• 자원리싸이클링
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• 제31권1호
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• pp.46-55
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• 2022

최근 희유금속 자원 회수에서 초경합금 스크랩 재활용의 중요성이 증가하고 있다. 그러나 IV, V족 전이금속 질화물로 코팅된 초경합금 스크랩에서 고순도 분말 회수에서 어려움을 겪고 있다. 제1원리 계산을 사용하여 IV 및 V족 전이금속 질화물(TiN, VN, ZrN, NbN, HfN 및 TaN)의 구조, 탄성 및 기계적 특성을 조사하였다. IV족 전이금속 질화물은 V족 전이금속 질화물보다 높은 공유결합 특성을 보였다. 따라서 IV족 전이금속 질화물은 V족 전이금속 질화물보다 취성 거동을 보였다. 대조적으로 V족 전이금속 질화물은 최외각전자 농도에 영향받는 금속결합의 특성 때문에 IV족 전이금속 질화물보다 전단응력에 대한 약한 저항성과 연성 거동을 보였다. Crystal orbital Hamilton population 분석 결과는 모든 전이금속 질화물의 전단 저항 경향성이 일치함을 보여주었다.

• 한국정밀공학회지
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• 제15권2호
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• pp.124-133
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• 1998

This paper describes a research work of developing a computer-aided design of blanking and piercing for irregular-shaped sheet metal products. An approach to the development of compact and practical CAB system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer. Based on knowledge-based rules, the system, STRT-DES, is designed by considering several factors, such as complexities of blank geometry and punch profile, availability of press equipment and standard parts, utilization ratio which minimizes the scrap in a single or a pairwise operation, bridge width, grain orientation and design requirements which maximize the strength of the part when subsequent bending is involved. This system checks a forming feasibility with both internal and external features, a dimension of blanked hole, and a corner and a fillet radius for irregualrly shaped sheet metal products. Therefore this system can carry out a die design for each process which is obtained from results of an automated blank layout drawing with a best utilization ratio for irregular shape of product that was successful in production feasibility check module and those of an automated strip layout drawing and generate part drawings and the assembly drawing of die set in graphic forms.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.393-397
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• 2001

The innovatory process, that is the direct separation and recovery of the iron and zinc metals contained in the high temperature exhaust gas generated from the electric arc furnace fer the inn scrap melting and/or the dust treatment, has been proposed. This proposed process consists of the moving coke bed filter that is directly connected to the electric furnace, and the following heavy metal condenser. The exhaust gas passes through the filter and the condenser right after exhausting from the electric furnace. The moving coke bed filter is being controlled at about 1000℃ and collects iron and slag components contained in the high temperature exhaust gas. Heavy metals such as zinc and lead pass through the filter as vapor. Based on the thermodynamic considerations, the iron oxide and the zinc oxide are reduced in the filter. The solution loss reaction rate is comparatively low at about 1000℃ in the coke bed filter by the analysis using the mathematical simulation model. The heavy metal condenser is installed in the position after the coke bed filter, and rapidly cools the gas from about 1000℃ to 450℃ by a full of the cooling medium like the solid ceramic ball in addition to the cooling from the wall. The zinc and lead vapor condense and separate f개m the gas in a liquid state. The investigation of the characteristics of the exhaust gas of the commercial electric arc furnace, the fundamental experiments of the laboratory scale and the bench scale ensured the formation of this proposed process. A small-scale pilot plant examination is carrying out at present to confirm the formation of the process. It is certain that the dust generation of the electric arc furnace is extremely decreased, and it can save the energy consumption of usual dust treatment processes by the realization of this process.

• 한국분말재료학회지
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• 제20권6호
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• pp.467-473
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• 2013

This research presents a preparation method of dental components by metal injection molding process (MIM process) using titanium scrap. About $20{\mu}m$ sized spherical titanium powders for MIM process were successfully prepared by a novel dehydrogenation and spheroidization method using in-situ radio frequency thermal plasma treatment. The effects of MIM process parameters on the mechanical and biological properties of dental components were investigated and the optimum condition was obtained. After sintering at $1250^{\circ}C$ for 1 hour in vacuum, the hardness and the tensile strength of MIMed titanium components were 289 Hv and 584 MPa, respectively. Prepared titanium dental components were not cytotoxic and they showed a good cell proliferation property.

• 자원리싸이클링
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• 제27권1호
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• pp.84-91
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• 2018

본 연구에서는 레이저유도 플라즈마 분광법(Laser induced breakdown spectroscopy, LIBS) 기반의 금속 종류별 스펙트럼 데이터를 이용하여 연성정보(soft information)를 추정하고 최빈 클래스로 분류하는(most probable classification) 금속 분류 방법을 제안한다. 폐금속 자원과 같이 사전 정보가 없는 금속을 분류하는 경우 몇 가지 핵심 구성성분에 대한 정량 분석을 통해서 클래스를 추정하는 방법이 효율적이다. 이에 따라 부분 집합 기반의 부분최소제곱회귀법(Partial Least Square Regression, PLSR)을 이용하여 LIBS 검출 스펙트럼으로부터 각 성분의 농도를 독립적으로 신뢰성 있게 추정하고, 인증 표준물질(CRM) 등 알려진 모집합의 농도정보에 기반하여 최고 확률을 갖도록 분류하는 기술을 제안한다. 샘플 스펙트럼들의 다변량 분석을 통해서 여러 성분의 추정 농도를 다변량 정규 분포를 갖는 것으로 가정하고 통합(Joint) 추정 연성정보를 구할 수 있으며, 이를 활용한 최빈 확률 검출이나 추가적인 사전 정보의 결합 등을 통해서 분류 성능을 향상시킬 수 있다. 제안된 기술의 평가를 위해서 9가지 종류의 CRM 금속시료의 LIBS 스펙트럼 데이터를 사용하며, 부분 집합 기반의 PLSR 농도 추정 기술을 기반으로 단변량 혹은 다변량 정규 분포 연성 정보추정을 통해 미지 금속의 검출과 연성 정보의 검출 등을 테스트 하였다. 또한 방사형 차트(Radar chart)를 이용하여 추정된 농도와 획득한 연성정보를 효과적으로 시각화함으로써 기존 라이브러리에 포함된 부분 집합의 금속과 비교하여 해당 금속과의 유사성을 그래프를 통해 추정할 수 있다.

