• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.235-248
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• 2018

The present work was performed in order to study the effect of competing cation of $Ca^{2+}$ ion on ion exchange of $Cs^+$ on zeolite Y (Si/Al = 1.56). Three single-crystals of fully dehydrated and partially $Cs^+$-exchanged zeolites Y (Si/Al = 1.56) were prepared by the flow method using mixed ion-exchange solutions. The $CsNO_3:Ca(NO_3)_2$ molar ratios of the ion exchange solution were 1 : 1 (crystal 1), 1 : 100 (crystal 2), and 1 : 250 (crystal 3) with a total concentration of 0.05 M. The single-crystals were then vacuum dehydrated at 723 K and $1{\times}10^{-4}Pa$ for 2 days. The structures of the crystals were determined by single-crystal synchrotron X-ray diffraction technique in the cubic space group $Fd{\bar{3}}m$, at 100(1) K. The unit-cell formulas of crystals 1, 2, and 3 were ${\mid}Cs_{21}Ca_{27}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, ${\mid}Cs_2Ca_{36.5}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, and ${\mid}Cs_1Ca_{37}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, respectively. In all three crystals, the $Ca^{2+}$ ions preferred to occupy site I in the D6Rs, with the remainder occupying sites I', II', and II. On the other hand, the significant differences in the fractional distribution of $Cs^+$ ions are observed depending on the intial $Cs^+$ concentrations in given ion exchange solution. In Crystal 1, $Cs^+$ ion are located at sites II', II, III, and III', and in crystal 2, at sites II, IIIa, and IIIb. In crystal 3, $Cs^+$ ions are only located at sites IIIa and IIIb. The degree of $Cs^+$ ion exchange decreased sharply from 28.0 to 2.7 to 1.3 % as the initial $Ca^{2+}$ concentration increases and the $Cs^+$ content decreases.

• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.307-323
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• 2018

The Inseong Au-Ag and base metal deposit, located in Chungchengbuk-do, Korea, consists of series of quartz veins filling fissures. The deposit occurs in Hwanggangri meta-sediment formation, a lime pebble-bearing phyllite, in the Okcheon Supergroup. Abundant ore minerals in the deposit are pyrite, arsenopyrite, sphalerite, chalcopyrite and galena. The gangue minerals are quartz, calcite and chlorite. Hydrothermal alteration such as chlorization, silicitication, sericitization and carbonitization can be observed around the quartz veins. 4 vein stages can be distinguished based on its paragenetic sequence, vein structure, alteration features and ore minerals. Microthermometry of the fluid inclusion assemblages occur in the veins are conducted to reconstruct a hydrothermal P-T evolution. Fluid inclusions in clean and barren quartz vein in stage 1 have Th of $270{\sim}342^{\circ}C$ and salinity of 1.7~6.4 (NaCl eqiv.) wt%. Euhedral quartz crystal in stage 2 have Th of $108{\sim}350^{\circ}C$ and salinity of 0.5~7.5 wt%. Barren milky quartz vein in stage 3 have Th of $174{\sim}380^{\circ}C$ and salinity of 0.8~7.5 wt%. Calcite vein in stage 4 have Th of $103{\sim}265^{\circ}C$ and salinity of 0.7~6.4 wt%. Calculated paleodepth about 0.5~1.5 km (hydrostatic pressure) indicate epithermal ore-forming condition. Shallow depth but relatively high-T hydrothermal fluids possibly create a steep geothermal gradient, sufficient for base metal precipitation in the Inseong deposit.

• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.295-306
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• 2018

Despite the utility of solid-state NMR, NMR studies of iron-bearing silicate glasses remain a challenge because the variations in the peak position and width with increasing iron content reflect both paramagnetic effect and iron-induced structural changes. Therefore, it is essential to elucidate the effect of temperature on the NMR signal for iron-bearing silicate glasses. Here, we report the $^{29}Si$ and $^{27}Al$ MAS NMR spectra for $(Mg_{0.95}Fe_{0.05})SiO_3$ and $Fe_2O_3$-bearing $CaAl_2Si_2O_8$ (anorthite) glasses with varying spinning speed to interpret the NMR spectra for iron-bearing silicate glasses. The increase in the spinning speed results in an increase in the sample temperature. The current NMR results allow us to understand the origins of the changes in NMR signal with increasing iron content and to provide information on the dipolar interaction between nuclear spins. The $^{29}Si$ NMR spectra for $(Mg_{0.95}Fe_{0.05})SiO_3$ glass and $^{27}Al$ NMR spectra for $Fe_2O_3$-bearing $CaAl_2Si_2O_8$ glasses show that the peak shape and position of iron-bearing glasses do not change with increasing spinning speed up to 30 kHz. These results suggest that the NMR signal in the Fe-bearing glasses may stem from the 'survived nuclear spins' beyond the cutoff radius from the Fe, not from the paramagnetic shift. Based on the current results, the observed apparent shifts toward lower frequency of Al peak for $Fe_2O_3$-bearing $CaAl_2Si_2O_8$ glasses with increasing $Fe_2O_3$ at all spinning speed (15 kHz to 30 kHz) indicate the increase in the fraction of ${Q^4}_{Al}$(nSi) with lower n (i.e., 1 or 2) with increasing $Fe_2O_3$ and the spatial proximity between Fe and ${Q^4}_{Al}$(nSi) with higher n (i.e., 3 or 4). The present results show that changes in the NMR signal for iron-bearing silicate glasses reflect the actual iron-induced structural changes. Thus, it is clear that the applications of solid-state NMR for iron-bearing silicate glasses hold strong promise for unraveling the atomic structure of natural silicate glasses.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.473-483
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• 2018

Green-blue coloured supergene minerals are covering host rocks along the gallery wall in the Gukjeon mine, a lead - zinc skarn deposit located in Miryang, Gyeongsangnam-do. These minerals have been described as azurite or malachite, but recent study recognized that the green minerals are devilline and blue minerals are Cu-Zn hydrated sulfates, but exact identification and detailed mineral characteristics are also not well known. In this study, we divide green-blue minerals into five groups (GJG) according to their external features and conducted XRD and SEM analyzes in order to identify mineral name and clarify the mineralogical characteristics. GJG-1, a bright bluish green group, consists of brochantite and quartz and GJG-2, a pale green colour with easily crumbly, of schulenbergite and a small amount of gypsum. Although pale blue GJG-3 and glassy lustrous bluish green GJG-4 have the same mineral assemblages with serpierite and gypsum in spite of different colour and luster, gypsum content may control the physical properties. GJG-5 with a gel phase mixture of pale blue and dark blue mineral is comprised of hydrowoodwardite, glaucocerinite, bechererite, serpierite and gypsum. The six green-blue minerals from the Gukjeon mine could be classified by Cu:Zn ratio, (Si + Al) content, Si:Al ratio, and Ca content. The physico-chemical environment of mineral formation is considered to be controlled by the geochemical factors in the surrounding fluid, and it looks forward that the accurate formation environment will be revealed through additional research. This paper gives greater mineralogical significance in the first report of several hydrated sulfate such as serpierite, glaucocerinite and bechererite in Korea. It has also rarely been reported the occurrence of several Cu-Zn hydrated sulfate in the same deposit in the world.

• Journal of the Mineralogical Society of Korea
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• v.32 no.1
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• pp.41-49
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• 2019

Probing the Na environments in Na silicate and aluminosilicate glasses is essential to the macroscopic properties of melts in the Earth. In particular, exploring the atomic structure of Na silicate and aluminosilicate glasses reveals Na-O distance, which plays an important role in transport properties of melts. Here we report the local environment around Na using $^{23}Na$ magic angle spinning (MAS) NMR. We also obtain $^{23}Na$ isotropic chemical shift (${\delta}_{iso}$) of Na silicate and aluminosilicate glasses with varying composition using Dmfit program. The Q mas 1/2 model simulates the experimental results with three simulated peaks while the CzSimple model simulates with one peak. The ${\delta}_{iso}$ decreases with increasing $SiO_2$ content in Na silicate and aluminosilicate glasses. The ${\delta}_{iso}$ increases with increasing $Na_2O$ content in Na-Ca silicate and Na aluminosilicate glasses when the $SiO_2$ content is fixed. Considering the ${\delta}_{iso}$ of Na aluminosilicate glasses available in the previous studies, together with the current simulation results, we confirm that the ${\delta}_{iso}$ has positive correlation with Al / (Al + Si). Those experimental results were reproduced better using Q mas 1/2 model. The disorder of Na in Na silicate and aluminosilicate glasses can be revealed through the simulation of 1D $^{23}Na$ MAS NMR spectra using Dmfit program in a short time.

