신지혜 Ji Hye Shin , 유재형 Jaehyung Yu , 정용식 Yong Sik Jeong , 김세영 Seyoung Kim , 고상모 Sang-mo Koh , 박계순 Gyesoon Park

DOI: Vol.29(No.3) 89-101, 2016

This study investigated spectral characteristics of heavy metal contaminated soil samples in the vicinity of abandoned Boksu mine. Heavy metal concentrations including arsenic, lead, zinc, copper and cadmium were analyzed by XRF analysis. As a result, all of the soil samples excluding control sample were over-contaminated based on the counter measure standard. The XRD results revealed that quartz, kaolinite and smectite were detected for all of the soil samples and heavy metals in soil were adsorbed on clay minerals such as kaolinite and smectite. The spectral analyses confirmed that spectral reflectance of near-infrared and shorter portion of shortwave-infrared spectrum decreases as heavy metal concentration increases. Moreover, absorption depths at 2312 nm and 2380 nm, the absorption features of clay minerals, decreases with higher heavy metal concentration indicating adsorption of heavy metal ions with clay minerals. It indicates that spectral features and heavy metal contamination of soil samples have high correlations.

복수광산, 중금속오염, 분광특성, 점토광물, Boksu mine, heavy metal concentration, spectral characteristics, clay minerals

구효진 Hyo Jin Koo , 이부영 Bu Yeong Lee , 조현구 Hyen Goo Cho , 고상모 Sang Mo Koh

DOI: Vol.29(No.3) 103-111, 2016

Li-bearing hectorite, one member of trioctahedral smectite, occurred large in quantity and confirmed in Turkey western sedimentary boron deposit. Li-bearing hectorite attracted a particular attention because it is one of potential lithium resources. There have been no consensus for the change of hectorite due to heat and acid treatment although it is very important to use in industrial application. In this study, we examined changes of hectorite after heat and acid treatment as well as acid treatement followed by heating. We used clay ores collected in Bigadic deposit, which contained the highest Li2O content in Turkey boron deposits. Hectorite showed a strong endothermic reaction at 84℃ due to dehydration of absorbed water and interlayer water and a weak endothermic reaction above 600℃ owing to dehydration of crystallization water. The first endothermic reaction accompanied a large weight loss about 6%. Hectorite decomposed into enstatite, cristobalite and amorphous Fe material at 762℃ with exothermic reaction. When hectorite reacted with 3 kinds of 0.1 M acid during 1 hours, it had a good dissolution efficiency with H2SO4 ≥ HCl > HNO3 in order.

헥토라이트, 터키 붕소 광상, 리튬, 산 처리, 열처리, Hectorite, Turkish Boron deposit, Li, Acid treatment, Heat treatment

김봉주 Bong-ju Kim , 조강희 Kang-hee Cho , 최낙철 Nag-choul Choi , 박천영 Cheon-young Park

DOI: Vol.29(No.3) 113-122, 2016

This study aims to improve the recovery of gold and silver by removing hematite from gold ore of an oxidation zone with ammonia solution. Quartz, hematite and muscovite were present in the oxidation zone, while hematite was hydrogenous. As a result of performing an ammonia leaching test on variables, it is found that the maximum Fe leaching parameter was -45 μm particle size, 1.0 M sulfuric acid concentration, 5.0 g/l ammonium sulfate concentration and 2.0 M hydrogen peroxide concentration. It is also confirmed that goethite was precipitated and formed from that ammonia elution. As the amount of Fe-removal was increased in a solid-residue, the recovery of Au and Ag were increased, too.

산화대, 적철석, 암모니아용출, 침철석, 금회수율, Oxidation zone, Hematite, Ammonia leaching, Goethite, Gold recovery

우현동 Hyeon Dong Woo , 김옥순 Ok Soon Kim , 장윤득 Yun Deuk Jang

DOI: Vol.29(No.3) 123-129, 2016

This study is conducted to estimate the firing temperature and condition of the 4-6th Century earthenwares excavated from the ancient tombs in the Seonggok-ri, Cheongdo through mineralogical approaches, and to contrast to the characteristics of the earthenware from the Changnyeong the adjacent area to the Cheongdo. The Cheongdo earthenware was mainly composed of quartz, pores and vitric matrix with minor parts of feldspars, felsic volcanic fragments and opaque minerals, of which quartz crystals frequently show embayed texture and pores was partly filled with amorphous quartz. Mullite, hematite and cristobalite were found by XRD spectrometer additionally, and in the SEM image the Mullite contents are evenly distributed from the central part to the marginal part. As a result, the firing temperature of the Cheongdo earthenware could be 1,100 to 1,200℃, which is higher than that of the Changnyeong. Distribution characteristics of mullite in the Cheongdo and the Changnyeong earthenware indicate that the Cheongdo earthenware was under the longer firing time or more homogeneous thermal condition in the kiln than the Changnyeong.

