• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.583-595
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• 2006

Quartz veins from the Hwawon area are an epithermal quartz vein that is filling the fault zone within Precambrian metasedimentary rocks and Jurassic granite. Mineralization can be divided into hypogene and supergene stages. Hypogene stage is associated with hydrothermal alteration minerals(propylitic and argillic zones) such as epidote, chlorite, illite, sericite and sulfides such as pyrite, sphalerite, chalcopyrite, galena, bornite, cubanite, argentian tetrahedrite, Pb-Ag-S system and Pb-Te-S system. Supergene stage is composed of Fe-Mn oxide, Zn-Fe oxide and Pb oxide. Fluid inclusion data indicate that homogenization temperatures and salinity of hypogene stage range from $291.2^{\circ}C$ to $397.3^{\circ}C$ and from 0.0 to 9.3 wt.% eq. NaCl, respectively. It suggests that ore forming fluids were cooled and diluted with the mixing of meteoric water. Oxygen($-0.7{\sim}3.5%_{\circ}$(white quartz: $-0.7{\sim}3.5%_{\circ}$, transparent quartz: $2.4%_{\circ}$)) and hydrogen($-70{\sim}55%_{\circ}$(white quartz: $-70{\sim}55%_{\circ}$, transparent quartz: $-62%_{\circ}$)) isotopic composition indicates that hydrothermal fluids were derived from magmatic and evolved by mixing with meteoric water during mineralization.

• Journal of Conservation Science
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• v.29 no.4
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• pp.355-366
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• 2013

Diverse scientific analyses, including microstructure, ICP-AES, SEM-EDS, and P-XRF(Bench Top type and Gun type), were carried out on 6 bronze artefacts which handed from generation to generation. Also, we attempted to study applicability for authenticity of the bronze artefacts using scientific analyses based on the specific element. The results of ICP-AES analysis showed that the bronze were formed from an alloy of Cu, Sn, Pb with trace elements such as Ag, As, Co, Fe, but there were not Zn found. The result of P-XRF are 10~25% lower in Cu and 10~20% higher in Sn than that of ICP-AES. This is because of destannification that the compound of $SnO_2$ are present on the surface. The results of SEM-EDS represented that there is lead segregation. It was difficult to study applicability for authenticity of bronze artefact according to the microstructures and chemical components of the bronze artefacts. Therefore, as bronze artefacts have shown different corrosion materials depending on the buried environment and conserving environment, identifying the authenticity would be possible on the basis of the additional researches on the corrosion and comparative research of ancient art.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.199-206
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• 2013

The Daehyun gold-silver deposit consists of two hydrothermal quartz veins that fill NE-trending fractures in the Cambro-Ordovician calcitic marble. I have sampled wallrock, hydrothermaly-altered rock and gold-silver ore vein to study the element dispersion and element gain/loss during wallrock alteration. The hydrothermal alteration doesn't remarkably recognized at this deposit and consists of mainly calcite, dolomite, quartz and minor epidote. The ore minerals composed of arsenopyrite, pyrrhotite, pyrite, sphalerite, stannite, chalcopyrite, galena, electrum, native bismuth and silver-bearing mineral. Based on analyzed data, the chemical composition of wallrock consists of mainly $SiO_2$, CaO, $CO_2$ with amounts of $Al_2O_3$, $Fe_2O_3(T)$ and MgO. The contents of $SiO_2$, $Fe_2O_3(T)$, MgO, CaO and $CO_2$ vary significantly with distance from ore vein. The element dispersion doesn't remarkably recognized during wallrock alteration and only occurs near the ore vein margin because of physical and chemical properties of wallrock. Remarkable gain elements during wallrock alteration are $Fe_2O_3(T)$, total S, Ag, As, Bi, Cd, Cu, Ni, Pb, Sb, Sn, W and Zn. Remarkable loss elements are $SiO_2$, MnO, MgO, CaO. $CO_2$ and Sr. Therefore, Our result may be used when geochemical exploration carry out at deposits hosted calcitic marble in the Hwanggangri metallogenic district.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.645-655
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• 2014

