노진환 No Jin Hwan

DOI: Vol.16(No.3) 201-213, 2003

The adsorption property and ability of domestic zeolites for some heavy metal ions (Ag, Pb, Cr, Cu, Zn, Mn), which may cause a serious environmental problem in industrial wastewater, were evaluated on ore unit through a series of adsorption experiments together with careful examinations of mineral composition and properties of the zeolites. Though the adsorption behavior basically took place in the form of a cation exchange reaction, the higher CEC value does not necessarily to imply the higher adsorption capacity for a specific heavy metal. A general trend of the adsorption selectivity for heavy metals in the zeolites is determined to be as follow: Ag≥Pb>Cr,Cu≥Zn>Mn, but the adsorption properties of heavy metal ions somewhat depend on the species and composition of zeolite. Clinoptilolite tends to adsorb selectively Cu in case of Cr and Cu, whereas heulandite prefers Cr to Cu. A dominant adsorption selectivity of the zeolite ores for Ag and Pb is generally conspicuous regardless of their zeolite species and composition. The zeolite ores exhibit a preferential adsorption especially for Ag^(+) so as not to regenerate when treated with Na^(+). In the adsorption capacity for heavy meta ions, the zeolites differ in great depending on their species: ferrierite>clinoptilolite>heulandite. Considering the CEC value of mordenite, the mordenite-rich ore appears to be similar to the clinoptilolite ore in the adsorption capacity. The adsorption capacity for heavy metals is not positively proportional to the CEC values of the zeolites measured by the exchange reaction with ammonium ion. In addition, the adsorption capacity roughly tends to depend on the zeolite contents, i.e., the grade of zeolite ore, but the trend is not consistent at all in some ores. These may be caused by the adsorption selectivity for some specific heavy metals, the presence of possible stacking micro-faults and natural cations such as K hardly to exchange in the zeolite. Considering the economic availability and functional effectiveness as natural zeolite resources, clinoptilolite ores could be applicable to utilize the domestic zeolites for the removal of heavy metals.

중금속 이온, 제올라이트, 흡착선호도, 흡착능력, 산업폐수, 교환성 양이온, 클리놉틸로 라이트, heavy metal ion, zeolite, adsorption selectivity, adsorption capacity, industrial wastewater, exchangeable cation, CEC, clinoptilolite

이철규 Lee Cheol Gyu , 송윤구 Song Yun Gu , 전철민 Jeon Cheol Min , 김신애 Kim Sin Ae , 성기훈 Seong Gi Hun

DOI: Vol.16(No.3) 215-222, 2003

The Rietveld structure refinement for the natural trioctahedral mica, phlogopite-l M (Parker Mine, Quebec, Canada) has been done by high resolution neutron powder diffraction at 25℃ and -263℃. The structural formula of phlogopite determined by electron probe microanalysis is K₂(Mg_(4.46)Fe_(0.83)Al_(0.34)Ti_(0.22)) (Si_(5.51)Al_(2.49))O_(20)(OH_(3.59)F_(0.41)). Cell parameters are α=5.30-5.31 A, b=9.18-9.20 A, c=l0.18-10.21 A, β=l00.06-100.08˚. Refinements converged to R values in the range of R_(p)=2.35 -2.51%, R_(wp)=3.01 -3.18%, respectively. In this study, the OH bond length is calculated to 0.93 Å at room temperature and 1.03 Å at -263℃, and the angles between OH vector and (001) plane are obtained 9.4˚∼9.6˚. The decrease in the length of OH with the increase in temperature should be due to the hydrogen bonding in the structure of phogopite.

금운모, 리트벨트법, 중성자분말회절법, OH기, phlogopite, Rietveld refinemnet, neutron powder diffraction, hydroxyl ion

최진범 Choe Jin Beom , 박종완 Park Jong Wan , 이승원 Lee Seung Won

DOI: Vol.16(No.3) 223-232, 2003

The co-precipitation method is applied to synthesize the cathode material Li[Li_(x)Mn_(1-x-y) Cr_(y)]O₂ for lithium rechargeable batteries at 650%` (CR650) and 850 C (CR850), respectively. Rietveld indices indicate that R_(wp) with respect to R_(exp)(R_(wp)/R_(exp)) are 9.2%/10.1% for CR650 and 15.9%/9.76% for CR850, respectively. R_(B) and S (GofF) shows 10.9%, 8.54% and 1.9, 1.6, respectively. Rietveld structure refinement reveals that layer structure of LiMnO₂ (R3m) coexists with lower symmetry of Li[Li_(1/3)Mn_(2/3)]O₂(C2/c) due to superlattice ordering of Li and Mn in metal-transition containing layers. Unit-cell parameters are calculated as a=2.8520(2)Å, c=14.248(2)Å, V=100.40(1)ų for CR650, and a=2.8504(1)Å c=14.2371(7)A, V=l00.179(8)ų for CR850. Final chemistry is obtained as Li[Li_(0.35)Mn_(0.56)Cr_(0.09)]O₂ (CR6.50) and Li[Li_(0.27)Mn_(0.61)Cr_(0.13)]O₂ (CR850), respectively.

