• Economic and Environmental Geology
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• v.45 no.4
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• pp.377-384
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• 2012

The main field component of the Earth's magnetic field was modeled from the tri-axial magnetometer onboard KOrean MultiPurpose SATellite-II (KOMPSAT-II) for the purpose of satellite attitude control. The model computed by the KOMPSAT-II magnetometer measurement data is compared with the International Geomagnetic Reference Field (IGRF) model of a degree of up to 13 in spherical harmonic coefficients. The previous study with KOMPSAT-I (Kim et al. 2004) indicated a good correlation of power spectrum of spherical harmonic coefficients with respect to the degree up to 5. This study, however, showed an agreement of the degree up to 8-9 of the coefficient power spectrum and a discrepancy between degrees 10 and 13. We have concluded that relevant data selection process, removal of the external field from the data in the high latitude region, an accuracy of the magnetometer all play an important role in finding a coherence with the IGRF model. This study will be extended to the secular variation model of geomagnetism if longer-period data become available.

• Resources Recycling
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• v.11 no.4
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• pp.11-16
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• 2002

Analysis and separation of constituent materials of old car have been performed by using the industrial shredding line. For this aim, three old cars made by domestic automobile manufacturers, Sonata II, Sephia and Prince were chosen and delivered in pressed form without engine, tires and doors, etc. Shredding line was substantially composed of pre- and main-shredder. cyclone, magnetic separation, eddy current separation and man-power separation. From the separation of shredder products, iron scrap was observed to be the major material of old car accounting for 60.1 ％ of total weight and non-ferrous metals involving Al, Cu and Zn, etc. were about 2％. Light fluff, about 90％ of total fluff product, was comprised with plastic, fiber and sponge, etc. and the fraction of 5 cm undersize in light fluff was 70.5%. In case of heavy fluff, however. rubber and plastic were found to be the major constituent materials of it. Among the constituent materials of fluff, plastic showed the highest calorific value, more than 10,000 cal/gr and leather and rubber showed relatively high chlorine content, 10.3 and 2.55 wt%, respectively.

• Resources Recycling
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• v.12 no.3
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• pp.25-30
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• 2003

The synthesis of SiC used for the parts of the gas turbine and the heat exchanger, was carried out. In this study, wire cutting slurry of silicon wafer and the graphite rod of spent zinc-carbon battery were applied to the starting materials for the synthesis. The powders of Si or Si+SiC were obtained from the waste material by filtration, gravity separation and magnetic separation. Graphite powder was produced by dismantling, grinding and gravity separation from spent zinc-carbon battery. The synthesis of SiC could be completed from the mixture powders of Si and C or Si+SiC and C at the condition of equivalent ratio of Si and C, atmosphere of Ar or vacuum, temperature of above 1$600^{\circ}C$ and 2 hours reactions. The purity of synthesized Si-C was above 99%.

• Resources Recycling
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• v.29 no.6
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• pp.3-14
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• 2020

This study aims to introduce and review on the recovery technologies of rare earth elements(REEs) from coal ash. Many researchers have been carried out by various beneficiation processes, such as particle size separation, magnetic separation, specific gravity, and flotation to recover rare earth elements from coal ash generated from Pulverized Coal(PC) boiler. Through the beneficiation process, it was confirmed that concentration of rare earth elements was much lower than the 4,700 ppm, and that additional enrichment treatment through wet process was needed for the products recovered after the beneficiation process. It was confirmed that the rare earth elements contained in coal ash were applied to the leaching process after pretreatment such as alkali-fusion to improve leaching efficiency. Although beneficiation and leaching methods have been studied, its optimum recovery technologies for rare earth elements not been confirmed up to now, research on the recovery of rare earth contained in coal ash is reported to continue. In case of Korea, the technology for the recovery of rare earth elements from coal ash and coal by-product could not been confirmed up to present. In these reasons, it is urgent to develop technologies such as beneficiation and leaching process continuously.

• Journal of Korea Foundry Society
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• v.29 no.1
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• pp.38-44
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• 2009

Magnetic separation of Fe contaminated Al-Si cutting chip scraps was performed for the recyclability assessment. It was also aimed to investigate the casting and solidification characteristics of the cutting chip scraps. The magnetically separated cutting chip scraps were adequately treated for the casting procedure and test specimens were made into a stepped mold inducing different cooling rates. The test specimens were evaluated by the combined analysis of ICP, Spectroscopy, OM-image analyzer, SEM/EDS, etc. Solidification characteristics of cutting chip scraps were examined as functions of Fe content and cooling rate. It is concluded that the magnetic separation process can be utilized to recycle the Fe contaminated Al-Si cutting chip scraps in the high cooling rate foundry process.

• Journal of Industrial Technology
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• v.15
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• pp.175-185
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• 1995

Under the new environmental regulations announced by the government, utilities will have to cut their sulfur dioxide emissions by 60% from 1991 levels by the year of 1999. Sulfur dioxide emissions can be reduced prior to combustion by physical, chemical or biological coal cleaning. The new technology of high gradient magnetic separation (HGMS) offers the potential of economic separatoins of a variety of fine, weakly magnetic minerals including inorganic sulfur and many ash-forming minerals from coals. In the present paper, magnetic separation tests have been conducted on Korean anthracite and high-sulfur Chinese coal to investigate the feasibility of these techniques for reducing sulfur content from coals. In wet magnetic separation, the studied operating parameters include particle size, pH, matrix types, feed solids content, feed rate, number of cleaning stages and etc. The results shows that for wet separation, 60~70% of total sulfur was removed from coals with over 80% combustible recovery, on the other hand, for dry separation, 47.6% of total sulfur was removed from coals with 75% recovery.