In order to obtain pure metallic Te from gold concentrate, roasting treatment, hypochlorite leaching, Fe removal and electrolysis experiments were carried out. The contents of Au, Ag and Te from the concentrate sample and roasted sample were much more soluble in the hypochlorite solution than in aqua regia digestion, whereas the metals Pb, Zn, Fe and Cu were easier to leach with the aqua regia than the hypochlorite. With the addition of NaOH in the hypochlorite leaching solution prior to electrolysis, the Fe removal rate achieved was only 96% in the concentrate sample, while it reached 98% in the roasted sample. The results of electrolysis for 240 min, 98% of the metallic copper was recovered from the concentrate sample, while 99% was obtained from the roasted sample due to the removal of S by roasting. The amount of anode slime was also greater in the electrolytic solution with the roasted sample than with the concentrate sample. The results on the anode slime after the magnetic separation process showed the amount of metallic pure native tellurium recovered was greater in the roasted sample than in the concentrate sample.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.363-379
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• 2014

The Haenam Pb-Zn skarn deposit is located at the Hwawon peninsula in the southwestern part of the Ogcheon Metamorphic Belt. The deposit is developed along the contact between limestone of the Ogcheon group and Cretaceous quartz porphyry. Petrography of ore samples, chemical composition of skarn and ore minerals, and geochemistry of the related igneous rocks were investigated to understand the characteristics of the skarn mineralization. Skarn zonation consists of garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone, pyroxene+garnet+quartz${\pm}$calcite zone, calcite+pyroxene${\pm}$garnet zone, quartz+calcite${\pm}$pyroxene zone, and calcite${\pm}$chlorite zone in succession toward carbonate rock. Garnet commonly shows zonal texture comprised of andradite and grossular. Pyroxene varies from Mn-hedenbergite to diopside as away from the intrusive rock. Chalcopyrite occurs as major ore mineral near the intrusive rock, and sphalerite and galena tend to increase as going away. Electron probe microanalyses revealed that FeS contents of sphalerite become decreased from 5.17 mole % for garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone to 2.93 mole %, and to 0.40 mole % for calcite+pyroxene${\pm}$garnet zone, gradually. Ag and Bi contents also decreased from 0.72 wt.% and 1.62 wt.% to <0.01 wt.% and 0.11 wt.%, respectively. Thus, the Haenam deposit shows systematic variation of species and chemical compositions of ore minerals with skarn zoned texture. The related intrusive rock, quartz porphyry, expresses more differentiated characteristics than Zn-skarn deposit of Meinert(1995), and has relatively high$SiO_2$ concentration of 72.76~75.38 wt.% and shows geochemical features classified as calc-alkaline, peraluminous igneous rock and volcanic arc tectonic setting.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.6
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• pp.507-513
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• 2000

This study was conducted to investigate the shelf life of beef stored in antimicrobial pottery during 12days storage at 4'C and Five kinds of antimicrobial potteries were prepared with antimicrobial materials such as TiO$_2$, Ag (NO$_3$)$_2$, Cu(NO$_3$)$_2$ and Zn(NO$_3$)$_2$. In changes of color during storage, Hunter's L- and b-value of beef were not changed, but Hunter's a-value was low significantly. The pH of beef meats were low at 6 days, but were added from 6 days. TBA value of beef in "A" pottery containing TiO$_2$ 1% and "C" Pottery containing TiO$_2$ 0.5%, Cu(NO$_3$)$_2$ were lower than "B", "D" and "I" pottery. VBN contents of beef in "A", "B", "C", "D" and "I" Pottery stored during 12 days were 9.8, 12.5, 9.3, 11.9 and 13.7mg%, respectively. In changes of total plate count of beef during storage at 4$^{\circ}C$, the antimicrobial activity of "A" and "C" pottery were superior.g storage at 4$^{\circ}C$, the antimicrobial activity of "A" and "C" pottery were superior.ttery were superior.

• Economic and Environmental Geology
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• v.24 no.2
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• pp.131-150
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• 1991

