• Journal of the Korean Ceramic Society
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• v.36 no.4
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• pp.410-416
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• 1999

The reactivity of three kinds of spinels which CaO-Al2O3-SiO2 slag was investigated in terms of mineral phases and microstructures. New crystal products were not formed by reaction of 12CaO.7Al2O3 in the slag with spinels and free MgO components was preferenctially dissolved into slag for MgO-rich spinel and stoichiometric spinel. Meanwhile mineral phase was changed from 12CaO.7Al2O3 to CaO.Al2O3 to CaO.2Al2O3 finally to CaO.6Al2O3 having high melting point for Al2O3 -rich spinel. The Fe-oxide component of the slag was taken up by only stoichiometric spinel grains within the spinel clinker and the trapped amount of Fe-oxide was independent of MgO content of MgO in spinel clinker the more th resistance to slag corrosion but the less resistance to slag penetration.

• Journal of Sensor Science and Technology
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• v.9 no.2
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• pp.141-145
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• 2000

In order to measure the thickness of the slag layer on the molten metal in the melting vessels for steel making foundaries, we manufactured the slag-thickness measuring system consisting of the probe and its driving system, which is based on the principle of detecting the change in the electrical resistivity. Experimental results show that there is a very wide difference of the electrical resistivity by the order of about $10^3$ between the molten metal and the hot slag and, hence, the air/slag and slag/molten metal interface can be exactly detected with the use of the probe which can be moved toward the melt. Therefore, it can be concluded that the proposed scheme of the slag measurement system in this study is Proven to be excellent in its efficiency and accuracy.

• 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.

• Resources Recycling
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• v.17 no.4
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• pp.57-65
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• 2008

The behavior of Na-A type zeolite formed in hydrothermal synthesis of melting slag from municipal incineration ash has been investigated with varying synthesis time and $SiO_2/Al_2O_3$ ratio. Sodium silicate and sodium aluminate feed was found to initially form nuclei of Na-A type zeolite in the behavioral study of the reaction products with different synthesis times. As the synthesis time increased, the nuclei have grown to Na-A type zeolite crystals by reacting with $SiO_2$ and $Al_2O_3$ dissolved from the melting slag. The hydrothermal synthesis was completed in 10 hr in the $SiO_2/Al_2O_3$ ratio of 1.38 and after that time, the Na-A type zeolite formed was dissolved and transformed into hydroxysodalite. Only Na-A type zeolite was formed in the $SiO_2/Al_2O_3$ ratio ranging 0.80 to 1.96, whereas Na-P type zeolite as well as Na-A type was formed in the $SiO_2/Al2O_3$ ratio of 2.54.

• Journal of the Mineralogical Society of Korea
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• v.19 no.1 s.47
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• pp.7-14
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• 2006

Melting slag generated from the lots of municipal incineration ash, which causes the one of big urban problems in modern industrial society, was used as starting material for the hydrothermal synthesis of zeolite. P-type zeolite has been successfully synthesized by the combined process of both 'hydrogelation' and 'clay conversion' method. Commercial sodium silicate was used as Si source, and $NaAlO_2$ was prepared by the reaction in a $Na_{2}O/Al_{2}O_{3}$ molar ratio of 1.2. The optimum conditions for zeolite synthesis was found to be the $SiO_{2}/Al_{2}O_{3}$ ratio in the 3.2 and 4.2 range, the $H_{2}O/Na_{2}O$ ratio in the 70.7 and 80.0 range, and more than 15-hour reaction time at $80^{\circ}C$, In the synthesized zeolite, inhomogeneous melting slag particles were disappeared and homogeneous P-type zeolite crystal was grown. The cation exchange capacity of the synthesized zeolite was determined to be approx. 240 cmol/kg.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.561-564
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• 2005

Gasification has been regarded as a very important technology to decrease environmental pollution and to obtain higher efficiency. The gasification process converts carbon containing feedstock into a synthesis gas, composed primarily of CO and $H_2$. And the synthesis gas can be used as a source for power generation or chemical material production. Through more than nine years, IAE developed and upgraded several gasification/melting pilot plant system, and obtained a good quality synthesis gas. This paper illustrates the gasification characteristics and operation results of two 3 ton/day synthesis gas production facilities. One is entrained-bed slagging type coal gasifier system which is normally operated in the temperature range of $1,400\~1,450^{\circ}C,\;8\~10$ bar pressure. And the other is fixed-bed type gasification/melting furnace system using MSW and industrial wastes as a feedstock.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.352-352
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• 2000

