• Economic and Environmental Geology
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• v.54 no.6
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• pp.671-687
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• 2021

This study investigated the firing temperature and thermal deformation process of roof tiles excavated from the connected stone-mound tomb in Seokchon-dong, Seoul, based on mineralogical and physical properties. A large number of roof tiles were excavated from the tomb site and some roof tiles were deformed by heat and were fired in uneven conditions. The colors of original roof tiles and their cores are mostly yellowish-brown, with high water absorption over 12%, containing fine-grained textures and some minerals such as quartz, feldspars, amphibole, and mica. It is estimated that the original roof tiles were fired below 900℃ in oxidation condition, showing loose matrices and mica layers by scanning electron microscopy. However, deformed roof tiles have the uneven surface color of reddish-brown and bluish-gray, and those cross-sections have sandwich structures in which dense reddish-brown surface and porous grey core coexist. They contained mullite and hercynite, so it was estimated to have been fired over 1,000℃, with 0.81~11% water absorption. In some samples, bloating pores by overfiring were observed, which means that they were fired at more than 1,200℃. In addition, the refirng experiments that the original roof tile was fired between 800℃ and 1,200℃ were carried out to investigate the physical and mineralogical properties of roof tiles compared to deformed ones. As a result, the water absorption decreased rapidly and the mineral phase started to change over 1,000℃. As the temperature gradually rises, the matrices are partially melted and recrystallized, resulting in similar thermal characteristics of deformed roof tiles. Therefore, the roof tiles from ancient tombs in Seokchon-dong seem to experience the secondary high temperature of 1,000 to 1,200℃ under uneven firing conditions, resulting in deformation characteristics such as shape transformation and mineral phase transition. It is considered to have been related to cremation rituals at the tombs of Seockchon-dong during the Baekje period.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.409-421
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• 2022

Achieving a highly resolved spatial distribution of Mn-bearing minerals and elements in the natural ferromanganese nodules can provide detailed knowledge of the temporal variations of geochemical conditions affecting the formation processes of nodules. While a recent study utilizing Raman spectroscopy has reported the changes in the manganate mineral phases with growth for spherical nodules from the Arctic Sea, the distributions of minerals and elements in the nodules from the shallow Arctic Sea with non-spherical forms have not yet fully elucidated. Here, we reported the micro-laser Raman spectra with varying data acquisition points along three different profiles from the center to the outermost rim of the non-spherical ferromanganese nodules collected from the East Siberian Sea (~73 m). The elemental distributions in the nodule (such as Mn, Fe, etc.) were also investigated by energy dispersive X-ray spectroscopy (EDS) analysis to observe the internal structure and mineralogical details. Based on the microscopic observation, the internal structures of a non-spherical nodule can be divided into three different regions, which are sediment-rich core, iron-rich substrate, and Mn-Fe layers. The Raman results show that the Mn-bearing mineral phases vary with the data acquisition points in the Mn-Fe layer, suggesting the changes in the geochemical conditions during nodule formation. In addition, we also observe that the mineral composition and structural characteristics depend on the profile direction from the core to the rim. Particularly, the Raman spectra obtained along one profile show the lack of Fe-(oxy)hydroxides and the noticeably high crystallinity of Mn-bearing minerals such as birnessite and todorokite. On the other hand, the spectra obtained along the other two profiles present the presence of significant amount of amorphous or poorly-ordered Fe-bearing minerals and the low crystallinity of Mn-bearing minerals. These results suggest that the diagenetic conditions varied with the different growth directions. We also observed the presence of halite in several layers in the nodule, which can be evidence of the alteration of seawater after nodule formation. The current results can provide the opportunity to obtain detailed knowledge of the formation process and geochemical environments recorded in the natural non-spherical ferromanganese nodule.