The Weolseong diatreme was temporally and spatially related to the intrusion of the Gadaeri granite, and was -mineralized by meteoric aqueous fluids. In the Nokdong As-Zn deposit, pyrite, aresenopyrite and sphalerite are the most abundant sulfide minerals. They are associated with minor amount of magnetite, pyrrhotite, chalcopyrite and cassiterite, and trace amounts of Pb-Sb-Bi-Ag sulphosalts. The AsZn ore probably occurred at about $350^{\circ}C$ according to fluid inclusion and compositional data estimated from the arsenic content of arsenopyrite and iron content of sphalerite intergrown with pyrrhotite + chalcopyrite + cubanite. Heating studies of fluid inclusions in quartz indicate a temperature range between 180 and $360^{\circ}C$, and freezing data indicate a salinity range from 0.8 to 4.1 eq.wt % NaCl. The coexisting assemblage pyrite + pyrrhotite + arsenopyrite suggests that $H_2S$ was the dominate reduced sulfur species, and defines fluid parameter thus: $10^{-34.5}$ < ${\alpha}_{S_2}$ < $10^{-33}$, $10^{-11}$ < $f_{S_2}$ < $10^{-8}$, -2.4 < ${\alpha}_{S_2}$ < -1.6 atm and pH= 5.2 (sericte stable) at $300^{\circ}C$. The sulfur isotope values ranged from 1.8 to 5.5% and indicate that the sulfur in the sulfides is of magmatic in origin. The carbon isotope values range from -7.8 to -11.6%, and the oxygen isotope values from the carbonates in mineralized wall rock range from 2 to 11.4%. The oxygen isotope compositions of water coexisting with calcite require an input of meteoric water. The geochemical data indicate that the ore-forming fluid probably was generated by a variety of mechanisms, including deep circulation of meteoric water driven by magmatic heat, with possible input of magniatic water and ore component.

• Economic and Environmental Geology
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• v.21 no.3
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• pp.287-307
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• 1988

The Cheongju gold-silver mine is located at approximately $36^{\circ}28^{\prime}$north latitude and $127^{\circ}31^{\prime}$ east longitude in the Cheongju City of the Chung cheong bug Do, South Korea. Gold-Silver bearing hydrothermal quartz veins, occur in Cheongju Granit of Jurassic age. K-Ar isotope data for sericite in quartz vein indicate that the Au-Ag mineralization took place in early Cretaceous ($97.5{\pm}2.18$ MA. Park, et ai, 1986). Three stage of mineralization recognized anre, from early to later, (I) Sulide stage: pyrite, arsenopyrite, pyrrhotite (Hpo), sphalerite, chalcopyrite, electrum and quartz (II) Electrum stage: pyrite, sphalerite, galena, chalcopyrite, electrum and quartz. (III) Silver mineral stage: pyrite, marcasite, pyrrhotite (Mpo), sphalerite, galena, electrum, native silver argentite, fluorite, calcite and quartz. In this paper, mode of occurrences and chemical compositions of electum and native silver have been investigated by means of microscope and EPMA. Electron probe microanalysis shows that an individual grain of electrum is almost homogeneous in composition. Silver content of electrum ranges from 44.7-67.1 atom.%. Gold content of native silver ranges below 0.2 atom. %. Vicker's hardness number (VHN) of electrum and native silver ranges $78.2-81.8kg/mm^{2}$ respectively. The filling temperature of fluid inclusions in quartz ranges from $130-280^{\circ}C$. On the basis of arsenpyrite geothemometer, the equilibrium temperature and sulfur fugacity of the pyrite-arsenopyrite-pyrrhotite(Hpo) assemblage is assumed to be in ange from $300-310^{\circ}C$ and $10^{-10}$ to $10^{-11}$ atm. The estimated ore reserviors on Cheongju mine area are calculated to 8000 T/M, averaing 8.6g/t Au, 27.8 g/t Ag, 1.25% Pb, l.65% Zn.

• Solar Energy
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• v.20 no.2
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• pp.43-54
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• 2000

We prepared and characterized $Cu(In_{1-x}Ga_x)Se_2$(CIGS) films using a elemental co-evaporation method for absorbing layer of high efficiency thin film solar cells. The CIGS films deposited on a soda-lime glass exhibited low resistivity because of higher carrier concentration. Na was accumulated at the CIGS surface and the 0 and Se were also accumulated at the surface, suggesting that oxidation is a driving force of Na accumulation. The structure of CIGS film was modified or a secondary phase was formed in the Cu-poor CIGS bulk films probably due to the incorporation of Na into Cu vacancy sites. As the Ga/(In+Ga) ratio increased, the diffraction peaks of $Cu(In_{1-x}Ga_x)Se_2$ films were shifted to larger angle and splitted, and the grain size of $Cu_{0.91}(In_{1-x}Ga_x)Se_2$ films became smaller. All $Cu_{0.91}(In_{1-x}Ga_x)Se_2$ films showed the p-type conductivity regardless of the Ga/(In+Ga) ratio. Ag/n-ZnO/i-ZnO/CdS/$Cu_{0.91}(In_{0.7}Ga_{0.3})Se_2$/Mo solar cells were fabricated. The currently best efficiency in this study was 14.48% for $0.18cm^2$ area ($V_{oc}=581.5mV,\;J_{sc}=34.88mA$, F.F=0.714).