• Journal of Energy Engineering
• /
• v.26 no.4
• /
• pp.45-56
• /
• 2017

Coal power plants produce electricity for the nation's power grid, but they also produce more hazardous air emissions than any other industrial pollution sources. The quantity is staggering, over 386,000 tons of 84 separate hazardous air pollutants spew from over 400 plants in 46 states. In South Korea also, annual coal ash generation from coal-fired power plants were about 6 million tons in 2015. Pollutants containing particulate matter 10, 2.5 (PM10, PM2.5), heavy metals and dioxins from coal-fired power plant. The emissions threaten the health of people who live near these power plants, as well as those who live hundreds of miles away. These pollutants that have long-term impacts on the environment because they accumulate in soil, water and animals. The present study is to investigate the physical and chemical characteristics of coal-fired power plant fly ash and bottom ash contains particulate matter, whose particulate sizes are lower than $PM_{10}$ and $PM_{2.5}$ and heavy metals. There are wide commercial technologies were available for monitoring the PM 2.5 and ultra-fine particles, among those carbonation technology is a good tool for stabilizing the alkaline waste materials. We collected the coal ash samples from different coal power plants and the chemical composition of coal fly ash was characterized by XRF. In the present laboratory research approach reveals that potential application of carbonation technology for particulate matter $PM_{10}$, $PM_{2.5}$ and stabilization of heavy metals. The significance of this emerging carbonation technology was improving the chemical and physical properties of fly ash and bottom ash samples can facilitate wide re use in construction applications.

• Applied Chemistry for Engineering
• /
• v.33 no.5
• /
• pp.466-470
• /
• 2022

The catalytic thermal oxidizer process has recently attracted considerable attention for the oxidation and decomposition of volatile organic compounds at low temperatures (< 450 ℃) with high efficiency (> 95%). Although many noble metal catalytic materials are well established, they are expensive and hazardous. Herein, highly active and low-cost Cu-Mn bimetallic catalysts were prepared using a simple and facile synthesis method involving the co-precipitation of Cu and Mn precursors. The synthesis of the catalyst was optimized by controlling the composition ratio of Cu and Mn. The optimized catalyst exhibited a large surface area of 230.8 m²/g with a mesoporous structure. To demonstrate the catalytic performance, the Cu-Mn catalyst was tested for the oxidation reaction of ethyl acetate, showing a high conversion efficiency of 100% at a low temperature of 250 ℃.

• The Korean Journal of Food And Nutrition
• /
• v.18 no.1
• /
• pp.63-71
• /
• 2005

Panax ginseng leaves are produced as the by-product when Panax ginseng roots were harvested. The Panax ginseng leaves was examed for the applicable possibility as the functional food. In this study, the changes in chemical composition of Panax ginseng leaves was examed by three methods as the hot-air dried(DRT), the aged tea(AGT) and the heat processed tea(HPT). The general composition of Panax ginseng leaves tea was shown as similar results in 3 different process methods. The level of the crude lipid and reducing sugar concentration were decreased slightly in HPT. The free sugar content of DRT was higher than the HPT and AGT. The existence of the higher content of free sugar composition in order are sucrose, fructose and glucose. The concentration of serine was the highest in the free amino acids, which were shown from 309.6 mg% to 336.6 mg%. The contents of free amino acid in Panax ginseng leaves made by DRT was higher than by AGT and HPT. The concentration of Ca was shown as the highest content among the minerals and was 2,115 mg%. The contents of minerals were existed in order of Ca, K, Mg, P, Na, Mn, Fe, Zn and Cu. But there were hardly any remarkable differences of mineral concentrations of Panax ginseng leaves tea made by different processing methods. The concentration of water soluble solid of Panax ginseng leaves tea processed by HPT was higher than by DRT and AGT. The concentration of ascorbic acid was shown the highest value of 424.4mg% in HPT. There was no differences in the fatty acid composition according to their processing methods. The concentration of palmitic acid was higher than that of other fatty acid. The order of fatty acid concentration were palmitic aicd, linoleic acid, linolenic acid, oleic acid and stearic acid, abundantly. As a conclusion, HPT was shown as the best process method for the production of Panax ginseng leaves tea.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.3
• /
• pp.505-510
• /
• 1999

