• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.43.2-43.2
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• 2010

In this study, metallurgical grade (MG) silicon with 99% purity produced by arc furnace process was systematically investigated for slag refining. The most problematic impurities to remove from MG silicon are boron (B) and phosphorus (P). To remove B and P from MG-silicon, we used synthetic slag in the molten state. MG-silicon with synthetic slag of CaO, $SiO_2$, and $CaF_2$ was melted using by high-frequency induction furnace with electrical output of 50kW. Specimens prepared by various refining process conditions(holding time, mixture ratio) were inspected by combined analysis of ICP-MS and XRF. With this approach, B has been reduced to <5ppm, P to <1ppm and other impurities to 0.1~0.2% except for Calcium. Calcium has been increased from 17ppm to 1500ppm. Problem of calcium contamination will be resolved by additional refining processes.

• 한국주조공학회지
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• 제15권3호
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• pp.235-241
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• 1995

In order to improve the production process of low cost and high purity Vanadium, this study was done to reduce $V_2O_5$ into V-Al master alloy by Aluminothermic Reduction, followed by refining of V-Al master alloy electron beam melting. As melting time was increased in electron beam melting of V, the contents of interstitial impurities and Al, Fe were decreased but the contents of Si, Mo and W were increased due to lower vapor pressure of these elements than that of matrix V. Consequently, it was profitable that melting of V was done for 180 seconds. In addition, with number of melting, the purity of V did not significantly vary, because volatile impurities in V were removed mostly during the first step of melting. As a result of V refining by electron beam melting, high purity Vanadium of 3N(99.91wt%) was acquired including interstitial impurities total contents of which were maximum 400ppm.

• 한국주조공학회지
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• 제23권2호
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• pp.63-68
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• 2003

Al-Ti-C grain refiner form a relatively new alternative to the existing class of Al-Ti-B type grain refiners for achieving fine equiaxed structures in aluminum alloys during casting and solidification. The present study was carried out to investigate the influence of Al-Ti-C master alloys on the grain structure of Al-7Si alloys. The present study also investigates the relationship between grain refining efficiency and concentrations of Fe and Si in hypo-eutectic Al-Si alloys using Al-3Ti-0.13C master alloys. It is found that several parameters affect significantly the grain refining performance in silumin alloys. The present study reports the influence of various parameters such as alloy content, master alloy addition level, melt holding time and superheat on the grain refining efficiency in Al-7Si alloys.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.16.2-16
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• 2003

• 한국주조공학회지
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• 제18권5호
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• pp.474-480
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• 1998

Microstructural characteristics of semi-solid state processed hypereutectic Al-Si alloys have been investigated. Main concern of the present study is to investigate the effects of P and Sr addition on the size and morphology change of the primary Si particles. Refinement of the primary Si particles was observed with the addition of P and Sr at the early stage of semi-solid state processing, but such a refining effects became negligible resulting in Si particles with a near-spherical morphology with continuous stirring. This implies that the microstructural transformation mechanism became more dependent to stirring effects than to the alloying effects during semi-solid state processing. Brittle fracture and agglomeration were proposed as the mechanisms for microstructural alterations during semi-solid state processing.

• 한국주조공학회지
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• 제17권3호
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• pp.267-275
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• 1997

Fabrication of high strength Mg-Li-Al alloys by squeeze casting was established by the stabilization of melt and mold temperatures, applied pressure and the refining method. The entrapment of inclusions during pouring was prevented using 30 ppi alumina foam filter. The as-cast microstructure consists of a mixture of ${\alpha}$ and ${\beta}$ phases including AILi and $MgLi_2$, Al particles, which are distributed in the ${\beta}$ matrix. The grain sizes of gravity and squeeze casting alloys were 288 ${\mu}m$ and 207 ${\mu}m$ respectively. The addition of Al in Mg-Li alloys promoted the formation of second phase particles, which were adjusted to optimize the properties of Mg-Li-Al alloys. The Mg-10wt%Li-5wt%Al alloy after heat treatment at $350^{\circ}C$ for 1 hour showed the maximum hardness value. This is due to the facts that the amounts of ${\alpha}$ and ${\beta}$ phases and their distributions are dependent upon the solution treatment temperature, and that the amounts of AILi and $MgLi_2Al$ particles are dependent upon the Al content.