• Journal of the Mineralogical Society of Korea
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• v.32 no.1
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• pp.51-61
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• 2019

Clay minerals, a major component of mud volcano (MV) sediments, are expected to provide important information for characterizing mud volcano formation mechanisms, but clay minerals have rarely been studied. The purpose of this study is to investigate the characteristics of 420 MV and surrounding marine sediments. Clay minerals and grain size were analyzed for 8 box cores from 420 MV and Mackenzie Trough. The relative proportions of the four major clay minerals in the Mackenzie Trough are almost constant in the order of illite, chlorite, kaolinite, and smectite, regardless of the distance from the Mackenzie River. However, the grain size tends to become fining as they move away from the Mackenzie River. Comparing the clay mineral characteristics of river (Colville River, Kuparuk River, Sagavanirktok River, Canning River, Mackenzie River) sediments entering the Beaufort Sea in order to determine the origin of the Mackenzie Trough and 420 MV sediments, the sediments of the Mackenzie Trough are characterized mainly by the Mackenzie River with a low ratio of smectite/illite and a high ratio of kaolinite/chlorite. In 420 MV sediments, the contents of clay minerals decrease in the order of illite, kaolinite, chlorite, and smectite, and the grain size with depth is almost constant. The content of smectite and coarse sediments is about two times higher than the reference core. No river with higher kaolinite content than chlorite exists in the Beaufort Sea, and the ratio of smectite/illite to kaolinite/chlorite is different from the reference core such as the ratio of the Mackenzie River. Compared to the reference core, the high contents of coarse sediments and the constant grain size with depth might be attributed to the ejection by MV. The reference core is interpreted as originating from Mackenzie River, and sediment of 420 MV is interpreted as originating from eruption of MV.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.427-437
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• 2020

Manganese nodules, which are evaluated as potential metal resources, have been found in the Arctic Ocean as well as in the abyssal plains of the Pacific and Indian Oceans. Manganese nodules exhibit strong variations in the morphology, internal texture, chemical composition and mineralogy as they grow. The relationship between the texture and chemical elemental composition during the growth process is well documented, but the mineral composition variation during the growth process is not. Because the manganese oxide minerals in nodules are fine-grained and poorly crystalline, quantitative analysis for the mineral composition is challenging for the bulk nodule sample. This study investigated the internal texture and Mn-oxide mineral composition of manganese nodules obtained from the East Siberian Sea. Semi-quantitative analysis was attempted for three main Mn-oxide minerals constituting the manganese nodules (i.e., todorokite, buserite and birnessite) using the peak area ratio of X-ray diffraction analysis graphs. In the East Siberian Sea manganese nodules, birnessite is more abundant than buserite or todorokite, and no correlation is found between the mineral composition and the internal texture. Instead a correlation is found between the relative content of todorokite and the lamellae depth. The todorokite content tends to increase from the surface to the core of the nodules, which can be attributed to a recrystallization process or difference in the growth rate within the nodule. This study shows that semi-quantitative analysis of manganese oxide minerals using the peak area ratio is useful in the mineralogical study of manganese nodules.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.407-417
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• 2020

