LED 폐자원의 재활용 현황

이덕희,신동윤,김태형,이찬기,박경수,이기웅,이재령,Lee, Duk-Hee,Shin, Dongyoon,Kim, Tae-Hyung,Lee, Chan-Gi,Park, Kyung-Soo,Lee, Ki Woong,Lee, Jaeryeong 한국자원리싸이클링학회 2019 資源 리싸이클링 Vol.28 No.2

Development of technology makes LED an economical option because of lower energy consumption and better environmental impact. Because higher consumer demand the LED market is expanding rapidly due to its environment-friendly advantages. Expansion of LED application, development of various fusion technologies, the emergence of new markets, and the large-scale expansion of markets would lead to a large volume of e-waste generation with valorization potential. Currently, most of the generated waste being that landfilled and incinerated due to the absence of technology and management system. In this paper, we review the current status of LED waste recycling and analyzes the available recycling technologies.

복합유기용제의 누적 폭로 정도에 따른 신경행동학적 변화

이덕희,박인근,김진하,이용환,강성규,김두희,Lee, Duk-Hee,Park, In-Geun,Kim, Jin-Ha,Lee, Young-Hawn,Kang, Sung-Gye,Kim, Doo-Hie 대한예방의학회 1995 Journal of Preventive Medicine and Public Health Vol.28 No.2

A cross sectional study was performed to evaluate the neurobehavioral effects of chronic exposure of complex organic solvents, using NCTB(Neurobehavioral Core Test Battery) recommended by WHO(World Health Organization). Forty female shoe factory workers and twenty-two controls matched with age were participated. The tests were performed in the morning before start of work, to exclude the effects of acute exposure. Workers were exposed mainly to toluene, methyl ethyl ketone, n-hexane, cyclo-hexane, dichloroethylene, trichloroethylene, benzene, xylenes etc. The ranges of present solvent exposure of hygienic effect were $0.46\sim0.71$ in the process using adhesives indirectly, and $1.83\sim2.39$ in the process using it directly. We reclassified the subjects, according to cumulative exposure. It showed significantly poorer performances in high exposed group on Santa Ana Dexterity and Benton Visual Retention, compared with control group. After controlling confounder, the significances were still remained. But, further cohort studies, having the information of personal exposure dose from entering a factory, are required to clarify the effects of chronic exposure of complex organic solvents in relation to dose and duration of exposure.

유기금속화학증착 분진(MOCVD dust)을 이용한 갈륨 함유 고순도 수용액 제조 연구

이덕희,윤진호,박경수,홍명환,이찬기,박정진,Lee, Duk-Hee,Yoon, Jin-Ho,Park, Kyung-Soo,Hong, Myung-Hwan,Lee, Chan-Gi,Park, Jeung-Jin 한국자원리싸이클링학회 2015 資源 리싸이클링 Vol.24 No.4

본 연구에서는 LED 칩 제조를 위해 이용되는 유기금속화학증착(MOCVD) 장비에서 발생하는 분진(dust)으로부터 용매추출을 통해 고순도 갈륨(Ga) 함유 수용액을 회수하는 연구를 수행하였다. 추출제 종류, 추출제의 농도 변화에 대한 연구를 통해 Ga 추출에 효과적인 추출제를 선정하고자 하였으며 다단계 추출/역추출 공정을 통해 추출 효율을 향상시켜 고순도 Ga 수용액을 제조하였다. 선행연구에서 원료에 대한 분석을 바탕으로 Ga의 추출 및 분리를 위해 PC88A, DP-8R, Cyanex 272 추출제 중 Cyanex 272를 선택하였으며 1.5M일 때 43.8%의 효율이 나타났다. 다단계 추출을 통해 Ga의 추출 효율은 83%까지 상승하였으며 0.1 M HCl을 이용한 역추출 공정으로 불순물이 없는 5N급 고순도 Ga 수용액을 제조할 수 있었다. In this study, we have investigated solvent extraction of Ga and recovery of high pure Ga solution from MOCVD dust for manufacturing of LED chip. Effect of extractan, concentration of extractant were examined for choosing the more effective extractant and high pure Ga solution was fabricated by multi-stage extraction/stripping process. For extraction/separation of Ga based on the analysis of raw-material in previous study, 3 different extractants PC 99A, DP-8R, Cyanex 272 has been investigated and the extraction efficiency of 1.5 M Cyanex 272 was 43.8%. It was conformed that extraction efficiency of Ga was 83% in multi-stage extraction and 5N high purity Ga stripping solution without impurities also obtained.

