김현수 Hyun Soo Kim , 푸레브오윤빌렉 Purev Oyunbileg , 박천영 Cheon-young Park

DOI: Vol.32(No.1) 1-14, 2019

This study used microwave-nitric acid leaching with the aim of removing penalty elements such as As and Bi. Moreover, enhanced gold content from the gold concentrate sample. The leaching conditions were changed: leaching time, nitric acid concentrations and solid-liquid ratio; In order to improve the removal of penalty elements. As a result of the experiment; sample weight loss rate, As and Bi removal rate and gold content in the solid-residues have been increased when the nitric acid concentration and leaching time were increased while the solid-liquid ratio was decreased. The leaching conditions for the maximum As and Bi removal and gold content were: leaching with a 6.0 M nitric acid solution doing 5 min. At these, the solid-residue sample weight loss was 87 %. As removal rate was 98.23 % and Bi was completely removed (100 %). Furthermore, gold content increased from 81.36 g/t to 487.32 g/t. The XRD of the solid residue showed that pyrite disappeared as the nitric acid concentration was increased, whereas sulfur peaks was increased, too.

페널티 원소, 마이크로웨이브-질산침출, 비소, 비스무스, 금, Penalty element, microwave-nitric acid leaching, arsenic, bismuth, gold

송석환 Suckhwan Song

DOI: Vol.32(No.1) 15-39, 2019

An ultramafic complex occurs as an isolated lenticular body in the Andong area. The Andong ultramafic complex comprises ultramafic and mafic rocks, but mainly peridotites. The complex extends for several kilometer to ENE direction, adjacent to the Andong fault line. This study is for petrochemistry of the peridotites within the ultramafic complex and characteristics of asbestos occurrences. The peridotites are igneous origin, ranging from lherzolite to wehrlites and are characterized by high Fo olivine (Fo_0.85-0.87), Mg clinopyroxene (Mg_87.5-93.5), and tremolitic to tschermakitic hornblende. Geochemically, these rocks show high magnesium number (mainly Mg = 85.3-87.38) and transitional element and low alkali element contents. The peridotites host asbestos, including chrysotile, tremolite and actinolite asbestos, but dominated by amphibole asbestos. The amphibole asbestos are found along small fault face, and cleavage and fracture showing several cm to ten cm in width as slip and oblique fibers, while the chryostiles occur at cleavage and vein showing several mm-cm in width as cross and slip fibers. They are confirmed by PLM, XRD and SEM results. Overall characteristics of peridotites from the Andong ultramafic complex and occurrences of the asbestos are similar to those of worldwide orogenic related Alpine type ultramafic rocks and serpentinized ultramafic bodies in Chungnam, Korea, respectively.

안동, 페리도타이트, 백석면, 각섬석계 석면, Andong, peridotite, chrysotile, amphibole asbestos

박선영 Sun Young Park , 이성근 Sung Keun Lee

DOI: Vol.32(No.1) 41-49, 2019

Probing the Na environments in Na silicate and aluminosilicate glasses is essential to the macroscopic properties of melts in the Earth. In particular, exploring the atomic structure of Na silicate and aluminosilicate glasses reveals Na-O distance, which plays an important role in transport properties of melts. Here we report the local environment around Na using ²³Na magic angle spinning (MAS) NMR. We also obtain ²³Na isotropic chemical shift (δ_iso) of Na silicate and aluminosilicate glasses with varying composition using Dmfit program. The Q mas 1/2 model simulates the experimental results with three simulated peaks while the CzSimple model simulates with one peak. The δ_iso decreases with increasing SiO₂ content in Na silicate and aluminosilicate glasses. The δ_iso increases with increasing Na₂O content in Na-Ca silicate and Na aluminosilicate glasses when the SiO₂ content is fixed. Considering the δ_iso of Na aluminosilicate glasses available in the previous studies, together with the current simulation results, we confirm that the δ_iso has positive correlation with Al / (Al + Si). Those experimental results were reproduced better using Q mas 1/2 model. The disorder of Na in Na silicate and aluminosilicate glasses can be revealed through the simulation of 1D ²³Na MAS NMR spectra using Dmfit program in a short time.

