• Title/Summary/Keyword: converter slag

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A Study on the Fundamental Properties of Mortar Mixed with Converter Slag and Ferronickel Slag (전로슬래그 및 페로니켈슬래그를 혼입한 모르타르의 기초물성 연구)

  • Kim, Ji-Seok;Park, Eon-Sang;Ann, Ki-Yong;Cho, Won-Jung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.2
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    • pp.152-160
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    • 2021
  • Converter steel slag(BOF slag) is a vast amount of solid waste generated in the steelmaking process which has very low utilization rate in Korea. Due to the presence of free CaO which can derive bad volume stability in BOF slag, it usually land filled. For recycling BOF and identify its applicability as fine aggregate, this study investigates the fundamental characteristics of mortar with cement replaced ferronickel slag(FNS), which has the potential to be used as a binder. The results suggest that the mineral phases of BOF slag mainly include larnite(CaSiO4), mayenite(Ca12Al14O33) and wuestite(FeO) while olivine crystallines are shown in FNS. The results of flow and setting time reveals that the flowability and process of hardening increased when the amount of FNS and BOF slag incorporated was increased. The length change shows that the amount of change in the length of the mortar was almost constant regardless of mix proportion while compressive strength was reduced. Micro structure test results revealed that FNS or/and BOF slag mix took a long time to react in the cement matrix to form a complete hydration products. To achieve the efficient utilization of B OF slag as construction materials, proper replacement rate is necessary.

The Properties of Steel Slag Aggregate Treated with Aging Process in Concrete (에이징 처리한 콘크리트용 제강슬래그 골재의 품질)

  • 문한영;유정훈;천승환;백우열
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.105-108
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    • 2001
  • In this paper, we evaluated the suitability of steel slag(is divided with electric arc furnace slag and converter slag) as concrete aggregate by measuring physical and chemical characteristics of it. The steel slag mainly contains SiO$_2$ and CaO as the chemical composition. The reaction with water and a little of free CaO in the slag causes slag's volume to expand. Therefore, we used several aging methods in order to decrease the characteristics of slag volume expansion. The physical properties of steel slag aggregate are researched and then the strength of concrete with the steel slag aggregate is measured.

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Considerations of Permeability of Converter Slag for Recycling (재활용을 위한 전로슬래그의 투수성 고찰 (I))

  • 이광찬;이문수
    • Journal of the Korean Geotechnical Society
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    • v.15 no.4
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    • pp.69-83
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    • 1999
  • The permeability of converter slag, replacing material of sand mat on improving soft clay foundation, was evaluated in the laboratory. The effects of grain size, flow water time and aging were investigated using sea and fresh water. In the case of converter slag submerged with fresh water, the coefficients of permeability in A and B samples less than 10 mm grain sizes were measured as $6.52\times10^{-2}cm\; per\; sec\; and\; 5.99\times10^{-1}/cm$ per sec respectively, while they were $1.88\times10^{-2}/cm\; per\; sec,\; 3.86\times10^{-1}/cm$ per sec respectively under sea water condition. Also, the condition of turbulent flow may exit and was experimentally identified from the relationship between hydraulic gradient and seepage velocity. After 100 days under sea water condition, the coefficients of permeability of A and B samples decreased ten times than initial values. The reduction of permeability coefficient was considered to result from the filling of voids in high-calcium quicklime(CaO).

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Relation between Leaching Characteristics of the positive Ions and Phosphate Removal by granular Converter Slag for the different Conditions and Concentrations of Phosphate (인산염 농도와 폐수조건 변화에 따른 입상 전로슬래그의 양이온 용출 특성과 인산염 제거의 관계에 관한 연구)

  • Lee, In-Gu;Lee, Sang-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.2
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    • pp.372-379
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    • 2007
  • The converter slag can be used to remove phosphate ion into the form of solid state from the wastewater. This research aims to evaluate the change of pH, alkalinity, leaching of positive ion in the wastewater and the removal of phosphate from the initial condition of wastewater. The change of pH was abruptly increased upto pH 11 for the initial condition of pH from 7.0 to 8.5 fer 0.5 unit of pH. The alkalinity was steadily increased from 10 hours of reaction time not same as pH increase. The removal of phosphate was very effective till 10 hours of reaction then it was slow after that time. The positive ion, magnesium ion was leached from the concentration of 2.0 mg/L to 4.3mg/L at the reaction time of 27 hours and 36 hours. Therefore, converter slag can be used to remove the phosphate in the form of Struvite from the wastewater.

