온현성 Hyun-sung On , 톡토흐마 B. Togtokhmaa , 박천영 Cheon-young Park

DOI: Vol.31(No.3) 137-147, 2018

The aim of this study was to leach penalty elements, such as Bi and As, effectively through microwave leaching of a gold concentrate sample containing penalty elements with nitric acid solution. For this purpose, the time effect of microwave leaching, nitric acid concentration effect, and sample addition effect in a microwave were examined. The experiment, demonstrated that the leaching rate of penalty elements increased as microwave leaching time and nitric acid concentration increased and concentration addition decreased. When a microwave heating experiment was carried out on the concentrate and ore minerals, Bi was removed by as much as 90%, and the phase of arsenopyrite was transformed in the order of arsenopyrite (FeAsS), pyrrhotite (FeS), and hematite (Fe2O3). When the X-ray diffraction (XRD) analysis was carried out with solid residue, elemental sulfur and anglesite were identified. The intensity of the XRD peaks of elemental sulfur and anglesite increased, and the peaks were sharper when the microwave leaching time was 12 min instead of 1 min, the nitric acid concentration was 4 M in rather than 0.5 M, and the concentration addition was 30 g rather than 5 g. This was probably because more elemental sulfur and anglesite were generated in the leaching solution as the leaching efficiency increased. Bi can be leached as valuable elements in the leaching solution through microwave leaching processes while they are released to the environment through a microwave heating processes.

마이크로웨이브 가열, 페널티원소, 비스무스, 비소, 마이크로웨이브 용출, Microwave heating, penalty element, bismuth, arsenic microwave leaching

도진영 Jin Young Do , 김정진 Jeong Jin Kim

DOI: Vol.31(No.3) 149-159, 2018

The Gyeongju Bunhwangsa Stone Brick Pagoda, which was built with bricks of andesite, is the oldest brick stone pagoda of Silla period. The damage patterns in the stone pagoda are pollutants such as white crust, black crust, discoloration, soil adsorption, and microorganisms, and repair materials. The damage pattern of structural factors in the Stone Brick Pagoda is a bulging phenomenon. According to the X-ray diffraction analysis, white crust are mainly consist of calcite (CaCO₃) and thermonatrite (Na₂CO₃·H₂O) that evaporite finds in nature. Damage pattern varies depending on location of stone pagoda. The pollutants are first story body of pagoda. The microorganisms are confirmed at base, lion statues, first and second story capstone, and repair materials observed at base. The bulging phenomenon appeared on the first story body of the pagoda. Occupancy rates by damage type were higher in the order of microorganisms, pollutants, repair material, bulging phenomenon, and peeling. The highest percentage of individual damage patterns were black microorganisms (39.3%), followed by lichen (17.9%), discoloration (8.0%), white crust (5.5%), cement mortar (5.1%) and peeling (3.1%).

모전석탑, 손상양상, 생물서식, 오염물, 풍화, 보수물질, Stone Brick Pagoda, damage pattern, microorganisms, pollutants, weathering, repair material

김은정 Eun Jeong Kim , 이성근 Sung Keun Lee

DOI: Vol.31(No.3) 161-172, 2018

Multi-anvil press (MAP) is one of the high pressure apparatuses and often generates the pressure-conditions ranging from 5 to 25 GPa and temperature-conditions up to 2,300℃. The MAP is, therefore, suitable to explore the pressure-induced structural changes in diverse earth materials from Earth’s mantle and the bottom of the mantle transition zone (~660 km). In this study, we present the experimental results for pressure-load calibration of the 1,100-ton multi-anvil press equipped in the authors’ laboratory. The pressure-load calibration experiments were performed for the 14/8 step, 14/8 G2, 14/8 HT, and 18/12 assembly sets. The high pressure experiments using α-quartz, wollastonitestructure of CaGeO₃, and forsterite as starting materials were analyzed by powder X-ray diffraction spectroscopy. The phase transition of each mineral indicates the specific pressure that is loaded to a sample at 1,200℃: a transition of α-quartz to coesite at 3.1 GPa, that of garnet-structure of CaGeO₃ to perovskite-structure at 5.9 GPa, that of coesite to stishovite at 9.2 GPa, and that of forsterite to wadsleyite at 13.6 GPa. While the estimated pressure-load calibration curve is generally consistent with those obtained in other laboratories, the deviation up to 50 tons is observed at high pressure above 10 GPa. This is partly because of the loss of oil pressure at high pressure resulting from the differences in a sample chamber, and the frictional force between pressure medium and second anvil. We also report the ~200 ℃/mm of thermal gradient in the vertical direction of the sample chamber of 14/8 HT assembly. The pressure-load calibration curve and the observed thermal gradient within the sample chamber can be applied to explain the structural changes and the relevant macroscopic properties of diverse crystalline and amorphous earth materials in the mantle.

