• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.48-53
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• 2003

The steel slag, a by-product which is produced on the process of manufacturing steel by refining pig iron is mainly used as road materials after aging it. It is necessary to age steel slag for long time in air because the reaction with water and free-CaO in steel slag could make the volume expanded. Due to this reason it prevents steel slag from being used as aggregate of concrete. But steel slag used in this study is controled by a air-jet method which rapidly cools substance melted at a high temperature. Rapid cooling prevents from generating of free-CaO in steel slag. In this study, it was investigated that steel slag manufactured by air-jet method affects on concrete in the freezing and thawing. As results of this study, concrete mixed with steel slag was worse in the freezing and thawing than concrete mixed with sand in spite of using air entraining agent. To obtain durability of concrete in the freezing and thawing, it is desirable to mix 50% of steel slag in concrete per unit weight of volume.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1997.10a
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• pp.59-65
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• 1997

Bench Scale급 석탄가스화기에서 배출된 slag의 거동을 살펴보기 위해서 Drayton탄(호주)과 Kideco탄(인도네시아)으로부터 생성된 slag의 조성, 형상, 잔존탄소함량 및 중금속 성분들을 분석하였다. Drayton탄 slag는 표면이 매끄럽고 다공성을 띄며 crack이 거의 없었고 결정구조가 비정형(amorphous)인 반면에, KIDECO탄 slag의 경우는 표면이 거칠고 crack이 상당히 많이 존재하는 것으로 나타났다. Slag중에 함유된 잔존탄소함량은 두 대상탄 모두 1% 이하를 보임으로써 slag의 재활용 기준인 3%를 만족하였다. Slag 재활용시 중금속의 2차적인 환경오염을 우려하여 석탄중에 포함된 중금속 함량 분석결과 대부분의 중금속이 slag중에 용융되어 안정한 화합물로 존재하고 있었으며, slag의 용출수 분석결과 중금속으로 인한 2차 환경오염 문제는 없을 것으로 판단된다.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.3
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• pp.11-17
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• 2014

We investigated the applicability of steel slag as a capping material in order to minimize phosphorus(P) release into seawater. Steel slag is a byproduct from the iron and steel industries and the use of steel slag has some advantages in respect of both cost and environmental concern. P removal by steel slag were studied in a batch system with respect to changes in contact time and initial concentration. Kinetic adsorption data were described well by pseudo 2nd order model, indicating rate limiting step for P adsorption to steel slag is chemical sorption. Equilibrium adsorption data fitted well to Langmuir isotherm model which describes for single layer adsorption. The maximum P adsorption capacity of steel slag was 7.134 mg-P/L. Increasing the depth of steel slag produced a positive effect on interruption of P release. More than 3 cm of steel slag was effective for blocking P release and 5 cm of steel slag was recommended as the depth for capping of P contaminated marine sediments. Increasing P concentration and flow rate had a negative effect on P removal ratio. It was concluded that the steel slag has a potential capping material for blocking P release from marine sediments.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.53-60
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• 2010

The effects of blast furnace slag, hwang-toh, and reinforcing fiber on the physical and mechanical properties of porous concrete using blast furnace slag coarse aggregates have been evaluated in this study. The effect of the depending on replacement ratio of blast furnace slag to cement was investigated such that the replacement ratio was varied to 0 %, 25 % and 50 %. Also, the replacement ratios of hwang-toh were 0, 20 and 30 %. The polyvinyl alcohol fiber was used for the reinforcing fiber. A series of pH, unit mass, and void ratio tests have been performed to study the physical properties of the porous concrete using blast furnace slag coarse aggregates with the polyvinyl alcohol fiber and the replacement ratios of blast furnace slag, hwang-toh, while a series of compressive tests have been performed to evaluate the strength property depending on polyvinyl alcohol fiber and the replacement ratios of blast furnace slag, hwang-toh. The test results indicated that the physical and mechanical properties of porous concrete using blast furnace slag coarse aggregates is affected by the replacement ratio of blast furnace slag, and the fiber contents. According to the tests with polyvinyl alcohol fiber contents, the void ratio was decreased and the compressive strength was upgraded.

