• Ceramist
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• v.18 no.3
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• pp.41-47
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• 2015

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.293-304
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• 2002

Wet purification process for the selective separation of montmorillonite from Gampo 13 and 35 bentonite ores was studied using physical processes such as ultrasonic scrubbing, decantation and centrifugation. Ultrasonic Scrubbing of Gampo 13 and 35 bentonite ores was revealed excellent result at 7 wt.% of slurry density and was almost finished within 30 minutes in the sample of Gampo 13 and 10 minutes in the sample of Gampo 35, respectively After decantation, approximately 52 wt.% from the bentonite of Gampo 13 and 64wt.% from the bentonite of Gampo 35 were recovered as purified products and the CEC was reached up to 119.4 meq/100 g and 124.5 meq/100 g, respectively. Particle separation by centrifugation showed that most of the impurity minerals such as quartz and feldspar were removed within the condition of 1,000 rpm.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.283-291
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• 2002

Dry-based processes such as crushing, milling, sieving, magnetic and gravity separation were employed in order to investigate the purification characteristics of bentonite. The CECs of Gampo 13 and 35 bentonites were estimated at 88.3 and 93.3 meq/100 g and the samples contained quartz and feldspar as impurity minerals. According to the physical properties of constituent minerals of bentonite, the purification techniques were adopted to enhance the grade of montmorillonite High grade of montmorillonite could be obtained by the combination of each process. Consequently, the recovery of final products of Gampo 13 and 35 bentonite were 68.6 and 49.5%, and the CECs of them were 96.9 and 109.6 meq/100 g, respectively.

• Journal of the Korean Ceramic Society
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• v.37 no.10
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• pp.933-937
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• 2000

고기능성 전자재료용 TiO$_2$분말 및 박막제조에 사용되는 중간생성물인 TiCl$_4$는 99% 이상의 고순도가 요구된다. 고순도.미립의 TiO$_2$분말 및 TiCl$_4$는 황산법으로 제조한 저순도 TiO$_2$원료를 사용하여 염소화법으로 Ti-염화물 및 염화불순물로 제조한 후, 대부분의 염화불순물들은 3단계 과정을 거쳐 고순화 하였다. 대부분의 염화불순물은 분리.응축 및 분별증류로, VOCl$_3$는 mineral oil을 첨가하여 비등점을 변화시켜, 그리고 미량의 염화불순물은 열가수분해하여 침전시킨 후 유기용제 처리하여 제거하였다. 유기용제 처리는 TiO$_2$분말의 고순도화에 도움이 되었으며, 입자간의 응집을 적게 하여 TiO$_2$입자크기도 작아졌다. 또한 anatase에서 rutile 결정구조로의 전이온도도 낮아지는 부수적인 효과를 보였다.

• Journal of the Mineralogical Society of Korea
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• v.19 no.1 s.47
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• pp.1-5
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• 2006

In this study, we have investigated the purification characteristics of quartz which size was 0.1mm to 0.3 mm by using physical separation techniques. The A and B samples which contained 95,864 mg/kg and 4,568 mg/kg of impurities were reduced upto 126 mg/kg and 174 mg/kg of impurities, respectively. So, removal ratios of the total impurities were about 97.85 wt.% and 96.19 wt.%, individually. At that time, the yields of the purified quartz (over 99.98 wt.% $SiO_2$) were 79.05 wt.% and 75.43 wt.% by using purification process including magnetic separation, gravity separation and scrubbing process. The most benefit in purification process of both different raw materials for iron element can be achieved by magnetic separation. Also, gravity separation is extremely successful for reducing aluminium element.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.305-305
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• 2007

고경도 및 내침식재료가 새로운 기계구조 및 기계 절삭공구재료로서 각광을 받고 있으며 질화붕소(BN)는 고융점, 고경도의 물리적 특성으로 다이아몬드 대체 물질로 주목되고 있다. 원하는 질화붕소의 합성을 위해서는 출발 원료와 합성법에 의존하는 것으로 보고되고 있다. 본 연구에서는 붕소 산화물과 환원제로써 활성 탄소를 출발 원료로 하였으며 치환제로써 질소를 사용하여 기상 반응로에서 질화붕소를 합성하였다. 합성된 시료는 XRD, SEM, PSA 등으로 물성을 측정하였고 합성 변수에 따라 순도의 차이를 보였으며, 본 연구를 통하여 최적의 합성 조건을 제시할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.223-223
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• 2016

