• Resources Recycling
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• v.15 no.4 s.72
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• pp.27-35
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• 2006

In order to use alunite as an activator of blast furnace slag, we studied the hydration characteristics of the calcined alunite and the ground blast furnace slag. The alunite calcined at $650{\cire}C$ consists of KAl($KAl(SO_{4})_{2}$ and $Al_{2}O_{3}$. The calcined alunite reacts with $Ca(OH)_{2}$ and gypsum to form etrringite ($3CaO{\cdot}Al_{2}O_{3}{\cdot}3CaSO_{4}{\cdot}32H_{2}O$) as fellows:$2KAl(SO_{4})_{2}+2Al_{2}O_{3}+13Ca(OH)_{2}+5CaSO_{4}{\cdot}2H_{2}O+73H_{2}O{\rightarrow}3(3CaO{\cdot}Al_{2}O_{3}{\cdot}3CaSO_{4}{\cdot}32H_{2}O)+2KOH$. The $SO_{4}^{2-}$ ions from calcined alunite reacts with CaO in blast furnace slag to from gypsum, which reacts with CaO and $Al_{2}O_{3}$ to from ettringite in calcined alunite-blast furnace slag system. Therefore blast furnace slag can be activated by calcined alunite.

• Journal of the Mineralogical Society of Korea
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• v.2 no.2
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• pp.81-89
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• 1989

Alunite occurs as massive, cavity-filling and veinlets in the Cretaceous Hwangsan Formation in the Sungsan mine, Korea. It is a hydrothermal alteration product of rhyolitic tuffs, and associated with dickite, quartz and barite. The average chemical formula of alunite in the mine is $(K_{0.93}Na_{0.07})_{1.00}Al_{3.00}(SO_4)_{2.00}(OH)_6$. Atomic percentage of Na substituting for K in A site of the alunite structure varies from 5.9 to 9.2. Unit-cell volume and c dimension decrease with increasing Na atomic percentage. On the basis of thermal and high temperature XRD analyses, the decomposition of alunite into $KAl(SO_4)_2$ and $NaAl(SO_4)_2$ concomitant with the liberation of structural water (12.86%) occurs at about $550^{\circ}C$. The reconstruction of $KAl(SO_4)_2$ and $NaAl(SO_4)_2$ to $Al_2(SO_4)_3$, arcanite and thenardite, and the crystallization of ${\gamma}-Al_2O_3$ take place at about $720^{\circ}C$. The destruction of $Al_2(SO_4)_3$ structure takes place at about $760^{\circ}C$ removing 3/4 of total $SO_3$ (27.32%).

• Journal of the Mineralogical Society of Korea
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• v.5 no.1
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• pp.42-47
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• 1992

The oscillatory zoning pattern in alunite from the Sungsan mine, Korea was studied by the back-scattered electorn(BSE) imaging and electron microprobe analysis. This zoning is not visible under the polarizing microscope, but is spectacularly illustrated in BSE image. Electron microprobe analysis reveals that the zoning is substantially due to the variation in the content of Na substituting for K in the A site of the alunite structure. With increasing brightess in BSE image, conternt of K increases but that of Na decreases. Delicate fine-scale zoning and sharp boundaries between adjacent zones suggest that the zoning would be ascribed to the variation in the composition of hydrothermal fluid around the growing alunite crystals. The effective factors for such a variation would be 1) the fluctuation in the composition of entering fluid. and/or 2) the rapid change in composition of fluid due to the rapid precipitation of more stable. Na-poor alunite.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.37-47
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• 2004