• Geomechanics and Engineering
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• v.31 no.2
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• pp.149-158
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• 2022

Ladle furnace (LF) slag, waste from the steel-making process, was incorporated to improve the compressive strength of soil cement. LF slag was mixed to replace the cement in the soil-cement samples with wt% ratio 20:0, 15:5, and 10:10 of cement and slag, respectively. LF slag in the range of 5, 10, and 20 wt% was also separately added to the 20-wt% cement-treated soil samples. The soil-cement mixed LF slag samples were incubated in a plastic wrapping for 7, 14, and 28 days. The strength of soil cement was highly developed to be higher than the standard acceptable value (0.6 MPa) after incorporating slag into soil cement. The mixing of LF slag resulted in more hydration products for bonding soil particles, and hence improved the strength of soil cement. With the LF slag mixing either a replacement or additive materials in soil cement, the LF slag to cement ratio is considered to be less than 1, while the cement content should be more than 10 wt%. This is to promote a predominant effect of cement hydration by preventing the partially absorbed water on slag particles and keeping sufficient water content for the cement hydration in soil cement.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.191-194
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• 1999

Recently in Korea, may workers have reported the effects of the granulated blast furnace slag[BFS] of high fineness on the strength development of slag cement. We have studied the effect of slag fineness on the strength development of mortar with curing conditions, in order to get the basic data of high strength concrete using BFS. In this paper, we discussed the effects of slag fineness and porosity of mortar and the reaction of slag in hardened slag cement.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.1035-1040
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• 2001

The effects of polymer-binder ratio and slag content on the properties of combined wet/dry-cured polymer-modified mortars using granulated blast-furnace slag (slag) are examined. As a result, the flexural and compressive strengths of polymer-modified mortar using slag reaches a maximum at a slag content of 40%, and is inclined to increase with increasing polymer-binder ratio. The water absorption, carbonation depth and chloride ion penetration depth tend to decrease with increasing polymer-binder ratio and slag content.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.21-24
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• 2014

In the entrained-flow coal gasifier, coal ash turns into a molten slag most of which deposits onto the wall to form liquid and solid layers. Critical viscosity refers to the viscosity at the interface of the two layers. The slag layers play an important role in protecting the wall from physical/chemical attack from the hot syngas and in continuously discharging the ash to the slag tap at the bottom of the gasifier. For coal with high ash melting point and slag viscosity, CaO-based flux is added to coal to lower the viscosity. This study evaulates the effect of critical viscosity temperature and ash/flux ratio on the slag behavior using numerical modelling in a commercial gasifier. The changes in the slag layer thickness, heat transfer rate, surface temperature and velocity profiles were analyzed to understand the underlying mechanism of slag flow and heat transfer.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.481-486
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• 2001

Ground granulated blast-furnace slag shows very high strength when proper alkali-activator exists. This paper deals with setting time, heat evolution rate and the strength development of alkali-activated slag cement activated by KOH, Ca(OH$)_{2}$, $Na_{2}$ $So_{4}$ , and alum(potassium aluminum sulfate). Alkali-activated slag mortar is studied by comparison with GGBF slag cement mortar. The experimental results indicate that for moisture curing at $25^{\circ}C$, the addiction of either 4% $Na_{2}$ $So_{4}$ or 4% alum increases the strength of GGBF slag cement mortar consisting of 50% GGBF slag and 50% portland cement at early age. Strength of activated GGBF slag cement mortars at 1, 3 and 7 days exceeded that of GGBF slag cement mortar. A conduction calorimeter was used to monitor early age hydration.

• Journal of the Korean Ceramic Society
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• v.13 no.3
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• pp.21-27
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• 1976

Foam formation of Slag-Quartz-$\textrm{Na}_2\textrm{CO}_3$ system was investigated. The foaming agent used was sulphide and sulphate compounds which are present in the slag. The microstructures and x-ray analysis of foam slag, the effect of composition and particle size of slag on the formation temperature, and foam size and distribution of slag foam were studied. The Increment of $\textrm{Na}_2\textrm{O}$ in the slag batch composition decrease the initial foam formation temperature and enhance the foam growth. The formation of temperature and soaking time had pronounced effect on the foam growth and increasing the glass phase in the slag foam.