• Journal of the Mineralogical Society of Korea
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• v.16 no.4
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• pp.321-331
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• 2003

We researched the variation of mineral composition with depth and the Cu adsorption behavior of Hwangto in the Okjong area, Hadong. The 4 Hwangto samples were collected from depth 10 cm, 25 cm, 2∼3 m and under 3 m from surface, and analyzed using the X­ray Diffractometer. The Hwangto samples were mostly composed of clay minerals such as kaolinite and halloysite. Two samples from 10 cm and 25 cm contained Fe or Al hydroxide minerals, for example goethite or gibbsite. As depth increases, the content of quartz decreases but that of kaolinite increases. The amount of Cu removal was rapidly rised from pH 4, and reached about 90％ at pH 6 and above 90％ at pH 7. It is regarded that the trend of Cu removal was affected by the difference in mineral composition. It was relatively well matched between experimental value and calculated value by MINTEQA2 program in the case of high Cu concentration. From this study the precipitation has important role for the removal of Cu ions, particularly in the case of high Cu concentration. However, it was discord between experimental value and calculated one in the dilute concentration circumstances. The reason may be the mistake in parameters, insufficient reaction time, and inadequate consideration of reaction site in mineral surface.

• Journal of the Mineralogical Society of Korea
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• v.19 no.2 s.48
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• pp.71-80
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• 2006

We examined the mineralogical composition of pyrite-bearing rocks by quantitative powder X-ray diffraction analysis using the matrix-flushing method and ROCKJOCK (a full pattern fitting computer program). The neutralization potential (NP) and acid generating potential (AP) were calculated on the basis of mineralogical compositions. The mineralogical AP was compared with the conventional AP calculated from bulk sulfur concentration to assess the applicability to the prediction of acid rock drainage(ARD). The pyrite content calculated by matrix-flushing method showed a high positive correlation($r^2$=0.95) with those by ROCKJOCK. The pyrite contents by matrix-flushing method was 1.45 times larger than those by ROCKJOCK. The pyrite content and mineralogical AP obtained by the matrix-flushing method had a better correlation($r^2$=0.98) with those by the total sulfur concentrations in the all samples except KB sample. The mineralogical NPs of YJ sample were 23.0 and 34.0(kg $CaCO_3$ equivalent per tonne) by matrix-flushing method and ROCKJOCK, respectively. The AP calculated by matrix-flushing method and ROCKJOCK program were 47% and 72% of those by the conventional ABA test. We hereby suggested that the quantitative analysis using XRD data can be applied to prediction of ARD. For more reliable calculation of the mineralogical NP and AP, other sulfide and carbonate minerals such as pyrrhotite, dolomite, ankerite, siderite, rhodochrosite which can affact the mineralogical NP and AP should be considered.

• Economic and Environmental Geology
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• v.49 no.5
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• pp.349-360
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• 2016

This study determined mineralogical characteristics and discussed the meaning of mineralogical changes of the lower Choseon Supergrouop in the Weondong area based on the field geological investigation and the drilling core description using X-ray diffraction (XRD) mineral quantification and Scanning Electron Microscopy (SEM) observation. 100 samples with depth were collected from the core (250 m long) at a site in the study area. Especially, to investigate the changes from the upper Daegi Formation to the lower Hwajeol Formation, the samples were collected closely with the interval of about 0.3 m at this section. All samples were made into power using mortar for XRD. Mineral quantitative analysis was executed using Relative Intensity Ratio (RIR) method with corundum as an internal standard phase. Calcite, $2M_1$ illite and quartz are main constituents in most of samples. Dolomite and siderite are significantly observed in the Sesong Formation. As the results of quantitative analysis for the major minerals, the upper Daegi Formation is dominated by calcite with over 80%. The Sesong Formation includes high percentage of dolomite and siderite with the intercalation of thin layers containing high calcite and $2M_1$ illite contents. Hwajeol Formation is characterized by the alternation between thin layers of $2M_1$ illite and quartz-dominated layer (IQDL) and calcite-dominated layer (CDL). IQDL is more frequent in the lower part, whereas CDL is more common in the upper part. The boundary between Daegi Formation and the Sesong Formation is distinct, whereas the boundary between the Sesong Formation and the Hwajeol Formation tends to be changed gradually in mineralogy. The result of SEM observation shows that quartz and $2M_1$ illite are detrital, and a significant amount of calcite also shows detrital form with some recrystallized one, indicating that the repeated influx of terrestrial materials had changed the mineralogy of the shallow sea depositional environment in the early Paleozoic era.