Sulfates such as alunite and schwertmannite formed under oxidation condition play a important role in geochemical processes taken place at waste dumps and a creek from Dalseong mine, Daegu. Water chemistry shows pH decreases from upstream toward downstream creek, mainly due to formation of schwertmannite that is the most abundant phase along the creek. The removal of Al from the creek is preferentially attributed to formation of Al-bearing minerals and Al-sulphates. Among them, alunite is the most important Al-sink phase that occurs at higher pH than $pK_1$, Al hydrolysis constant. With high saturation index, alunite formed at the creek has a spherical form, commonly associated with schwertmannite. Secondary minerals formed on the surface of altered or weathered surfaces of heavy metals from the wasted dump that underwent severe oxidation, where alunite has characteristic habits which are spheric, radiating, and botrytis-like aggregates. Natroalunite occurs in association with alunite, or as mixtures of both of them. Because the pH decreases with distance due to formation of schwertmannite, although total contents of dissolved ions slowly lessen at least in the AMD, it is expected that the minerals precipitated at the creek can be exposed to subsequent dissolution, which may induce possible environmental problems.

• Economic and Environmental Geology
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• v.28 no.6
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• pp.571-577
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• 1995

Several acid-sulfate clay deposits associated with silicic magmas occur in the Haenam area of the southwestern part of Korea. Geology of the studied area consists of tuffs, granitic rocks, quartz porphyry, rhyolite, andesite and sedimentary rocks. The granitic rocks and quartz porphyry intruded tuffs and sedimentary rocks. The rhyolite and tuffs around the mines have undergone hydrothermally weak or strong alteration. Gold contents with major and trace elements have been determined for a total of sixty-seven specimens of fresh igneous rocks, wall rocks and minerals such as dickite and alunite by graphite furnace atomic absorption spectrometer and inductively coupled plasma. Gold is enriched in the alunite vein and the silicified zone, but is depleted in dickites and hydrothermally altered rocks with dickite of the Seongsan deposit. Gold is especially concentrated near the faults or conjunction area of two faults. High content of gold is shown in the mineral assemblages of alunitequartz- pyrite in the alunite vein and silicic zone of the Seongsan deposit compared with that of minerals and rocks from another deposits distributed in the studied area. Gold content in tuffs and dickites with pyrite is generally low. Gold content in silicified tuff tends to show positive correlations with content of As, Hg and Sb. Variation trends of Cd, Hg and Sb are similar to those of gold content. From the result of gold content variations, gold may be transported and concentrated by mineralizing solutions ascending along the cracks like fault. Therefore, it is important to survey alunite vein and silicified zone at the conjunction of faults, and to analyze pathfinder elements such as As, Hg and Sb for geological and geochemical exploration of gold in the studied deposits.

• Resources Recycling
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• v.7 no.5
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• pp.33-40
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• 1998

The formation reation of anhydrite (CaSO$_{4}$) depends upon the amount and velocity of the SO$_{3}$(g) and CaO(s) produced in the process of the thermal decomposition of alunite[K$_{2}SO_{4}{\cdot}Al_{2}(SO_{4})_{3}{\cdot}4Al(OH)_{3}$] and limestone (CaCO$_{3}$) respectively. Therefore, this study had carried out to investigate the amount and velocity of SO$_{3}$(g) produced by roasting alunite and pyrolytic materials. In air, alunite was transfouned into KAl(SO$_{4})_{2}$ and Al$_{2}O_{3}$ by dehydration at 500~580$^{\circ}C$. The dehydration velocity of alunite was found to be kt=(1-(1-${\alpha})^{1/3})^{2}$, the activation energy, 73.01 kcal/mol. SO$_{3}$(g) ware slowly produced by the thermal decomposition of KAl(SO$_{2})_{2}$, at 580~700$^{\circ}C$, rapidly, at 700~780$^{\circ}C$, The pyrolysis velocity of KAl(SO$_{4})_{2}$ was found to be kt=1-(1-${\alpha})^{1/1}$; activation energy, 66.84kcal/mol. The SiO$_{2}$ and kaolinite in alunite ore scarcely affected the temperature and velocity in which SO$_{3}$(g) were produced.

