• Journal of the Korea Institute of Building Construction
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• v.16 no.4
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• pp.321-329
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• 2016

The use of ternary blended cement consisting of Portland cement, granulated blast-furnace slag (GGBFS) and fly ash has been on the rise to improve marine concrete structure's resistance to chloride attack. Therefore, this study attempted to investigate changes in chloride attack resistibility of concrete through NT Build 492-based chloride migration experiments and test of concrete's ability to resist chloride ion penetration under ASTM C 1202(KS F 2271) when 1.5-2.0% of alkali-sulfate activator (modified alkali sulfate type) was added to the ternary blended cement mixtures (40% ordinary Portland cement + 40% GGBFS + 20% fly ash). Then, the results found the followings: Even though the slump for the plain concrete slightly declined depending on the use of the alkali-sulfate activator, compressive strength from day 2 to day 7 improved by 17-42%. In addition, the coefficient from non-steady-state migration experiments for the plain concrete measured at day 28 decreased by 36-56% depending on the use of alkali-sulfate. Furthermore, total charge passed according to the test for electrical indication of concrete's ability to resist chloride ion penetration decreased by 33-62% at day 7 and by 31-48% at day 28. As confirmed in previous studies, reactivity in the GGBFS and fly ash improved because of alkali activation. As a result, concrete strength increased due to reduced total porosity.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.129-137
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• 1998

본 연구에서는 해수 및 염화나트륨이 공급되는 환경에서 실리카 흄의 알칼리실리카 반응에 대한 억제효과를 구명한 것이다. 연구에 사용된 염화나트륨 농도는 2.8%, 10%, 20%여Tdmaum 반응성 골재는 일본산 안산암이었다. 실리카 흄은 노르웨이산으로 비표면적인 20$m^2$/g인 것을 사용했다. 실리카 흄의 치환율은 시멘트 중량에 대해 5%, 7%, 10%로 하였다. 연구결과, 20%의 염화나트륨이 공급되는 환경에서 알칼리실리카반응에 의한 유해한 팽창이 억제는 본 연구에서 사용된 실리카 흄의 경우, 치환율 % 이상에서 달성되었다.

• Analytical Science and Technology
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• v.14 no.5
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• pp.422-431
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• 2001

One pulp manufacture facility was selected as surveying facility to examine the discharged amount and generation mechanism of dioxins excepts for bleaching stage wastewater. In recovery and finishing process, 2,3,7,8-TCDF, OCDD and OCDF were mainly detected, and the ratio of PCDDs and 1,2,3,4,7,8-HxCDD as the concentration of 2,3,7,8-substitute isomer were discharged which is known as the typical emission pattern of pulp and paper manufacture facility, and the 1,2,3,7,8-PeCDD and 1,2,3,4,7,8-HxCDD were discharged more than 90% in toxic equivalent concentration. Also, the OCDD and 2,3,7,8-TCDF for 2,3,7,8-isomer concentration, and 1,2,3,7,8-PeCDD and 2,3,7,8-TCDF as toxic equivalent concentration were discharged in effluent. The detected PCDDs/PCDFs concentration were surveyed 0.2266 ng-TEQ/L for influent and 0.0377 ng-TEQ/L for effluent.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.53-57
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• 2013

For the purpose of development of the extraction process of lithium ion from concentrated water eliminated from desalination process, an experimental research on the solvent extraction of lithium ion from aqueous solutions was performed. The effects of operating parameters, such as concentration of extractant, ratio of extracting solution/aqueous solution, pH of aqueous solution, were examined. The effect of sodium chloride, the major component of sea water, was also examined. Lithium ion in aqueous solutions of pH=10.2~10.6 adjusted by ammonia solution was most effectively extracted by extracting solution composed of 0.02 M TTA and 0.04 M TOPO in kerosine. The addition of sodium chloride in lithium aqueous solution significantly interfered the extraction of lithium ion.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.73-79
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• 1997

Removal of the Arsenic components from the closed mine tailings has been attempted by the alkali-leaching method. Two tailings collected from the Daduck and Yuchon mine which were already closed many years ago were leached with caustic soda solutions. The Arsenic components in the leach liquor resulted from the alkali treatment of tailings could be removed fairly well in the form of insoluble calcium-Arsenic compound by the precipitation with calcium chloride. As a result, the extraction of about 60~90% Arsenic from the tailings could be obtained depending on the leaching conditions and the influence of temperature and the slurry density on the extraction of Arsenic was also found to be very small at the NaOH concentration more than 0.5N. In addition, it seemed that a caustic soda solution over 0.5N NaOH could be used repeatedly for the leaching of tailings since the consumption of NaOH was not so great in a leaching of them. As far as the precipitation of Arsenic components was concerned, more than 99% of Arsenic could be precipitated within 10 minutes by the addition of 2wt% CaC12 in to the leach liquor.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.261-266
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• 1997

