• Title/Summary/Keyword: converter slag

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Considerations of Permeability of Converter Slag for Recycling in vertical drainage method (연직배수공법에 있어서 제강슬래그의 재활용을 위한 투수성 연구)

  • 이광찬;정규향;김영남;이문수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.02a
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    • pp.12-31
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    • 2000
  • 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. Converter slag being submerged with fresh water, the coefficients of permeability in A and B samples less than 10mm grain sizes were measured as 6.52${\times}$10$\^$-2/cm/sec and 5,99${\times}$10$\^$-1/cm/sec, while changed as 1,88${\times}$10$\^$-2/cm/sec, 3.86${\times}$10$\^$-1/cm/sec 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 180 days on using sea water, the coefficients of permeability of sample A and B samples decreased ten times smaller than those initial values. And after that time continually decreased as for till 360 days. The reduction of permeability coefficient was considered to influence filled with voids in high-calcium quicklime(CaO). However, in-situ coefficient of permeability was practically satisfactory.

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Solidification of Digested Sewage Sludge with Converter Slag (제강전로(製鋼轉爐)슬래그를 이용한 하수소화(下水消化)슬러지의 고화처리(固化處理))

  • Kim, Eoung Ho;Cho, Jin Kyu
    • Journal of Korean Society of Water and Wastewater
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    • v.9 no.3
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    • pp.108-115
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    • 1995
  • The feasibility study of using converter slag as a solidifying agent of digested sewage sludge cake has been performed. The availability of converter slag as solidifying agent has been investigated by several trial tests. Based on the trial test results, the optimum mixing ratios of sludge cake and solidification additive are estabilished. Finally the solidification characters of sludge cake are elucidated by SEM and EDS. It is ascertained that converter slag with a small amount of quicklime enhences the solidification. From the result of pH test, overall pH of specimens tends to decrease slowly with curing time. After solidifying specimens had been cured for 7 days, these are water-cured for 24 hours. The weight and strength of all the specimens are nearly the same regardless of the mixed ratios of solidifying agent. The result of leaching tests for four heavy metal ions, Cd, $Cr^{6+}$, Pb and Cu show that the leaching strength becomes below the decision criteria of the specific wastes, respectively. The SEM observation of the delicate structure shows that needlelike crystals appear after solidification which are not observed before. From the EDS analysis, it is found that the main ingredients of needlelike crystals are Ca, Si, Al and O.

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Comparable Influencing Factors to evaluate the Phosphate Removal on the Batch and the fix-bed Column by Converter Slag (회분식과 연속흐름 칼럼에서 전로슬래그에 의한 인제거 영향에 미치는 요소에 관한 연구)

  • Lee, Sang-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.29 no.5
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    • pp.565-573
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    • 2015
  • The influencing factors to remove phosphate were evaluated by converter slag (CS). Experiments were performed by batch tests using different CS sizes and column test. Solutions were prepared at the different pH and concentrations. The maximum removal efficiency was obtained over 98% with the finest particle size, $CS_a$ within 2 hours in batch tests. The removal efficiency was increased in the order of decreasing size with same amount of CS for any pH of solutions. The adsorption data were well fitted to Freundlich isotherm. From the column experiment, the specific factors were revealed that the breakthrough removal capacity (BRC) $x_b/m_{cs}$, was decreased by increasing the influent concentration. The breakthrough time, tb was lasted shorter as increasing the influent concentration. The pH drop simultaneously led to lower BRC drop during the experimental hours. The relation between the breakthrough time and the BRC to influent concentration was shown in the logarithmic decrease. Results suggested that the large surface area of CS possessed a great potential for adsorptive phosphate removal. Consequently particle size and initial concentration played the major influencing factors in phosphate removal by converter slag.

Studies of the Recovery of Iron Content from Iron and Steel-Making Slags by Magnetic Separation (자력 선별에 의한 철강 슬래그로부터의 철분 회수에 관한 연구)

  • Ban Bong-Chan;Yu Sung-Nam;Kim Dong-Su
    • Resources Recycling
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    • v.12 no.5
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    • pp.36-41
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    • 2003
  • Although slag has an enough potential as the secondary resources due to its high content of iron, quite a large amount of slags are simply landfilled when market prices of iron and steel are not so beneficial. The purpose of this study is to investigate the basic characteristics regarding the recovery of iron content from slag by magnetic separation method for the enhancement of its recycling rate. Three kinds of slags such as blast furnace slag, water-cooled converter slag, and air-cooled converter slag were tested taking the strength of magnetic field, revolving speed of drum, and feeding rate of slag as the influential factors on the magnetic separation. For blast furnace slag, the recovery of iron was observed to increase as drum speed and feeding rate were lowered. For water-cooled converter slag, iron recovery was raised as feeding rate was increased and drum speed was lowered. Also, finer slag particles were observed to be more favorable for the higher recovery of iron content. Regarding air-cooled converter slags, higher iron recovery was accomplished when both feeding rate and drum speed were increased or decreased. In addition, when the magnetic field strength was increased the iron recovery was raised, however, the iron grade of separated product was observed to diminish because of the co-separation of impurities.

A Study on the Preparation of Modified Belite Cement Using Converter Slag (전로슬래그를 이용한 Modified Belite Cement의 제조에 관한 연구)

  • 박종옥;김승진;박홍수;신현택
    • Journal of the Korean Ceramic Society
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    • v.32 no.8
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    • pp.873-880
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    • 1995
  • In order to prepare the modified belite (C2S-C4A3S-C4AF-CS) cement with low energy, clinkers were synthesized by converter slag, limestone, gypsum and clay. The synthesized clinkers were characterized and the hydration processes were investigated by XRD, SEM and microconduction calorimetry. The hydrates were mainly C-S-H and ettringite. The needle-like ettringite formed by the hydration of C4A3S at the early stage of hydration was filled in the inner vacant spaces of the hardened body and it might contribute to the rapid-hardening phenomena. The hardened body became stronger due to the hydration of C2S at the later period. The compressive strengths of the cement-3 mortars hydrated for 3, 7 and 28 days were 115, 128 and 211 Kgf/$\textrm{cm}^2$, respectively.