• KDI Journal of Economic Policy
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• v.10 no.4
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• pp.83-114
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• 1988

본고(本稿)의 목적은 서독(西獨) 일본(日本) 양국(兩國)의 의료보험제도(醫療保險制度)를 비교 검토하여 그들의 경험에서 배울 수 있는 교훈을 토대로 우리나라의 실정에 적합한 정책방안을 제시하려는 데 있다. 일반적으로 서독(西獨)은 제도내용이 효율성(效率性)보다는 형평성(衡平性)에, 일본(日本)은 비용효과(費用效果) 측면에 치중함으로써 서독(西獨)에서는 의료비 증가로 비용억제(費用抑制)가, 일본(日本)에서는 급여의 형평문제(衡平問題)가 중심과제로 되어있다. 이들 양국(兩國)의 경험을 토대로 한국제도(韓國制度)의 개선(改善)에 유용한 일련의 정책대안(政策代案)을 제시하면, 프로그램간 부담과 급여의 균등화를 추진하고, 정부(政府)의 보조금지원(補助金支援)은 목표인구(目標人口)를 대상으로 규모를 최소화하여 비용효과적으로 실시해 나가야 할 것이다. 소단위조합(小單位組合)의 지속적인 광역화(廣域化) 추진과 조합운영에 자율적인 기능을 부여해 나가는 한편 지역보험(地域保險) 보험료부과기준(保險料賦課基準)의 단순화 및 형평제고를 위해 자력조사(資力調査)를 조기에 실시할 것을 제안한다. 후송체계(後送體系)를 전국적으로 확대 적용시켜 나가면서 고소득계층에 대하여는 강제적용보다 임의적용으로 전환하여 민간보험시장(民間保險市場)의 개발을 꾀하고, 소득 있는 피부양자를 선별하여 보험료(保險料)를 부과(賦課)함으로써 보험재정(保險財政)의 안정을 도모하여야 할 것이다.

• Resources Recycling
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• v.6 no.1
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• pp.17-22
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• 1997

An electromagnetic fluidized bed was proposed for the continuous separation of magnetic particles from the fine a admixtures with nonHmagnetic particles. The effects of operating variables on the magnetic fraction in the separated p particles were examined, including superficial gas velocity, mixing fraction of magnetic particles (= 100-mixing fraction of n non-magnetic particles) in the admixture, and electric current supplied to the electwmagnet. It was found that the s separation was possible when a magnetic force formed by the electromagnets works on the magnetic particles over the hydrodynamic force caused by a gas stream for fluidizing the fine admixture.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.37-40
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• 2005

폐 프린터의 발생량이 해마다 증가하고 있으며 이에 대한 재활용이 필요하다. 폐 프린터의 재활용에 있어서 다른 구성성분보다 기판의 처리가 문제가 된다. 본 연구는 폐 프린터의 기판을 재활용하는 데에 습식처리공정을 적용하기 위하여 먼저 전처리로 분쇄와 분리를 실시하였다. 기판을 1cm 이하로 분쇄한 다음 자력선별기를 이용하여 자성물질을 제거하고 비자성물질을 대상으로 4, 12, 40 mesh의 체를 이용하여 시료를 분리하였다. 전처리를 통하여 금속성분 특히 구리가 다량 함유된 12/40# 에 속한 시료를 대상으로 산에 의한 침출실험을 실시하였다. 실험 변수로는 산의 종류, 산 농도, 반응 온도, pulp density 등이었다.

• Resources Recycling
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• v.6 no.3
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• pp.3-8
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• 1997

The EA.F. sleelmaking slag (slag that follow) of a cnmvany 1 Co.. containzd a simple substance of a metal, wustlte (FeO), magnetite (Fe,O,), gehlenite (CaAl,SiO,), monlicellite (CaMgSiO,), dc. To recovere a metal (Fe grade . t95%) in the slag, it is desirable that the particles of a metal are isolated from thc slag and madc for a liberated subslance. Then, the liberaled melal is easlly recoveled by a magnetic separation. If thc rcclarnalcd slag, the sizc of which ranges under 40 nun, have a mulli-stage crushing, the most of a metal in thc slag is simply isolaled as a liberated subslance. If the mad, lhat is a liberated subslance and a sphere, is recovered by a magnetic field intensity. the minimum intensity, at which a metal is attracted, is approximately IOOG and did no1 dcpcnd on the particle size of a metad in the same particles. TIe recovered material. that contdined a iron (Fe) over 95% is a metal which is crushed slag by l00G in the multi-stage. If the magnetic field intcns~ty increase, the recovery mcrcasc, but the concentration grade decrease Bewusc thc concentration eams more and more impurities, iron oxide and the coml~ound of alkali earth element. 'll~ercforc If the rccla~nated slag have the multi-stage crushing, the metal is almostly recovered in the crushed slag by lO0G on each particles. If the slag, used as a rcclamatian lhat is a amount of 350,000 tan from I Co., was undcr the multistage crushing and then separaled by 100gauss, it is possible to recova a metal approximately 2.500 Ion, lhat is 0.73% of n ~eclamated slag. in 304.7 mm particles and to recover 4.200 tan in 0.3-1.7 mm particles , that is 1.2% nf a rcclamated slag, in a year. Therefore, ihe told recoverable meld is 6,700 ton, that is 19% of a reclmated slag, in a year, too.