The seasonal variations of chemical composition of jujuba leaf were studied by analyzing general composition, amino acid composition, fatty acid composition, mineral, phenol, condensed tannin, flavonoid contents. Fresh jujuba leaf contained 4.42~6.31% protein and 4.31~5.71% fat on wet basis. Jujuba leaf was rich in aspartic acid, glutamic acid and leucine, but methionine was a limiting amino acid. Four kinds of free sugar, i.e. glucose, fructose, sucrose and maltose were found in jujuba leaf. The contents of fructose and glucose increased during growth, while the contents of disaccharides, sucrose and maltose, decreased. The main fatty acids of the leaf were palmitic acid, linoleic acid, stearic acid and oleic acid. Jujuba leaf was rich in K, Na and Ca, however, the amounts of Fe, Mn and Cu were low. The contents of Ca and Na increased during growth but the content of Mg decreased. The content of total phenolic compound was 0.83~0.89% and the content of condensed tannin was 0.40~0.45%. Two major flavonoids such as rutin and isoquercitrin were detected and their contents were 103.8~125.2mg/kg and 26.2~40.0mg/kg, respectively.

• Journal of the Mineralogical Society of Korea
• /
• v.21 no.4
• /
• pp.373-382
• /
• 2008

First reported geochemical characteristics of mantle xneoliths (spinel peridotites) from Sunheul-ri, Jeju Island, provide important clues for understanding the lithosphere composition, equilibrium temperature, and the period of entrainment and transport of the xenoliths in the host magma. Core and rim of mineral phases in the xenoliths are constant chemical compositions as $Fo_{89-90}$ of olivines. The ranges of equilibrium temperature, obtained by two pyroxenes geothermometer, are about $951{\sim}1035^{\circ}C$ for Sunheul-ri spinel peridotite xenoliths and are similar to the range of equilibrium temperatures for the xenoliths from other sites in Jeju island. The period of entrainment and transport of the xenoliths in the host magma of Sunheul-ri mantle xenoliths is about 42 days.

• Korean Journal of Materials Research
• /
• v.19 no.4
• /
• pp.212-219
• /
• 2009

A study on the dry beneficiation of sericite occurring in the Daehyun Mine of the Republic of Korea region as performed by applying selective grinding and air classification techniques. Quartz and sericite occurred in the raw ore as major components. The results of liberation using a ball mill and an impact mill showed that the contents of $R_2O$ were increased while $SiO_2$ was decreased in proportion to decreasing particle size. According to the XRD, XRF analysis and the EDS of SEM analysis, the ball mill gave a better grade product in $R_2O$ content than the impact mill when the particle size was the same. When the raw ore was ground by the impact mill with arotor speed 57.6 m/sec and then followed by 15,000rpm classification using an air classifier, the chemical composition of the over flowed product was 49.65wt% $SiO_2$, 32.15wt% $Al_2O_3$, 0.13wt% $Fe_2O_3$, 10.37wt% $K_2O$, and 0.14wt% $Na_2O$. This result indicates that the $R_2O$ contents were increased by 49.5% compared to that of the raw ore. From these results described above, it is suggested that hard mineral such as Quartz little ground by selective grinding using impact mill whereas soft mineral such as sericite easily ground to small size. As a result of that hard minerals can be easily removed from the finely ground sericite by air classification and the $R_2O$ grade of thus obtained concentrate was improved to higher than 10wt% which can be used for ceramics raw materials.

• Analytical Science and Technology
• /
• v.20 no.6
• /
• pp.468-473
• /
• 2007

The chemical composition distribution of the surface samples collected from the loess plateau in China were estimated. Major elements concentration distribution difference between 10 different sampling site were not found except sample 3. This sample had higher contents of Ca, Mg, LOI and lower contents of Si, Fe, P, Na, Ti. And also, minor element contents such as Ba, Cr, Nb, Pb, Rb, Zr, V were lower than other samples. UCC-normalized abundances of the most elements were within $0.5-1.5{\times}UCC$ and Cr showed enrichment aspect. Rare-earth element (REE) analysis results showed light REE enriched pattern compared to heavy REE with negative Eu anomaly in condrite-normalized REE pattern.

