• 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.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.709-716
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• 2021

In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe₂O₃) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO₃) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m²·g^-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g^-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L^-1, and the fluoride removal rate was about 50%.

• Economic and Environmental Geology
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• v.8 no.3
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• pp.117-124
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• 1975

Wet chemical analysis (for $MnO_2$, MnO, and $H_2O$(+)) and electron microprobe analysis (for $Fe_2O_3$ and PbO) give $MnO_2$ 74.91, MnO 11.33, $Fe_2O_3$ (total Fe) 4.19, PbO 0.03, $H_2O$ (+) 9.46, sum 99.92%. 'Available oxygen determined by oxalate titration method is allotted to $MnO_2$ from total Mn, and the remaining Mn is calculated as MnO. Traces of Ba, Ca, Mg, K, Cu, Zn, and Al were found. Li and Na were not found. The existence of (OH) is verified from the infrared absorption spectra. The analysis corresponds to the formula $Mn^{4+}{_{4.85}}(Mn^{2+}{_{0.90}}Fe^{3+}{_{0.30}})_{1.20}O_{8.09}(OH)_{5.91}$, on the basis of O=14, 'or ideally $Mn^{4+}{_{5-x}}(Mn^{2+},Fe^{3+})_{1+x}O_{8}(OH)_{6}$ ($x{\approx}0.2$). X-ray single crystal study could not be made because of the distortion of single crystals. But the x-ray powder pattern is satisfactorily indexed by an orthorhombic cell with a 9.324, b 14.05, c $7.956{\AA}$., Z=4. The indexed powder diffraction lines are 9.34(s) (100), 7.09(s) (020), 4.62(m) (200, 121), 4.17(m) (130), 3.547(s) (112), 3.212(vw) (041), 3.101(s) (300), 2.597(w) (013), 2.469(m) (331), 2.214(vw)(420), 2.098(vw) (260), 2.014 (vw) (402), 1.863(w) (500), 1.664(w) (314), 1.554(vw) (600), 1.525(m) (601), 1.405(m) (0.10.0). DTA curve shows the endothermic peaks at $250-370^{\circ}C$ and $955^{\circ}C$. The former is due to the dehydration: and oxidation forming$(Mn,\;Fe)_2O_3$(cubic, a $9.417{\AA}$), and the latter is interpreted as the formation of a hausmannite-type oxide (tetragonal, a 5.76, c $9.51{\AA}$) from $(Mn,\;Fe)_2O_3$. Infrared absorption spectral curve shows Mn-O stretching vibrations at $515cm^{-1}$ and $545cm^{-1}$, O-H bending vibration at $1025cm^{-1}$ and O-H stretching vibration at $3225cm^{-1}$. Opaque. Reflectance 13-15%. Bireflectance distinct in air and strong in oil. Reflection pleochroism changes from whitish to light grey. Between crossed nicols, color changes from yellowish brown with bluish tint to grey in air and yellowish brown to grey through bluish brown in oil. No internal reflections. Etching reactions: HCl(conc.) and $H_2SO_4+H_2O_2$-grey tarnish; $SnCl_2$(sat.)-dark color; $HNO_3$(conc.)-grey color; $H_2O_2$-tarnish with effervescence. It is black in color. Luster dull. Cleavage one direction perfect. Streak brownish black to dark brown. H. (Mohs) 2-3, very fragile. Specific gravity 3.59(obs.), 3.57(calc.). It occurs as radiating groups of flakes, flower-like aggregates, colloform bands, dendritic or arborescent masses composed of fine grains in the cementation zone of the supergene manganese oxide deposits of the Janggun mine, Bonghwa-gun, southeastern Korea. Associated minerals are calcite, nsutite, todorokite, and some undetermined manganese dioxide minerals. The name is for the mine, the first locality. The mineral and name were approved before publication by the Commission on New Minerals and Mineral Names, I.M.A.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.83-100
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• 2022

