• Title, Summary, Keyword: CaO회수

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Changes in Hydration and Watertightness of Cement Containing Two-Component Fluosilicate Salt Based Chemical Admixture (2성분 규불화염계 혼화제가 첨가된 시멘트의 수화반응 및 수밀성 변화)

  • Kim, Jae-On;Nam, Jae-Hyun;Kim, Do-Su;Khil, Bae-Su;Lee, Byoung-Ky
    • Journal of the Korean Ceramic Society
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    • v.41 no.10
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    • pp.749-755
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    • 2004
  • Fluosilicic acid ($H_2SiF_6$) is recovered as aqueous solution which absorbs $SiF_4$ produced from the manufacturing of industrial-graded $H_3PO_4$ or HF. Generally, fluosilicate salts prepared by the reaction between $H_2SiF_6$ and metal salts. Addition of fluosilicate salts to cement endows odd properties through unique chemical reaction with the fresh and hardened cement. In this study, two-component fluosilicate salt based chemical admixtures (MZ) of $4\%,\;6\%$, and $8\%$ concentration were prepared by the reaction of $H_2SiF_6$ ($25\pm2\%$) and metal salts. The effect of concentration of MZ at a constant adding ratio on the hydration and watertightness of cement were investigated respectively. In a cement containing MZ, metal fluorides such as $CaF_2$ and soluble silica by hydrolysis were newly formed during hydration. The total porosity of the hardened cement was lower in the presence of U because of packing role of metal fluoride and pozzolanic reaction of soluble $SiO_2$. Consequently, the watertightness of the hardened paste containing MZ was more improved than non-added (plain) due to an odd hydration between cement and MZ.

Studies on the Grassland Development in the Foerst III. Effect of fertilizer level on quality , mineral constituents and tree growth of grass-clover mixtures grown under pine trees (임간초지 개발에 관한 연구 III. 임간혼파초지에서 3요소 시비수준이 목초의 품질과 무기성분함량 및 나무생장에 미치는 영향)

  • Seo, S.;Han, Y.C.;Park, M.S.;Lee, J.Y.
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.5 no.3
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    • pp.187-194
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    • 1985
  • This field experiment was carried out to determine the effects of thirteen different fertilizer levels of nitrogen(N), phosphorus($P_2O_5$) and potassium($K_2O$) on the content of crude protein, crude fiber, mineral constituents of product and tree growth forest pasture with 40-50% shading. The experiment was arranged as a randomized block design and performed in the suburban forest of Suweon in 1984. The results obtained are summarized as follows: 1. Crude protein content and total protein yield were higher in the plot of 28 and 42kg $N/_{10a}$, regardless of $P_2O_5\;and\;K_2O$ level, while those were the lowest in zero fertilizer and N-zero fertilizer plots. 2. The contents of lignin and silica were significantly low in the high N fertilizer level, and the contents of NDF, ADF, cellulose and hemicellulose were not affected by different fertilizer levels. However, the content of crude fiber tended to be low with high N, regardless of $P_2O_5\;and\;K_2O$. 3. The contents of N,K and $SiO_2$ of grasses were influenced by different fertilizer levels. However, those of P,Ca,Ma and Na showed little differences. 4. The recovery percentage of NPK was higher in the plot of standard fertilizer level with 28-20-24 kg/10a, and higher recovery percentage was observed in $K_2O$, followed by N and $P_2O_5$ in that order. 5. The growth of tree was increased as the level of N fertilizer was increased, but no such trend was noted by $P_2O_5\;and\;K_2O$ levels. 6. Crude protein, crude fiber, some mineral contituents of grasses, and growth of tree were influenced by N level, regardless of $P_2O_5\;and\;K_2O$. And the optimum fertilizer level of $N-P_2O_5-K_2O$ seemed to be 28-20-24 kg/10a for the production of grasses with higher quality and more yield in the forest.

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Synthesis and Use of a Ligand for the Extraction of Uranium (I) (우라늄 추출을 위한 리간드의 합성 및 응용 (제 1 보))

  • Chong Min Park;Suk Nam Choi
    • Journal of the Korean Chemical Society
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    • v.31 no.4
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    • pp.315-321
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    • 1987
  • The ligand, 2,10-dibenzyl-4,6,8-trioxo-3,9-diaza undecane dioic acid(DTDA) for the extraction of uranium was synthesized under dry nitrogen from phenylalanine and 3-oxoglutaric acid. Extraction was performed by stirring a solution of DTDA in dichloromethane for 1 hour with an aqueous solution of $UO_2(ClO_4)_2{\cdot}6H_2O$ at various pH values and at different $DTDA/UO_2{^{2+}}$ molar ratios. Extraction efficiency reaches a maximum when the pH of the aqueous phase was ca 8.0. The extraction percentage was affected by concentration of DTDA and increases with the $DTDA/UO_2{^{2+}}$ molar ratio to complete extraction with a 4 fold excess of DTDA. The high selectivity of the DTDA for uranium was ascertained by competition experiments with other cations. The bound uranyl ion was quantitatively liberated within few minutes from the organic phase by treatment with an aqueous 1M HCI solution and DTDA was recovered very satisfactorily from the organic phase. The values of the over-all formation constants of the complex between uranyl ion and DTDA were determined to be the following : ${\beta}_1=1.20{\times}10^5\;,\;{\beta}_2=1.01{\times}10^8$.

