선방안)

  • Seong, Suk-kyoung;Choi, Chui-Im;Jeong, Dae-Hong
    • Journal of the Korean Chemical Society
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    • v.53 no.3
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    • pp.368-376
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    • 2009
  • In this study we investigated and tried to understand problems monitored in an experiment on reactivity of metals in chemistry I. Three problems were discussed. First, the reason that aluminium plate does not react with other metal ions such as zinc, iron and copper was studied and the way to overcome this problem was suggested. Second, the reason that the bubbles were generated when FeS$O_4$(aq) and Zn(s) react was discussed. Third, the precipitates which appeared in the reaction of FeS$O_4$(aq) and Zn(s) were identified. Through reference study and experimental investigation, we could reach the following results. First, aluminium could not react with other metal ions due to the surface oxide layer that is formed very fast and prevents aluminium from reacting with metal ions in solution. This problem could be overcome by allowing a competing reaction of acid and aluminium during the reaction of aluminium and metal ions. Second, the observed bubbles were identified to be hydrogen gas, produced by the reaction between metals and hydronium ion in the solution. Third, black precipitates that were produced on the surface of zinc plate and exhibited magnetic property were characterized to be $Fe_3O_4$(s), and brown precipitates that were produced in the solution phase were to be $Fe_2O_3$(s) by the analysis of X-ray photoelectron spectra.

Introduction to Electrochemical Quartz Crystal Microbalance Technique for Leaching Study of Metals (금속 침출연구를 위한 전기화학적 미소수정진동자저울 기술 소개)

  • Kim, Min-seuk;Chung, Kyeong Woo;Lee, Jae-chun
    • Resources Recycling
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    • v.29 no.1
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    • pp.25-34
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    • 2020
  • Electrochemical Quartz Crystal microbalance is a tool that is capable of measuring nanogram-scale mass change on electrode surface. When applying alternating voltage to the quartz crystal with metal electrode formed on both sides, a resonant frequency by inverse piezoelectric effect depends on its thickness. The resonant frequency changes sensitively by mass change on its electrode surface; frequency increase with metal dissolution and decrease with metal deposition on the electrode surface. The relationship between resonant frequency and mass change is shown by Sauerbrey equation so that the mass change during metal dissolution can be measured in real time. Especially, it is effective in the case of reaction mechanism and rate studies accompanied by precipitation, volatilization, compound formation, etc. resulting in difficulties on ex-situ AA or ICP analysis. However, it should be carefully considered during EQCM experiments that temperature, viscosity, and hydraulic pressure of solution, and stress and surface roughness can affect on the resonant frequency. Application of EQCM was shown as a case study on leaching of platinum using aqueous chlorine for obtaining activation energy. A platinum electrode of quartz crystal oscillator with 1000 Å thickness exposed to solution was used as leaching sample. Electrogenerated chlorine as oxidant was purged and its concentration was controlled in hydrochloric acid solution. From the experimental results, platinum dissolution by chlorine is chemical reaction control with activation energy of 83.5 kJ/mol.

Effect of Agitation and Additive on the Vaterite Contents of Precipitated Calcium Carbonate from Oyster Shell Waste (폐 굴껍질 이용 침강성 탄산칼슘 제조에서 교반속도와 첨가제가 Vaterite 함유량에 미치는 영향)

  • Young-Cheol Bak
    • Clean Technology
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    • v.29 no.2
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    • pp.95-101
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    • 2023
  • An experiment was conducted to produce vaterite-type precipitated calcium carbonate from waste oyster shells in order to use them as recyclable resources. Calcined oyster shells containing calcium oxide as their main component were prepared at a temperature of 800℃ for 24 h. The oyster shells were dissolved in nitric acid or hydrochloric acid solution to make 0.1 M calcium nitrate or calcium chloride aqueous solution, and a carbonation reaction was performed using a 0.1 M sodium carbonate aqueous solution under various experimental conditions, which included varying the amount of aspatic acid additive, the amount of NH4OH added, the reaction time, the reaction temperature, the stirring speed, and the type of dissolved acid. The XRD, SEM, and size distributions were analyzed and the vaterite content was calculated. Spherical precipitated calcium carbonate with a vaterite content of 95.9% was synthesized by adding 0.1 mol aspatic acid/1 mol CaO and 2 cm3 of NH4OH, and reacting for 1 h at 25℃ while stirring at 600 rpm. The average particle diameter was found to be 12.11 ㎛. Calcium carbonate contatining high vaterite is used as high value added calcium carbonate for medical, food, inke additiver, etc.

Effect of Wollastonites on Silica Uptake by Rice Plant (규회석(珪灰石)의 가용성(可溶性) 규산함량(珪酸含量)이 수도(水稻)의 규산흡수(珪酸吸收)에 미치는 효과)

  • Lee, Yun Hwan;Choi, Eae Ung;Han, Ki Hak
    • Korean Journal of Soil Science and Fertilizer
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    • v.6 no.4
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    • pp.221-226
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    • 1973
  • In order to investigate the silica effect of insufficient wollastonite to the official standard (above than 15% of suluble silica (N/2 HCl) on rice plant as silica fertilizer, 9 kinds of wollastonites and slag were adopted to examine the amount of silica absorbed by rice straw during growing period, and soluble silica of wollastonites extracted by 7 buffer solutions were compared with silica content in rice straw. Crystalls of ingredient in wollastonite ores were identified by X-ray diffractometer. The results were that silica content of rice plant at growing stages were increased as same ratio of soluble silica. content in wollastonite. Wollastonite containing more than 10% of souble silica (N/2 HCl) could be applied as fertilizer because absorbed amount of silica by rice plant from them are higher than from slag which contained 30% of soluble silica. Wollastonite powder mixed with impure ores in which soluble silica could not be extracted had the same effect on silica absorption of straw as wollastonite powder which contained conformable amount of soluble silica. The soluble silica of wollastonite extracted by buffer solutions (2% citric acid, N. NaOAc, N. $NH_4OAc$, Petermann solution, 0.1M. EDTA, and Hot water) had high significant relation to silica content in rice straw, but soluble silica extracted N/2 hydrochloric acid solutilon, also, had deep relation to them in rice straw. The adequate solution to extract silica from wollastonites is N/2 hydrochloric acid solution because its extracted silia amount is much higher than other solution (about one hundred times) and can be determined by gravimetric analysis. X-ray diffraction pattern would identify qualitatively purity of wollastonite, and large amount of soluble silica was extracted from wollastonite which was appeared to be weathered.

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