The Zhenzigou Pb-Zn deposit, which is one of the largest Pb-Zn deposit in the northeast of China, is located at the Qingchengzi mineral field in Jiao Liao Ji belt. The geology of this deposit consists of Archean granulite, Paleoproterozoinc migmatitic granite, Paleo-Mesoproterozoic sodic granite, Paleoproterozoic Liaohe group, Mesozoic diorite and Mesozoic monzoritic granite. The Zhenzigou deposit which is a strata bound SEDEX or SEDEX type deposit occurs as layer ore and vein ore in Langzishan formation and Dashiqiao formation of the Paleoproterozoic Liaohe group. White mica from this deposit are occured only in layer ore and are classified four type (Type I : weak alteration (clastic dolomitic marble), Type II : strong alteration (dolomitic clastic rock), Type III : layer ore (dolomitic clastic rock), Type IV : layer ore (clastic dolomitic marble)). Type I white mica in weak alteration zone is associated with dolomite that is formed by dolomitization of hydrothermal metasomatism. Type II white mica in strong alteration zone is associated with dolomite, ankerite, quartz and alteration of K-feldspar by hydrothermal metasomatism. Type III white mica in layer ore is associated with dolomite, ankerite, calcite, quartz and alteration of K-feldspar by hydrothermal metasomatism. And type IV white mica in layer ore is associated with dolomite, quartz and alteration of K-feldspar by hydrothermal metasomatism. The structural formulars of white micas are determined to be (K_0.92-0.80Na_0.01-0.00Ca_0.02-0.01Ba_0.00Sr_0.01-0.00)_0.95-0.83(Al_1.72-1.57Mg_0.33-0.20Fe_0.01-0.00Mn_0.00Ti_0.02-0.00Cr_0.01-0.00V_0.00Sb_0.02-0.00Ni_0.00Co_0.02-0.00)_1.99-1.90(Si_3.40-3.29Al_0.71-0.60)_4.00O₁₀(OH_2.00-1.83F_0.17-0.00)_2.00, (K_1.03-0.84Na_0.03-0.00Ca_0.08-0.00Ba_0.00Sr_0.01-0.00)_1.08-0.85(Al_1.85-1.65Mg_0.20-0.06Fe_0.10-0.03Mn_0.00Ti_0.05-0.00Cr_0.03-0.00V_0.01-0.00Sb_0.02-0.00Ni_0.00Co_0.03-0.00)_1.99-1.93(Si_3.28-2.99Al_1.01-0.72)_4.00O₁₀(OH_1.96-1.90F_0.10-0.04)_2.00, (K_1.06-0.90Na_0.01-0.00Ca_0.01-0.00Ba_0.00Sr_0.02-0.01)_1.10-0.93(Al_1.93-1.64Mg_0.19-0.00Fe_0.12-0.01Mn_0.00Ti_0.01-0.00Cr_0.01-0.00V_0.00Sb_0.00Ni_0.00Co_0.05-0.01)_2.01-1.94(Si_3.32-2.96Al_1.04-0.68)_4.00O₁₀(OH_2.00-1.91F_0.09-0.00)_2.00 and (K_0.91-0.83Na_0.02-0.01Ca_0.02-0.00Ba_0.01-0.00Sr_0.00)_0.93-0.83(Al_1.84-1.67Mg_0.15-0.08Fe_0.07-0.02Mn_0.00Ti_0.04-0.00Cr_0.06-0.00V_0.02-0.00Sb_0.02-0.01Ni_0.00Co_0.00)_2.00-1.92(Si_3.27-3.16Al_0.84-0.73)_4.00O₁₀(OH_1.97-1.88F_0.12-0.03)_2.00, respectively. It indicated that white mica of from the Zhenzigou deposit has less K, Na and Ca, and more Si than theoretical dioctahedral mica. Compositional variations in white mica from the Zhenzigou deposit are caused by phengitic or Tschermark substitution [(Al³⁺)^VI+(Al³⁺)^IV <-> (Fe²⁺ or Mg²⁺)^VI+(Si⁴⁺)^IV] substitution. It means that the Fe in white mica exists as Fe²⁺ and Fe³⁺, but mainly as Fe²⁺. Therefore, white mica from layer ore of the Zhenzigou deposit was formed in the process of remelting and re-precipitation of pre-existed minerals by hydrothermal metasomatism origined metamorphism (greenschist facies) associated with Paleoproterozoic intrusion. And compositional variations in white mica from the Zhenzigou deposit are caused by phengitic or Tschermark substitution [(Al³⁺)^VI+(Al³⁺)^IV <-> (Fe²⁺ or Mg²⁺)^VI+(Si⁴⁺)^IV] substitution during hydrothermal metasomatism depending on wallrock type, alteration degree and ore/gangue mineral occurrence frequency.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.379-393
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• 2002

