Jae-Young Yu | Kangwon National University (original) (raw)

Papers by Jae-Young Yu

Typescript (photocopy). Thesis (Ph. D.)--Colorado School of Mines. Includes bibliographical refer... more Typescript (photocopy). Thesis (Ph. D.)--Colorado School of Mines. Includes bibliographical references (v. 1 leaves 151-157).

Journal of the geological society of Korea, 2014

Environmental Geology, 1996

ABSTRACT Osheepcheon Creek running through the Dogyae area is being polluted by the influx of the... more ABSTRACT Osheepcheon Creek running through the Dogyae area is being polluted by the influx of the abandoned coal mine drainage. Generally, the more polluted water has lower pH and Eh and higher conductivity values. The concentrations of Mg, Ca, Fe, SO4, and some trace elements, such as Cd, Co, Cr, Mo, Ni, Pb, Rb, Sr, U and Zn, are tens to hundreds of times more concentrated in the abandoned coal mine drainage than in the unpolluted streamwater. However, most immobile toxic pollutants from the mine drainage are quickly removed from the streamwater by the precipitation of amorphous Fe hydroxide and sorption on the precipitated Fe hydroxide. The fast removal of the pollutants from the streamwater maintains the water quality of the creek as acceptable at most places along the stream path, except where the abandoned coal mine drainage flows in. However, the creek has the potential of deteriorating quickly if the mine drainage is allowed to be continuously combined with the streams. A function of pH, Eh, and conductivity has been developed with discriminant function analysis for the purpose of easy, fast, and inexpensive measurement of the degrees of pollution of the streams. The estimated pollution of the streams with the discriminant function are consistent with what the chemical compositions of the water samples indicate. The pollution map of the study area was constructed from the calculated scores with the discriminant function. The pollution map suggests that the pollutants mainly come from the west side of Osheepcheon Creek. Thus, the abandoned coal mine drainage from the west side has to be appropriately treated as soon as possible to prevent Osheepcheon Creek from being further polluted. Considering the topography, climate, and the amount of the mine drainage, an active treatment method is recommended.

Minerals, 2021

Carbonate formations of the Cambro-Ordovician Period occur in the Taebaek and Jeongseon areas, lo... more Carbonate formations of the Cambro-Ordovician Period occur in the Taebaek and Jeongseon areas, located in the central–eastern part of the Korean Peninsula. This study analyzed the rare earth element (REE) contents and Sr–Nd isotope ratios in these carbonates to elucidate their depositional environment and diagenetic history. The CI chondrite-normalized REE patterns of the carbonates showed negative Eu anomalies (EuN/(SmN × GdN)1/2 = 0.50 to 0.81), but no Ce anomaly (Ce/Ce* = CeN/(LaN2 × NdN)1/3 = 1.01 ± 0.06). The plot of log (Ce/Ce*) against sea water depth indicates that the carbonates were deposited in a shallow-marine environment such as a platform margin. The 87Sr/86Sr ratios in both Taebaek and Jeongseon carbonates were higher than those in the seawater at the corresponding geological time. The 87Sr/86Sr ratios and the values of (La/Yb)N and (La/Sm)N suggest that the carbonates in the areas experienced diagenetic processes several times. Their 143Nd/144Nd ratios varied from 0....

Journal of the Geological Society of Korea, 2019

Geosciences Journal, 2007

The meteoric water deposited in the Chuncheon area was collected from July 2002 to May 2004 and i... more The meteoric water deposited in the Chuncheon area was collected from July 2002 to May 2004 and its chemical and isotopic compositions were analyzed to examine if the isotopic data can help trace the sources of the sulfur pollutant and understand the details of acid formation processes in the air. The chemical compositions of the meteoric water indicate that the sulfate mostly comes from anthropogenic sources. The sulfur isotopic compositions of the dissolved sulfate in the meteoric water (δ 3 4 SSO4) vary from 2.6 to 7.5‰ with little seasonal differences, which are significantly different from those of the sulfur in the coal being locally consumed (−4.5 to −0.7‰). This difference indicates that the local coal consumption gives insignificant contribution to the pollutant sulfur in the acid deposition of the area. The relationship between δ 3 4 SSO4 and the concentration of sulfate suggests that the sources of pollutant sulfur are variable and inhomogeneous. The oxygen isotopic compositions of the dissolved sulfate in the meteoric water (δ 1 8 OSO4) range from 9.0 to 17.2‰, which are generally lower in winter than in spring. Comparison between the measured and calculated values of δ 1 8 OSO4 suggests that the oxygen isotopic exchange between sulfite and water occurs before its oxidation to sulfate. The extent of isotopic exchange seems to be not controlled by equilibrium but by kinetic fractionation. The poor correlation between δ 1 8 OSO4 and the oxygen isotopic composition of the meteoric water confirms the disequilibrium nature of the isotopic exchange.

