The properties of dust collected from electric arc furnace of ferro manganese production units was investigated, and also the metallic manganese was recovered from the dust by aluminothermy process. The ferromanganese dust collected from electric arc furnace contained about 15% of manganese oxide (Mn3O4) and 9% of carbon as the contaminant, and have a 5um of 50% median diameter and irregular particle shape. The carbon contaminant in the dust could be reduced until about 0.1~0.5% level by roasting in the air at a temperature of 600~900C for 60minutes. The recovery of manganese could not be carried out using only ferromanganese dust from electric arc furnace by aluminothermy process, but the ferromanganese which contained manganese of about 92% and iron of about 5% could be obtained from the mixture of ferromanganese dusts from electric arc furnace and converter. The best mixing condition of dust fixed at electric arc furnace dust / converter dust ratio of 1:9 and 2:8, and the mixing rato of 3:7 or more could not separated the metal and slag from the reactant after aluminothermy reaction.

PURPOSES: This paper, presents the results of a laboratory study aimed to verify the suitability of a particular type of Electric Arc Furnace (EAF) steel slag to be recycled in the lithic skeleton of both dense graded and porous asphalt mixtures for flexible pavements. METHODS : Cyclic creep and stiffness modulus tests were performed to evaluate the mechanical performance of three different asphalt mixtures (dense graded, porous asphalt, and stone mastic) prepared with two types of EAF steel slag. For comparison purposes, the same three mixtures were also designed with conventional aggregates (basalt and limestone). RESULTS : All the asphalt mixtures prepared with EAF steel slag satisfied the current requirements of the European standards, which support EAF steel slag as a suitable material for flexible pavement construction. CONCLUSIONS : Based on the experimental work, the use of waste material obtained from steel production (e.g. EAF steel slag) as an alternative in the lithic skeleton of asphalt mixtures can be a satisfactory and reasonable choice that fulfills the “Zero Waste”objective that many iron and steel industries have pursued in the past decades.

The potential of marginal materials as components of road infrastructures has been studied for many years. The list of materials includes non-traditional natural materials (rocks and soils), industrial by-products (from metallurgical industry, thermal electric power stations, and chemical industry) and wastes (mining and quarrying, municipal, industrial and demolition wastes). Among these materials, Electric Arc Furnace Steel Slags (EAFSS) presents physical-mechanical characteristics and full chemical compatibility with the hydrocarbon binders used in road construction and, therefore, have high potential for being re-used. This paper presents the results of a laboratory study conducted to verify the suitability of a particular type of Electric Arc Furnace Steel Slag (EAFSS) to be recycled in the aggregate skeleton of dense graded and porous asphalt mixtures for pavements application. One dense graded mixture for wearin gcourse(WCAC), one Stone Mastic Asphalt(SMA) and one Porous Asphalt(PA) were prepared and compacted for this purpose. The computed results of Marshall Stability, Flow and Indirect Tensile Strength (ITS) values are presented in Table 1.

한국원자력연구소 내의 연구용 원자로(TRIGA II, III) 해체 시 발생한 방사성 알루미늄 해체 폐기물의 감용 및 제염 특성을 평가하기 위해 아크로에서 알루미늄의 용융 특성 및 방사성 핵종의 분배 특성에 대한 연구를 수행하였다. 알루미늄 폐기물은 흑연전극(graphite electrode)을 이용한 전기아크로에서 4가지 종류의 플럭스를 함께 첨가하여 용융시켰다. 또한 알루미늄의 용융 시 방사성 핵종의 분배 특성을 고찰하기 위해 알루미늄 시편에 방사성 모의 핵종인 코발트, 세슘, 스트론튬의 화합물을 오염시킨 후 혹연도가니에 넣어 알루미늄 용융실험을 수행하였다. 전기아크로에서 알루미늄의 용융실험을 수행한 결과 플럭스의 종류에 따라 다소 차이는 있으나 플럭스의 첨가에 의해 알루미늄 용융체의 유동성이 증가됨을 확인할 수 있었다. 아크 용융에 의해 생성된 슬래그의 발생량은 플럭스 A와 B를 첨가한 알루미늄 용융실험에 비해 플럭스 C와 D를 첨가한 실험에서 상대적으로 많은 양이 생성됨을 알 수 있었으며, 첨가된 플럭스의 양이 증가할수록 이에 비례하여 슬래그의 발생량이 증가함을 알 수 있었다. 슬래그(slag)의 XRD 분석을 통해 방사성 핵종이 주괴에서 슬래그 상으로 이동한 후 슬래그를 구성하고 있는 산화알루미늄과 결합하여 안정한 화합물로 슬래그 상에 포집됨을 알 수 있었다. 알루미늄 폐기물의 용융시 Co의 분배율은 플럭스를 첨가한 경우에 보다 높은 제염계수를 나타냈으며, 모든 플럭스에서 40% 이상의 제염 효과를 나타내었다. 반면에 휘발성 핵종인 Cs과 Sr은 주괴로부터 98% 이상이 제거되어 대부분이 슬래그상과 분진으로 이동되는 특성을 확인할 수 있었다.

