• Journal of the Korean Professional Engineers Association
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• v.3 no.10
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• pp.3-6
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• 1970

The scheelite occurred in Sang Dong mine are disseminated with a fine grain, and shelved pale blue or white color under the fluorescence. But among them, We can often observe the yellow fluorescent color mineral grains, which were called the powellite from the past time without any detail mineral study. I studied the characteristics of Sang-Dong scheelite and the so called powellite. In the result, the so called powellite is proved to be the molybdenum bearing scheelite in the view of specific gravity, index of refraction, chemical composition, other microscopic properties, and dressing. Such a scheelite is contained usually Zor 3% Mo, and oftenly 4 or 6% Mo, and fluorescent colors are pale yellow, leman yellow and chrome yellow.

• Economic and Environmental Geology
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• v.12 no.4
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• pp.197-206
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• 1979

Sangdong scheelite deposit is confirmed to have been formed by replacement of limestone beds by metasomatic mineralization. Mineralogical zonal distribution and filling temperatures are related with order of its formation and tungsten mineralization. The first formed garnet-pyroxene zone, left in the margins of the ore body, shows the highest filling temperature of fluid inclusions in pyroxene, averaging $420^{\circ}C$. The central part of the ore body, mainly composed of quartz-mica-scheelite, shows higher fi11ing temperatures of fluid inclusions in quartz, than hornblende-quartz-scheelite zone surrounding the quartz-mica-scheelite zone, averaging $240^{\circ}C$. The distribution of highter filling temperatures above average temperature is applicable to the richest part of scheelite distribution. Generally scheelite shows higher filling temperature by about 20 to $100^{\circ}C$ than quartz in a given sample. The crystallization temperature of the main phase of scheelite deposition is $311^{\circ}C$ at the pressure of 230 to 500 bars at Sangdong area. Gas-rich inclusions in the pyroxene are homogenized into either gas or liquid phase or into both phases in a given crystal of the pyroxene, which suggests boiling at the formation of skarn.

• Economic and Environmental Geology
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• v.13 no.2
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• pp.117-127
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• 1980

Molybdenum as by-products of Sangdong tungsten mine occurrs in the form of molybdenite in quartz vein. The molybdenum contents of scheelite in Sangdong ore bodies ranges from trace to 8%, therefore the scheelites show variable fluorescence colores under ultra-violet lamp (short wave). The fluorescence color are in order high content of molybdenum, yellow, white and blue. The yellow fluorescing scheelite is dominant in upper ore vein, otherwise the blue fluorescent variety is dominant in lower ore vein. The fluorescence color of scheelite in the main ore vein show zonal distribution becoming progressively more blue outerwards, contrary more yellow innerwards, and even in single scheelite crystal, simillar zonal pattern is observed, too. Molybdenite occurrs as flakes or elongated blades at the margins of the quartz vein only molybdenite bearing quartz veins but also other sulfides mineral bearing quartz veins have mainly blue flourescing scheelites. We suggest that the molybdenum contents of the early stage ore solution are progressively decreased by a subsequent crystallization of the yellow fluorescing scheelites.

• Economic and Environmental Geology
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• v.11 no.4
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• pp.143-167
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• 1978

The Sangdong tungsten (mostly scheelite) mine is located on the southern limb of a major syncline, the Hambaeg syncline, in a thick sequence of lower Paleozoic sedimentary rocks in the mideastern part of south Korea. Productive scheelite mineralization in Sangdong area is confined to one single formation, the Myobong Slate. Four major ore beds, which have an lateral extension over than 1 km and were not heavily subjected to spatial disturbance, are developed in the Myobong Formation. The original materials of the ore-comprising horizones were probably of either calcareous or silceous sediments. The four ore beds, especially in the case of Main ore bed, display both lateral and vertical zoning. Association quartz-mica-scheelite is predominant in the central, while association hornblende-quartz-diopside-scheelite, diopside-garnet and wollastonite-garnet are developed in this order towards the periphery of the ore beds. Petrologically, two phases of thermometamorphism are recognized. The first phase is represented by the association wollastonite-garnet and diopside-garnet, while the second phase by the association hornblende-quartz-diopside-scheelite and quartz-mica-scheelite. The associations of the second phase do constitute prodctive ore. The high background value of tungsten in the area surrounding the Sangdong mine reveals that the area can be considered a geochemical zone enriched in tungsten. Studies on the trace element patterns were carried out to draw useful criteria for the purpose of future geochemical exploration in the area. The increasing trend of the ratio Rb $({\times}1000)/K_2O$ of the Myobong Slate towards the known mineralization area proved to be indicative for the presence of tungsten mineralization.

• Applied Chemistry for Engineering
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• v.4 no.3
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• pp.591-600
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• 1993

Chlorination of tungsten from scheelite ore in a fluidized bed reactor has been investigated to develope tungsten extractive metallurgical process by the chlorination. All of the results in this experiment showed tungsten component could be sucessively chlorinated in a fluidized bed reactor. The proper conditions are as follows; reaction temperature $900^{\circ}C$, reaction time : 20min, $Cl_2$ gas velocity : 3.2cm/sec and petroleum coke-to-scheelite ore weight ratio : 0.2. Also the mean diameters of scheelite and petroleum coke were $150.5{{\mu}m}$ and $750.9{{\mu}m}$ respectively. Under these conditions, over 95% of tungsten component in scheelite was chlorinated.