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Preparation of Slow-Release Potassium Silicate Fertilizer Using Converter Slag (전로(轉爐)슬래그를 활용(活用)한 완효성(緩效性) 칼리 비료(肥料)의 제조(製造) 특성(特性))

  • Yang, Yeong-Ho;Kim, Young-Hwan;Ko, In-Yong
    • Resources Recycling
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    • v.16 no.4
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    • pp.10-16
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    • 2007
  • As a basic study for reusing converter slag as slow-release potassium fertilizer by a sintering process, powdery converter slag and reagent grade $SiO_2\;and\;K_2CO_3$ were mixed with ball mill above 24 hours and sintered at $900^{\circ}C{\sim}1000^{\circ}C\;for\;10{\sim}60$ min. Basicity of the mixed powder was controlled to 0.7, 1.0 and 1.4 and content of $K_2O$ was fixed with 22 mass%. After sintering, property of the potassium fertilizer was investigated with X-ray diffraction pattern and ICP analysis. Also effects of basicity, sintering temperature and time on the making slow-release potassium fertilizer was investigated. Water solubility of KBO in sample were decreased with sintering time, temperature and decreased with basicity. Citric acid solubility of $K_2O$ were increased with basicity and decreased with sintering temperature.

The Interface Reaction Between Molten Converter Slag and $C_3A(3CaO{\cdot}Al_2O_3)$ Pellet (용융전로(熔融轉爐)슬래그와 $C_3A(3CaO{\cdot}Al_2O_3)$ 펠렛사이의 계면반응(界面反應))

  • Kim, Young-Hwan;Ko, In-Yong
    • Resources Recycling
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    • v.14 no.5 s.67
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    • pp.13-17
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    • 2005
  • As a basic study for recycling molten converter slag as an ordinary portland cement (OPC) by a conversion process, the reaction mechanism and the rate of the formation of $C_4AF$ which is one of the main components of OPC were investigated. The converter slag whose basicity was controlled by adding reagent grade $SiO_2$ was melted and hold for 30 minutes in MgO crucible at $1300^{\circ}C{\sim}1350^{\circ}C$. Then, the sintered CaO pellet heated at the same temperature was dipped into the molten slag and hold for $10{\sim}30$minutes. After the reaction, the crucible was cooled in air and the specimen was cut off to the horizontal direction of the crucible. The dissolution rate of $C_3A$ pellet was measured by the change of radius of the sintered $C_3A$ pellet, and the formed phase of $C_4AF$ was observed by SEM/EDX. As a result, the dissolution rate of $C_3A$ pellet into molten slag was increased from $0.75{\times}10^{-4}(cm/sec)$ at $1300^{\circ}C$ to $1.67{\times}10^{-4}(cm/sec)$ at $1350^{\circ}C$, and the mixed layer of $C_4AF$ and $C_{12}A_7$ was found between slag and $C_3A$ pellet.

Recovery of copper from the copper converter slag(II) (동제연소 전노슬래그로부터 동의 회수(II))

  • Oh, Jae-Hyun;Kim, Mahn;Kim, Mi-Sung;Yoo, Taik-Soo
    • Resources Recycling
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    • v.2 no.4
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    • pp.33-41
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    • 1993
  • In recovering copper from the copper converter slag, various separation methods, such as flotation, sieving and magnetic separation had been tried. The copper converter slag used in this study was prepared in two ways, i.e. 2 hour cooled and 10 hour cooled. From the flotation of copper slag, 45% Cu concentrate is obtained and the amount of copper recovery is about 93%. Before the flotation, copper in the slag could be also pre-recovered using sieving and separation. It is also found that as the content of copper in the concentrate increa-ses, that of arsenic increase, while zinc and iron contents decrease.