• Proceedings of the Mineralogical Society of Korea Conference
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• 1996.10a
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• pp.7-24
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• 1996

'90년대 전반기 중 세계 경제 상황은 정치, 경제 및 환경의 급격한 변화에 따른 불황으로 유황시장에도 심대한 영향을 미치게 되었다. 이와 같은 경기의 후퇴는 다수의 생산자로 하여금 전반적인 시장 상황을 바꿀 수 있는 전략 변경 및 새로운 시장 개발을 촉진시키게 하였다. 최근에 전개되고 있는 극단적인 정치$\cdot$경제적인 변화는 재래시장과 무역균형을 변경시키게 되었다. 개선되는 세계경제에 따른 광범위한 구조조정과 지난 2년간 진행되어온 전반적으로 농업에 유리한 조건에 힘입어 1995년 유황공업은 회복이 시작되어 54.63백만 톤이 생산되었다 국제 유황 무역은 수요와 공급 면에서는 균형을 못 찾고 있다. 1995년 유황생산 중 무역량은 $45\%$에 이르렀다. 유황생산에 영향하는 요소가 변함에 따라 무역의 형태가 변하게 되고 세계 유황 수급 균형에 영향을 주게 되었다. 지난 2년간 있었던 유황생산 회복은 다음 십년간 지속될 것으로 예측된다. 대부분 수요의 증가는 자연가스의 생산을 지배하는 요소에 따라 결정 될 것이다 1986년 이래 유가가 떨어진 후 세계 에너지 수요는 연간 $2.3\%$ 증가하였다. 석유와 가스는 미래 에너지 수요의 증가로 $70\%$이상을 공급하게 될 것이다. 동아시아에서 회수 유황은 원유의 정제로부터 유래된 것으로 가장 신장이 큰 공급원으로 2005년까지 주요유황생산 부분이 될 것이다. 동아시아에서 주요 회수 유황생산국은 일본으로 전체의 $66\%$를 차지한다. 석유 정제로부터 회수 유황생산량은 동아시아에서 증가하고 있다. 유황회수 시설 투자는 일본을 위시하여 한국, 싱가폴 및 태국에서 이루어지고 있으며 이는 점차 증대되는 환경규제에 기인된다. 동아시아 공업국가 예컨대 일본과 한국에서의 유황소비는 인산생산 저조로 정체해 있으나 지난 10년간 여타의 아시아 국가에서의 유황소비는 꾸준히 증가되었다. 이 같은 증가는 앞으로 10년간 계속 될 것으로 추정된다. 이는 유황비료 소비가 4.81백만 톤에서 6.6백만 톤으로 증가될 것으로 예상되고 이는 주로 중국이 내수 인산생산을 증가시키려는 데 기인된다. 더욱이 다가올 10년은 다수의 아시아 국가의 급속한 경제 발전으로 비료 이외의 유황의 소비가 꾸준히 증가 될 것이다. 동아시아는 10.29백만 톤을 생산하고 10.99백만 톤을 소비하여 1995년에는 70만 톤의 유황이 부족하였다. 이와 같은 영향이 계속된다면 동아시아 유황부족은 2005년에는 1.05백만 톤으로 증가될 것으로 예상된다. 그러나 중국에서 황화철에서부터 공급되는 유황함량이 많아 이 지역에서의 원소유황의 진정한 균형에 대해서는 정확하게 평가되지 못한다. 1995년 동아시아에서는 1.3백만 톤의 원소유황을 일본, 캐나다, 미국에서 수입했다. 이들 국가는 앞으로도 이 지역의 주요 공급자가 될 것이다. 황산의 많은 양은 일본에서 이 지역으로 수출되는데 그 양은 1995년 10만톤 이상에 이른다. 더욱이 경제?환경적 이점 때문에 중국이 황화물에서 회수하는 유황대신 원소 유황의 수입을 지속적으로 증가시키고 있어 지역내의 유황 부족이 증가 될 것이다. 이 같은 상황진전으로 앞으로 10년 이내에 2.5백만 톤의 추가시장이 있게 될 것이다. 이 기간내 한국으로서 현재 326,000톤의 부족에서 2005년에는 309,000톤의 과잉으로 유황균형이 변할 수 있는 주요계기가 될 것이다 이 같은 과잉은 회수 유황생산이 1995년 333,000톤에서 2005년 870,000톤으로 $161\%$가 증가될 것으로 예상된다. 동기간 내에 기타 유황생산은 280,000톤에서 320,000톤으로 $14\%$ 증가되는 것으로 추정된다. 그리하여 2005년 한국에서 유황 공급은 1.19백만 톤이고 수요는 881,000톤으로 추정 된다. 미래 한국에서 유황의 또 다른 잠재시장은 식물양분으로서 이다. 인산비료 생산은 유황산업의 골격으로 1995년 세계적으로 인산비료는 유황소비의 53%인 53.60백만 톤을 점유하였다. 작물의 유황결핍 현상은 세계도처에서 나타나고 있어 식물양분으로서 유황시장은 20년전의 시장과 같이 현황을 띠는 시장으로 유황공업이 때를 만나게 될 것이다. 공업국에서 유황의 대기로의 방출억제로 자연 공급량이 감소되고 개발도상국에서 증산으로 유황의 탈취가 증가됨에 따라 유황 부족은 점차 중요한 문제로 확산되고 있다. 세계적으로 $1993\~1994$년간 7.52백만 톤으로 추정되는 유황 부족이 농산물의 수량과 질을 하락시키는 결과를 가져오게 하였다: 이와 같은 현상으로 유황비료의 수요가 증대되었고 산업계는 수요증대에 대응할 기술개발에 노력하게 되었다. 현재의 식량생산과 비료 소비추세가 지속된다면 아시아에서 2000년까지 매년 4.5백만 톤의 유황부족이 있게 될 것이다 이와 같은 유황비료의 부족은 적절한 대책을 취하지 않는 한 2010년에는 6.5백만 톤으로 증가 될 것이다. 동아시아는 경제발전으로 유황비료 장기 잠재시장이 기대되고 새로운 시장으로 $50\%$이상을 점유하게 될 것이다. 서구와 북미에서 유황비료 산업은 이윤 있는 잠재시장으로 인정되고 상업적으로 앞서 있는 시장이다. 점증하는 수요에 대한 대처와 유황비료의 성공은 시장에서 가격에 좌우된다. 실제로 북미와 서구에서 현재의 소매가격은 유황 톤당 $266\~466\$$의 범위에 있다. 인도에서는 비료로서 유황시장은 덜 발달된 단계로서 대표가격은 $120\$$이다. 이 가격 범위로 보아 2010년에 동아시아 시장의 잠재 유황비료 시장은 3.4백만 톤에 이르고 비료공업에서 추가로 얻는 이윤은 408백만 내지 1조5천억$\$$이 될 것이다. 이와 같은 시장이 발전 될 수 있는 것은 계속된 제품개발과 비료산업 시장개척에 달려있다.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.227-237
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• 2008