멀티 앤빌 프레스, 고압실험, 온도구배, 압력-부하 보정, 광물의 상전이, Multi-anvil press, high-pressure experiments, thermal gradient, pressure-load calibration, phase transition of minerals

윤영진 Young Jin Yoon , 이지은 Ji Eun Lee , 방상제 Sang Je Bang , 백영두 Young Doo Baek , 김영규 Yeongkyoo Kim

DOI: Vol.31(No.3) 173-182, 2018

The precipitation and phase transformation processes of iron minerals in acid mine drainage have a great influence on the behavior of trace elements in drainage. However, it is not easy to accurately trace these processes in natural environments, and therefore, most studies have carried out in the laboratory to obtain the information on the precipitation and transformation of those minerals. In this study, the precipitation of minerals and the changes of trace elements in drainage water were investigated at different pH values in actual acid mine drainage collected from the Dalsung mine. The amount of some precipitated minerals was not enough for the mineral identification. However, from the minerals identified, amorphous minerals were formed first, and then goethite was precipitated probably from schwertmannite. When the pH of the sample was high (10), amorphous phases of minerals were still observed at even high pH (pH 10). With increasing time, the pH values decreased by precipitation and transformation of minerals. All the elements showed low concentrations at high pH (8, 10), which might be due to the precipitation of minerals at high pH and the effect of surface charge, and the concentrations of elements gradually increased with time. In the case of sulfur, it also increased in water due to the transformation of schwertmannite to goethite.

산성광산배수, 미량원소, pH, 침철석, 슈베르트마나이트, Acid mine drainage, trace element, schwertmannite, goethite

오일환 Il-hwan Oh , 허철호 Chul-ho Heo , 최상훈 Sang-hoon Choi , 이선진 Sunjin Lee , 조성준 Seong-jun Cho

DOI: Vol.31(No.3) 183-191, 2018

It is reported that Li-bearing minerals regarding as a promising battery industrial commodity occur in the Mogok metamorphic belt, Myanmar. Preliminary considerations on the mineralization of pegmatite occurrences within Mogok metamorphic belt such as Singu, Mogok and Momeik are as follows. In Singu area, lepidolite and rubellite occur together (Letpanhla No. 2 & 7 pegmatite) while rubellite only occur (Letpanhla No. 4 pegmatite). In Mogok area, lepidolite and rubellite occur together (Sakangyi pegmatite). In Momeik area, lepidolite and rubellite occur together (Pheyeou pegmatite) while rubellite only occur (Khetchel Ywar Thit pegmatite). In the future, it is estimated that it is necessary to implement the detailed exploration for the resource evaluation of lithium-bearing mineral targeted for the pegmatite of Mogok metamorphic belt.

리튬, 페그마타이트, 모곡변성대, 미얀마, Lithium, pegmatite, Mogok metamorphic belt, Myanmar

이재호 Jae-ho Lee , 진광민 Kwang-min Jin , 허철호 Chul-ho Heo

DOI: Vol.31(No.3) 193-213, 2018

Soil geochemical exploration to check anomalies related to mineralization was carried out targeting around Quy Hop area within Nghe An province, Northern Vietnam. The interval of sampling are horizontal 250 m with 13 line and longitudinal 300 m with 25 line, resulting in 325 soil samples. Based on the result of soil geochemical exploration, the pitting survey was carried out targeting the grid point with high TREO content, resulting in 73 soil samples within 8 pits. The geology of the survey area are consisted of Ban Chieng biotite granite complex intruding Bu Khang formation comprising of schist, gneiss and limestone. In order to elucidate the source rock of monazite and xenotime confirmed from heavy sand, soil geochemical exploration was carried out. By ICP-MS result of soil samples, total REE oxide content of background amount is about 1.4 times of crustal abundance, depleting the light rare earth (about 0.2 times) and enriching the heavy rare earth (about 1.5 times). By ICP-MS result of pit soil samples, we identified TREO more than 1,000 ppm in 6 pits. It may be considered that REE ore bodies may develop in NE-SW direction, compared with the geochemical results of Quy Chau area.

희토류, 뀌홉, 네안성, 베트남, REE, Quy Hop, Nghe An, Vietnam

김남훈 Namhoon Kim , 고상모 Sang-mo Koh , 이범한 Bum Han Lee

DOI: Vol.31(No.3) 215-225, 2018

Musan iron deposit in North Korea and iron deposits in Anshan-Benxi area in China are Archean banded iron formations and included in Longgang block in Eastern block of North China Craton. Host formations of Musan iron deposit and Anshan-Benxi iron mineralized belt are Musan group and Anshan group, respectively. These groups consist of magnetite-bearing quartzite, amphibolite, schist, and migmatite. Host rock of banded iron formation in Musan deposit and Anshan-Benzi mineralized belt is magnetite-bearing quartzite. Shape of ore bodies in Musan deposit is horse's hoof due to the fold while shape of orebodies in Anshan-Benxi mineralized belt is layer. The previous studies revealed the both of banded iron formations are contemporaneously deposited during the late Archean (Musan deposit and iron deposits in Anshan-Benxi area: 2.66-2.52 Ga and 2.55-2.53 Ga, respectively). Musan deposit and iron deposits in Anshan-Benxi mineralized belt belolng to Algoma type BIFs. In conclusion, the characteristics of geology, formation ages, and deposit types of Musan deposit and Anshan-Benxi minerlized belt are very similar.

호상철광층, 무산 철 광상, 안산-번시 철 광화대, 알고마 유형, Banded iron formation, Musan iron deposit, iron deposits in Anshan-Benxi area, Algoma type