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Leaching of Copper and Other Metal Impurities from a Si-Sludge Using Waste Copper Nitrate Solution (실리콘 슬러지로부터 폐질산구리용액을 이용한 구리 및 금속불순물의 침출)

  • Jun, Minji;Srivastava, Rajiv Ranjan;Lee, Jae-chun;Jeong, Jinki
    • Resources Recycling
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    • v.25 no.3
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    • pp.11-19
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    • 2016
  • A fundamental study to recycle a Si-Sludge and waste copper nitrate solution acid solution generated by domestic electronic industries was carried out. The waste copper nitrate solution was used as the lixiviant to leach the metals like Cu, Ca, Fe, etc. from the sludge leaving Si in the residues. The effect of reaction temperature, time and pup density on the metals leaching from the sludge was investigated. To enhance the extractability of Fe, the effect of HCl, $HNO_3$ and $H_2O_2$ introduced additionally during the leaching was also examined. Considering the leaching efficiency of Fe along with Cu, the leaching conditions comprising of 200 ~ 225 g/L pulp density and $90^{\circ}C$ temperature for 30 min were optimized. Under this condition, 98.27 ~ 99.17% Cu could be dissolved in the leach liquor with the obtained purity of Si in the residues as 98.69 ~ 98.86 %. The study revealed that the leaching of Cu contained in the Si-Sludge with the waste copper nitrate solution is a plausible approach by which the obtained leach liquor can further be treated suitably to recover Cu as the high pure value-added products.

Characterisitics of the Copper Converter Slag -Recovery of Copper from the Copper Converter Slag(I)- (동제연소 전노슬래그의 생성에 관하여 -동제연소 전노슬래그로 부터 동의 회수(I)-)

  • Kim, Mahn;Kim, Mi-Sung;Yoo, Taik-Soo;Oh, Jae-Hyun
    • Resources Recycling
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    • v.1 no.1
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    • pp.14-22
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    • 1992
  • As a basic study to recover the copper from the copper converter slag, the characterisitcs of converter slag was studied. The results obtained in this work are as follows. 1. The copper converter slag is composed of Cu, $Cu_2$S, $Fe_3$$O_4$, Fayalite and silicate. 2. It is supposed that magnetite in converter slag is oxidized to hematite at $720^{\circ}C$ and this phase is soluted to fayalite. 3. As the converter slag is added in the water solution, pH increased and the heavy metal ions in the water are adsorbed on the slag. 4. Work index of the converter slag cooled for the 10 hour and the 2 hour are 25~27 kWh/ton and 35 kWh/ton, respectively. 5. In the case of grinding test of converter slag, fayalite in converter slag is easily grinded than magnetite in converter slag.

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Scientific Analysis of Slags and Furnace Wall collected from Iron Production Site at Suryong-ri Wonmorongi in Chungju (충주 수룡리 원모롱이 야철지 수습 철재 및 노벽의 과학적 분석)

  • Cho, Hyun-Kyung;Cho, Nam-Chul;Kang, Dai Ill
    • Journal of Conservation Science
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    • v.29 no.2
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    • pp.139-147
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    • 2013
  • This study focused on iron making related information through analyzing slags and furnace wall collected from iron production site of Suryong-ri Wonmorongi, Chungju. Total Fe content of slags were from 36.98% to 44.47% and this range was general recovery rate of iron in ancient. Compounds of calcium included slags was supposed to add intentionally during smelting process as deoxidation agent in order that these helped to separate iron from impurities. Furnace wall didn't make of high alumina clay because of low $Al_2O_3$. Microstructure and main components of slags show that No. 1 to 3 slags with fayalite and wustite were products of iron ore smelting. However, No.4 slag is more likely to smelt by iron sand because of ulvospinel with $TiO_2$ in No. 4 slag. Therefore, iron ore were not only used but iron sand in smelting and furnace wall made of general clay with low $Al_2O_3$ content in this area.

A Study on the Froth Flotation Characteristics for Development of Scheelite Ore (회중석광 개발을 위한 부유선별 특성연구)

  • Jeon, Ho-Seok;Kim, Su-Gang;Go, Byung-Hun;Baek, Sang-Ho;Kim, Byoung-Gon
    • Journal of the Korean Society of Mineral and Energy Resources Engineers
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    • v.54 no.4
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    • pp.397-408
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    • 2017
  • Froth flotation characteristics study was carried out on Yeongwol Sangdong mine Scheelite ore in order to produce $WO_3$ concentrate using oleic acid as collector. In case of using oleic acid, due to the low selectivity of the purpose mineral, the selection of the gangue mineral depressant and pH adjustment are important. As a result, it was confirmed that the optimum pH for providing optimum scheelite froth flotation characteristics while depressing silicate gauge minerals was in the alkalic region. In order to separate the Ca ion containing minerals and scheelite, -200 mesh ground sample, 35% solid in pulp density, 1,500 rpm and the addition of reagents in sequence such as $Na_2CO_3\;3kg/ton$, $Na_2SiO_3\;4kg/ton$, Oleic acid 250 g/ton, Lankropol-8,300 50 g/ton, respectively. As a result, final concentrate was obtained $WO_3$ grade of $67.6%WO_3$ with a recovery of 88.16%.