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The Study of Milling Properties for Optimization of Treatment and Recycling of Converter Slag (제강슬래그 처리 및 재활용의 최적화를 위한 분쇄 특성에 관한 연구)

  • Kuh, Sung-Eun;Hwang, Kyoung-Jin;Kim, Dong-Su
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.6
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    • pp.1139-1148
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    • 2000
  • To treat and recycle a large quantity of converter slag. the milling properties of -14/ +24 mesh-sized slag has been considered. The optimal conditions in milling process were investigated for producing powder-type slag and the required consumption was derived for the economical grinding. The characteristics of milling processes were studied in the variation of the rotational speed, milling time, filling ratio of ball, and size and amount of feed. The grinding efficiency was also examined. The optimal rotational speed in this experimental condition was observed to be the value of 79% of critical speed. The extent of grinding was increased with increasing the grinding time. but the efficiency of milling was decreased with the time. 50% ball filling was shown to have the optimal grinding effect, and less amount and small-sized feed made the milling efficiency high. As the result, using Bond's equation, power required for efficient milling was considered and the highest value was observed in the condition of high grinding time and optimal rotational speed.

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Interface Reaction of Molten Converter Slag and Sintered CaO Pellet (용융 전로슬래그와 소결 CaO 펠렛 사이의 계면반응)

  • Kim Yaung-Hwan;Ko In-Yang
    • Resources Recycling
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    • v.13 no.1
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    • pp.47-53
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    • 2004
  • As a basic study of the re-using molten converter slag as an ordinary portland cement by conversion process, molten slag and sintered CaO pellet was reacted each other. The dissolution rate of the sintered CaO pellet into the molten slag was measured and the changes of the reaction layer was also investigated. The converter slag reagent-grade $SiO_2$ added was melted and hold for 30 minutes in MgO crucible between $1350∼1500 ^{\circ}C$. Then sintered CaO pellet heated at the same temperature was dipped into the molten slag and hold for 10∼30 min. After the reaction, the crucible was cooled in air and the specimen was cut off to the horizontal direction of the crucible. The dissolution rate of CaO pellet was measured by the change of the radius of sintered CaO pellet and the interface layer was observed by SEM/EDX and XRD. The dissolution rate of sintered CaO pellet contacted with the slag of basicity 1 was 9.8 $\mu\textrm{m}$/min at $1350^{\circ}C$ and increased to 18.0 $\mu\textrm{m}$/min at $1500^{\circ}C$. The rate was slightly decreased to 7.6 $\mu\textrm{m}$/min at $1350^{\circ}C$ and 15.0 $\mu\textrm{m}$/min at $V^{\circ}C$ in the slag of basicity 2. The dissolution rate of CaO in converter slag was followed to the rule of Arrhenius' temperature dependency, and the apparent activation energy of the dissolution of CaO was 36 kcal/mole. In case of the slag basicity of 1, the thickness of $C_2$S layer was 64-118 $\mu\textrm{m}$ and the thickness of $C_3$S was 28∼90 $\mu\textrm{m}$ for 10∼30 minutes at $1500^{\circ}C$. And the thickness of the $C_3$S layer was 90∼120 $\mu\textrm{m}$ at the same conditions in the slag basicity of 2.

Phosphate removal efficiency and the removal rate constant by particle sizes of converter slag and conditions of the wastewater (전로슬래그의 입도 크기 및 폐수의 조건 변화에 따른 인산염 제거효율과 제거 속도상수에 관한 연구)

  • Lee, Sang Ho;Hwang, Jeong Jae
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.6
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    • pp.841-849
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    • 2012
  • The effluent quality of phosphorus is strengthened by the national standard to conserve water resources to lessen the eutrophication threat. The soluble phosphate in the wastewater effluent can be removed using the converter slag as solid waste produced through the steel making process. The experiments for removal efficiencies and removal constants were performed for this research with the artificial wastewater following several different conditions, particle size, phosphate concentration and initial pH. The correlation coefficients of Freundlich adsorption isothem were 0.9505 for $PS_A$, 0.9183 for $PS_B$, respectively. The removal efficiency was 87-94 % for $PS_A$ and 90-96 % for $PS_B$ respectively. The pH of the wastewater was elevated to pH 11.8 for the initial pH 8.5, phosphate removal efficiency was the highest as 84 % ~ 98 %. In case of 10 mg/L of the intial phosphate, the removal efficiency was 96 ~ 98 %. The more initial pH increases, the higher the reaction rate constant is.