ESR(ElectroSlag Remelting) Process is secondary fine process and melts steels by electric resistance heat and fines the melting steels by an appropriate solidification process parameters which affects the melting and solidification processes to get the high quality products. This paper describes a method to derive the mathematical model and analysis the dynamic characteristics for designing a controller of the ESR processes. The ESR process consists of a melting and solidificating processes and electrical system include the contact resistance mechanism. In this paper, we consider only the static relationship between inputs and outputs of the electric system because the dynamics of the electric system is so fast compared with the melting and solidificating processes which are analysed by using finite difference method. As the results, the fine processing in ESR is analysed and the process controller could be designed based on the process dynamic analysis.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.76.4-76
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• 2001

ESR(ElectroSlag Remelting) Process is secondary fine process and melts steels by electric resistance heat and fines the melting steels by an approproate solidification process. The final products are determined through the velocity of melting and the course of solidification in the process that is achieved by way of proper course of solidification. Thus, it is very important to monitor and control the process parameters which affects the melting and solidification process to get the high quality products. This paper describes a method to derive the mathematical model and analysis the dynamic characteristics for designing a controller of the ESR processes. The process consists of a melting and solidifying process and electrical system include the contact resistance mechanism ...

• Korean Journal of Materials Research
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• v.27 no.5
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• pp.281-288
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• 2017

In this study, Fe-Ni slag, converter slag and dephosphorization slag generated from the steel industry, and fly ash or bottom ash from a power plant, were mixed at an appropriate mixing ratio and melted in a melting furnace in a mass-production process for glass ceramics. Then, glass-ceramic products, having a basalt composition with $SiO_2$, $Al_2O_3$, CaO, MgO, and $Fe_2O_3$ components, were fabricated through casting and heat treatment process. Comparison was made of the samples before and after the modification of the process conditions. Glass-ceramic samples before and after the process modification were similar in chemical composition, but $Al_2O_3$ and $Na_2O$ contents were slightly higher in the samples before the modification. Before and after the process modification, it was confirmed that the sample had a melting temperature below $1250^{\circ}C$, and that pyroxene and diopside are the primary phases of the product. The crystallization temperature in the sample after modification was found to be higher than that in the sample before modification. The activation energy for crystallization was evaluated and found to be 467 kJ/mol for the sample before the process modification, and 337 kJ/mol for the sample after the process modification. The degree of crystallinity was evaluated and found to be 82 % before the process change and 87 % after the process change. Mechanical properties such as compressive strength and bending strength were evaluated and found to be excellent for the sample after process modification. In conclusion, the samples after the process modification were evaluated and found to have superior characteristics compared to those before the modification.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.159.2-159.2
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• 2010

Asbestos is the collective name for a group of naturally occurring minerals in their fibrous form and hydrous silicates of magnesium and a mineral fiber that has been used commonly in a variety of building construction materials for insulation and as a fire-retardant. Asbestos has been used for a wide range of manufactured goods, because of its fiber strength and heat resistant properties. Nevertheless harmful of asbestos is quite serious. Exposure to airborne friable asbestos may result in a potential health risk because persons breathing the air may breathe in asbestos fibers. Continued exposure can increase the amount of fibers that remain in the lung. Fibers embedded in lung tissue over time may cause serious lung diseases including asbestosis, lung cancer. In this paper, we carried out as fundamental study for dispose of asbestos cement slate safely and perfectly. Melting Temperature of asbestos need to more than $1,520^{\circ}C$ and specially asbestos cement slate need more energy than that of pure asbestos. We need to decrease melting temperature of asbestos cement slate for economical efficiency. To the purpose, glass and bottom ash were chosen as additives for basicity control. we analyzed about properties of asbestos cements slate, melting characteristics on the additives ratio and temperature. We confirmed about harmlessness of melting slag through analysis of scanning electron microscope(SEM) and x-ray diffractometer(XRD).