Arsenic has recently become of the most serious environmental concerns, and the worldwide regulation of arsenic fur drinking water has been reinforced. Arsenic contaminated groundwater and soil have been frequently revealed as well, and arsenic contamination and its treatment and measures have been domestically raised as one of the most important environmental issues. Arsenic behavior in geo-environment is principally affected by oxides and clay minerals, and particularly iron (oxy)hydroxides have been well known to be most effective in controlling arsenic. Among a number of iron (oxy)hydroxides, for this reason, 2-line ferrihydrite was selected in this study to investigate its effect on arsenic behavior. Adsorption of 2-line ferrihydrite was characterized and compared between As(III) and As(V) which are known to be the most ubiquitous species among arsenic forms in natural environment. Two-line ferrihydrite synthesized in the lab as the adsorbent of arsenic had $10\sim200$ nm for diameter, $247m^{2}/g$ for specific surface area, and 8.2 for pH of zero charge, and those representative properties of 2-line ferrihydrite appeared to be greatly suitable to be used as adsorbent of arsenic. The experimental results on equilibrium adsorption indicate that As(III) showed much stronger adsorption affinity onto 2-line ferrihydrite than As(V). In addition, the maximum adsorptions of As(III) and As(V) were observed at pH 7.0 and 2.0, respectively. In particular, the adsorption of As(III) did not show any difference between pH conditions, except for pH 12.2. On the contrary, the As(V) adsorption was remarkably decreased with increase in pH. The results obtained from the detailed experiments investigating pH effect on arsenic adsorption show that As(III) adsorption increased up to pH 8.0 and dramatically decreased above pH 9.2. In case of As(V), its adsorption steadily decreased with increase in pH. The reason the adsorption characteristics became totally different depending on arsenic species is attributed to the fact that chemical speciation of arsenic and surface charge of 2-line ferrihydrite are significantly affected by pH, and it is speculated that those composite phenomena cause the difference in adsorption between As(III) and As(V). From the view point of adsorption kinetics, adsorption of arsenic species onto 2-line ferrihydrite was investigated to be mostly completed within the duration of 2 hours. Among the kinetic models proposed so for, power function and elovich model were evaluated to be the most suitable ones which can simulate adsorption kinetics of two kinds of arsenic species onto 2-line ferrihydrite.

