• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.257.2-257
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• 2001

• 한국재료학회지
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• 제27권5호
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• pp.263-269
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• 2017

Fe-Si-Cr ferroalloy is predominantly produced by carbothermic reduction. In this study, silicothermic and carbothermic mixed reduction of chromite ore to produce Fe-Si-Cr alloy is suggested. As reductants, silicon and silicon carbide are evaluated by thermochemical calculations, which prove that silicon carbide can be applied as a raw material. Considering the critical temperature of the change from the carbide to the metallic form of chromium, thereduction experiments were carried out. In these high temperature reactions, silicon and silicon carbide act as effective reductants to produce Fe-Si-Cr ferroalloy. However, at temperatures lower than the critical temperature, silicon carbide shows a slow reaction rate for reducing chromite ore. For the proper implementation of a commercial process that uses silicon carbide reductants, the operation temperature should be kept above the critical temperature. Using equilibrium calculations for chromite ore reduction with silicon and silicon carbide, the compositions of reacted metal and slag were successfully predicted. Therefore, the mass balance of the silicothermic and carbothermic mixed reduction of chromite ore can be proposed based on the calculations and the experimental results.

• The Korean Journal of Ceramics
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• 제4권4호
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• pp.387-393
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• 1998

The formation of titanium diboride ($TiB_2$ ) via the reduction of $TiO_2$ with boric oxide and carbon was studied in a partially reducing atmosphere of argon mixed with 4 vol.%H2. The effect of reaction time, temperature, partial pressure of nitrogen and $TiO_2/B_2_O3$ stoichiometric ratio on the reducibility of oxides has been studied. The phases formed were analysed by using X-ray rowder diffraction and scanning sosctron microscopic techniques. In this paper, we also investigated the presence of $CaC_2$ as a reducing agent on the reducibility of oxide mixtures and on the Ti-B-C-Ca-O phase equilibria. The morphology of $TiB_2$ formed in the presence of $CaC_2$ is compared with the microstructure of $TiB_2$ formed as a consequence of carbothermic reduction. The observed variation in $TiB_2$ crystals formed is also explained.

• 한국분말재료학회지
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• 제15권2호
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• pp.87-94
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• 2008

In order to investigate a nitriding process of spent oxide fuel and the subsequent change in thermal properties after nitriding, simulated spent fuel powder was converted into a nitride pellet with simulated fission product elements through a carbothermic reduction process. Nitriding rate of simulated spent fuel was decreased with increasing of the amount of fission products. Contents of Ba and Sr in simulated spent fuel were decreased after the carbothermic reduction process. The thermal conductivity of the nitride pellet was decreased by an addition of fission product element but was higher than that of the oxide fuel containing fission product elements.

• 한국재료학회지
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• 제20권1호
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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.

• 자원리싸이클링
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• 제27권2호
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• pp.68-76
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• 2018

전기로 제강분진은 아연, 연, 철의 2차자원으로서 매우 중요하다. 또한 제강분진의 리싸이클링은 분진 중에 함유되어 있는 증금속 성분 등의 유해원소에 의한 환경문제의 처리에 유용한 방법이다. 본 조사는 기존의 전기로 제강분진을 처리하는 방법의 개선이나 새로운 처리방법의 개발을 위해 건식처리 방법에 대하여 알아보았다. 상업중인 처리방법은 노의 형상 등에 따라 로터리 킬른형, 회전노상형, 샤프트형, 용융환원로형 등으로 구분할 수 있었다. 이러한 처리에서의 생성물은 ZnO와 환원철 또는 슬래그이다. 제강분진으로부터 ZnO를 만드는 기구는 탄소 열환원과 공기에 의한 아연증기의 산화에 의한 것이다.