콘크리트의 수축현상은 체적 변화를 발생시키며 균열의 원인이 되어 구조물 내구성 및 안정성에 영향을 미친다. 콘크리트의 수축 에 영향을 미치는 요인은 매우 다양하며, 특히 골재는 시멘트 페이스트의 변형을 구속하여 수축 발생을 억제하기 때문에 골재의 특성은 수축 현상에서 중요하게 고려하여야 하는 부분이다. 한편, 골재 부족 현상으로 인해 천연 골재 대체재 개발 및 적용에 대한 연구가 다방면으로 진행되고 있으며 콘크리트용 골재로 사용 되는 재료도 점차 다양해지고 있다. 따라서 본 연구에서는 전기로 산화 슬래그를 굵은 골재로 사용한 콘크리 트의 수축 특성을 평가하기 위해 수축 실험을 진행하였으며, 실험 결과와 수축 예측 모델을 비교하여 기존 예측 모델의 적용성을 검토하였다. 실험 결과, 전기로 산화 슬래그를 굵은 골재로 사용함에 따라 수축량이 감소하는 결과가 나타났으며, 특히 자기수축 저감 효과가 크게 나타났다. 예측 모델과의 비교 시 건조수축과 자기수축 각각 GL2000 모델과 Tazawa 모델이 가장 유사한 예측값을 나타냈으나, 보다 정확한 예측을 위해서는 골재 및 혼화재의 물성을 고려할 수 있도록 보완이 필요한 것으로 판단된다.

첨단산업의 발전으로 재활용이 어려운 산업부산물의 발생량이 증가하고 있으며, 건설산업에서는 골재 수급이 부족한 실정이다. 이에 본 연구에서는 중금속이 함유된 폐브라운관 유리를 잔골재로 100% 대체하고 전기로 산화슬래그를 굵은골재로 대체한 콘크리트의 감마선 차폐효율을 진단하여, 산업폐기물로 납과 철의 함유량을 높인 콘크리트의 차폐콘크리트 적용성을 검토하였다. 연구 결과, 일반 굵은골재를 사용한 콘크리트보다 반가층이 감소하는 경향을 나타냈으며, 중금속을 함유한 산업폐기물의 적용으로 고밀도의 콘크리트 제조가 가능할 것으로 사료된다.

In this study, the fundamental properties of concrete using industrial waste as aggregate were evaluated. The concrete specimens were prepared using the steel slag as coarse aggregate and heavyweight waste glass. It was found that when the electric arc furnace slag substitution ratio increased, air contents and density also increase. However, the slump is decreased with an increase in the substitution ratio of electric arc furnace slag.

In this study, chloride penetration resistance and electrical resistivity properties of concrete using industrial waste were evaluated. From the results, the chloride diffusion coefficient increases and electrical resistivity decreases when electric furnace slag is mixed. It is needed that the comparison of results with long-term because the electric furnace slag has a ferrous component.

In this study, the compressive strength and elastic modulus of concrete mixed with electric furnace slag were evaluated. The concrete specimens were prepared using the steel slag as coarse aggregate and heavyweight waste glass as fine aggregate. From the results, compressive strength and the elastic modulus were improved with the addition of electric furnace slag.

In this paper, the mechanical properties of GGBFS concrete according to the replacement ratio of electric arc furnace oxidizing slag fine aggregate was evaluated. As the replacement rate of EOS fine aggregate increased, the amount of slump and air content decreased. In addition, EOS concrete increased the initial compressive strength, but, it tended to decrease at 28 days.

In this paper, the mechanical properties of fresh concrete were evaluated by using electric arc furnace oxidizing slag(EOS) aggregate. Water-Cement(W/C) ratio was selected as 0.45 and 0.30, and the mixing amount of EOS aggregate as 0%, 50%, 100%. Experimental items of fresh concrete were slump, flow, air content, unit volume weight. As a results, As the mixing amount of EOS aggregate increased, the slump and flow increased but the air content decreased.

In this paper, the mechanical properties of hardened concrete were evaluated by using electric arc furnace oxidizing slag(EOS) aggregate. Water-Cement(W/C) ratio was selected as 0.45 and 0.30, and the mixing amount of EOS aggregate as 0%, 50%, 100%. Experiments were carried out to compare the unit volume weights by concrete mixing, and the compressive strength test was carried out at 28 days of age. The unit volume weight and compressive strength of the EOS aggregate increased as the amount of the mixture increased. It also shows the difference according to the W/C ratio.

본 논문은 전기로 산화슬래그 골재를 사용하여 콘크리트를 제작하여 물리적 성능을 평가하였다. 실험은 전기로 산화슬래그 골재를 치환하여(잔골재-굵은골재) 0%-0%, 0%-100%, 50%-100%, 100%-100%으로 각 4수준으로 일반강도영역 W/C 45%와 고강도영역인 W/C 30% 의 2수준으로 제작하여 진행하였다. 굳지 않은 콘크리트에서는 공기량, 플로우 및 슬럼프, 단위용적질량 실험을 진행하였으며, 경화 콘크리트 에서는 압축강도 및 휨강도, 단위용적질량 실험을 통하여 물리적 특성을 검토하였다. 본 연구의 실험결과 전기로 산화슬래그의 혼입량이 증가 함에 따라 콘크리트의 강도 증진 효과가 나타났으며, 이는 전기로 산화슬래그 골재 내에 β-C2S로 인하여 골재 내외부에서 강도 증진 효과를 발 휘한 것으로 사료된다.