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Chemical Properties of Converter Slag according to CO2 Nanobubble Acceleration Aging Time (CO2 나노버블 에이징 시간에 따른 전로슬래그의 화학적 특성)

  • Lim, Chang-Min;Im, Geon-Woo;Kim, Young-Min;Lee, Gun-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.91-92
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    • 2023
  • In this study, the chemical composition of converter slag according to CO2 nanobubble promotion aging time was examined. The CO2 nanobubble water immersion time was 0, 12, 24, 36, 48 hours, and then dried and pulverized to perform XRD analysis. As a result, the longer the sample was immersed in CO2 nanobubble water, the higher the amount of calcite produced, and the change after 36 hours was minimal.

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An Effect of $Al_{2}O_{3}$ on the Reaction between Molten Converter Slag and CaO pellet (용융전로(熔融轉爐)슬래그와 CaO펠렛의 상호반응(相互反應)에 미치는 $Al_{2}O_{3}$의 영향(影響))

  • Kim, Young-Hwan;Ko, In-Yong
    • Resources Recycling
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    • v.15 no.2 s.70
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    • pp.3-9
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    • 2006
  • As a basic study on the conversion of molten converter slag to the ordinary portland cement, the effects of $Al_{2}O_{3}$ addition on the interface reaction between solid CaO and molten converter slag has been studied. Alumina added converter slag whose basicity was controlled to 1 and 2 was melted and hold for 30 minutes in MgO crucible at $1500^{\circ}C$. Then sintered CaO pellet heated at the same temperature was dipped into the molten slag and held for 30minutes. 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 with the addition of $Al_{2}O_{3}$ was measured by the change of the radius or sintered CaO pellet and the interface layer was observed by SEM/EDX. As a result. At the basicity 2 slag, thickness of created $C_{3}S$ layer increased 3.5 times and quantity of $C_{6}AF_{2}\;or\;C_{4}AF$ phase increase 2 times than baisicy 1 slag.

A Study on the Preparation of Precipitated Calcium Carbonate from Steelmaking Slag

  • Shon, Byung-Hyun
    • International Journal of Advanced Culture Technology
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    • v.10 no.1
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    • pp.284-293
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    • 2022
  • After extracting the calcium component from the KR slag and the converter slag using ammonium chloride solution, the extract was reacted with carbon dioxide to synthesize precipitated calcium carbonate (PCC). In order to understand the effect of ultrasonic waves on calcium extraction from slags and calcium carbonate synthesis, the efficiency of calcium carbonate synthesis according to the with or without of ultrasonic waves was analyzed. The synthetic efficiency of PCC was investigated according to various experimental conditions, and the synthesized calcium carbonate was analyzed using XRD and SEM. In both slags, the amount of PCC decreased as the reaction temperature increased. The pH at the end of the experiment capable of synthesizing the maximum PCC in the carbonation reaction was 7 (irradiated with ultrasound) and 8 (irradiated without ultrasound), respectively. Because the pH of the extraction filtrate is different when irradiated with or without ultrasound, the pH was adjusted to 9 by injecting an additive (10 M NaOH) before the carbonation experiment, and then the experiment was performed. When calcium was extracted from KR slag, the crystal phase appeared as calcite regardless of the pH at the end of the experiment. However, when calcium was extracted from the converter slag and the pH was set to 7 at the end of the experiment, the crystal phase of PCC appeared as a mixture of calcite and vaterite.

A Fundamental Study on the Converter Slag Coarse Aggregate Used in Concrete (전로슬래그 굵은골재를 콘크리트용으로 사용하기 위한 기초적 연구)

  • 문한영;유정훈;정호섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.233-236
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    • 1999
  • In this paper, we carried out fundamental experiments to use the steel manufacturing slag as a concrete aggregate. Generally there are two types of slag, the blast-furnace slag and the steel manufacturing slag. The latter is classified by the difference of manufacturing method of steel into the convertor slag and the electric-furnace slag. The steel manufacturing slag mainly contains SiO2 and CaO as the chmical composition. The reaction with water and a little of free CaO in the steel manufacturing slag makes the expansion of volume change. Therefore, we primarily investigated physical properties, expansion mechanism, pH value, aging effects and aging methods in the steel manufacturing slag. Then compressive strength of concrete with steel slag aggregate is measured.

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Fundamental Properties of Converter Slag Aggregate Treated with Accelerated Aging (촉진에이징처리한 전로슬래그 골재의 기초물성)

  • 문한영;유정훈;천승환
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.275-278
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    • 2000
  • In this paper, we carried out fundamental experiments to use steel manufacturing slag as a concrete aggregate. Generally, there are two types of slag, the blast-furnace slag and the steel manufacturing slag. The latter is classified by the difference of manufacturing method of steel into the convertor slag and the electric-furnace slag. The steel manufacturing slag mainly contains $SiO_2$ and CaO as the chemical composition. The reaction with water and a little of free CaO in the steel manufacturing slag made the expansion of volume change, Therefore, we primarily investigated physical properties, expansion mechanism, pH value, aging effect and aging methods in the steel manufacturing slag, Then compressive strength of concrete with steel slag aggregate is measured.

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