AOD공정으로 재활용된 니켈합금의 산소주입량에 따른 조직과 기계적 성질 변화

이덕희,우기도,강황진,윤진호,Lee, Duk-Hee,Woo, Kee-Do,Kang, Whang-Jin,Yoon, Jin-Ho 한국자원리싸이클링학회 2016 資源 리싸이클링 Vol.25 No.2

본 연구에서는 Inconel 713C 스크랩을 원료로 아르곤-산소 탈탄 공정을 이용하여 니켈계 초내열합금을 재활용 하였다. 아르곤-산소 탈탄 공정에서 아르곤은 1,000 sccm으로 지속적으로 주입되었고 산소는 100, 250, 500 sccm의 유량으로 10, 20, 30 분씩 주입되었다. 산소 주입 초기 단계에서는 산소 양이 증가하면서 Al, Cr, 및 Mo 함량은 증가하였고 탄소 함량은 감소하였다. 그리고 Al 함유량은 탄소의 반응이 끝난 후 Al, Cr 등의 원소와 산화가 일어났기 때문에 첨가원소와 탄소의 반응에 의해 감소하였다. 결과적으로, Al 함유량이 감소하였기 때문에 ${\gamma}^{\prime}$상이 줄어들었으며 이는 Al이 ${\gamma}^{\prime}$을 형성하는 주요 원소이기 때문이다. 또한, 탄소의 양이 줄어들면서 탄화물도 줄어들었으며 산소가 과잉 공급된 시료의 기계적인 물성(강도, 경도 등)은 감소하게 된다. In this study, the Ni base superalloy was recycled by Argon oxygen decarburization(AOD) process using an inconel 713C scrap. During AOD process, argon gas was continuously injected 1,000 sccm and oxygen gas was injected into 10, 20 and 30 minutes of 100, 250 and 500 sccm.. In early stage of oxygen injection, the oxygen dose increased with increasing Al, Cr, and Mo content and decreasing C content. And Al content was decreased by carburization with added elements in late stage Because of oxidation was occurred with Al, Cr etc. after the reaction of carbon has been finished. From the results, the ratio of ${\gamma}^{\prime}$ phase reduced due to decreasing of Al content for that reason Al is the main element to form the ${\gamma}^{\prime}$ phase. Also carbide reduced owing to decreasing of C content so the mechanical properties of the specimens excessively injected by excess $O_2$ gas were decreased.

유기인계 농약 중독 환자에서 약물의 종류에 따른 임상 양상 및 예후의 차이

이덕희,정진희,정구영,어은경,Lee, Duk-Hee,Jung, Jin-Hee,Jung, Koo-Young,Eo, Eun-Kyung 대한임상독성학회 2007 대한임상독성학회지 Vol.5 No.1

Purpose: Organophosphorus insecticides tend to be regarded as a homogeneous single entity. We aimed to determine whether organophosphate poisoning differs by subgroups in clinical features and severity. Methods: We retrospectively reviewed medical records of all patients with acute organophophorus poisoning from January 1998 to December 2006. We investigated clinical features, Glasgow coma scale (GCS), laboratory findings, QTc intervals, management, and outcomes. Results: A total of 109 patients were included. The dimethoxy group experienced significantly longer times than the diethoxy group for ventilation duration (0.6 day vs. 0.2 day, p=0.006), ICU duration (2.0 day vs. 0.8 day, p=0.037), and total admission duration (2.8 day vs. 0.9 day, p=0.008), except in cases of dichlorvos poisoning. Also, the GCS of the dimethoxy group (except with dichlorvos) was significantly lower than for the diethoxy group (dimethoxy, $11.2{\pm}5.2$ vs. diethoxy, $13.8{\pm}2.4$, p= 0.021). QTc intervals for the dimethoxy group (except with dichlorvos) tended to be somewhat greater than for the diethoxy group (dimethoxy, $452.9{\pm}16.1\;msec$ vs. diethoxy, $429.6{\pm}40.9\;msec$). There were 65 patients with dichlorvos ingestion, and 2 of these patients (3%) died. Conclusion: When compared to the diethoxy group, the dimethoxy group of organophosphates (with the exception of dichlorvos) were associated with poorer prognostic value for indicators such as GCS, QTc interval, requirement for intubation, ICU duration, and total admission duration. Within the dimethoxy group, patients with dichlorvos poisoning had relatively better prognoses than for the other dimethoxy group organophosphates studied.

Ammonium Hexafluorotitanate 전구체로부터 습식 공정을 이용한 불소 함유 TiO₂ 나노 분말 제조 및 광촉매 특성 연구

이덕희,박재량,이찬기,김현모,박경수,Lee, Duk-Hee,Park, Jae-Ryang,Lee, Chan-Gi,Kim, Hyeon-Mo,Park, Kyung-Soo 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.3

F-containing $TiO_2$ nanopowders are synthesized using simple wet processes (precipitation-based and hydrothermal) from ammonium hexafluorotitanate (AHFT, $(NH_4)_2TiF_6$) as a precursor to apply as a photocatalyst for the degradation of rhodamine B (RhB). The surface properties of the prepared samples are evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results confirm that the synthesized anatase $TiO_2$ has sphere-like shapes, with numerous small nanoparticles containing fluorine on the surface. The photocatalytic activity of F-containing $TiO_2$ compared with F-free $TiO_2$ is characterized by measuring the degradation of RhB using a xenon lamp. The photocatalytic degradation of F-containing $TiO_2$ exhibits improved photocatalytic activity, based on the positive effects of adsorbed F ions on the surface.

