• Title/Summary/Keyword: 백운석

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일본 광물산업의 현황

  • 정기영
    • Mineral and Industry
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    • v.13 no.1
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    • pp.64-72
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    • 2000
  • 한동안 일본의 급성장 수출경제는 멈출 수 없는 것처럼 보였었다. 그러나 이제 지난 10년간 경제가 후퇴하면서 그 희생을 치르고 있다. 제조업 전 분야가 하락세를 면치 못하고 있거나, 기껏해야 현상 유지함으로서 결국 광물 소비량에 영향을 미치고 있다. 대규모 석회석 백운석 자원, 상당한 벤토나이트 및 납석 자원, 그리고 소다회, 융합광물(fused minerals) 등의 합성 원료를 제외하면, 일본에는 규모 있는 광물자원이 거의 없다. 광물자원의 부족과 최근의 엔고 현상 때문에 일본은 중국과 같은 나라의 주요 광물 수출 시장이 되고 있다.

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Mineralogical Characteristic and Occurrence of Tremolite and Actinolite in the Dong-A mine, Korea (동아광산 일대 투각섬석과 양기석의 산출상태 및 광물학적 특성 연구)

  • Kim, Seong Ho;Kim, Jeong Jin
    • Journal of the Mineralogical Society of Korea
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    • v.28 no.4
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    • pp.333-341
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    • 2015
  • As results of X-ray diffraction analysis, samples of asbestos and soil were composed maily of dolomite ($CaMg(Co_3)_2$, tremolite ($Ca_2Mg_5Si_{18}O_{22}(OH)_2$), actinolite ($Ca(Mg,\;Fe)_6Si_8O_{22}(OH)_2$), talc ($Mg_3Si_4O_{10}(OH)_2$), calcite ($CaCO_3$) and small amounts of quartz ($SiO_2$) and clay minerals. The average size of asbestos fibers was about $100{\mu}m$ and maximum of some asbestos was $250.0{\mu}m$ in length. The aspect ratio of asbestos fiber were over 3 : 1 and inclined extinction in the range of $8.0-19.5^{\circ}$. Single isolated fragments of asbestos are probably fiber and acicula form in crystal edge along the cleavage plane. Tremolite that composed main asbestos mineral in rock and soil around Dong-a mine is higher content of Fe than actinolite asbestos.

Particle-Size Distribution Dependent upon Crushing Mechanism and Crushing Circuit (파쇄 메카니즘과 파쇄회로에 따른 입도분포)

  • Choi, Do-Young;Kim, Wan-Tae;Kim, Sang-Bae
    • Journal of the Mineralogical Society of Korea
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    • v.23 no.4
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    • pp.297-303
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    • 2010
  • We report the particle-size distribution and comminution charactersitics of dolomite depending upon crushing equipment (hammer crusher and roll crusher) and crushing circuit (open and closed). The quantity of fine particles (< 100 mesh) produced by hammer crusher was 34 wt.% which is about three times that by roll crusher. The quantity of 14~25 mesh size fraction by roll crusher was 20 wt.% higher than that produced by hammer crusher. 80 wt.% of the crushing products by hammer crushing was under 35 mesh in size, while the particles produced by roll crushing were relatively coarse. The particle size of both the hammer and roll crushers decreased by employing closed crusing circuit in comparison to open circuit. Products of required particle-size were obtained effectively depending on appropriate crushing equipment and crushing circuit.

A Study on Synthesis of Ca and Mg Compounds from Dolomite with Salt Additional React (MgCl2·6H2O) (염 첨가 반응(MgCl2·6H2O)을 이용하여 백운석으로부터 Ca 화합물과 Mg 화합물 합성에 관한 연구)