가장 넓게 쓰이고 있는 알칼리염소법에 의한 도금폐수 처리법은 약 50년전에 Dodge와 Zabban에 의해 발표된 이론에 기초하고, 이것은 pH 및 ORP에 의존하는 반응으로 차아염소산이 시안화물을 시안산염으로 산화시키는 것이며, 알칼리조건하에서 염소화를 하는 동안에 시안화물이 파괴되고 중금속염은 침전을 생성한다. 이 반응은 1단계에서 시안산기가 바로 시안산나트륨으로 되는 것이 아니고 반응의 중간생성물인 염화시아노겐(CNCI)이라고 하는 독성물질이 생성되기 때문에 안전상의 문제가 있다. 또 알카리 염소법은 고농도일 경우에는 처리가 대단히 어렵고, 저농도일지라도 철, 니켈 및 구리와 같이 중금속성분이 다량 혼입되면 배출허용기준치이하로 처리하기는 사실상 불가능하다. (중략)

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.650-657
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• 2021

Alkali activators that stimulate mineral compounds are expensive materials, but in order to replace industrial products of high alkali in gredien ts, both product an d econ omic feasibility must be satisfied. In this study, alkali in dustrial waste(LW) from the LCD man ufacturin g process were used for the purpose of alkali active reaction of GGBFS for high stren gth concrete over 50MPa. Concrete mixed with LW had reduced workability, but it had the characteristic of increasing compressive strength. Analysis using ACI 209 Compressive Strength Model Equation was made to compare the changes in strength coefficients according to LW mixing. The durability test of concrete, such as Chloride Penetration Resistance and carbonation resistance, also showed excellent performance. In the Adiabatic temperature rise test results, the concrete mixed with LW had the effect of accelerating the initial hydration heat. However, the final Adiabatic temperature rise was not significantly affected by the mixing of LW.

• Resources Recycling
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• v.29 no.5
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• pp.28-37
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• 2020

In this study, the effect of precipitation temperature, ammonium chloride amount and addition method, vanadium and sodium hydroxide content of the solution on the precipitation of ammonium metavanadate were examined by using the sodium vanadate(NaVO₃) solution in alkali region as a starting material. As the pH of solution decreased, the addition amount of ammonium chloride and the vanadium content of the solution increased, the precipitation rate of ammonium metavanadate increased. In this research condition, the basic conditions for obtaining more than 90% of precipitation yield were 10,000mg/L of vanadium content, 2equivalents of ammonium chloride addition, room temperature, and 2 hours of precipitation time. The size of precipitated particles decreased with increasing precipitation rate. Especially when liquid ammonium chloride was injected into the solution, the precipitation rate was the slowest and the particle size of the precipitate was the largest. After the primary precipitation by adding ammonium chloride as a solid, the secondary precipitation was carried out by adding new reactants. At this time, the precipitation with added ammonium chloride solid was not affected by the precipitates present in the solution. However, when liquid ammonium chloride was added, new precipitate was deposited on the surface of the precipitate present in the solution, increasing its size. Due to the difference in ammonium metavanadate solubility to temperature, the precipitation temperature at the vanadium content of 10,000mg/L in the solution affected the precipitation rate of ammonium metavanadate and the precipitation temperature did not affect the precipitation rate at a high concentration of more than 30,000mg/L vanadium content in the solution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1292-1295
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• 2006

Three kinds of electrolyte membranes were prepared by impregnating filter papers with one of the electrolyte solutions fur primary manganese battery ($NH_4Cl$, $ZnCl_2$, and alkaline types) and hygroscopic agent ($CaBr_2$ or $CaCl_2$), respectively. The thickness of them was $250{\sim}300{\mu}m$, and they were very flexible. The electrochemical characteristics greatly depended on the hygroscopic agent to supply water to the cell. The electrolyte membrane containing $CaCl_2$ showed the highest ionic conductivity and the largest discharge capacity.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.1-7
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• 2019

Recently, studies on alkali activated slag(AAS) binders that do not use cement have been actively conducted. It is known that AAS concrete is highly resistant to chloride damage based on the test method used for ordinary concrete. However, it is fully not understood whether the test method used for concrete can be applied to AAS mixtures. Therefore, in this study, we verified the consistency of NT Build 492 and ASTM C 1202 test methods by applying various experimental variables. According to the experimental results, the two tests yielded opposite results. Therefore, the chloride durability of AAS mortar can be different depending on the evaluation method.