토기, 소성온도, 소성환경, earthenware, firing temperature, firing condition

김현나 Hyun Na Kim , 박창근 Changkun Park

DOI: Vol.29(No.3) 131-139, 2016

Detailed knowledge on maskelynite, a glassy phase of plagioclase found in shocked meteorites and impact craters, is essential to understand a shock metamorphism. Here, we explore an inhomogeneous shock metamorphism in the lunar meteorite Mount DeWitt (DEW) 12007 with an aim to understand the formation mechanism of maskelynite. Most plagioclase grains in the DEW 12007 partially amorphized into maskelynite with a unidirectional orientation. Back-scattered electron (BSE) images of maskelynite show a remnant of planar deformation fracture possibly indicating that the maskelynite would be formed by solid-state transformation(i.e., diaplectic glass). Plagioclase with flow texture is also observed along the rim of maskelynite, which would be a result of recrystallization of melted plagioclase. Results of Raman experiments suggest that shock pressure for plagioclase and maskelynite in the DEW 12007 is approximately 5-32 GPa and 26-45 GPa, respectively. The difference in shock pressures between plagioclase and maskelynite can be originated from 1) external factors such as inhomogeneous shock pressure and/or 2) internal factors such as chemical composition and porosity of rock. Unfortunately, Raman spectroscopy has a limitation in revealing the detailed atomic structure of maskelynite such as development of six- or five-coordinated aluminum atom upon various shock pressure. Further studies using nuclear magnetic resonance spectroscopy are necessary to understand the formation mechanism of maskelynite under high pressure.

마스컬리나이트, 달운석, 충격변성, 비정질화, 라만 분광분석, maskelynite, lunar meteorite, shock metamorphism, amorphization, Raman spectroscopy

임으뜸 Euddeum Lim , 유봉철 Bongchul Yoo , 신동복 Dongbok Shin

DOI: Vol.29(No.3) 141-153, 2016

The Manjang deposit is emplaced in Hwajeonri formation comprising limestone that is interbeded with slate and phyllite in the central Okcheon Group. It consists of the Main and the Central orebody of Cu-bearing hydrothermal vein deposit and the Western orebody of iron skarn deposit. Based on coexisting mineral assemblage the skarnization can be divided into prograde skarnization (stage I : clinopyroxene ± magnetite ± quartz, stage II : garnet + clinopyroxene ± magnetite ± quartz) and retrograde hydrothermal alteration (stage III: magnetite + amphibole + quartz ± garnet ± clinopyroxene± chlorite ± epidote ± fluorite ± calcite, stage IV: fluorite ± pyrrhotite ± chalcopyrite ± amphibole ± quartz ± calcite). Diopside is abundant in stage I, and hedenbergite was produced in stage II and III. Garnet compositions change from grandite to andradite, which suggests a redox transition from relatively reduced to oxidized condition during the skarn formation. Magnetite in stage I and II has relatively constant Fe contents, while in the stage III it has increased Si and Ca concentrations. This variation could indicate that magnetite was more strongly affected by host rocks during the retrograde stage. Sulfur isotope compositions of pyrrhotite and chalcopyrite produced in stage IV are within the range of +5.9~6.9 ‰, corresponding to igneous origin, but slightly high sulfur isotope values could be attributed to an interaction with host rocks, limestone.

스카른, 철 광화작용, 자철석, 황안정동위원소, 만장광상, Skarn, Fe-mineralization, Magnetite, Sulfur stable isotope, Manjang deposit

이아침 A Chim Lee , 이성근 Sung Keun Lee

DOI: Vol.29(No.3) 155-165, 2016

Understanding the effect of boron content on atomic structures of boron-bearing multicomponent silicate melts is essential to reveal the atomistic origins of diverse geochemical processes involving silica-rich magmas, such as explosive volcanic eruption. The detailed atomic environments around B and Al in boron-bearing complex aluminosilicate glasses yield atomistic insights into reactivity of nuclear waste glasses in contact with aqueous solutions. We report experimental results on the effect of boron content on the atomic structures of sodium borate glasses and boron-bearing multicomponent silicate melts [malinkoite (NaBSiO₄)-nepheline (NaAlSiO₄) pseudo-binary glasses] using the high-resolution solid-state NMR (¹¹B and ²⁷Al). The 11B MAS NMR spectra of sodium borate glasses show that three-coodrinated boron (^[3]B) increases with increasing B₂O₃content. While the spectra imply that the fraction of non-ring species decreases with decreasing boron content, peak position of the species is expected to vary with Na content. Therefore, the quantitative estimation of the fractions of the ring/non-ring species remains to be explored. The ¹¹B MAS NMR spectra of the glasses in the malinkoite-nepheline join show that four-coordinated boron (^[4]B) increases as X_ma [= NaBSiO₄/(NaBSiO4 + NaAlSiO₄)] increases while ^[3]B decreases. ²⁷Al MAS NMR spectra of the multicomponent glasses confirm that four-coordinated aluminum (^[4]Al) is dominant. It is also observed that a drastic decrease in the peak widths (full-width at half-maximum, FWHM) of ^[4]Al with an addition of boron (X_ma = 0.25) in nepheline glasses. This indicates a decrease in structural and topological disorder around ^[4]Al in the glasses with increasing boron content. The quantitative atomic environments around boron of both binary and multicomponent glasses were estimated from the simulation results of ¹¹B MAS NMR spectra, revealing complex-nonlinear variation of boron topology with varying composition. The current results can be potentially used to account for the structural origins of the change in macroscopic properties of boron-bearing oxide melts with varying boron content.

비정질 소듐 보레이트, 붕소를 포함한 다성분계 비정질 규산염(말린코아이트와 네펠린의 유사이원계), 핵자기 공명 분광분석, 원자 구조, Sodium borate glasses, boron-bearing multicomponent silicate melts (malinkoite-nepheline pseudo-binary glasses), NMR, atomic structure