• Resources Recycling
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• v.13 no.3
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• pp.19-26
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• 2004

In order to use the mine tailing which was generated in the flotation process of scheelite ore into the raw material of ordinary portland cement, the characteristics of the prepared cement clinker was investigated. Scheelite mine tailing is composed of 68.8% of $SiO_2$, 8.6% of $Al_2$$O_3$, 10.8% of $Fe_2$$O_3$, 5.0% of CaO, respectively. It exists as $\alpha$-quartz, muscovite, clinochlore and has 8.0% of 88 $\mu\textrm{m}$ residue. When LSF, SM, and IM of the raw materials (such as limestone, convertor slag, fly ash, and mine tailing) are 91.0, 2.60, and 1.60, respectively, the burnability index of the raw materials is 50.7, the crystal size of $C_3$S and $\beta$-C$_2$S in the prepared clinker is 15∼35$\mu\textrm{m}$, and about 3.8% of scheelite mine tailing can be used as raw material.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.17-24
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• 1963

The fundamental investigations of surface properties of scheelite were made by electrophoretic mobility adsorption and contact angle measurements, and results have been correlated with its floatability obtained by Hallimond tube flotation test. The role of the interfacial electrical condition on the adsorption of collectors on mineral surfaces is discussed with the flotation of scheelite. From electrokinetic measurements made on scheelite, $Ca^{++}$ and $WO_4^{--}$ are identified to act as potential-determining ions, thus controlling the surface properties on this mineral. Therefore, at the fixed pH, the scheelite surface become to be less negatively charged with increasing $Ca^{++}$ concentration and more negatively charged with increasing $WO_4^{--}$ concentration in the pulp. Adsorption of collectors then depends strongly on the concentration of $Ca^{++}$ or $WO_4^{--}$ in the solution; anionic collectors are adsorbed on less negatively charged surfaces and cationic collectors on more negatively charged surfaces, which in turn defines the effective flotation range with respective collectors for this mineral.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.82-93
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• 1993

To extract the tungsten component from the scheelite by the chlorination process, effects of major variables such as the reducing agent, reaction temperature, reaction time, flow rate of the $Cl_2$ gas, and the particle size of the sample, were examined in the batch-boat system. The optimum conditions for this chlorination process were as follows ; reaction temperature above $700^{\circ}C$, carbon weight ratio to the scheelite 0.08, reaction time 20 min, flow rate of the $Cl_2$ gas $0.6{\ell}/min$, particle size of scheelite ore -200 mesh. Under the above conditions, 99% of tungsten component was extracted from scheelite ore. The diffusion step and chemical reaction step were the rate-determining steps at high and low temperature, respectively. Activation energy was 7.98kcal/mol at high temperature region and 31.2kcal/mol at low temperature one.

• Economic and Environmental Geology
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• v.2 no.2
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• pp.73-75
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• 1969

Ogbang scheelite deposit imbedded in amphibolite of unknown age was believed, by the previous workers, to be of pegmatite vein. The vein material is composed mainly of plagioclase (albite and oligoclase) and minor amount (less than 5 to 10% each) of hornblende, biotite and quartz. Orthoclose and tourmaline are accompanied in few places and scheelite and minor amount of fluorite, are the ore minerals. On the basis of mineralogical constituents of the vein, vein structures, mode of occurrence of the vein and gradational contact between veins and amphibolite, the present writer conclude that the deposit was formed by segregation from the parent basic igneous rock of amphibolite. The main portions of the deposit were formed by intrusion of ore solution into already solidified amphibolite after being segregated in deeper horizone, whereas the minor portion by segregation of ore solution in situ.

• Economic and Environmental Geology
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• v.16 no.1
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• pp.37-49
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• 1983

The skarn type tungsten deposits are developed in the contact aureole of Jurassic biotite-hornblende granodiorite and limestone beds. The latter can be divided into the Great Limestone Series of Joseon System and Gabsan Formation which is correlative to the Hongjeom Series of Pyeongahn System. The skarns are impregnated in the limestone, sandstone, schist and granodiorite, and showing zonal distribution. The five skarn zones are from fresh limestone inwards to wollastonite-skarn, clinopyroxene-skarn, clinopyroxene-garnet skarn, garnet skarn and vesuvianite skarn zone. The ore mineral, scheelite, disseminates in the clinopyroxene-garnet and vesuvianite skarn zone, and the size of the scheelite crystals in vesuvianite skarn zone is larger than in clinopyroxene- garnet skarn zone. According to the mineral paragenesis and the composition of skarn minerals, oxygen fugacity ($fo_2$) is low. Fluid inclusions in quartz comprise much $LCO_2$ and fluid inclusion studies revealed that the homogenization temperatures range $240-290^{\circ}C$.