As the amount of slag generated annually increases, attempts to recycle slag as high value products are underway in order to develop an efficient resource recycling industry based on slag and derive economic benefits as well. However, the application of electric arc furnace (EOS) slag as construction material is practically limited because of the unstable substances included in it, such as free CaO.(EOS contains a small amount of free CaO, but several limitations still exist. Slag is stored for more than 3 months depending on the quantity of slag, which leads to additional economic loss. In this study, the amount of free CaO present in EOS is quantitatively evaluated to examine its qualities as a potential construction material and verify its application as concrete material. The quantitative analysis of free CaO present in EOS is performed using ethylene glycol. The free CaO contents of EOS samples were found to be below 0.5%. This satisfies the criteria specified in KS F 4571, which states that the CaO content should be below 40% and CaO/SiO2 ratio should be below 2.0. In addition, it was confirmed that free CaO content difference appears to be dependent on the aging period and storage position.

In this study the optimum conditions for recovery of valuable metal in Electric Arc Furnace Dusts were investigated. 2M of H2SO4, 1~5 of solid/liquid ratio, 0~180 min of leaching time has been established for leaching condition, and for electrowinning, each of Pt, C, Zn, Pb anode and Zn, Cu cathode was compared respectively at pH 2, 4 and 6. The result of elemental analysis of Zn crystal, a lagre quantity of Fe and H has been observed with Zn and other heavy metal, therefore, impurities removing process would be requir for enhancing purity of Zn. As the result, about 60% of Zn has been recovered under condition of 2 M of H2SO4, 1:2 of S/L ratio at 120 min, and Pt or Pb for anode, Zn for cathode has been shown the highest efficiency of electrowinning at pH 6.

Hydrometallurgical process, which is one of the recycling method of EAFD in zinc, is a process to recover metallic crystal form that deposited on the cathod through electrolytic extraction by leaching valuable metals in appropriate solvent. Still, there is a lot of variable at electrowinning process, such as initial pH, space between electrode, voltage, current, cathod, or anode, Thus, many studies have been conducted previously. In this study, the consideration of optimistic condition in electrowinning process to recover the valuable metal in EAFD have been carried. The extraction amount by changing pH shows increase according to high initial pH, also, the alteration of extraction amount by controling the space between electrode, voltage or current has been measured. The difference of efficiency represent by decrease of electromotive force, sudden loss of voltage under specific condition, and using platinum as electrode shows most stable extraction. Furthermore, when distance between electrode are too close, the extracted zinc contact with anode, which make recovery difficult. The analysis result of zinc metallic crystal which been recovered draws spherical and cylindrical shapes are scattered and mixed, and consequence of EDX, content of zinc appear about 60%.

Currently, a technique to subdivide the process refining is introduced, can be divided into the steel slag. In this study, Free-CaO in the electric arc furnace slag by the ethylene glycol method for the quantitative analysis for the expansion to proceed with construction materials.

CO2 emitted from building materials and construction materials industry reaches about 67 million tons, which occupy about 30% of CO2 emitted from the construction field. Controls on the use of consumed fossil fuels and reduction of emission gases are essential for the reduction of CO2 in the construction area as we reduce the second and third curing to emit CO2 in the construction materials industry. Accordingly, this study applied the low energy curing admixture (hereinafter “LA”) to the extruded panels to observe the physical properties, depending on the mixing amount of fiber, type of fiber and mixing ratio of fiber. The type of fiber did not appear to be a main factor to affect strength, while the LA mixing ratio and mixing amount of fiber appeared to be major factors to affect strength. Especially, the highest strength was developed when the LA mixing ratio was 40%, whereas the test object with the mixing ratio of 50% resulted in the decrease of strength. In addition, it appeared that the mixing ratio of fiber greatly affected flexural strength and strength increased as the mixing ratio increased.

This laboratory study showed the performance evaluations of a improved C12A7 based mineral accelerator (I-CA) by both mortar and shotcrete tests. Performance of I-CA as a shotcrete accelerator was excellent by KCI-SC-102, which is a Korean specifications of shotcrete accelerator. In addition, I-CA showed equal qualities to the setting time and the compressive strength when compared those of the existing C12A7 based mineral accelerator (CA). The I-CA was manufactured with 40wt.% of electric arc furnace reducing slag, 24wt.% of lime, and 36wt.% of bauxite, indicating that the commercialization of I-CA contributed to recycle electric arc furnace reducing slag and to reduce the manufacturing cost of C12A7 based mineral accelerator due to the use a cheap raw material(electric arc furnace reducing slag), and to reduce the greenhouse gas emission due to the reductions in usage of lime and bauxite.