• 보존과학연구
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• s.31
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• pp.43-57
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• 2010

This study intends to provide quantitative data about the extraction characteristics of major elements of earthenware by executing soaking test of cleaning agents. It aims at providing basic data for the stability assessment when applying the cleaning agents for conserving earthenware. The data will be extracted from the analysis of co-relationship between the physical characteristics and the ion extraction characteristics. XRD analysis displayed that AT-1, AT-2 and AT-3 which did not generate mullite were fired at lower than 1,000 whereas AT-3 and AT-5 that included mullite were higher than 1,000. The degree of absorption was AT-4 > AT-2 > AT-1 > AT-3 > AT-5 in order and the correlation between the degree of absorption and firing temperature of earthenware displayed a positive correlation. Extraction amount of oxalic acid which was used for the removing iron oxide was AT-1 > AT-2 AT-4 > AT-3 > AT-5 in order. and the ion extraction data displayed that there is a positive correlation with absorption level. However AT-1 and AT-2 which were fired at lower temperature showed that there was no correlation between the ion extraction characteristics and absorption level. Ion extraction of citric acid produced little amount compared with the one of oxalic acid, yet it caused less damage to earthenware than oxalic acid when it applied. The result of ion extraction level in the absorption test displayed that Fe had higher level than in Si, Al from the test for both oxalic acid and citric acid. Based on the regression analysis of the data from the previous studies, the physical characteristics of the earthenware and ion extraction level, further studies will be conducted on the predicting technique on the extraction characteristics of major elements of earthenware samples for the conservation in future.

• Journal of the Korean Ceramic Society
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• v.50 no.3
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• pp.231-237
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• 2013

Thermodynamic modeling of the $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ complex ferrite system has been adopted as a rational approach to establish routes to better synthesis conditions for pure phase $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ complex ferrite. Quantitative analysis of the different reaction equilibria involved in the precipitation of $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ from aqueous solutions has been used to determine the optimum synthesis conditions. The spinel ferrites, such as magnetite and substitutes for magnetite, with the general formula $MFe_2O_4$, where M= $Fe^{2+}$, $Co^{2+}$, and $Ni^{2+}$ are prepared by coprecipitation of $Fe^{3+}$ and $M^{2+}$ ions with a stoichiometry of $M^{2+}/Fe^{3+}$= 0.5. The average particle size of the as synthesized $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$, measured by transmission electron microscopy (TEM), is 14.2 nm, with a standard deviation of 3.5 nm the size when calculated using X-ray diffraction (XRD) is 16 nm. When $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ ferrite is annealed at elevated temperature, larger grains are formed by the necking and mass transport between the $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ ferrite nanoparticles. Thus, the grain sizes of the $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ gradually increase as heat treatment temperature increases. Based on the results of Thermogravimetric Analysis (TGA) and Differential Scanning Calorimeter (DSC) analysis, it is found that the hydroxyl groups on the surface of the as synthesized ferrite nanoparticles finally decompose to $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ crystal with heat treatment. The results of XRD and TEM confirmed the nanoscale dimensions and spinel structure of the samples.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.313-322
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• 2011

On September 2007, numerous slopes at Jeonranam-Do collapsed as a result of rainfall related to Typhoon Nari. Failure occurred at a road cut-slope on the ${\bigcirc}{\bigcirc}$ detour road, damaging transport infrastructure. This study aims to determine the cause of failure based on field investigations, the geotechnical properties of soil, clay mineral composition, and quantitative analysis. The studied cut slope consists of weathered soil that originated from volcanic rocks, and minor faults and a mafic dyke. Surface water tends to seep into the soil because the roadway is not sealed and because of poorly installed drainage. Sieve and XRD analyses indicate that soils in the failure zone are ML and CH, which are prone to swelling due to the presence of clay minerals such as smectite and vermiculite. The slope failed due to the improper construction of drainage facilities, the presence of geological weak zones, and high soil contents of swelling clay.