• Journal of the Mineralogical Society of Korea
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• v.32 no.2
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• pp.127-143
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• 2019

The geology of the Chulmasan area consists of Precambrain Sogeunri formation, granitic gneiss, foliated biotite granite, foliated mica granite, basic dyke and acidic dyke. REE mineralization in the area occurs at granitic gneiss and foliated mica granite. Minerals with minor amounts of REE and Th from granitic gneiss and foliated mica granite are zircon ($Y_2O_3$ 0.00~1.18 wt.%, $Gd_2O_3$ 0.00~0.59 wt.%, $Er_2O_3$ 0.00~0.22 wt.%, $Yb_2O_3$ 0.00~0.34 wt.%, $Lu_2O_3$ 0.00~0.48 wt.%, $ThO_2$ 0.00~0.33 wt.%), thorianite ($Nd_2O_3$ 0.00~0.24 wt.%, $Lu_2O_3$ 0.00~0.26 wt.%), berthierine ($La_2O_3$ 0.04~0.26 wt.%, $Nd_2O_3$ 0.00~0.20 wt.%, $Tb_2O_3$ 0.04~0.12 wt.%, $Dy_2O_3$ 0.17~0.26 wt.%, $Er_2O_3$ 0.33~0.44 wt.%, $Lu_2O_3$ 0.00~0.19 wt.%, $ThO_2$ 0.61~0.93 wt.%), chlorite ($La_2O_3$ 0.44~0.68 wt.%, $Ce_2O_3$ 0.12~0.13 wt.%, $Nd_2O_3$ 0.31~0.44 wt.%, $Eu_2O_3$ 0.03~0.08 wt.%, $Dy_2O_3$ 0.09~0.21 wt.%, $Ho_2O_3$ 0.04~0.14 wt.%, $Er_2O_3$ 0.18~0.32 wt.%, $Lu_2O_3$ 0.07~0.21 wt.%, $ThO_2$ 0.00~0.97 wt.%), biotite ($Nd_2O_3$ 0.02~0.08 wt.%, $Gd_2O_3$ 0.07~0.08 wt.%, $Tb_2O_3$ 0.02~0.07 wt.%, $Dy_2O_3$ 0.35~0.43 wt.%, $Ho_2O_3$ 0.15~0.26 wt.%, $Er_2O_3$ 0.24~0.28 wt.%, $Yb_2O_3$ 0.06~0.18 wt.%, $ThO_2$ 0.00~0.12 wt.%), orthoclase ($Dy_2O_3$ 0.05~0.12 wt.%, $Ho_2O_3$ 0.05~0.06 wt.%, $Er_2O_3$ 0.28 wt.%, $Yb_2O_3$ 0.06~0.12 wt.%) and plagioclase ($Ho_2O_3$ 0.01~0.03 wt.%, $Er_2O_3$ 0.10~0.27 wt.%, $ThO_2$ 0.11~0.13 wt.%). REE minerals (bastnaesite and fergusonite) were sealed fractures in mainly fledspar, mica, zircon, apatite and ilmenite. Therefore, bastnaesite and fergusonite from the Chulmasan area were formed from redissolution/reconcentration of REE-and Th-bearing minerals from granitic gneiss and foliated mica granite at late stage by several igneous activies and metamorphism.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.153-168
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• 2022

