김봉주 Bong Ju Kim , 조강희 Kang Hee Cho , 최낙철 Nag Choul Choi , 박천영 Cheon Young Park

DOI: Vol.28(No.3) 209-220, 2015

The aim of this study was leaching valuable metal ions from mine waste rocks which were abandoned mine site using indigenous aerobic bacteria. In order to tolerate the the indigenous aerobic bacteria to the heavy metal ions they were repeatedly adapted in CuSO4·5H2O environment. As the repeated generation-adaptation progressed, the pH values of the growth-medium were gradually decreased. During bio-leaching experiments with indigenous aerobic bacteria raised in a heavy metal ion environment for 42 days, the pH of the leaching solution was decreased while increasing the adaptation period. The indigeous bacteria were much more active on the surface of Younhwa waste rocks which contained relatively few the chalcopyrite and Cu content than the Goseong mine waste rocks, and also the amount of Cu and Fe ions were leached more in the Younhwa sample(leaching rate of 92.79% and 55.88%, respectively) than the Goseong sample(leaching rate of 66.77% and 21.83%, respectively). Accordingly, it is confirmed that valuable metal ions can be leached from the mine waste rocks, if any indigenous bacteria which inhabits a mine environment site for a long time with heavy metal ions can be used, and these bacteria can be progressively adapted in the growth-solutions containing the target heavy metals.

폐광석, 토착호산성박테리아, 적응, 미생물용출, mine waste rock, indigenous acidophilic bacteria, adaptation, bioleaching

곽지영 Ji Young Kwak , 최진범 Jin Beom Choi

DOI: Vol.28(No.3) 221-231, 2015

Precambrian Jirisan gneiss complex suffered retrograde metamorphism ranging from granulite facies to the amphibolite facies and/or greenschist facies. Intrusive anorthositic rocks in gneiss complex are influenced by late metamorphism. Mafic mineral in anorthositic rock composed mainly of amphiboles, which can anticipate the information about metamorphic conditions and metamorphic facies. Amphiboles from anorthositic rock show subhedral to anhedral in shape and mostly blueish green and/or green in colour in plane polarized light. Some of brownish amphiboles show zonal texture with brownish to blueish green in color from core to rim. Reaction parts in clinopyroxene which exchange with amphibole. It suggests retrograde metamorphism and/or alteration. Amphiboles composing anorthositic rocks can be classified into two types depending on the size and occurrence of amphibole. The first type is microcrystalline amphibole occurring matrix [Group I: ferrohornblende]. The second type is amphibole with 1 mm or larger in size, which is usually occurred in the boundary between opaque mineral and plagioclase [Group II: ferropargasite]. Electron microscopic analyses base on the Alvi composition in amphiboles suggest that the metamorphic pressure of anorthositic rock was low with 5 kbar or less. Ti compositional range in amphibole and representing hornblende+plagioclase+garnet+biotite+chlorite mineral assemblage suggest that metamorphic facies of anorthositic rock is in amphibolite facies.

회장암, 각섬석, 저압 변성작용, 각섬암상, anorthosite, amphibole, low pressure metamorphism, amphibolite facies

유돈상 Don Sang You , 박천영 Cheon Young Park

DOI: Vol.28(No.3) 233-244, 2015

In order to study the phase transformation of pyrite and to determine the maximum Fe leaching factors, pyrite samples were an electric furnace and microwave oven and then ammonia leaching was carried out. The rim structure of hematite was observed in the sample exposed in an electric furnace, whereas a rim structure consisting of hematite and pyrrhotite were found in the microwave treated sample. Numerous interconnected cracks were only formed in the microwave treated sample due to the arcing effect, and these cracks were not found in the electric furnace treated sample. Under XRD analysis, pyrite and hematite were observed in the electric furnace treated sample, whereas pyrite, hematite and pyrrhotite were found in the microwave treated sample. The results of the pyrite sample leaching experiments showed that the Fe leaching was maximized with the particle size of -325 mesh, sulfuric acid of 2.0 M, ammonium sulfate of 1.0 M, and hydrogen peroxide of 1.0 M. The electric furnace and microwave treated samples were tested under the maximum leaching conditions, the Fe leaching rate was much greater in the microwave treated sample than in the electric furnace treated sample and the maximum Fe leaching time was also faster in the microwave treated sample than in the electric furnace treated sample. Accordingly, it is expected that the microwave heating can enhance (or improve) Fe leaching in industrial minerals as well as pyrite decomposition in gold ores.