• 대한지리학회지
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• 제39권1호
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• pp.88-101
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• 2004

본 연구는 재활용 생활계 폐기물의 수거경로를 살펴보고, 재활용품에 의한 수거유형과 지역특성과의 관계를 밝히는 것을 목적으로 한다. 분석결과는 다음과 같다. 인구규모가 크고 증가율이 높으며 제2차 산업 인구구성비와 재정자립도가 높은 지역에서는 종이류와 고철류가 주로 수거되고, 인구규모가 작고 증가율도 낮거나 감소하며, 제1차 산업 인구구성비와 농가율이 높은 농촌지역에서는 기타를 포함하여 고철류, 종이류, 병류 등의 다양한 수거가 나타난다. 이는 지역에 발달한 산업에 의해 재활용 생활계 폐기물의 수거유형이 다르다는 것을 의미한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.140-143
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• 2001

A study has been made on the recovery of nitric acid and valuable metals such as Cu, Sn, Pb from the spent nitric etching solutions. The nitric acid was extracted effectively by TBP but the heavy metals such as Fe, Cu, Sn, Pb were not extracted by TBP from the spent nitric etching solutions. From the experimental results, 95% of nitric acid in spent etching solution was extracted at O:A ratio of 3:1 with five stage by 60% TBP and 98% of nitric acid was stripped from the loaded organic phase at O:A ratio of 1:1 with four stages by distilled water. After extracting nitric acid, Cu was recovered as a metal by electrowinning effectively and Sn was successfully removed by precipitation method by adjusting the pH of raffinate solution. Finally, Pb was recovered by cementation with iron scrap at $65^{\circ}C$. Parameters controlling the cementation process, such as temperature, pH and the effect of the additives were investigated.

• 자원리싸이클링
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• 제6권4호
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• pp.3-10
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• 1997

Electric are furnace dust (EAF dust) generated in steel production based on scrap melting is contained Zn and Fe about 25 and 30 percent by weight, respectively. From a metallurgical point of view, the dust could be regarded as a raw material for Zn and Fe source. To recover the Zn in the metal from EAF dust, many system are proposed such as Arc Plasma Furmace and Pb splasher method. In this study, to recover high purity Zn from Pb splasing alloy, Zn distillation is carried out at the temperature of 1123, 1173, 1223, 1273 K, the gas flow rate of 2.5, 5.0, 8.0 Ni/min and the distilling time of 10, 30, 60, 90 minutes. The main results obtained from this study are as follows:(1) The amount of evaporated Zn and its evaporating rate increased with increasing temperature, but purity of Zn decreased with increasing temperature. Optimum temperature range was found out to be between 1173∼1223K. (2) The amount of evaporated Zn and evaporation rate increased with increasing gas flow rate at a given temperature and distillation time. Gas flow rate has more influence over the amount of evaporated Zn and evaporation rate with increasing temperature.

• Advances in concrete construction
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• 제5권4호
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• pp.391-405
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• 2017

Cement acts as the most important component of concrete as it binds and holds the concrete together. But it is one of the major $CO_2$ emitters all over the world, during manufacturing (900 kg of $CO_2$ per 1000 kg). Some of the modern construction methods aim at reducing the amount of usage of cement and came out with numerous solutions for replacement of the same. One such supplement in current trend is the Steel dust or the Electric Arc Furnace Dust (EAFD), which is a waste product from the electric arc furnace when the scrap metal is melted. When the concrete containing steel dust is exposed to atmosphere, the environmental oxygen and moisture play role to form rust and ultimately the member becomes harder. As Cement is the binder of conventional concrete, only certain percentage of the same could be replaced by the new material, steel dust. Tests were conducted for the 28 days cube strength of M45 grade (suitable for prestressing) concrete which has 0%, 10%, 20%, 30%, 40% and 50% steel dust instead cement. From the test, the optimum percentage replacement of steel dust was obtained, for which the beams and overhead poles were cast, prestressed and tested for the failure load and deflections. A conventional concrete beam and overhead pole were also cast, prestressed and tested to compare the results with those of the beam and pole that contained steel dust. The load vs. deflection plot and other results from the test is also discussed.

• 대한안전경영과학회지
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• 제13권2호
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• pp.203-210
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• 2011

Incheon Port has been served as not only the center of the Yellow Sea and port for trade with China but also domestic gateway port for the metropolitan area, playing a professional role as the greatest domestic Port which processes a variety of items such as imported raw materials, bulk cargo, oil and gas and so on. This study was conducted based on step by step business process between port entry and departure of ship, and incurred cost according to port industry classification and performance on the port facility. Bulk cargo and general cargo such as grain, food, steel, scrap metal, wood, coal, LNG, LPG and oil etc., which have a vast majority of import goods, have been treated by 57,062 thousand tons and 7,409 thousand tons of container cargo were processed at Incheon Port in 2009. Bulk vessels and carriers moving items such as LPG, LNG and oil recorded 38,836 thousand won and full-container vessels recorded 11,001 thousand won as the amount of notified port facility usage fees in 2008.