• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.203-204
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• 2016

In this research, it used cement power and reduction slag, which generates high hydration heat in hydration reation without heat cure below -5℃ degree. Purpose of final research is preventing freezing and thawing by making the compressive strength 5MPa in 3days below zero temperature due to own heat of concrete. and it is the result of physical characteristic and thermal property evaluation of reduction slag. Because reduction sag generates high hydration heat, compressive strength development is excellent. By generating highly Hydration heat by C₁₂A₇ and C₃A in reduction slag, compressive strength is developed in low temperature. In case of displacing only reduction slag without SO₃, it is indicated that quick-setting occurs by shortage of SO₃. For preventing quick-setting, gypsum is used essentially. According to this research result, in case of using reduction slag and gypsum as a ternary system, Compressive strength developed 5MPa in 3days below zero temperature. It is identified to prevent early frost damage of concrete below zero temperature.

• Korean Journal of Metals and Materials
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• v.50 no.10
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• pp.753-761
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• 2012

The reduction behavior of low level oxides such as (T.Fe), (MnO) and ($P_2O_5$) in molten EAF slag was investigated using commercial reductants. In an air atmosphere, the slag volume increased and the reduction rate of the slag was very low due to the oxidation loss of reductants by oxygen in the air. The reduction rate of the slag was also low when a commercial reductant was used alone in an Ar gas atmosphere. The reason is probably because the material transfer through the interface between the slag and reductant is difficult due to the formation of high melting point oxide. When reductants were mixed with burnt lime in order to form low melting point reaction products, the reduction rate of the slag increased up to the range of 45-70%. By using the mixtures of reductants and burnt lime so as to form a low melting point slag at the reaction end, the reduction rate of the slag was improved up to 60-85%.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.380-385
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• 2014

Spherical atomizing reduction steel slag was prepared by atomizing technology using reduction steel slag (ladle furnace slag, LFS) generated from steel industry. In order to develop the mass-recycling technology of atomizing reduction steel slag, polymer concrete composite was prepared using spherical atomizing reduction steel slag instead of fine aggregate (river sand) and coarse aggregate (crushed aggregate), depending on the grain size. Different polymer concrete specimens were prepared with the various proportions of polymer binder and replacement ratios of atomizing reduction steel slag in order to investigate the characteristics of polymer concrete composite. Results showed that compressive strengths of polymer concrete specimens decreased with the increase of replacement ratios of atomizing reduction steel slag, but flexural strengths of the specimens showed a maximum strength at the 50% of replacement ratios of atomizing reduction steel slag. It was concluded that addition ratio of polymer binder, which affect greatly on the prime cost of production of polymer concrete, could be reduced by maximum 18.2 vol% because the workability of the polymer concrete was remarkably improved by using the atomizing reduction steel slag. However, further study is required because the mechanical strength of the specimen using atomizing reduction steel slag was greatly reduced in hot water resistance test.

• Korean Journal of Materials Research
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• v.20 no.1
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• pp.42-46
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• 2010

Phosphorus exhibits considerable segregation in steelmaking slag. In order to recover phosphorus from slag to $K_3PO_4$ via molten iron, a carbothermic reaction using microwave heating was suggested recently. The carbothermic reduction of phosphorus from slag to molten iron using microwave heating was carried out at 2073K. However, at this temperature the thermodynamic properties of both slag and molten iron cannot be determined experimentally. Therefore, the computational approach of the so-called CALPHAD method is very useful to understand the transfer of phosphorus from slag to metal and to enhance this reaction. In the present investigation, a theoretical study of the reduction behavior of phosphorus in slag was carried out at much lower temperatures using the recently developed thermodynamic database in the FactSage program. The calculated results showed reasonable accordance with the experimental data; namely, the thermodynamic database could be applied successfully to higher temperature reactions. The current study found that higher temperature and high $SiO_2$ concentration are favorable for the recovery of phosphorus from slag.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6890-6897
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• 2014