• Advances in materials Research
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• 제13권3호
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• pp.161-171
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• 2024

This study aimed to investigate the effect of physicochemical properties and mix ratios of iron ore (oxide feed): coke (reductant) on the carbothermic reductions of iron ore. Coke size was fixed at ≤63 ㎛ while iron ore size varied between 150-63 ㎛ and ≤63 ㎛ respectively. Mix ratios were changed from 100:0 (reference) to 80:20 and 60:40 while the temperature, heating rate and soaking duration in muffle furnace were fixed at 1100 ℃, 10 ℃/min and 1 hour. Particle size analyzer, XRF, CHNS and XRD analyses were used for determination of raw feed characteristics. The occurrence of phase transformations from various forms of iron oxides to iron during the carbothermal reductions were identified through XRD profiles and supported with weight loss (%). XRF analysis proved that iron ore is of high grade with 93.4% of Fe₂O₃ content. Other oxides present in minor amounts are 2% Al₂O₃ and 1.8% SiO₂ with negligible amounts of other compounds such as MnO, K₂O and CuO. Composite pellet with finer size iron particles (≤63 ㎛) and higher carbon content of 60:40 exhibited 45.13% weight lost compared to 32.30% and 3.88% respectively for 80:20 and 100:0 ratios. It is evident that reduction reactions can only occur with the presence of coke, the carbon supply. The small weight loss of 3.88% at 100:0 ratio occurs due to the removal of moisture and volatiles and oxidations of iron ore. Higher carbon supply at 60:40 leads into better heat and mass transfer and diffusivity during carbothermic reductions. Overall, finer particle size and higher carbon supply improves reactivity and gas-solid interactions resulting in increased reductions and phase transformations.

• 자원리싸이클링
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• 제19권1호
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• pp.21-26
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• 2010

본 연구에서는 마이크로웨이브 열탄소환원에 의한 제철 슬래그의 Fe 회수를 위한 기초연구로서, CaO-$SiO_2$-FeO계 슬래그의 열탄소환원 반응에 미치는 가스 분위기(질소 및 대기분위기) 및 탄소 첨가량의 영향을 살펴보았다. 실험결과, 질소 분위기에 비하여 대기 분위기에서 반응 시 최고 도달 온도 및 환원률이 증가하고, 대기 분위기에서는 탄소 당량 증가에 따라 최고 도달 온도 및 환원률이 증가하는 경향을 나타내었다. 대기 중 탄소 당량($C_{eq}$)이 5인 조건에서 최고 온도는 1800K에 도달하였으며 약 90%의 철회수율을 얻을 수 있었고, 탄소 당량이 5 이상 증가할 경우 최고 온도 및 환원율의 변화는 크지 않음을 알 수 있었다.

• 자원리싸이클링
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• 제28권3호
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• pp.59-67
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• 2019

본 연구는 동제련슬래그 내에 존재하는 Fe와 Cu의 동시 환원을 통해 주물용 선철을 제조하고, 선철 제조 시 황 함량 저감에 대한 실험을 진행하였다. Roasting 실험은 실험온도 $500^{\circ}C$, $700^{\circ}C$, $900^{\circ}C$ 온도 조건에서 1시간에서 9시간까지 2시간 간격으로 시간을 변화시키면서 실험을 진행 하였다. 산소분압에 따른 실험은 산소분압 0.5, 0.8, 1.0, 실험 온도는 $900^{\circ}C$, 유지시간 30분으로 설정하여 실험을 진행하였다. 실험 결과 Roasting 및 산소분압에 따른 황 저감의 영향은 없는 것으로 확인되었다. 첨가제로 CaO를 사용하여 첨가량 15 % 이상부터 S 성분 함량은 0.001 wt% 이하로 확인되었다. 반응온도에 따른 선철 및 슬래그 분리 실험의 조건은 $1300^{\circ}C{\sim}1600^{\circ}C$까지의 온도조건에서 유지시간 30분, Ar 가스 분위기에서 진행하였으며, 반응시간에 따른 선철 및 슬래그 분리 실험의 조건은 유지시간 5 ~ 25분까지 5분 간격, 반응온도 $1600^{\circ}C$, Ar가스분위기에서 실험을 진행하였다. 실험 결과 $1600^{\circ}C$, 30분 유지 환원 조건에서 선철의 회수율이 가장 높았다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.91-91
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• 2014

주석함유 2차 공정 부산물인 양극 슬라임내의 금속을 회수하기 위하여 탄소환원반응을 통해 금속 회수에 미치는 공정변수의 영향을 조사하였다. 열역학 모델링과 금속환원 실험결과, 환원 온도와 고체 환원제인 코크스(cokes)에 공정 변수에 따라 금속으로 환원이 될 수 있음을 확인하였다.