Within the Boseong-Jangheung area of Korea, five hydrothermal gold (-silver) quartz vein deposits occur. They have the characteristic features as follows: the relatively gold-rich nature of e1ectrurns; the absence of Ag-Sb( -As) sulfosalt mineral; the massive and simple mineralogy of veins. They suggest that gold mineralization in this area is correlated with late Jurassic to Early Cretaceous, mesothermal-type gold deposits in Korea. Fluid inclusion data show that fluid inclusions in stage I quartz of the mine area homogenize over a wide temperature range of 200$^{\circ}$ to 460$^{\circ}$C with salinities of 0.0 to 13.8 equiv. wt. % NaCI. The homogenization temperature of fluid inclusions in stage II calcite of the mine area ranges from 150$^{\circ}$ to 254$^{\circ}$C with salinities of 1.2 to 7.9 equiv. wt. % NaCI. This indicates a cooling of the hydrothermal fluid with time towards the waning of hydrothermal activity. Evidence of fluid boiling including CO2 effervescence indicates that pressures during entrapment of auriferous fluids in this area range up to 770 bars. Calculated sulfur isotope composition of auriferous fluids in this mine area (${\delta}^34S$_{{\Sigma}S}$$\textperthousand$) indicates an igneous source of sulfur in auriferous hydrothermal fluids. Within the Sobaegsan Massif, two representative mesothermal-type gold mine areas (Youngdong and Boseong-Jangheung areas) occur. The ${\delta}^34S values of sulfide minerals from Youngdong area range from -6.6 to 2.3$\textperthousand$ (average=-1.4$\textperthousand$, N=66), and those from BoseongJangheung area range from -0.7 to 3.6$\textperthousand$ (average=1.6$\textperthousand$, N=39). These i)34S values of both areas are comparatively lower than those of most Korean metallic ore deposits (3 to 7TEX>$\textperthousand$). And, within the Sobaegsan Massif, the ${\delta}^34S values of Youngdong area are lower than those of Boseong-Jangheung area. It is inferred that the difference of ${\delta}^34S values within the Sobaegsan Massif can be caused by either of the following mechanisms: (1) the presence of at least two distinct reservoirs (both igneous, with ${\delta}^34S values of < -6 $\textperthousand$ and 2$\pm$2 %0) for Jurassic mesothermal-type gold deposits in both areas; (2) different degrees of the mixing (assimilation) of 32S-enriched sulfur (possibly sulfur in Precambrian pelitic basement rocks) during the generation and/or subsequent ascent of magma; and/or (3) different degrees of the oxidation of an H2S-rich, magmatically derived sulfur source ${\delta}^34S = 2$\pm$2$\textperthousand$) during the ascent to mineralization sites. According to the observed differences in ore mineralogy (especially, iron-bearing ore minerals) and fluid inclusions of quartz from the mesothermal-type deposits in both areas, we conclude that pyrrhotite-rich, mesothermal-type deposits in the Youngdong area formed from higher temperatures and more reducing fluids than did pyrite(-arsenopyrite)-rich mesothermal-type deposits in the Boseong-Jangheung area. Therefore, we prefer the third mechanism than others because the ${\delta}^34S values of the Precambrian gneisses and Paleozoic sedimentary rocks occurring in both areas were not known to the present. In future, in order to elucidate the provenance of ore sulfur more systematically, we need to determine ${\delta}^34S values of the Precambrian metamorphic rocks and Paleozoic sedimentary rocks consisting the basement of the Korean Peninsula including the Sobaegsan Massif.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.211-220
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• 2002