  • Hwang, Dae Ju;Yu, Young Hwan;Cho, Kye Hong;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.59 no.3
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    • pp.399-409
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    • 2021
  • In order to utilize dolomite as a calcium/magnesium compound material, it was prepared highly reactive calcined dolomite(CaO·MgO) using a microwave kiln (950 ℃, 60 min). The experiment was performed according to the standard of the hydration test (ASTM C 110) and hydration reactivity was analyzed as medium reactivity (max 74.1 ℃, 5 min). Experiments were performed with calcined dolomite and salt (MgCl2·6H2O) (a) 1:1, (b) 1:1.5, and (c) 1:2 wt% based on the hydration reaction of calcined dolomite. The result of X-ray diffraction analysis confirmed that MgO of calcined dolomite increased to Mg(OH)2 as the salt addition ratio increased. After the separating reaction, calcium was stirred at 80 ℃, 24 hr that produced CaCl2 of white crystal. XRD results, it was confirmed calcium chloride hydrate (CaCl2·(H2O)x) and CaO of calcined dolomite and salt additional reaction was separated into CaCl2. And it was synthesized with Ca(OH)2 99 wt% by NaOH adding reaction to the CaCl2 solution, and the synthesized Ca(OH)2 was manufactured CaO through the heat treatment process. In order to prepare calcium carbonate, CaCO3 was synthesized by adding Na2CO3 to CaCl2 solution, and the shape was analyzed in cubic form with a purity of 99 wt%.

Controls on Diagenetic Mineralogy of Sandstones and Mudrocks from the Lower Hayang Group (Cretaceous) in the Daegu Area, Korea (대구 부근 하부 하양층군(백악기) 사암과 이암의 속성 광물과 속성 작용의 규제 요인)

  • Shin, Young-Sik;Choo, Chang-Oh;Lee, Yoon-Jong;Lee, Yong-Tae;Koh, In-Seok
    • Journal of the Korean earth science society
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    • v.23 no.7
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    • pp.575-586
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    • 2002
  • Authigenic minerals found in sandstones and mudrocks of the Lower Hayang Group (Cretaceous) in the central part of the Kyungsang Basin are carbonate minerals (calcite, dolomite), clay minerals (illite, chlorite, C/S, I/S and kaolinite), albite, quartz and hematite. Characteristic diagenetic mineral assemblages are as follows: albite-chlorite (including C/S)-hematite in the Chilgog Formation, albite-illite-calcite in the Silla Conglomerate, illite-chlorite-hematite in the Haman Formation and albite-chlorite-dolomite in the Panyawol Formation, respectively. Among clay minerals reflecting the physical and chemical change of the diagenetic process, illite, the dominant clay mineral, occurs in every formation in the study area. Chlorite occurs mainly in green or gray sandstones and mudrocks, or in sandstones and mudrocks of the Chilogok Formation which contains a high content of volcanic materials. Based on the mineral assemblage, diagenetic minerals are strongly related with source rocks. Judging from the illite crystallinity, diagenesis of sandstones and mudrocks in the study area reached the late diagenetic stage or low grade metamorphisim. The diagenetic process was much influenced by intrusion of the Bulguksa granite, content of organic materials, grain size, and depositional environment rather than burial depth.

Material Characteristics and Nondestructive Deterioration Assessment for the Celestial Chart Stone, Korea (천상열차분야지도 각석의 재질특성과 비파괴 훼손도 평가)

  • Yoo, Ji Hyun;Lee, Myeong Seong;Choie, Myoungju;Ahn, Yu Bin;Kim, Yuri
    • The Journal of the Petrological Society of Korea
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    • v.27 no.4
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    • pp.207-222
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    • 2018
  • Celestial Chart Stones (original and reproduction) in the National Palace Museum are representative scientific cultural heritage of Korea. Material analysis and nondestructive deterioration assessment were conducted for long-term preservation of these stones. Material analysis revealed that the original was composed of slate and the reproduction was made of dolostone. The original consists of quartz, mica, dolomite minerals, while the reproduction was made up of dolomite, calcite and forsterite. Major deterioration factors of the original stone were cracks and breakouts. In case of the reproduction, scratches and artificial materials were mainly observed. The green and black surface contaminants present at the sides and back of the two celestial chart stones were interpreted as resin-based paint materials. The physical property evaluation using ultrasonic velocity showed a low velocity in the upper left side of the original, while the front right side of the reproduction showed a weak property. Meanwhile, the To-Tc method using ultrasonic velocity was applied to major cracks that impede stability of the original. As a result, it has been calculated that the beginning and the center of the crack are the deepest.

