• Ocean and Polar Research
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• v.33 no.4
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• pp.435-445
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• 2011

We investigated geochemical properties, and microbial sulfate- and iron(III) reduction in sediment influenced by the aquaculture of abalone in the Nohwa-do, southern coastal sea in Korea. Concentrations of ammonium, phosphate, and sulfide in the pore-water were higher at farm sites than at control sites. The differences between the 2 types of sites were most apparent in terms of the weights of abalone and the temperature increase during September. Accordingly, the rates of sulfate reduction at the farm sites during September (61 mmol S $m^{-2}d{-1}$) were 3-fold higher than the sulfate reduction during May (20 mmol S $m^{-2}d{-1}$). In contrast, Fe(III) reduction rates were highest at the control sites in May, but its significance was relatively decreased at farm sites during September when sulfate reduction rates were highest. During September, benthic ammonium flux was 3-fold greater at the farm sites (35 mmol N $m^{-2}d{-1}$) than at the control sites (12 mmol N $m^{-2}d{-1}$), and phosphate flux was 8-fold higher at the farm sites (0.018 mmol P $m^{-2}d{-1}$) than at control sites (0.003 mmol P $m^{-2}d{-1}$). Overall results indicated that the inappropriate operation of a large-scale aquaculture farm may result in excess input of biodeposits and high nutrient fluxes from the sediment, thereby decreasing diversity of the benthic ecosystem and deepening eutrophication in coastal waters.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.75-82
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• 2006

Acid drainage occurs when sulfide minerals are exposed to an oxidizing environment. The objective of this study was to examine the optimum condition for creating a phosphate coating on standard pyrite surfaces for reduction of pyrite oxidation. The solution of $10^{-2}M\;KH_2PO_4,\;10^{-2}M\;H_2O_2$ was identified as the best phosphate coating agent for the reduction of pyrite oxidation. The formation of an iron phosphate coating on pyrite surfaces was confirmed with ore microscope and scanning electron microscope equipped with energy dispersive spectroscopy. The temperature did not significantly affect the formation of phosphate coating on the surface of pyrite. However, the phosphate coating was less stable at higher temperature than at lower temperature. The phosphate coating was quitely stable at wide range of pH and $H_2O_2$ concentration. The less than $3.4\%$ of phosphate was dissolved at pH 2.79 and 10.64 and less than $1.0\%$ of phosphate was dissolved at 0.1M $H_2O_2$. On the basis of these results, the phosphate coating can effectively reduce the negative environmental impact of acid rock drainage.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.57-67
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• 2021

The geology of the Iskaycruz project are mainly composed of sedimentary rocks within Cretaceous basin. The basal part is composed up of dark-gray shale, gray sandstone, and clastic rock of Oyon formation interbedded with coal measures. In the folded zone in the eastern part of the survey area, there is Chimu formation that has medium-grained massive and white quarztite. In terms of geological structure, the Iskaykruz region is located in the folded and overthrust zones of the central part of the Occidental Mountains. Ore body was formed by hydrothermal replacement process and consists of zinc, lead, silver, and copper. Stratabound-type deposits are hosted in limestone of Santa formation. It extends 12 kilometers discontinuously from northern Canaypata to southern Antapampa. Irregular iron oxide and sulfide minerals hosted in Santa and Parihuanca formations are observed. The mineralization observed on the surface consist of primary sulfides consisting of sphalerite with galena and chalcopyrite, and iron and manganese oxide produced from oxidation of primary sulfides. Skarn minerals are accompanied by tremolite, garnet, epidote and quartz.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1046-1054
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• 2001