황철석, 마이크로웨이브 가열, 적철석, 자류철석, pyrite, microwave heating, hematite, pyrrhotite

김성희 Seong Hee Kim , 이상우 Sang Woo Lee , 김정진 Jeong Jin Kim , 김순오 Soon Oh Kim

DOI: Vol.28(No.3) 245-253, 2015

The performance of TiO2 photo-catalytic oxidation process is significantly dependent on the amount of hydroxyl radicals produced during the process, and it is an essential prerequisite to quantify its production. However, precise and accurate methods for quantification of hydroxyl radicals have not been developed so far. For this reason, this study was initiated to compare existing methods for analysis of hydroxyl radicals produced by TiO2 photo-catalytic oxidation and to propose a new method to overcome the limitation of established methods. To simulate TiO2 photo-catalytic oxidation process, Degussa P25 which has been widely used as a standard TiO2 photo-catalyst was used with the dose of 0.05 g/L. The light source of process was UVC mercury low-pressure lamp (11 W, 2,975 mW/cm2). The results indicate that both potassium iodide (KI)/UV-vis spectrometer and terephthalic acid (TPA)/fluorescence spectrometer methods could be applied to qualitatively measure hydroxyl radicals via detection of triiodide ion (I3 -) and 2-hydroxyterephthalic acid which are produced by reactions of iodine ion (I-) and TPA with hydroxyl radicals, respectively. However, it was possible to quantitatively measure hydroxyl radicals using TPA method coupled with high-performance liquid chromatograph (HPLC). The analytical results using TPA/HPLC method show that hydroxyl radical of 0.013 M was produced after 8 hours operation of photo-catalytic oxidation under specific experimental conditions of this study. The proposed method is expected to contribute to precise the evaluation of the performance of photo-catalytic oxidation process.

광촉매 산화, 수산기 라디칼, 요오드화칼륨, 테레프탈산, TiO2, photo-catalytic oxidation, hydroxyl radical, potassium iodide, terephthalic acid

김지연 Ji Yeon Kim , 김영규 Yeongkyoo Kim

DOI: Vol.28(No.3) 255-263, 2015

To investigate the effect of the weathering process of biotite on Cs sorption, sorption experiment of Cs with 10-3 M solution was carried out on the biotite reacted at different reaction times at pH 2 and 4, and 1 M solutions of Na, K, Ca, Mg, Rb, and Cs. Peak changes were observed for some samples by XRD, indicating that new mineral phase formed by biotite weathering. Among several factors, cations in solutions have the most significant influence on the mineralogical changes. The samples reacted with Na showed the most outstanding change with increasing peak width and appearance of 12 A peak and 14 A peak. This new peaks indicate the formation of hydrobiotite and vermiculite. The new peaks had stronger peak intensity for the sample reacted at pH 4 than that at pH 2, probably due to the fast dissolution of small particles and edges and resultant decrease in the formation of expandable layers. The biotite reacted at Mg solution showed small intensity at 14 A. Based on XRD results, the degree of biotite weathering was in the order of Na, Mg, and Ca. The samples reacted with K, Rb, Cs solutions did not show noticeable mineralogical changes caused by weathering. The amount of sorbed Cs on weathered biotite showed close relationship with the degree of weathering indicated by XRD. At both pH 2 and 4, the biotite reacted with Na solution showed the highest Cs sorption, and those with Mg and Ca solutions showed the next highest ones. The sorbed amounts of Cs on the bitote reacted with K, Rb, Cs solutions were relatively low. This indicates that at the Cs concentration (10-3 M) which we used for this experiment and which was much higher than the maximum Cs concentration sorbed on the frayed edge site, expandable layer plays more important role than frayed edge. In the cases of K, Rb, and Cs solutions, Cs sorption was decreased because K is the same cations as the one in the interlayer or the sorption of Rb and Cs on the frayed edge prevents the formation of expandable layers.