EAF reduction slag has unstable properties of expansion and destruction. Therefore, it cannot be used as a construction material. The purpose of this study was to use EAF reduction slag as a concrete admixture. EAF reduction slag contains $11CaO{\cdot}7Al_2O_3{\cdot}CaF_2$ and ${\beta}-C_2S$ (calcium aluminate compounds). To confirm the properties of EAF reduction slag as a concrete admixture, the condensation, compressive strength and activity factor due to substitution rate of EAF reduction slag were measured. Originally, EAF reduction slag was cured rapidly because of its chemical composition ($11CaO{\cdot}7Al_2O_3{\cdot}CaF_2$). On the other hand, when 8% gypsum was added, its properties of condensation and compressive strength were similar to the plain specimen. When 6% gypsum was added, the quality of the KS F 2536 standards (quality standard number 3) were met in terms of activity factor. Overall, 8% gypsum addition is the most appropriate by considering the activity factor in the long-term compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.150-151
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• 2016

In previous study, researchers studied development of early anti-freezing cement at low temperature (-5℃) using hydration characteristics of reduction slag. In this study, the durability of concrete using reduction slag was conducted. The experiment result, reduction slag makes high temperature and improves compressive strength due to quick setting. And then result of durability show that it is no problem. However, it is considered that further study is needed about high shrinkages which was indicated in dry shrinkage.

• Resources Recycling
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• v.25 no.4
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• pp.54-59
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• 2016

EAF processed slag which contains about 20 ~ 35 weight percent FetO is poured to slag pot and cooled. If we recover Fe from molten slag by the reduction, we will improve steel yield rate and reduce slag quantity poured from the furnace. Usually, carbon is used as a reductant and slag foaming agent in the EAF process. In this experiment, after melt the metal in induction furnace and then add slag with carbon and Al dross powder as a reductant, we investigated the reduction of FetO from slag and change of Phophorus content. As the result, when we use Al dross as a reductant, recovery rate is two times more than carbon. Phosphorus pick up is less than 50ppm with reduction of EAF slag.

• Resources Recycling
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• v.12 no.2
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• pp.21-27
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• 2003

Smelting reduction technique in arc furnace was applied for the recovery of valuable metal such as V from LD slag. In the present study, the parameters for increasing the reduction rate and the reduction efficiency were selected by changing the oxide additives, melting temperature and basicity. The optimum condition for LD-slag reduction was achieved by $Al_2$$O_3$ addition. The reduction ratio of V was increased in increasing the basicity.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.998-1001
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• 2010

Most firming agent used in Korea is cement-firming agent. Cement-firming agent absorb water for combination, and then it makes ettringite. Through this chemical process, soft ground is firmed by cement-firming agent. Although most cement-firming agent used in Korea made from CSA, it relies on imports. Therefore, the development of soft ground firming agent using new materials is required. In this study, we suggested that EAF reduction slag not used for anything in the steel industry is available for material of soft ground firming agent. If EAF reduction slag is used in soft ground firming agent, it will be possible to solve the problem with treatment of slag and improvement of soft ground.

• Resources Recycling
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• v.9 no.1
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• pp.52-62
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• 2000

In order to maximize the recycling of converter slag to the more valuable fields, such as high quality aggregates for construction, cement industry and flux for ion making. It will be very important to control the compositions and properties of converter slag to suit the purpose of utilizastion. In this study, converter slag (STELCO, CANADA) was mixed with 5%~30% $SiO_2$and 7% carbon, and then reduced at $1650^{\circ}C$. After the reduction was completed, the reformed slags were cooled to room temperature in the furnace. All of the slags were then characterized using SEM-EDX, XRD and chemical analysis. Also the compressive strengths and densities of the reformed slags were measured to compare with natural aggregates. XRD analysis shows that th phases of reformed slags are changed from bredigite+merwinite mixed phases of 10% $SiO_2$added reduction to akermanite phases of 20% and 30% $SiO_2$ added reduction. But the SEM-EDX analysis revealed that the phase distribution of the reformed slags was changed very sensitively and complicately depends on the change of slag compositions. And also the properties of reformed slags are changed very much depend on the phase distribution. About one third of Cadmium and on fifth of Vanadium are remained in reduction reformed converter slag. Another heavy metal elements such as cobalt, zinc, lead are removed up to more than 90-95% of original slag. The compressive strength and density of 25% $SiO_2$ added and reformed slag is very near to natural granite. This is superior more than 10% to Thyssen's $SiO_2$ added and oxidized converter slag aggregates.