Bioleaching is the process in which insoluble metal sulfide is oxidized by specialized iron- and/or sulfur-oxidizing lithotrophic bacteria in acidic, metal-rich environments. Most of these processes are carried out by the genus Thiobacillus. Three novel Thiobacillus strains (Thiobacillus thiooxidans AZ11, Thiobacillus thiooxidans MET, and thiobacillus thiooxidans TAS) associated with bioleaching have been isolated from soil and sludge (Korean patent No. 1999-0073060 for T. thiooxidans AZ11, Korean patent No. 1999-0005798 for T. thiooxidans MET, and Korean patent No. 1999-0073059 for T. thiooxidans TAS). A partial sequence of 16S ribosomal RNA gene (16S rDNA) and the entire sequence of 16S/23S intergenic spacer region (ISR) were determined in the three above novel strains and in Thiobacillus ferrooxidans ATCC19859 as a reference strain. When phylogenetic analysis was performed based on G+C contents and sequence alignments, T. ferroxidans ATCC19859 was found to be closely related to previously registered T. ferrooxidans strains in a monophyletic manner, while the three novel T. thiooxidans strains were classified in a paraphyletic manner. Close examination on the base composition of 16S/23S ISR revealed that the 5\` part (nucleotide residues 21-200) was specific for the genus Thiobacillus. On the other end, the 3\` part (nucleotide residues 201-520) showed specificity in T. ferrooxidans strains, but not in T. thiooxidans strains. These results suggest that the proximal and distal halves of 16S/23S could be used as a genetic marker for the identification of the genus Thiobacillus and the species T. ferrooxidans, respectively.

• Herbal Formula Science
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• v.14 no.1
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• pp.82-104
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• 2006

Objectives: The aim of this study is to find the therapeutic meaning of the Pyrite in herbal medication. Methods: About the origin, the component, the processing the drug, the properties and tastes of drugs, the meridian tropism, the effects, the treating disease, the contraindication and the method of administration. We have researched thirty three literatures to mention the pyrite in time sequence. Results: 1. The pyrite belongs to the metallic herbs and it consists of Iron sulfide, sometimes containing small amounts of cobalt, nickel. silver, and gold. 2. The processing the drug are the tempering, the annealing with vinegar. the refining drug with water or RADIX GLYCYRRHIZAE and et cetra, and accoring to these methods, the pyrite classified into three groups - the rough pyrite, the tempered pyrite, the annealed pyrite. 3. The properties and tastes of drugs is pungent and regular. If pyrite is well refine, it is nearly safe form the metallic virulence. the meridian tropism is mainly liver meridian. 4. From old times, pyrite has come into general use to treat the injury of muscles and tendons and bone facture because it is effective on dissipating blood stasis, alleviating pain and reunion of bone, muscles and ligament. 5. When the symptom is gone, a medicine to contain pyrite must be stoped taking. Because of pyrite's effect on regulateing Gi and promoting blood flow. Conclusions: This study showed that the pyrite is useful herb to treat the injury of muscles and tendons and bone facture.

• Journal of Soil and Groundwater Environment
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• v.27 no.1
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• pp.25-30
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• 2022

Mackinawite (FeS), as a ubiquitous reduced iron mineral, is known as a key controller of redox reactions in anaerobic subsurface environment. The reaction of FeS with redox-sensitive toxic element such as arsenic is substantially affected by pH conditions of the given environments. In this study, the interaction of As(V) with FeS was studied under strict anaerobic conditions with various pH conditions. The pH-dependent arsenic removal tests were conducted under wide ranges of pH conditions and X-ray absorption spectroscopy (XAS) was applied to investigate the reaction mechanisms under pH 5, 7, and 9. The removal efficiency of FeS for As(V) showed the higher removal of As(V) under low pH conditions and its removal efficiency decreased with increasing pH, and no As(V) reduction was observed in 1 g/L FeS solution. However, XAS analysis indicated the reduction of As(V) to As(III) occurred during reaction between FeS and As(V). The reduced form of As(III) was particularly identified as an arsenic sulfide mineral (As₂S₃) in all pH conditions (pH 5, 7, and 9). As₂S₃ precipitation was more pronounced in pH 5 where the solubility of FeS is higher than in other pH conditions. The linear combination fitting results of XAS demonstrated that As(V) removal mechanism is concerted processes of As₂S₃ precipitation and surface complexation of both arsenic species.