세슘, 흑운모, 풍화, 흡착, 양이온, Cs, biotite, weathering, sorption, cation

문동혁 Dong Hyeok Moon , 곽경윤 Kyeong Yoon Kwak , 이부영 Bu Yeong Lee , 구효진 Hyo Jin Koo , 조현구 Hyen Goo Cho

DOI: Vol.28(No.3) 265-277, 2015

Hydrothermal alteration patterns and environment are studied by mineral assemblages and chemical analyses of surface and core samples from Miryang pyrophyllite deposit. The alteration zones of this deposit can be divided into three zones on the basis of mineral assemblage; advanced argillic, phyllic, and propylitic zone. Advanced argillic zone mainly consists of pyrophyllite-dickite (-quartz) and corresponds to principal mining ore. The common mineral assemblage of phyllic zone and propylitic zone are sericite-quartz-dickite and chlorite-quartz, respectively. Horizontal and vertical alteration patterns and major element geochemistry indicate that pyrophyllite ores have been formed several times by hydrothermal alteration. And it also suggests that the huge ore bodies may be extended from the deeper part of recent quarries to the south-southeastern direction. The paragenesis of ore minerals and polytype (2M) suggest that ore deposit was formed at about 300-350℃.

밀양납석광상, 강이질변질대, 엽납석, 광물조합, 열수변질작용, Miryang pyrophyllite deposit, Advanced argillic alteration zone, Pyrophyllite, Mineral assemblage, Hydrothermal alteration

곽지영 Ji Young Kwak , 강창원 Chang Won Kang , 주수영 Soo Young Joo , 정재한 Jae Han Jeong , 최진범 Jin Beom Choi

DOI: Vol.28(No.3) 279-292, 2015

New occurrences of large-scaled Zn-Pb deposits are recently found in the Danjang-myeon, Milyang. They are skarn-type deposits which replaced the intercalated limestone beds in the Jeonggaksan Formation. This study aims at characterizing occurrences, mineralogy, and chemistry of Zn-Pb ores and skarn minerals. Skarn orebodies are mainly found in 3 areas, named Gukjeon-ri, Gorye-ri, and Gucheon-ri orebodies, where sphalerite found as main ore mineral in 200-300 m in height and amount of galena increases as altitude does. Ores are dark grey to dark green in color and closely related with clinopyroxene zone. They occur with hedenbergite, grossular, actinolite, epidote, and small amounts of axinite, calcite, and quartz. Main ore mineral is sphalerite which includes tiny spotted grains of galena and chalcopyrite and becomes rich in grade in association with clinopyroxene and epidote. FeS contents in sphalerite show relatively wide range between 1.53 and 23.07 mole%, whose contents intend to increase towards biotite granite known as ore-related igneous rocks. CdS contents are in the range of 0.22-0.93 mole%, showing decrease tendency from southwest (Gukjeon-ri) to northeast (Gucheon-ri). Zn-Pb deposits developed in Danjang-myeon reveal decrease in temperature with increase of altitude, leading to gradual changes in compositions of ore and skarn minerals.

아연-연 광상, 정각산층, 스카른, 섬아연석, 헤덴버자이트, 그로슐라, Zn-Pb deposits, Jeonggaksan Formation, skarn, sphalerite, hedenbergite, grossular