산업 및 기술의 발전에 의해 많은 신소재들이 개발되고 있다. 그 중에서 금속 나노 분말의 경우, 자성소재, 차세대 MLCC, 전도성 페이스트, 살균 등 여러 산업분야에서 관심을 보이면서, 다양한 재료들이 개발되고 있는 추세이다. 그 중에서 금속 나노 분말은 입자 미세화에 따른 경도, 인성, 연성들의 기계적 특성 향상, 전자기적 기능의 향상 등 기존재료에 비해 우수한 물성, 새로운 기능의 발현이 입증되면서 차세대 소재로서 많은 연구가 진행되고 있다. 또한 최근에는 단순한 나노입자의 제조단계를 뛰어넘어 입경 및 입도의 제어 형상제어를 통한 입자 균일성이 요구되고 있다 DC 열 플라즈마를 이용한 나노입자 합성 방법은 초고온의 온도의 달성이 가능하여, 모든 금속원소에 대한 나노화 및 고순도화가 용이할 뿐만 아니라, 제조공정이 단순한 친환경 공법으로 저비용으로 나노입자를 제조할 수 있는 장점을 갖고 있다. 본 연구에서는 이송식 DC 열 플라즈마를 이용한 Cu 나노분말 제조, 비이송식 DC 열 플라즈마를 이용한 Fe 나노분말 합성 연구를 통해 반응기의 압력과 플라즈마 파워, Gas 유량등의 공정 변수가 나노입자 생성 특성에 미치는 영향을 확인 하였다. 또한 DC 열플라즈마 나노입자 합성 시스템에 대한 장비와 기술도 소개한다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.29-35
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• 1998

Substrates, SiC raw materials and graphite crucibles were purified for growing the high quality 6H-SiC single crystal ingot. Especially, XRD data of raw materials were analyzed before and after purification. We have grown 6H-SiC single crystal ingot up to 33 mm in diameter and 11 mm in length and SiC wafer for using the substrate and observing the internal defects was about 33 mm in diameter and 0.5 mm in thickness. Utilizing optical microscpe and Raman spectroscopy, internal defects density and crystallinity of the SiC wafer obtained by purification processes before crystal growth were measured. As a result, micropipe density and planar defect density were 100/$\textrm{cm}^2$ and 30/$\textrm{cm}^2$ respectively. Therefore, high quality 6H-SiC single crystal could be grown because internal defects density of 6H-SiC single crystal ingot was decreased by the purification processes before crystal growth.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.1
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• pp.1-7
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• 2014

Aluminum nitride, which has outstanding properties such as high thermal conductivity and electrical resistivity, has been received a great attention as a substrate and packaging material of semiconductor devices. Since aluminum nitride has a high sintering temperature of 2173 K and its properties depends on the impurity level, it is necessary to synthesize high-purity and nano-sized aluminum nitride powders for the applications. In this research, we synthesized high purity aluminum nitride nanopowders from aluminum using RF induction thermal plasma system. Sheath gas (NH3) flow was controlled to establish the synthesis condition of high purity aluminum nitride nanopowders. The obtained aluminum nitride nanopowders were evaluated by XRD, SEM, TEM, BET, FTIR and N-O analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.181-187
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• 2016

Silica is an essential material in the electronics industries of LCDs and OLEDs, which particularly require high purity. This study attempted to find the optimal design of a magnetic separator for silica sand containing iron compounds using CFD simulation. Three designs of magnetic separation were prepared and their efficiency was examined. As a result of the evaluation, the sufficient contact of particulate silica with the surface of magnetic emitters improved the magnetic separation effects. In addition, the loss of $SiO_2$ and the removal rate of $Fe_2O_3$ depended strongly on the particle size, flow rate and magnetic flux density. In addition, magnetic separation is quite effective for a particle size of $10{\mu}m$ with a 0.2 m/s flow rate.