• Clean Technology
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• v.28 no.2
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• pp.103-109
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• 2022

Nd-Fe-B waste permanent magnet contains about 20~30% rare earth elements and about 60~70% iron elements, and the rare earth and iron components were recovered through sulfuric acid leaching and fractional crystallization. Oxidation roasting was not performed for separation and recover of the rare earth and iron elements. The leaching characteristics were confirmed by using as variables the sulfuric acid concentration and the mineral solution concentration ratio. Sulfuric acid leaching was carried out for 3 hours for each sulfuric acid concentration. The leached solid phase was characterized for its crystalline phase, composition, and quantitative components by XRD and XRF analysis, and the filtrate was analyzed for components by ICP analysis. With sulfuric acid leaching at 3M sulfuric acid concentration, neodymium compounds were formed, the iron content was the least, and the recovery rate was high. After the filtrate remaining after sulfuric acid leaching was subjected to fractional crystallization through evaporation and concentration, the neodymium component was found to be concentrated 7.0 times and the iron component 2.8 times. In this study, the recovery rate of waste permanent magnets through sulfuric acid leaching and a fractional crystallization method without an oxidation and roasting process was confirmed to be about 99.4%.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.489-500
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• 2017

It is not rare that pseudotachylite, dark colored rock with glassy texture, is recognizable in deep core samples drilled up to 900 m from the surface. Pseudotachylite with widths varying few to 20 cm is sharply contacted or interlayered with the host rocks composed of Jurassic granite and Precambrian amphibolite gneiss, showing moderately ductile deformation or slight folding. Pseudotachylite occurring at varying depths in the deep drill core are slightly different in texture and thickness. There is evidence of fault gouge at shallower depths, although brittle deformation is pervasive in most drill cores and pseudotachylite is identified at random depth intervals. Under scanning electron microscope (SEM), it is evident that the surface of pseudotachylite is characterized by a smooth, glassy matrix even at micrometer scale and there is little residual fragments in the glass matrix except microcrystals of quartz with embayed shape. Such textural evidence strongly supports the idea that the pseudotachylite was generated through the friction melting related to strong seismic events. Based on X-ray diffraction (XRD) quantitative analysis, it consists of primary minerals such as quartz, feldspars, biotite, amphibole and secondary minerals including clay minerals, calcite and glassy materials. Such mineralogical features of fractured materials including pseudotachylite indicate that the fractured zone might form at low temperatures possibly below $300^{\circ}C$, which implies that the seismic activity related to the formation of pseudotachylite took place at shallow depths, possibly at most 10 km. Identification and characterization of pseudotachylite provide insight into a better understanding of the paleoseismic activity of deep grounds and fundamental information on the stability of candidate disposal sites for high-level radioactive waste.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.5
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• pp.306-314
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• 2006

Instrumented indentation technique is a new way to evaluate nondestructive such mechanical properties as flow properties, residual stress and fracture toughness by analyzing indentation load-depth curves. This study evaluated quantitatively the flow properties of steels and residual stress of weldments. First, flow properties can be evaluated by defining a representative stress and strain from analysis of deformation behavior beneath the rigid spherical indenter and the parameters obtained from instrumented indentation tests. For estimating residual stress, the deviatoric-stress part of the residual stress affects the indentation load-depth curve, so that by analyzing the difference between the residual-stress-induced indentation curve and residual-stress-free curve, the quantitative residual stress of the target region can be evaluated. The algorithm for flow property evaluation was verified by comparison with uniaxial tensile test and the residual stress evaluation model was compared to mechanical cutting and ED-XRD results.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.23-29
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• 2011

The oxidation slag has been widely used in civil engineering project, whereas the reduced slag from electric furnace has yet to be applied. Consequently in order to find out the recycling method in civil engineering field, the mineral compositions of the reduced slag were analyzed and some tests on water quality were performed to estimate the potential release of toxic compounds. Slag-soil mixtures of 0, 10, 20 and 30%(dry weight) soil were prepared in lysimeter columns and the effluents were collected with the period of one, two and four week options in closed system, respectively. The result from qualitative and quantitative analysis using X-ray Diffraction(XRD) and X-ray Fluorescence(XRF) indicates that the main mineral of the reduced slag is $Ca_2(SiO_4)$, a kind of calcium silicate. Also, the leaching medium analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) showed that main heavy metals such as Al, Fe and Mn are included in the reduced slag due to the effect of steel production process. It can be seen that the leachate does not violate the regulation guide line of waste material of heavy metal. Also the pH levels were increased from pH 6.9 for 0% soil to pH 10 for 30% soil. However the influence on leachate circulation period of one through four weeks was negligible.