• Resources Recycling
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• v.31 no.5
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• pp.26-33
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• 2022

Molybdenum is widely used in many materials; thus, its recovery from ores and secondary resources has attracted considerable attention. In this study, the leaching of molybdenite ore using hydrochloric acid containing sodium chlorate as an oxidizing agent was studied. The effects of several variables, such as the concentrations of HCl and NaClO₃, reaction temperature and time, and pulp density, on the leaching of the ore were investigated. Under strong acidic and oxidizing conditions, the sulfide in the ore was dissolved as a sulfate ion, which formed gypsum with Ca(II), leading to a decrease in the leaching percentage of Mo(VI) from the ore. The leaching percentage of molybdenum was greater than 90%, while those of iron, calcium, and silicon were 38, 29, and 67%, respectively, under the optimum conditions: 2.0 M HCl, 0.5 M NaClO₃, pulp density of 5 g/L, temperature of 90 ℃, and treatment time of 60 min.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.87-94
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• 1979

In order to study the water pollution in Suyeong Bay, Busan, some chemical constituents were determined at 25 stations in the neap tides on 9 Aug. 1977 and spring tides on 30 Aug. 1977. Range and mean values of the constituents in the spring tides are as follows: $pH\;6.54\~8.06,\;7.54;$ electrical conductivity $0.413\~0.481\times10^5\;\mu\mho/cm,\;0.467\times10^5\;\mu\mho/cm;\;transparency\;0.2\~5.5m,\;2.2m;$ turbidity $1\~60ppm$, 14ppm, chlorosity $15.20\~18.11g/\ell,\;17.67g/\ell;$ fluoride ion $0.94\~1.03ppm$, 0.99ppm; dissolved oxygen $0.17\~7.60ppm$, 4.77ppm; sulfide $0\~0.46ppm$, 0.07ppm; chemical oxygen demand $1.20\~40.74ppm$, 6.11ppm; ammonia-nitrogen $0.060\~0.520ppm$, 0.180ppm; nitrite-nitrogen $0.001\~0.026ppm$, 0.009ppm; nitrate-nitrogen $0\~0.037ppm$, 0.014ppm; phosphate-phosphorus $0.002\~0.261ppm$, 0.050ppm; n-Hexane soluble $0.5\~5.4ppm$, 2.1ppm ; iron $1.0\~104.11\;ppb$, 24.15ppb ; copper $0\~27.45ppb$, 4.19ppb; lead $0\~2.50ppb$, 0.92ppb; zinc $0\~5.15ppb$, 1.47ppb ; cadmium $0\~0.26ppb$, 0.04ppb; and mercury $0.05\~0.37ppb$, 0.11ppb respectively. The variations of the contents of the chemical constituents in the spring tides were larger than in the neap tides. The contents of COD, sulfide, nutrient salts and heavy metals were the highest in the estuary of Suyeong River, and decreased in order of off Kwangan-Ri region, outer Bay and off Haeun-Dae region. The water quality in Suyeong Bay was particularly shown that the concentrations of COO, iron, copper and mercury were higher than those of other coastal aseas and deficiency in dissolved oxygen was observed in some parte of Suyeong Bay. In consideration of the relationship between the chlorosity and the concentrations of nutrient salts, COD and total heavy metals, water pollution of this area is considered due to the inflow of Suyeong River which was extremely polluted by sewage and industrial wastewaters.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.781-797
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• 2023