• Economic and Environmental Geology
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• v.50 no.1
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• pp.15-26
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• 2017

Advanced argillic, argillic, and phyllic zones are the most important alteration patterns to predict the hidden ore body during exploration of hydrothermal deposits. We examined the quantitative relationship between the spectral absorption characteristics and the mineral content of the synthetic mixtures such as alunite-kaolinite and illite-kaolinite using short wavelength infrared (SWIR) spectroscopy. In the alunite-kaolinite mixtures, the spectral absorption characteristics of the alunite was highly correlated with the Hull quotient reflectance(0.99) and the kaolinite had the highest correlation with the Gaussian peak(0.92). Illite-kaolinite mixtures are essential for Gaussian deconvolution because of the overlap of absorption region. Illite and kaolinite mixtures indicate the high correlation of 0.93 and 0.98, respectively. The error ranges in the alunite-kaolinite(8%) and illite-kaolinite mixtures(5%) derived from SWIR were smaller than the ones(29% and 26%) obtained from X-ray diffraction(Rietveld) analysis. These results show that SWIR spectroscopic analysis is more reliable than XRD Rietveld analysis in terms of quantification of allowed minerals.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.123.1-123
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• 2000

• Economic and Environmental Geology
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• v.25 no.4
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• pp.397-416
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• 1992

In the present study, three clay deposits, named the Seongsan, Ogmaesan and Haenam deposits, were investigated. The altered zones are recognized in the hydrothermally altered rocks of the clay deposits from the center of the alteration to the margin: Kaolin, Kaolin-Quartz, Quartz, Sericite and Chlorite zones in the Seongsan deposits; Quartz zone, Alunite zone, Kaolin zone, Sericite zone and Chlorite zone in the Ogmaesan deposits; Quartz zone, Pyrophyllite zone, Sericite zone and Chlorite zone in the Haenam deposits. These zones can be grouped into two types of alteration: Acidic alteration such as Pyrophyllite zone, Alunite zone, Quartz zone, Kaolin zone, Kaolin-Quartz zone and a part of Sericite zone; Propylitic alteration such as Chlorite zone and a part of Sericite zone. All clay deposits belong to high-sulfidation (acid-sulfate) system. The rocks of the acidic alterations are composed of pyrophyllite, alunite, kaolin minerals, sericite, quartz and pyrite. On the basis of bulk chemical compositions, it was found that some components such as $SiO_2$, $TiO_2$, $Fe_2O_3$, FeO, MgO, CaO, $K_2O$ and $Na_2O$ were mobilized considerably from the original rocks. The mobility of these major elements is related to, and controls, mineral assemblages in each altered zone. Polytypes of sericite are determined as $2M_1$ and 1M by X-ray diffraction method. The amount of $2M_1$ is nearly equal to that of 1M in the Seongsan deposits whereas $2M_1$ is less and higher than that of 1M in the Ogmaesan and the Haenam deposits. These facts indicate that formation temperature of sericite is relatively high in the Haenam deposits, moderate in the Seongsan deposits, and low in the Ogmaesan deposits. The ratios of Na/(K+Na) for alunite in the Ogmaesan deposits determined by electron microprobe analyzer (EPMA) are higher than those in the Seongsan deposits. Thus, the alunite of the Ogmaesan deposits must have been formed from the solutions with relatively high aqueous Na/(K+Na) ratios and low pH at a high temperature rather than that of the Seongsan deposits. From all data, it is clarified that alunite is hypogene in origin, and has been formed by oxidation of hydrogen sulfide in the steam-heated environment, and that alunite has been produced by the spectacular solfataric alteration observed at the surface of some present-day hydrothermal systems.

• The Science & Technology
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• v.29 no.8 s.327
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• pp.80-81
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• 1996

칼륨, 알루미늄을 함유하는 황산염 광물인 명반석을 가열하고 다시 냉각시킬 때 나타나는 변화를 연구하여 다른 광물질과 달리 가역반응을 일으키는 특성을 규명한 경상대 조현구박사. 경남 통영시가 고향인 조교사는 과학기술정책 결정 때는 많은 사람들의 의견을 수렴할 수 있는 제도적 장치가 마련되어야 한다고 강조한다.