Petrological and mineralogical analyses were conducted to identify minerals containing radioactive elements (uranium) in the Chiaksan gneiss complex and to confirm their association with the surrounding groundwater. Fourteen minerals were identified through the microscopic and electron microscopy (SEMEDS) investigation. The principal minerals included plagioclase, biotite, quartz, alkali feldspar, chlorite, and calcite. Minor minerals were sphene, allanite, apatite, zircon, thorite, titanite, pyrite, and galena. A small amount of thorite was observed in the size of ~1 mm within macrocrystalline allanite. Allanite, which includes a large amount of rare earth elements, appeared in three distinctive patterns. The results of the EPMA analyses indicated that macrocrystalline allanite had higher elemental contents of TiO₂~1.70 wt.%, Ce₂O₃~11.86 wt.%, FeO ~13.31 wt.%, MgO ~0.90 wt.% and ThO₂ ~1.06 wt.% with the lowest average content of Al₂O₃ 17.35 ± 2.15 wt.% (n = 7), CaO 12.13 ± 1.81 wt.% (n = 7). An allanite existing at the edge of the sphenes encompassing titanites had a higher element content of Al₂O₃ ~24.00 wt.%, Nd₂O₃ ~5.10 wt.%, Sm₂O₃~0.66 wt.%, Dy₂O₃~0.86 wt.% and Y₂O₃~1.38 wt.% with the lowest average content of TiO₂ 0.35 ± 0.21 wt.% (n = 11), Ce₂O₃ 5.25 ± 1.03 wt.% (n = 11), FeO 9.84 ± 0.26 wt.% (n = 11), MgO 0.12 ± 0.05 wt.% (n = 11), and La₂O₃ 1.49 ± 0.29 wt.% (n = 11). Allanites in a matrix of parental rocks exhibited intermediate values between the two elemental compositions mentioned above. None of the uranium-rich minerals were observed in the migmatitic gneiss within the study area. Consequently, the origin of uranium in the groundwater was not associated with the geology of the surrounding environment, but our investigation proved the existence of abundant allanites containing significant amounts of radioactive thorium and rare earth elements.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.237-253
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• 2012

The Mireuksaji stone pagoda is constructed Baekje Period in the 7th century which is located in Iksan, Korea. This stone pagoda designated by National Treasure No. 11 is the only remaining pagoda. This pagoda has lost the original form in part and the whole stonework wase dismantled. Work for the restoration is currently in progress. This study was divided into soil strata such as construct layer of the temple site, foundation layer of the pagoda basement, and construct layer of the stylobate by stratum to interpretation the skill of rammed earth and making techniques. The of physical, mineralogical and geochemical characteristics of soil samples were identified. Five pieces of soil in and around the Mireuksaji temple site was selected for the comparative study to interpretate the mutual homogeneity among soil stratum. As a result, artificial addition has not been identified in all soil samples using rammed earth. The soils used for the basement of the stone pagoda (construct layer of the temple site, foundation layer of the pagoda basement, construct layer of the stylobate) were confirmed to be the same origin as soil in and around Mireuksaji temple site. Thus these results indicate that the basement of the pagoda was constructed using soils in and around the Mireuksaji temple site without work as careful selection.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.207-226
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• 1986