Recently, there has been a rapid response from mineral-demanding countries for securing critical minerals in a high tech industries. Graphite, while overwhelmingly dominated by China in production, is changing in global supply due to the exponential growth in EV battery sector, with active exploration in East Africa. Rare earth elements are essential raw materials widely used in advanced industries. Globally, there are ongoing developments in the production of REEs from three main deposit types: carbonatite, laterite, and ion-adsorption clay types. While China's production has decreased somewhat, it still maintains overwhelming dominance in this sector. Recent changes over the past few years include the rapid emergence of Myanmar and increased production in Vietnam. Nickel has been used in various chemical and metal industries for a long time, but recently, its significance in the market has been increasing, particularly in the battery sector. Worldwide, nickel deposits can be broadly classified into two types: laterite-type, which are derived from ultramafic rocks, and ultramafic hosted sulfide-type. It is predicted that the development of sulfide-type, primarily in Australia, will continue to grow, while the development of laterite-type is expected to be promoted in Indonesia. This is largely driven by the growing demand for nickel in response to the demand for lithium-ion batteries. The global lithium ores are produced in three main types: brine lake (78%), rock/mineral (19%), and clay types (3%). Rock/mineral type has a slightly higher grade compared to brine lake type, but they are less abundant. Chile, Argentina, and the United States primarily produce lithium from brine lake deposits, while Australia and China extract lithium from both brine lake and rock/mineral sources. Canada, on the other hand, exclusively produces lithium from rock/mineral type. Vanadium has traditionally been used in steel alloys, accounting for approximately 90% of its usage. However, there is a growing trend in the use for vanadium redox flow batteries, particularly for large-scale energy storage applications. The global sources of vanadium can be broadly categorized into two main types: vanadium contained in iron ore (81%) produced from mines and vanadium recovered from by-products (secondary sources, 18%). The primary source, accounting for 81%, is vanadium-iron ores, with 70% derived from vanadium slag in the steel making process and 30% from ore mined in primary sources. Intermediate vanadium oxides are manufactured from these sources. Vanadium deposits are classified into four types: vanadiferous titanomagnetite (VTM), sandstone-hosted, shale-hosted, and vanadate types. Currently, only the VTM-type ore is being produced.

• Economic and Environmental Geology
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• v.34 no.6
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• pp.507-522
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• 2001

At the Tongyeong mine, quartz, rhodochrosite (kutnahorite), muscovite, illite, pyrite, galena, chalcopyrite. sphalerite, acanthite, and hessite are the principal vein minerals. They were deposited under epithermal conditions in two stages. Ore mineral assemblages and associated gangue phases in stage can be clearly divided into two general associations: an early cycle (band) that appeared with introduction of most of the sulfides and electrum, and a later cycle in which base metal and carbonate-bearing assemblages (mostly rhodochrosite) became dominant. Tellurides and some electrum occur as small rounded grains within subhedral-to euhedral pyrite or anhedral galena in stageII. Sulfide mineralization is zoned from pyrite to galena and sphalerite. We have used computer modeling to simulate formation of four stages of vein genesis. The reaction of a single fluid with andesite host rock at 28$0^{\circ}C$, isobaric cooling of a single fluid from 26$0^{\circ}C$ to 12$0^{\circ}C$, and boiling and mixing of a fluid with both decreasing pressure and temperature were studied using the CHILLER program. Calculations show that the precipitation of alteration minerals is due to fluid-andesite interaction as temperature drops. Speciation calculations confirm that the hydrothermal fluids with moderately high salinities and pH 5.7 (acid), were capable of transporting significant quantities of base metals. The abundance of gold in fluid depends critically on the ratio of total base metals and iron to sulfide in the aqueous phase because gold is transported as an Au(HS)$_2$- complex, which is sensitive to sulfide activity. Modeling results for Tongyeong mineralization show strong influence of shallow hydrogenic processes such as boiling and fluid mixing. The variable handing in stageII mineralization is best explained by maltiple boilings of hydrothermal fluid followed by lateral mixing of the fluid with overlying diluted, steam-heated ground water. The degree of similarity of calculated mineral assemblages and observed electrum composition and field relationships shows the utility of the numerical simulation method in identifying chemical processes that accompany boiling and mixing in Te-bearing Au-Ag system. This has been applied in models to narrow the search area for epithermal ores.