리튬2차전지, 양극소재, 전이금속, 공침법, 리트벨트법, 층상구조, 거대격자, lithium rechargeable battery, cathode material, transition-metal, co-precipitation method, Rietveld method, layer structure, superlattice

이영부 Lee Yeong Bu , 김윤중 Kim Yun Jung , 이석훈 Lee Seog Hun , 이정후 Lee Jeong Hu

DOI: Vol.16(No.3) 233-243, 2003

2092898 Microstructures and chemistRy of anorthoclase. a high-temperature phase of alkali feldspars, were studied using EPMA and TEM, BSE images of anorthoclase displayed mixtures of Na-rich areas and K-rich areas forming lamella of various sizes. EPMA analysis indicated that the Na-rich area is composed of Ab 81%, Or: 3% and An: 11% in average, while the K-rich area is composed of Ab: 45%, Or: 44% and An: 11% in average. TEM analysis revealed albite with Albite twins in the Na-rich area, contrasting to mixtures of albite with fine Albite twins and orthoclase without twins, forming regular lamella of about 100 nm sizes, in the K-rich area. The [001] electron diffraction pattern of the K-rich area also indicated coexistence of the two phases. While streaking parallel to the (010)* direction appeared only in albite due to the twin structure. streaking parallel to the (100)* direction appeared both in albite and orthoclase, probably due to strain on the interface as well as order-disorder phenomena of Al and Si. It is suggested that the reverse orientation of albite and orthoclme is caused by pole switching to reduce strain on their interfaces. Based on these observations and analyses, the mineral studied is identified as lower-temperature cryptoperthite rather than high-temperature anorthoclase, which has a midium degree of AI-Si ordering and 400℃ -6007` of eqtirnated temperatures for the microstructure formation.

앨바이트 쌍정, Al-Si의 배열-비배열, 왜력, Albite twin, Al-Si order-disorder, strain, anorthoclase, lamella

정정민 Jeong Jeong Min , 김희수 Kim Hui Su

DOI: Vol.16(No.3) 245-254, 2003

Stishovite was synthesized from hydrous basaltic starting materials at 10-15 CPa and 1000- 1400℃. Water content of synthetic stishovite has been determined, and solid solution mechanism of H2 and Al in stishovite was investigated. The maximum water content obtained from stishovite single crystal was up to 844±44 ppm H₂0. The concentration of hydrogen increased with increasing substitution of trivalent cation, mainly Al. The temperature effect on the hydrogen content in stishovite is more sensitive than that on any other impurities. Among the nominally anhydrous mantle-minerals, stishovite could he an important water-containing phase and contribute to the transportation of H₂O to lower mantle.

스티쇼바이트, 알루미늄, 수소, 함수 현무암질 물질, 맨틀, stishovite, aluminum, hydrogen, hydrous basaltic materials, mantle

이승준 Lee Seung Jun , 안중호 An Jung Ho

DOI: Vol.16(No.3) 255-263, 2003

Margarite, occurring in an Unkyori Formation of Miwon area, Chungcheongbukdo, South Korea, was investigated using a high-resolution transmission electron microscope (HRTEM) to reveal the microstructural intergrowth textures of margarite. HRTEM images of margarite, which was previously confirmed to have intergrowth textures by petrographic microscope and back-scattered electron images, show that chlorite occurs as thin packets of layers interlayered within margarite crystals, and intercalated chlorite layers are intergsown irregularly in areas as a few hundred angstroms thick slabs or isolated chlorite unit layers. Margarite crystals observed by HRTEM consist of a well-ordercd 2M polyiype, and electron dimaction pattern shows no prominent streaking along the 001 (or c*) direction, indicating that there is no significant stacking disorder in margarite. Intercalated extra brucite-like layers, which are approximately 5 Å thick are observed locally within margarite crystals. Insertion of such extra brucite-like layer at the interlayer of margarite would result in a chlorite-like structure unit. (001) margarite layers are parallel to (001) of chlorite, and margarite layers are not extended from (001) of chlorite, indicating that margarite was apparently produced through a dissolution-precipitation mechanism.

고분해능 투과전자현미경, HRTEM, 마가라이트, 녹니석, 부르사이트, 전자회절패턴, high-resolution transmission electron microscope, margarite, chlorite, extra brucite-like layer, electron diffraction pattern

박상준 Park Sang Jun , 최선규 Choe Seon Gyu , 이동은 Lee Dong Eun

DOI: Vol.16(No.3) 265-280, 2003

The Mugeuk mineralized area that associated with the pull-apart type Cretaceous Eumseong basin is composed of several gold-silver vein deposits that are emplaced in late Cretaceous biotite granite. The gold-silver deposits in the area show various hydrothermal alteration zones ar well as Au/Ag ratios and ore mineralogy. The Geumbong mine showing relatively high gold fineness is composed of multiple veins and show alteration pattern; vein→phyllic→subphyllic→propylitic→subpropylitic zone. In contrast, The Taegeuk mines show the low fineness values, in far southern part are characterized by increasing tendency of simple and/or stockwork veins. The deposit displays alteration pattern; vein→propylitic→subpropylitic zone. Variations of alteration zone with depth show that phyllic zone are dominant in deeper level and propylitic zone sporadically overlapped by argillic zone are dominant in shallow level. The differences of alteration pattern between the gold-silver deposits are reflect the evolution of the hydrothermal fluids; the ore-forming fluids of the Geumbong mine are at relatively high temperature and salinity and highly-evolved meteoric water, developing phyllic zone, the Taegeuk mine containing greater amounts of less-evolved meteoric waters shows relatively low temperature and salinity in ore-forming fluids. developing propylitic zone. The various physicochemical environment for gold-silver mineralization in the Mugeuk mineralired area is due to proximity from heat source area (Mugeuk mine) to marginal area (Taegeuk mine) in a geothermal tield. Therefore, it is suggested that the criteria for prqject exploration in the area are to focus on the area proximal to heat source and phyllic zone.

무극 광화대, 열수변질대, 금,은광화작용, 광화 유체, 열수계, Mugeuk mineralized area, hydrothermal alteration, gold-silver mineralization, ore-forming fluids, hydrothermal systems