• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2002.05a
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• pp.66-73
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• 2002

전기로제강분진을 적절한 공정을 통하여 처리하여 유가금속을 회수하고 처리잔사를 철원으로 재활용한다면 환경오염방지 및 폐자원의 재자원화 효과가 기대된다. 본 연구에서는 고온환원과 전해공정을 조합한 새로운 전기로제강분진 처리공정을 제안하고, 각 공정에 대한 기초실험을 수행하여 그 가능성을 조사, 검토 하였다. 전기로제강분진의 고온환원실험과 환원과정에서 분위기와 증기압의 차이를 이용한 Zn및 Pb 성분의 분리, 휘발실험의 결과들이 분석되었으며, 아울러 환원처리잔사 중의 Fe성분함량을 증가시켜 철원으로 재활용할 수 있는 가능성을 확인하기 위하여 전기로제강분진과 millscale을 혼합, 환원하는 실험을 수행하였다. 또한 환원과정의 휘발산물인 조산화아연의 침출 및 전해에 관한 기초실험을 수행하여 고순도금속아연회수의 가능성도 조사, 검토하였다.

• Resources Recycling
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• v.9 no.6
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• pp.45-52
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• 2000

Generally, the residues of EAF's dusts treated by reduction process at high temperature are disposed. If the residues can be recycled as iron sources of EAF by upgrading their iron contents, it can be expected to reduce the amounts of disposed wastes and the environmental impacts. Reduction of EAF's dusts mixed with millscale was carried out in rotary hearth furnace to upgrade iron contents of reduction residues. Dusts should be reduced rapidly to protect from reoxidation of reduced iron residue which can be reoxidized at high temperature. In our experimental conditions, optimum reduction time was about 40min. and iron contents of the residues were increased with increasing mixing ratio of millscale and upgrade to 85% at 50%wt mixing ratio. Zinc and lead contents in residues were about 3% and 0.5% respectively. The residues reduced rapidly must be recycled in EAF because heavy metal elements in the residues can be extracted easily and contaminate air and water.

• Resources Recycling
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• v.30 no.1
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• pp.66-76
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• 2021

Electric arc furnace dust (EAFD) contains compounds, such as oxides and chlorides, including large quantities of Zn, Pb and Fe. An efficient and stable method for the extraction of metal elements from EAFD is the Rotary Kiln Process. This method is used to recover Zn in the form of crude ZnO (approximately 60%) via the addition of a reducing agent (coke, anthracite) and limestone (for basicity control) to EAFD. This process is commonly used in industry as well as in research and development. Currently, this method is used in many Korean commercial plants, producing approximately 150,000 tons of Crude ZnO per year. The majority of Zn is found in crude ZnO (approximately 76%). In addition components such as Pb, Cd, Sn, In, Fe, Cl, and F are present as oxides, chlorides, and alkaline compounds. This elements have an adverse effect on the zinc smelting process. Therefore, a refining process that eliminates these impurities is essential. In this study, we developed a process technology that efficiently separates Zn and Pb from byproducts (mainly chlorides). A bag filter was used to collect Zn and Pb generated during the dry purification process of crude ZnO. Pure components were recovered as metals or metal carbonate.

• Resources Recycling
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• v.33 no.4
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• pp.47-61
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• 2024

As a recycling technology for recovering zinc contained in large amounts in electric arc furnace dust (EAFD), the most commercialized technology in the world is the Wealz Kiln Process. The Wealz Kiln Process is a process in which components such as Zn and Pb in EAFD are reduced/volatile (endothermic reaction) in high-temperature Kiln and then re-oxidized (exothermic reaction) in the gas phase and recovered in the form of Crude zinc oxide (60wt%Zn) in the Bag Filter installed at the rear end of Kiln. In this study, an experimental Wealz kiln was produced to investigate the optimal process variable value for practical application to the recycling process of large-scale kiln on a commercial scale. Additionally, Pellets containing EAFD, reducing agents, and limestone were continuously loaded into Kiln, and the amount of input, heating temperature, and residence time were examined to obtain the optimal crude zinc oxide recovery rate. In addition, the optimal manufacturing conditions of Pellets (drum tilt angle, moisture addition, mixing time, etc.) were also investigated. In addition, referring to the SiO₂-CaO-FeO ternary system diagram, the formation behavior of a low melting point compound, a reaction product inside Kiln according to the change in the basicity of Pellet, and the reactivity (adhesion) with the castable constructed on the inner wall of Kiln were investigated. In addition, in order to quantitatively investigate the possibility of using anthracite as a substitute for Coke, a reducing agent, changes in the temperature distribution inside Kiln, where oxidation/reduction reactions occur due to an increase in the amount of anthracite, the quality of Crude zinc oxide, and the behavior of tar in anthracite were also investigated.