• 펄프종이기술
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• 제32권4호
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• pp.10-17
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• 2000

The change of fiber length, freeness, initial forming drainage velocity, specific filtration resistance, final drainage time and wet web dryness were measured to investigate the effect of the refining load on the drainage characteristics of pulp. The arithmetic average fiber length after refining with higher refining load was shorter than that obtained with lower refining load. Higher refining load decreased initial forming drainage velocity, final drainage time and wet web dryness. The refining load also affected the relationship between freeness and specific filtration resistance, initial forming drainage velocity, final drainage time. It was found that the specific filtration resistance is better than freeness to predict the drainage characteristics of pulp and the wet dryness.

• 한국산업융합학회 논문집
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• 제4권1호
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• pp.27-34
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• 2001

Refining of powder particles and their dissolution into the Al matrix during mechanical alloying(MA) were investigated by using X-ray diffraction(XRD) transmission electron microscopy (TEM) functions of alloy composition, milling time and ball to powder ratio(BPR). It is found that Ti particles less than 20nm are observed in a dark field image of mechanically alloyed Al-10wt%Ti whose XHD pattern exhibits no Ti peak. The observed change of lattice constant of AI indicates that about 1 wt%Ti can he solved in Al after MA for a long time, independent of alloy composition, milling time and BPR, suggesting that most of Ti particles arc retained in the Al matrix. It is concluded that the disappearance of XRD peaks in mechanically alloyed Al-10wt%Ti is not simply attributable to the dissolution of Ti into Al, but associated mainly with extreme refining and/or heavy straining of Ti Particles.

• 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.

• Journal of the Korean Wood Science and Technology
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• 제29권1호
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• pp.31-42
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• 2001

본 실험은 생산지별 채취시기별 물리적 화학적 성상의 차이를 파악하여, 그 상이성을 최소화하여 비교적 높은 품질의 옻칠을 생산하기 위한 기초자료를 제공하고자 수행하였다. 실험에 사용한 생칠은 국내 원주산 생칠과 중국의 섬서성(陳西省)산 생칠, 귀주성(貴州省)산 생칠, 안휘성(安微省)산 생칠 등이었다. 정제 특성 실험은 실험실용 정제기에 의하여 수행하였으며 이 정제기에 의해서 생산된 옻칠은 도막의 건조시간, 인장강도, 도막의 균일성 등과 같은 기계적 성질을 시험하였다. 도막은 자동 도포기(Film applicator)로 만들었고, 만들어진 도막은 만능재료시험기를 이용하여 인장강도를 시험하였다. 도막의 균일성은 주사전자현미경과 공초점 현미경에 의하여 2차원 및 3차원 화상을 얻어 판정하였다. 채취시기에 따른 정제조건 변이는 없었으나 생산된 옻칠의 점도는 시기에 따라 크게 변함을 알 수 있었다. 흑칠 제조시 철분의 굵기에 따라 혼합시기를 다르게 함으로써 이 흑칠의 점도를 조절할 수 있었다. 정제시간의 길이, 점도, 인장강도 등이 정제조건보다는 산지에 따라서 크게 달라짐을 알 수 있었다.

• 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.

• 자원리싸이클링
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• 제26권6호
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• pp.84-90
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• 2017

저품위 동 함유 슬러지로부터 회수된 동 조금속을 황산구리 전해액에서 전해정련을 수행하여 고순도 동을 회수하고자 하였다. 유기첨가제 종류 및 농도에 따른 전해정련동 표면 형상 및 조도를 분석하였을 때, gelatin계 유기첨가제 5 ppm 및 thiol계 유기첨가제 5~10 ppm 혼합 조건에서 가장 우수한 표면 형상을 얻을 수 있었다. 건식환원공정을 통해 회수한 철(Fe), 니켈(Ni), 코발트(Co) 및 주석(Sn) 등의 불순물이 함유된 각 86.635, 94.969 및 99.917 wt.% 순도의 동 조금속을 사용하여 전해정련하였고, 순도 3N~4N급 전해정련동을 얻을 수 있었다. 동 조금속, 전해액, 전해정련동의 불순 원소 농도 및 동 순도 등의 분석을 통해, 순도 99.99 wt.% 이상 전해정련동을 회수할 수 있는 전해정련 공정시간 및 동 조금속 순도를 도출하였다.

• 보존과학회지
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• 제34권2호
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• pp.87-96
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• 2018

본 연구는 정련 단접 공정을 재현하고 그 과정에서 발생한 강괴 및 단조박편을 단접 횟수에 따라 분류하여 분석하였다. 강괴의 경우 단접 횟수가 증가함에 따라 불순물과 공극률이 26.09%에서 1.8%로 줄었다. 또한 경도는 평균 36.88HV 가량 높아졌다. 이는 금속 조직이 점차 치밀해지는 것을 관찰할 수 있었다. 단조박편의 경우 단접 횟수에 따라 전철량이 높아졌다. XRD 분석 결과 Quartz, Fayalite, $W{\ddot{u}stite$, Magnetite가 관찰되며 횟수가 증가함에 따라 Quartz의 양이 낮아졌다. 또한 단접 횟수가 늘어남에 따라 입상(粒狀)의 $W{\ddot{u}stite$들이 응집(凝集)하여 굵고 긴 백색의 띠 형태로 관찰되었다. 이상의 결과로 정련 단접 공정에서 발생한 강괴 및 단조박편의 횟수별 특징을 알 수 있었으며 향후 고대 제철공정 및 철기 제작기술 체계를 정립할 수 있는 기술 자료로 활용할 수 있을 것으로 본다.

• 한국세라믹학회지
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• 제42권7호
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• pp.483-489
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• 2005

For the raw materials of 3CaO$\cdot$3Al$_{2}$O$_{3}$ $\cdot$CaSO$_{4}$(CSA) clinker manufacturing, the applications of industrial wastes such as waste shell, spent oil-refining catalyst and desulfurized gypsum were examined. The c1inkerbility of the raw mix and the behaviour of formation of clinker minerals were studied and then some hydraulic properties of cements containing the clinker were also investigated. By virtue of the high reactivity of thermally decomposed raw materials, CSA clinkers were obtained at relatively low temperature of 1250$^{\circ}C$ and thus oil-refining catalysts were more desirable than aluminium hydroxide as an aluminous raw material. The expansive cement samples showed somewhat lower flow value than that of OPC, but their compressive strengths were developed earlier and higher than that of OPC due to formation of ettringite in the early hydration time, which indicated the possibility of practical use of low-cost CSA clinker using industrial wastes only.

• 한국염색가공학회지
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• 제18권6호
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• pp.31-36
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• 2006

Study has been made for producing anionic surfactant using waste fleshing scraps from the leather making process through refining, esterification, sulfonation and blending processes. As a most optimum lard oil refining method, refining was carried out for 4 hours under temperature of $120^{\circ}C$ and approximately 200 mbar vacuum, which gave a recovery of more than 80% lard oil. Refined lard oil obtained thus was undergone methlyl-esterification, then sulfonated to make a degreasing agent. By methyl-esterification using lard oil, more than 85% of fatty acid and $12{\sim}13%$ of glycerine were extracted from the oil. Sulfonation of the extracted fatty acid ester lard oil has shown most optimum at $15{\sim}20%$ chlorosulfonic acid content, and the content of bonding sulfate at this time was higher than 3.5%. Finally the followed anionic surfactant having degreasing force of 80% and higher could be made by blending process.

• 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.