Earth and Planetary Science Letters, 2008

growth phases oxygen and sulfur isotope composition of sulfate degassing of sulfur dioxide from a... more growth phases oxygen and sulfur isotope composition of sulfate degassing of sulfur dioxide from acid solutions sulfite The solution chemistry during the initial (slow increase of dissolved iron and sulfate) and main stage (rapid increase of dissolved iron and sulfate) of pyrite leaching by Acidithiobacillus ferrooxidans (Af) at a starting pH of 2.05 shows significant differences. During the initial stage, ferrous iron (Fe 2+) is the dominant iron species in solution and the molar ratio of produced sulfate (SO 4 2−) and total iron (Fe tot) is 1.1, thus does not reflect the stoichiometry of pyrite (FeS 2). During the main stage, ferric iron (Fe 3+) is the dominant iron species in solution and the SO 4 2− :Fe tot ratio is with 1.9, close to the stoichiometry of FeS 2. Another difference between initial and main stage is an initial trend to slightly higher pH values followed by a drop during the main stage to pH 1.84. These observations raise the question if there are different modes of bioleaching of pyrite, and if there are, what those modes imply in terms of leaching mechanisms. Different oxygen and sulfur isotope trends of sulfate during the initial and main stages of pyrite oxidation confirm that there are two pyrite bioleaching modes. The biochemical reactions during initial stage are best explained by the net reaction FeS 2 + 3O 2 ⇒ Fe 2+ + SO 4 2− + SO 2 (g). The degassing of sulfur dioxide (SO 2) acts as sink for sulfur depleted in 34 S compared to pyrite, and is the cause of the SO 4 2− :Fe tot ratio of 1.1 and the near constant pH. During the exponential phase, pyrite sulfur is almost quantitatively converted to sulfate, according to the net reaction FeS 2 + 15/4O 2 + 1/2H 2 O ⇒ Fe 3+ + 2SO 4 2− + H +. We hypothesize that the transition between the modes of bioleaching of pyrite is due to the impact of the accumulation of ferrous iron, which induces changes in the metabolic activity of Af and may act as an inhibitor for the oxidation of sulfur species. This transition defines a fundamental change in the growth strategy of Af. A mode, where bacteria gain energy by oxidation of elemental sulfur to sulfite but show little growth is switched into a mode, where bacteria gain a smaller amount of energy by the oxidation of ferrous iron, but induce much faster pyrite leaching rates due to the production of ferric iron.

Chemical Geology, 2001

Pyrite was oxidised by growth of Thiobacillus ferrooxidans aerobically at 328C by orbital shaking... more Pyrite was oxidised by growth of Thiobacillus ferrooxidans aerobically at 328C by orbital shaking at 90 revolutions per Ž. Ž. minute rpm in the laboratory. The analyses of the experimental solutions showed a long period of adaptation lag phase before the onset of rapid bio-oxidation. Lag phase lasted for approximately 400 h. During this period, the dissolved iron and sulphur content increased very slowly compared with a very rapid rise during the exponential phase of growth. The molar ratio of the dissolved Fe to S in solution decreased from 1.3 to approximately 1 during the lag phase. The molar ratio continued to fall during the exponential phase and reached approximately 0.5, which is the ratio defined by the stoichiometry of pyrite. The form of dissolved iron during the lag phase was ferrous, while during the exponential phase, it was mostly ferric. On the other hand, all the dissolved sulphur was in the form of SO during both the lag and exponential phase. These 4 indicate that the Fe is preferentially leached from pyrite, but S is the main source of energy for T. ferrooxidans during the lag phase. The solution chemistry and scanning electron microscope images of the pyrite surfaces reveals that both direct and indirect leaching are important for pyrite oxidation during the exponential phase. During the lag phase, however, direct leaching appears to be the dominant mechanism, which may explain the preferential oxidation of S during the early stages of growth.

Encyclopedia of Earth Science

Journal of the Geological Society of Korea

Journal of the Mineralogical Society of Korea

Journal of the geological society of Korea, 2015

Geochmica et Cosmochimica Acta