One-pot 습식화학공정을 이용한 TiO₂ 중공 구조체 제조 및 광촉매 활성 연구

이덕희,박경수,박재량,이찬기,Lee, Duk-Hee,Park, Kyung-Soo,Park, Jae-Ryang,Lee, Chan-Gi 한국분말야금학회 2020 한국분말재료학회지 (KPMI) Vol.27 No.2

A facile one-pot wet chemical process to prepare pure anatase TiO₂ hollow structures using ammonium hexafluorotitanate as a precursor is developed. By defining the formic acid ratio, we fabricate TiO₂ hollow structures containing fluorine on the surface. The TiO₂ hollow sphere is composed of an anatase phase containing fluorine by various analytical techniques. A possible formation mechanism for the obtained hollow samples by self-transformation and Ostwald ripening is proposed. The TiO₂ hollow structures containing fluorine exhibits 1.2 - 2.7 times higher performance than their counterparts in photocatalytic activity. The enhanced photocatalytic activity of the TiO₂ hollow structures is attributed to the combined effects of high crystallinity, specific surface area (62 ㎡g^-1), and the advantage of surface fluorine ions (at 8%) having strong electron-withdrawing ability of the surface ≡ Ti-F groups reduces the recombination of photogenerated electrons and holes.

정상 소아들의 혈중 연 농도와 지능지수와의 관련성

이덕희,이용환,김진하,박인근,한태영,장세한,Lee, Duk-Hee,Lee, Yong-Hwan,Kim, Jin-Ha,Park, In-Geun,Han, Tae-Young,Jang, She-Han 대한예방의학회 1995 Journal of Preventive Medicine and Public Health Vol.28 No.2

The association between blood lead of children and Intelligent Quotient(I.Q) was investigated in a sample of 100 boys and girls aged $6\sim8$ years from one primary school within an industrial area of Pusan. The trained undergraduates in school of public health administered an 1.0. test one by one. Parents answered a questionnaire on demographic, perinatal and socioeconomic variables. Atomic Absorbtion Spectrophotometer was used to determine blood lead levels. The geometric mean of blood lead value was $7.99{\mu}g/dl$. In total children, there was no significant relationship between blood lead level and I.Q. But in the children who were born of gestational age of less than 38 weeks, children with higher levels of blood lead performed more poorly on I.Q test with correlation coefficient from -0.68 to -0.71. But, the children who were born of gestational age of 38 weeks and more were same as total children. These results suggest that exposure to low levels of lead in the children who were born premature probably may result in impaired intelligent development. But, We think that more profound study should be performed with sufficient numbers of subjects.

TiO₂ 분말 합성을 위한 Ammonium Hexafluofide Titanate의 열적 거동 연구

이덕희,박재량,이찬기,박경수,김현모,Lee, Duk-Hee,Park, Jae-Ryang,Lee, Chan-Gi,Park, Kyung-Soo,Kim, Hyeon-Mo 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.5

In this study, $TiO_2$ powders are synthesized from ammonium hexafluoride titanate (AHFT, $(NH_4)_2TiF_6$) as a precursor by heat treatment. First, we evaluate the physical properties of AHFT using X-ray diffraction (XRD), particle size analysis (PSA), thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). Then, to prepare the $TiO_2$ powders, is heat-treated at $300-1300^{\circ}C$ for 1 h. The ratio of anatase to rutile phase in $TiO_2$ is estimated by XRD. The anatase phase forms at $500^{\circ}C$ and phase transformation to the rutile phase occurs at $1200^{\circ}C$. Increase in the particle size is observed upon increasing the reaction temperature, and the phase ratio of the rutile phase is determined from a comparison with the calculated XRD data. Thus, we show that anatase and rutile $TiO_2$ powders could be synthesized using AHFT as a raw material, and the obtained data are utilized for developing a new process for producing high-quality $TiO_2$ powder.

APACHE III 시스템을 이용한 병원간 중환자실 치료결과 비교분석

이덕희,노미영,김병성,Lee, Duk-Hee,No, Mee-Young,Kim, Byung-Sung 대한예방의학회 1994 Journal of Preventive Medicine and Public Health Vol.27 No.3

The objective of this study was to evaluate outcome for the patients of the intensive care unit, using APACHE III prognostic system. We prospectively collected the information of 429 patients in intensive care units at 2 tertiary care hospitals and 4 secondary care hospitals in PUSAN who had been admitted from December 1, 1993 to February 28, 1994. The results were as follows. 1. APACHE III scores were various from 0 to 173. But the distribution of the scores were similar between tertiary care hospitals and secondary care hospitals. 2. The mortality rate significantly increased as APACHE III score rised (p<0.001). Within the interval of same score, generally, the mortality of operative patients was higher in secondary care hospitals but in the case of nonoperative patients higher in tertiary care hospitals. 3. When the tertiary care hospitals compared with secondary for ratio of the predicted mortality rate to the actual mortality rate, there was little difference. 4. When we compared the 6 hospitals, one hospital had significantly better results and another hospital was significantly inferior (p<0.05).