• 보존과학회지
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• 제37권6호
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• pp.738-747
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• 2021

제철원료별 직접제련법 복원실험으로 생산된 단조박편의 재료과학적 분석을 통해 금속학적 특성을 규명하였다. 제련을 위해 경주감포사철과 양양철광석을 이용하며, 각각 4개의 그룹을 설정하였다. 분석은 주성분, 광물 동정, 미세조직 관찰을 하였다. 주성분 분석 결과 정련·단접이 진행될수록 Fe의 함량은 증가하고 비금속개재물의 함량은 감소하였다. 광물을 동정한 결과 산화철 계열의 광물이 확인되었다. 미세조직 관찰 결과 Wüstite, Fayalite가 관찰되었으며, 일부에는 응집된 Wüstite가 관찰되었다. 일부 다각형, 장주상의 Magnetite도 확인되었다. 또한, 공극 및 불순물, 비금속개재물은 점차 감소하였다. 차후 다양한 제철원료를 이용한 복원실험을 통해 생산된 단조박편의 재료과학적 분석을 통해 금속학적 특성을 규명하고, 이를 유적에서 출토된 단조박편과 비교·검토하는 것이 필요하다.

• 한국수소및신에너지학회논문집
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• 제7권1호
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• pp.81-92
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• 1996

Ar/Ar-$H_{2}$ 플라즈마법으로 V, Ta, B산화물과 금속의 환원 및 정련을 행하였다. 다시말해 Ar 플라즈마에서의 고온환원반응 및 Ar-(20%)$H_{2}$ 플라즈마에서의 정련 반응에 대한 연구를 각각 수행하였다. Ar 플라즈마 환원에 의하여 $C/V_{2}O_{5}$=4.50의 비에서 순도 96wt%의 조금속 Vdmf 얻었고, 바나듐 산화물의 열분해에 의한 $O_{2}$의 손실로 인해 $C/V_{2}O_{5}$=4.50에서 최대환원도가 얻어졌다. Ar-(20%)$H_{2}$ 플라즈마 정련에서는 $C/V_{2}O_{5}$=4.40의 비에서 99.2wt%의 금속 V을 얻었고, 주된 정련반응은 잔류탄소와 잔류산소의 반응으로 판단된다. 금속 Ta은 Ar 플라즈마 환원에 의하여 $C/Ta_{2}O_{5}$=5.10의 비에서 99.8wt%가 얻어졌고, $Ta_{2}O_{5}$의 열분해에 의한 $O_{2}$ 손실은 발생하지 않았다. Ar-(20%)$H_{2}$ 플라즈마 정련시 탈산반응이 탈탄반응보다 현저했으며, $C/Ta_{2}O_{5}$비가 4.50-5.10의 범위에서 99.9wt%의 금속 Ta을 제조하였다. 이 비에서는 탈산반응에 의한 잔류산소의 감소로 Ta외 Vickers 경도가 약 220Hv였다. 한편, Ar 및 Ar-$H_{2}$ 플라즈마에 의한 $B_{2}O_{3}$의 환원에는 C이 환원제로서 적합하지 않았으나, Fe원 소재와 C, $B_{2}O_{3}$ 및 페로보론을 고주파 유도 용해하였을 때 용강중에서의 $B_{2}O_{3}$의 환원으로 Fe-B-Si 합금을 얻었다.

• 한국표면공학회지
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• 제19권1호
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• pp.13-19
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• 1986

Manganese in the Anode slime and the paste-positive material of waste-dry cell was recovered by leaching with the hydrochloric acid solution. The impurities (Zn, Fe, Pb), co-leached with manganese were removed from the leached solution prior to electrolysis by hydrometallurgical techniques such as the neutralization with ammonium hydroxide and cementation on manganese powder. The electrodeposition of manganese from the purified chloride solution with sodium selenate was performed. Cathode current efficiency was found to be affected significantly by the concentration of sodium selenate and ammonium chloride salt, bath temperate, current density and PH. The current efficiency of about 88.7% was obtained by electrolysis manganese chloride solution with sodium selenate (0.1/g) at 10$^{\circ}C$.

• 자원리싸이클링
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• 제21권4호
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• pp.53-59
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• 2012

본 연구에서는 비철제련의 공정 부산물에서 얻어진 Bi-Pb-Sb 3원계 합금 용탕의 산화반응에 따른 Sb과 Pb의 제거거동에 대하여 조사하였다. $N_2+O_2$ 가스를 침지 노즐을 통해 1173 K의 합금 용탕 중에 취입하여 Sb을 산화물과 금속상의 혼합물로 분리 회수할 수 있었다. 그리고 923 K의 Bi-Pb 2원계 용탕에 $N_2+O_2$ 가스를 취입하면 Pb가 산화되어 슬래그상으로 제거될 수 있으나, Bi도 동시에 산화되어 Bi를 정제할 수 없었다.