Flotation for Recycling of a Waste Water Filtered from Molybdenite Tailings (몰리브덴 선광광미 응집여과액 재활용을 위한 부유선별 특성)

  • Park, Chul-Hyun;Jeon, Ho-Seok;Han, Oh-Hyung;Kim, Byoung-Gon;Baek, Sang-Ho;Kim, Hak-Sun
    • Journal of the Mineralogical Society of Korea
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    • v.23 no.3
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    • pp.235-242
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    • 2010
  • Froth flotation using the residual water in the end of flotation process has been performed through controlling of pH. IEP (isoelectric point) of molybdenite and quartz in distilled water was below pH 3 and pH 2.7, respectively and the stabilized range was pH 5~10. In case of a suspension in reusing water, zeta potential of molybdenite decreased to below -10 mV or less at over pH 4 due to residual flocculants. As result of pH control, flotation efficiency in the alkaline conditions was deteriorated by flocculation, resulting from expanded polymer chain, ion bridge of the divalent metal cations ($Ca^{2+}$), and hydrophobic interactions between the nonpolar site of polymer/the hydrophobic areas of the particle surfaces. However, the weak acid conditions (pH 5.5~6) improved the efficiency of flotation as hydrogen ions neutralize polymer chains and then weakened its function. In cleans after rougher flotation, the Mo grade of 52.7% and recovery of 90.1% could be successfully obtained under the conditions of 20 g/t kerosene, 50 g/t AF65, 300 g/t $Na_2SiO_3$, pH 5.5 and 2 cleaning times. Hence, we developed a technique which can continuously supply waste water filtered from tailings into the grinding-rougher-cleaning processes.

Preparation of Borosilicate Foamed Glass Body with Sound Absorption Characteristics by the Recycling Waste Liquid Crystal Display Glass (폐 LCD 유리를 이용한 흡음특성을 갖는 붕규산유리발포체 제조)

  • Lee, Chul-Tae
    • Applied Chemistry for Engineering
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    • v.27 no.6
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    • pp.612-619
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    • 2016
  • In this research, an alumino-borosilicate foamed glass with sound absorption property was prepared using the waste borosilicate glass obtained from the recycling process of waste liquid crystal display (LCD) panel. A 100 g of pulverized waste borosilicate glass with the particle size of under 325 mesh, was mixed with 0.3 g (wt/wt) of graphite, each 1.5 g (wt/wt) of $Na_2CO_3$, $Na_2SO_4$ and $CaCO_3$ as a foaming agent, and 6.0 g (wt/wt) of $H_3BO_3$ and 3.0 g (wt/wt) of $Al_2O_3$ as a pore control agent. Following mixture was under the foaming process for 20 minutes at a foaming temperature of $950^{\circ}C$. The result yielded the foaming agent with 45% of the opened porosity and 0.5-0.7 of the sound absorbing coefficient. This alumino-borosilicate foamed glass with the sound absorption property showed excellent physical and mechanical properties such as density of $0.21g/cm^3$, bending strength of $55N/cm^2$ and compression strength of $298N/cm^2$ which can be ideally used as sound absorption materials with heat-resisting and chemical-resisting property.

Immobilization of Cyclodextrin Glucanotransferase for Production of 2-O-\alpha-D-Glucopyranosyl L-Ascorbic Acid. (2-O-\alpha-D-Glucopyranosyl L-Ascorbic acid 생산을 위한 Cyclodextrin glucanotransferase의 고정화)

  • 성경혜;김성구;장경립;전홍기
    • Microbiology and Biotechnology Letters
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    • v.31 no.4
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    • pp.368-376
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    • 2003
  • Cyclodextrin glucanotransferase (CGTase) from Paenibacillus sp. JB-13 was immobilized on various carriers by several immobilization methods such as ionic binding, covalent linkage and ultrafiltration to improve the process performance. The ultrafiltration and covalent linkage with CNBr-activated sepharose 4B were found as the best method for immobilization of CGTase. The ability of CGTase immobilization onto CNBr-activated sepharose 4B was as high as 18,000 units/g resin when the conditions was as follows: contact time 9 hrs at $37^{\circ}C$, pH 6.0, 100 nm and enzyme loading 24,000 units/g resin. The optimum conditions for production of 2-O-$\alpha$-D-Glucopyranosyl L-Ascorbic acid by immobilized CGTase turned out to be: pH 5.0, temperature $37^{\circ}C$, 20% substrate solution containing 8% (w/v) of soluble starch and 12% (w/v) of L-ascorbic acid sodium salt, 100 rpm, far 25 hrs and with 800 units of immobilized CGTase/ml substrate solution. Moreover the CGTase activity could be stably maintained for 8 times of repetitive reactions after removing products by ultrafiltration through YM 10 membrane.