The Xiaoxinancha Cu-Au deposit in the Jilin province, located in NNE 800 km of Beijing, is hosted by diorite. The ore mineralization of Xiaoxinancha Cu-Au deposit show a stockwork occurrence that is concentrated on the potassic and phyllic alteration zones. The Xiaoxinancha Cu-Au deposit in the south is being mined with its reserves grading 0.8% Cu, 3.64 g/t Au and 16.8 g/t Ag and in the north, grading 0.63% Cu, 3.80 g/t Au and 6.8 glt Ag. The alteration assemblage occurs as a supergene blanket over deposit. Hydrothermal alteration at the Xiaoxinancha Cu-Au deposit is centered about the stock and was extensively related to the emplacement of the stock. Early hydrothermal alteration was dominantly potassic and followed by propylitic alteration. Chalcocite, often associated with hematite, account for the ore-grade copper, while chalcopyrite, bornite, quartz, epidote, chlorite and calcite constitute the typical gangue assemblage. Other minor opaque phases include pyrite, marcasite, native gold, electrum, hessite, hedleyite, volynskite, galenobismutite, covellite and goethite. Fluid inclusion data indicate that the formation of this porphyry copper deposit is thought to be a result of cooling followed by mixing with dilute and cooler meteoric water with time. In stage II vein, early boiling occurred at 497$^{\circ}$C was succeeded by the occurrence of halite-bearing type III fluid inclusion with homogenization temperature as much as 100$^{\circ}$C lower. The salinities of type 1II fluid inclusion in stage II vein are 54.3 to 66.9 wt.% NaCI + KCI equiv. at 383$^{\circ}$ to 495$^{\circ}$C, indicating the formation depth less than 1 km. Type I cupriferous fluids in stage III vein have the homogenization temperatures and salinity of 168$^{\circ}$ to 365$^{\circ}$C and 1.1 to 9.0 wt.% NaCI equiv. These fluid inclusions in stage III veins were trapped in quartz veins containing highly fractured breccia, indicating the predominance of boiling evidence. This corresponds to hydrostatic pressure of 50 to 80 bars. The $\delta$$^{34}S$ value of sulfide minerals increase slightly with paragenetic time and yield calculated $\delta$$^{34}S_{H2S}$ values of 0.8 to 3.7$\textperthousand$. There is no mineralogical evidence that fugacity of oxygen decreased, and it is thought that the oxygen fugacity of the mineralizing fluids have been buffered through reaction with magnetite. We interpreted the range of the calculated $\delta$$^{34}S_{H2S}$ values for sulfides to represent the incorporation of sulfur from two sources into the Xiaoxinancha Cu-Au hydrothermal fluids: (1) an isotopically light source with a $\delta$$^{34}S$ value of I to 2$\textperthousand$, probably a Mesozoic granitoid related to the ore mineralization. We can infer from the fact that diorite as the host rock in the Xiaoxinancha Cu-Au deposit area intruded plagiogranite; (2) an isotopically heavier source with a $\delta$$^{34}S$ value of > 4.0$\textperthousand$, probably the local porphyry.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.469-484
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• 2022

The Janggun Pb-Zn deposit has been known one of the four largest deposits (Yeonhwa, Shinyemi, Uljin) in South Korea. The geology of this deposit consists of Precambrian Weonnam formation, Yulri group, Paleozoic Jangsan formation, Dueumri formation, Janggum limestone formation, Dongsugok formation, Jaesan formation and Mesozoic Dongwhachi formation and Chungyang granite. This Pb-Zn deposit is hydrothermal replacement deposit in Paleozoic Janggum limestone formation. The wallrock alteration that is remarkably recognized with Pb-Zn mineralization at this deposit consists of mainly rhodochrositization and dolomitization with minor of pyritization, sericitization and chloritization. Wallrock alteration is divided into the five zones (Pb-Zn orebody -> rhodochrosite zone -> dolomite zone -> dolomitic limestone zone -> limestone or dolomitic marble) from orebody to wallrock. The white mica from wallrock alteration occurs as fine or medium aggregate associated with Ca-dolomite, Ferroan ankerite, sideroplesite, rutile, apatite, arsenopyrite, pyrite, sphalerite, galena, quartz, chlorite and calcite. The structural formular of white mica from wallrock alteration is (K_0.77-0.62Na_0.03-0.00Ca_0.03-0.00Ba_0.00Sr_0.01)_0.82-0.64(Al_1.72-1.48Mg_0.48-0.20Fe_0.04-0.01Mn_0.03-0.00Ti_0.01-0.00Cr_{0.00As0.01-0.00}Co_0.03-0.00Zn_0.03-0.00Pb_0.05-0.00Ni_0.01-0.00)_2.07-1.92 (Si_3.43-3.33Al_0.67-0.57)_4.00O₁₀(OH_1.94-1.80F_0.20-0.06)_2.00. It indicated that white mica from wallrock alteration has less K, Na and Ca, and more Si than theoretical dioctahedral micas. The white micas from wallrock alteration of Janggun Pb-Zn deposit, Yeonhwa 1 Pb-Zn deposit and Baekjeon Au-Ag deposit, and limestone of Gumoonso area correspond to muscovite and phengite and white mica from wallrock alteration of Dunjeon Au-Ag deposit corresponds to muscovite. Compositional variations in white mica from wallrock alteration of these deposits and limeston of Gumoonso area are caused by mainly phengitic or Tschermark substitution mechanism (Janggun Pb-Zn deposit), mainly phengitic or Tschermark substitution and partly illitic substitution mechanism (Yeonhwa 1 Pb-Zn deposit, Dunjeon Au-Ag deposit and Baekjeon Au-Ag deposit), and mainly phengitic or Tschermark substitution and partly illitic substitution or Na⁺ <-> K⁺ substitution mechanism (Gumoonso area).