The skarn type tungsten deposits in Jechon area are developed in the contact aureole of Jurassic granodiorite and lower Paleozoic limestone beds. The Tong Myeong mine contains scheelitebearing skarns found at and near the contacts between crystalline limestone and hornfels. Although the skarns are heterogeneous, there are clear patterns in the preferred associations and nonassociations of minerals on all scales. The skarn show a zonal arrangement from limestone to hydrothermal vein as follow: wollastonite skarn, clinopyroxene skarn, clinopyroxene-garnet skarn, garnet skarn, and vesuvianite skarn. Scheelite, abundant in all skarn units except wollastonite skarn and also in quartz veins near orebodies, is everywhere strongly correlated with pyrrhotite. It is implied that it was a stable phase throughout the evolution of the zoned skarns, at least in pyrrhotite.forming environments. Deposition of scheelite was probably widely caused by increasing $a_{Ca^{2+}}$ in the fluid, resulting from associated and interrelated reactions: $FeCl_2\;aq+H_2S\;aq{\rightarrow}FeS+2H^{+}+2Cl^-$; and $CaCO_3+2H^+{\rightarrow}Ca^{+2}+H_2CO_3$. The spectral reflection powers of nine sulfide species were studied, for three mineralization stage. The shapes and characteristics of the spectral reflectivity profiles are significant in their control of other optical properties. The characteristics of the Vickers microhardness and the optical symmetry for the minerals studied are discussed. Broad radicle groupings of the sulfides can be made with regard to the reflectivity-microhardness values.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.175-183
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• 2020

There have rarely been performed for the clay mineralogy of the East Sea sediments except for few studies about paleoenvironmental aspect. This study inferred the provenance of sediments based on the clay mineral characteristics and distribution pattern for the 120 sediment samples collected by the box corer from the Gangneung-Donghae area between 2017-2019. The relative proportions of the four major clay minerals are abundant in the order of illite, chlorite, kaolinite, and smectite. The continental shelf sediments below water depth 150 m have more chlorite and kaolinite content and better illite crystallinity, but less illite and smectite content, and S/I index than those of continental slope sediments. Clay mineral composition of the continental shelf sediments are influenced by the adjacent continental geology, because north site (Gangneung area) has more chlorite but south site (Donghae area) has more kaolinite. These characteristics and distribution pattern of clay minerals indicate that the provenance of sediments are different between continental shelf and continental slop. The continental shelf sediments may be introduced the study area by the adjacent small rivers whereas the continental slope sediment might be supplied by current from the south of the study area.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.243-250
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• 2020

The purpose of this study is to find out the possibility of applying microwave-hypochlorous acid leaching to effectively leaching Au in hydrothermal minerals on board. The comparative leaching experiment were confirmed that the leaching rate of Au with(T1)/with out(T2) of microwave nitric acid leaching. In addition, the leaching rate of Au on the conventional leaching by mechanical agitation(T3) and microwave leaching was compared. The result of microwave nitric acid leaching(solid-liquid ratio; 10%, leaching temperature; 90 ℃, leaching time; 20 min) confined that the metal leaching rate was high in the order of As>Pb>Cu>Fe>Zn, and the content of Au in the leaching residue was increased from 33.77 g/ton to 60.02 g/ton. As a result of the comparative leaching experiment using a chloride solvent, the dissolution rate of Au was high in the order of T1(61.10%)>T3(53.30%)>T2(17.30%). Therefore, chloride, which can be manufactured using seawater and that can be recycled by collecting chlorine gas generated in the leaching process, is expected to be an optimal solvent for Au leaching. In addition, the application of microwaves is believed to be effective in terms of time, efficiency and energy.