• Economic and Environmental Geology
• /
• v.26 no.3
• /
• pp.311-325
• /
• 1993

The Ohto and Tohyun copper mine which are located 4 km southeast of Euiseong, Gyeongsangbukdo, Republic of Korea show various common geologic and mineralogic features. Both copper deposits are of hydrothermal-vein types, and associated with fracture system developed during formation of the Geumseong-san caldera in late Cretaceous age. According to structures and mineral assemblages, the mineralization processes have progressed in four stages: three hypogene mineralization stages and one supergene stage. Three hypogene stages are 1) stage I forming $N5{\sim}20^{\circ}E$ veins in the Ohto mine, 2) stage II building $N5^{\circ}W{\sim}N5^{\circ}E$ veins in the Tohyun mine, and 3) stage ill bringing $N80^{\circ}E$ veins which crosscut veins of the stage II. The vein ores consist mainly of pyrite, arsenopyrite, galena and chalcopyrite, minor or trace amounts of magnetite, hematite, pyrrhotite, stannite, bournonite, boulangerite, stibnite, galenobismutite, native bismuth, marcasite, geothite and malachite. The main gangue minerals are quartz and calcite. Wallrock is altered by sericitization, chloritization, pyritization, carbonitization and argillization. Arsenic and copper contents in arsenopyrite increase from stage I to stage III (from 31.28 to 33043 atom.% As) and (from 0.04 to 0040 atom.% Co). Going from stage I to stage III Fe and Mn contents in sphalerite decreases from 12.56 to 0.44 wt.% and from 0.24 to 0.01 wt.%, respectively. The compositional data of arsenopyrite in the early stage I indicate a temperature of $420{\sim}365^{\circ}C$ and sulfur fugacity of $10^{-6.5}{\sim}10^{-8.3}$ atm. Chalcopyrite and pyrrhotite assemblage suggest that Middle stage I was deposited at below $334^{\circ}C$. The compositional data of arsenopyrite in early stage II suggest a temperature range of $425{\sim}390^{\circ}C$ and sulfur fugacity codition of $10^{-6.4}{\sim}10^{-7.3}$ atm. Based on fluid inclusion the Middle stage II was regarded as to be deposited at $420{\sim}337^{\circ}C$ (Chi et al., 1989). Referring composition of sphalerite and stannite middle-late stage II seem to be deposited around $246^{\circ}C$ and $10^{-16.5}$ atm. sulfur fugacity. The ${\delta}^{34}S$ values of sulfide minerals in the Stage I, II, III range from 4.9 to 7.6%0 and indicate igneous ore fluid origin. Based on differences in mineral assemblages, chemical composition and chemical environments of Ohto and Tohyun mine its mineralization are considered to be formed at diffent mineralization ages and by different ore fluids.

• Korean Journal of Soil Science and Fertilizer
• /
• v.33 no.6
• /
• pp.377-383
• /
• 2000

The composition of primary minerals of sand fractions and secondary minerals of clay fractions were investigated on the polder soils developed from alluvio-marine deposits near to Sapgyo-lake, constructed a sea dike across river estuary located in the west coast. The effects of a topographical sequence on the physico-chemical properties and mineralogical characteristics were evaluated using XRD, DTA, and TG with the chemical composition of $H^+$ saturated clays. Soils located on the seashore side were more silt fraction, higher pH and exchangeable cations than the others. The dominant minerals of soil parent materials are in the order of quartz, feldspars, micas, chlorite and amphibole. According to the greater distance from the lake, the amount of 1:1 minerals increased, but 2:1 minerals decreased. The dominant clay minerals of polder soils are kaolinite, vermiculite and illite. Hydroxy interlayer minerals are abundant in the clay fractions derived from the soil parent materials which have relatively low soil pH.

• Food Science and Preservation
• /
• v.20 no.1
• /
• pp.88-96
• /
• 2013

This study was investigated to compare the major chemical components of kohlrabi (Brassica oleracea var. gongylodes) flesh and kohlrabi peel. Among the proximate compositions, the crude fat of kohlrabi peel contained lower than that of kohlrabi flesh, while the contents of carbohydrate and the crude protein were higher in the kohlrabi peel. Total free sugar content of the flesh kohlrabi was higher than that of the peeled kohlrabi, and the major free sugars of the flesh kohlrabi and peeled kohlrabi were identified as fructose and glucose. The value of glutamic acid was greater in amino acids of kohlrabi flesh and kohlrabi peel, and the contents of total amino acids and essential amino acids were higher in kohlrabi peel compared with kohlrabi flesh. Kohlrabi flesh also contained a higher level of unsaturated fatty acids than kohlrabi peel. The contents of organic acid were higher in kohlrabi peel, and the level of oxalic acid was the highest in both kohlrabi. The vitamin C contents of flesh kohlrabi and peeled kohlrabi were 231.36 mg/100 g and 402.75 mg/100 g, respectively. The mineral content of the peeled kohlrabi was higher than that of the flesh kohlrabi, and the mineral contents of the flesh and peeled kohlrabi were greater in the order of K>Ca>Mg>Na. As a result, the contents of total amino acid, essential amino acid, organic acid, vitamin C and mineral were higher in the peeled kohlrabi, and the free sugar and unsaturated fatty acid contents of the flesh kohlrabiwere higher.