The capacity of the designated landfill site for asbestos-containing waste is approaching its limit because the amount of asbestos-containing slate is increasing every year. There is a need for a method that can safely and inexpensively treat asbestos-containing slate in large capacity and at the same time recycle it. A cement kiln can be an alternative for heat treatment of asbestos-containing slate. We intend to develop a pilot scale device that can simulate the high temperature environment of a cement kiln using a high temperature plasma reactor in this study. In addition, this reactor can be used to inactivate asbestos in the slate and to synthesize one of the minerals of cement, to confirm the possibility of recycling as a cement raw material. The high-temperature plasma reactor as a pilot scale experimental apparatus was manufactured by downsizing to 1/50 the size of an actual cement kiln. The experimental conditions for the deactivation test of the asbestos-containing slate are the same as the firing time of the cement kiln, increasing the temperature to 200-2,000℃ at 100℃ intervals for 20 minutes. XRD, PLM, and TEM-EDS analyses were used to characterize mineralogical characteristics of the slate before and after treatment. It was confirmed that chrysotile [Mg3Si2O5(OH)4] and calcite (CaCO3) in the slate was transformed into forsterite (Mg2SiO4) and calcium silicate (Ca2SiO4), a cement constituent mineral, at 1,500℃ or higher. Therefore, this study may be suggested the economically and safely inactivating large capacity asbestos-containing slate using a cement kiln and the inactivated slate via heat treatment can be recycled as a cement raw material.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.13-24
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• 2022

The Arctic Ocean is very sensitive to global warming and Arctic Ocean sediments provide a records of terrestrial climate change, analyzing their composition helps clarify global warming. The gravity core sediment ARA07C-St02B was collected at the East Siberian margin during an Arctic expedition in 2016 on the Korean ice-breaking vessel ARAON, and its provenance was estimated through sedimentological, mineralogical and geochemical analysis. The core sediment was divided into four units based on sediment color, sand content and ice-rafted debris content. Units 1 and 3 had higher sand and ice-rafted debris contents than units 2 and 4, and contained a brown layer, whereas units 2 and 4 were mainly composed of a gray layer. Correlation analysis using the adjacent core sediment ARA03B-27 suggested that the sediment units were deposited during marine isotope stage 1 to 4. The bulk mineral, clay mineral, and geochemical compositions of units including a brown layer differed from units including a gray layer. Bulk and clay mineral compositions indicated that coarse and fine sediments had a different origin. Coarse sediments might have been deposited mostly by the East Siberian Coastal Current from the Laptev Sea and the East Siberian Sea or by the Beaufort Gyre from the Chukchi Sea, whereas fine sediments might have been transpoted mostly by currents from the East Siberian Sea, the Chukchi Sea and the Beaufort Sea. Some of the coarse sediments in unit 1 and fine sediments in unit 3 might have been deposited by iceberg ice, sea ice or current from the Beaufort Sea and the Canada Archipelago. Investigating the geochemical composition of the potential origins will elucidate the origin and transportation of the study area's core sediments.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.2
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• pp.95-106
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• 2021

The SO₄ in the jarosite structure can be substituted by other oxyanions, and therefore, the transition of jarosite to goethite plays a very important role in controlling the behavior of oxyanions. In this study, the phase change according to the species of the oxyanion in jarosite and the related behavior of the oxyanion was studied by mineralogical and geochemical methods when jarosite, which is coprecipitated with various oxynions, undergoes a phase change by a reductive dissolution. Jarosite substituted by five oxyanions by 5 mol% was used in this study. The mineral phase change induced by reductive dissolution using ammonium oxalate was investigated, and the order of phase transition rate of jarosite to goethite was MoO₄-jarosite ≥ SeO₄-jarosite ≥ CrO₄-jarosite > pure jarosite > SeO₃-jarosite > AsO₄-jarosite, showing that the transition rates vary depending on the substituted oxyanion. The resultant concentration of the leached Fe was slightly different depending on the type of oxyanion and time but did not show a noticeable difference. The concentration of each oxyanion leached according to the change of the mineral phase showed that the order of concentration of oxyanions was Mo > Se(SeO₃) > As > Se(SeO₄) > Cr in general, and showed a slight increase with time. This trend was related to the species of oxyanions rather than mineral phase change. The results of this study showed that the phase transition of jarosite to goethite was affected by the species of oxyanions, but this tendency did not affect the concentrations leached oxyanions.