A Study on Performance Characteristics Planar angle diffuser with PIV (PIV를 이용한 평판형 디퓨저의 유동특성에 관한 실험적 연구)

  • Oh, Jeong Hun;Cho, Dae-Hwan;Seok, Baek Un
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2012.06a
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    • pp.261-262
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    • 2012
  • In planar angle diffuser, the increasement of cross-sectional area so rapidly cause possibly separate from the diffuser wall and forming areas of backflow. The flow characteristics of planar angle diffuser was investigated for three kind of inclined angle. Judging from the results, wide planar diffuser can be used as an effective means of improvement for diffuser performance and inclined angle of diffuser was through to be the best among three cases.

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Thin film acoustooptic beam deflector in proton-exchanged LiNbO$_{3}$ (양자교환된 LiNbO$_{3}$에서 박막도파형 음향광학 광변위기)

  • 김성국;백운석;김광택;정성갑;송재원
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.7
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    • pp.94-103
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    • 1995
  • Thin film acoustooptic beam deflector in proton-exchanged Y-cut LiNbO$_{3}$ was fabricated and measured. The planar waveguide was fabricated by using the proton-exchanged and annealing method in Y0cut LiNbO$_{3}$. Interdigital transducer for SAW(surface acoustic wave) was made by the laser lithography. Using above method, the thin film acoustooptic beam deflector was constructed. Its SAW wavelength was 20.mu.m at 174MHz center frequency. The interaction length between guided optical wave and SAW was 2.16mm. The measured 3dB bandwidth was 17MHz using He-Ne laser. And 70% diffraction efficiency was obtained at 970mW RF driving power.

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Strength Properties of the Concrete with Low Carbon Cement and Rapidly Cooled Electric Arc Furnace Oxidizing Slag (급냉 전기로 산화슬래그와 저탄소시멘트를 적용한 콘크리트의 강도특성)

  • Sun, Joung-Soo;Choi, Sun-Mi;Sung, Jong-Hyun;Bok, Young-Jae;Choi, Duck-jin;Kim, jin-Man
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.11a
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    • pp.164-165
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    • 2013
  • This study is on the performance evaluation of concrete being used the CaMg based low carbon cement(LCC) as a binder and the rapidly cooled electric arc furnace oxidizing slag(EAF slag) as a fine aggregate. When using the sand as a fine aggregate, compressive strength of the concrete using LCC, as a binder, was reduced 9% comparing with that of OPC concrete. However, when using the EAF slag as a fine aggregate, the compressive strength was increased by 9%. We found that combination LCC and EAF slag contribute to the strength properties of concrete.

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Experiments of bragg and off-bragg blazing phenomena by strip grating over a grounded dielectric slab for TM polarization Case (접지된 유전체판 위에 위치한 스트립 격자에 TM편파된 평면파가 입사되는 경우에서의 Bragg 및 Off-Bragg blazing 현상-실험)

  • Baek, W.S.;Cho, U.H.;Lee, J.I.;Lee, C.H.;Hong, J.P.;Cho, Y.K.;Son, H.
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.4
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    • pp.605-610
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    • 1997
  • An analysis method for the electromagnetic scattering of a Tm polarized plane wave from a periodic strip grating over a grounded dielectric slab is considered from the viewpoint of reflection grating problem. The parameters of strip gratings showing Bargg and Off-Bragg blazing phenomena at the frequency of 10GHz are derived teoretically. The strip grating structure is implemented using Aluminum plate(groung conductor), paraffin(dielectric material.epsilon.$_{r}$=2.24), and copper(strip conductor0.08m thickness). The experimental results(reflection power) of Bragg as well as Off-Bragg blazing phenomenon for TM polarized plane wave have been compared with the theoretical results and fairly good agreements between theory and experiment have been observed.d.

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