비정질 Na 규산염과 알루미노규산염, 무질서도, 고상 핵자기 공명 분광분석, 원자 구조, Dmfit 시뮬레이션, Na-silicate and -aluminosilicate glasses, degree of disorder, solid-state NMR spectroscopy, atomic structure, Dmfit simulation

장정규 Jeong Kyu Jang , 구효진 Hyo Jin Koo , 조현구 Hyen Goo Cho

DOI: Vol.32(No.1) 51-61, 2019

Clay minerals, a major component of mud volcano (MV) sediments, are expected to provide important information for characterizing mud volcano formation mechanisms, but clay minerals have rarely been studied. The purpose of this study is to investigate the characteristics of 420 MV and surrounding marine sediments. Clay minerals and grain size were analyzed for 8 box cores from 420 MV and Mackenzie Trough. The relative proportions of the four major clay minerals in the Mackenzie Trough are almost constant in the order of illite, chlorite, kaolinite, and smectite, regardless of the distance from the Mackenzie River. However, the grain size tends to become fining as they move away from the Mackenzie River. Comparing the clay mineral characteristics of river (Colville River, Kuparuk River, Sagavanirktok River, Canning River, Mackenzie River) sediments entering the Beaufort Sea in order to determine the origin of the Mackenzie Trough and 420 MV sediments, the sediments of the Mackenzie Trough are characterized mainly by the Mackenzie River with a low ratio of smectite/illite and a high ratio of kaolinite/chlorite. In 420 MV sediments, the contents of clay minerals decrease in the order of illite, kaolinite, chlorite, and smectite, and the grain size with depth is almost constant. The content of smectite and coarse sediments is about two times higher than the reference core. No river with higher kaolinite content than chlorite exists in the Beaufort Sea, and the ratio of smectite/illite to kaolinite/chlorite is different from the reference core such as the ratio of the Mackenzie River. Compared to the reference core, the high contents of coarse sediments and the constant grain size with depth might be attributed to the ejection by MV. The reference core is interpreted as originating from Mackenzie River, and sediment of 420 MV is interpreted as originating from eruption of MV.

진흙화산, 맥캔지곡, 보퍼트해, 맥켄지강, 점토광물, Mud volcano, Mackenzie Trough, Beaufort Sea, Mackenzie River, clay mineral

양기호 Kiho Yang , 박한범 Hanbeom Park , 김진욱 Jinwook Kim

DOI: Vol.32(No.1) 63-69, 2019

The oxidation states of structural Fe in minerals reflect the paleo-depositional redox conditions for the biologically or abiotically induced mineral formation. Particularly, nano-scale analysis using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) is necessary to identify evidence for the microbial role in the biomineralization. HRTEM-EELS analysis of oxidation states of structural Fe and carbon bonding structure differentiate biological factors in mineralization by mapping the distribution of Fe(II)/Fe(III) and source of organic C. HRTEM-EELS technique provides geomicrobiologists with the direct nano-scale evidence of microbe-mineral interaction.

전자에너지 손실 분광 분석법, 스펙트럼 영상법, 미생물-광물 간의 반응작용, EELS, spectrum imaging, microbe-mineral interaction

호르게아꼬스타 Jorge Acosta , 허철호 Chul-ho Heo , 에데르비야레얄 Eder Villarreal , 신씨아야울리 Synthia Yauli , 까를로스살라자르 Carlos Salazar , 양석준 Seok-jun Yang , 모이세스오르테가 Moises Ortega , 브라울리오조리야 Braulio Zorrilla

DOI: Vol.32(No.1) 71-77, 2019

New geochronological data of U-Pb, Re-Os and the lead isotope analysis of the Cu-Mo-Au mineral deposits are reported in the Trapiche and Constancia around Apurimac province, southeastern part of Peru. The measured ages were the first regional pulse of previously reported mineralization age between 28 and 33 Ma. The lead isotopic results indicate two sources of mineralization. The first source is thought to be derived from the upper crust and the second one is thought to be derived from a mixture of the upper crust and the lower crust.

U-Pb 지질연대, Re-Os, 금속광상성인, 안다우아일라스-야우리 저반, 페루, U-Pb geochronology, metallogeny. Andahuaylas-Yauri Batholith, Peru