• 자원환경지질
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• 제28권1호
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• pp.1-8
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• 1995

The smectite-rich clays were found locally in Paleozoic calcareous sedimentary rocks in the Samcheok area. Their occurrences were investigated in detail, and the physico-chemical properties of the clays were also determined by X-ray diffraction, chemical analysis, thermal analysis and cation exchanging experiment. The smectite clays occur as the fissure filling dyke developed in calcareous sedimentary rock and as alteration products of intrusive rhyolite. Most of clays occur at the contact between the sedimentary rock and the rhyolite, and the alteration zone was observed only in rhyolite body close to the contact. Judging from their occurrences, it is believed that the smectite-rich clays in this area were formed by the hydrothemal alteration. The smectite clays from the area are mainly composed of Ca-montmorillonite, and associated with small quantities of quartz, opal-CT and feldspar. The montmorillonites from this area are lower in Fe content, and higher in exchangeable Ca ion, compared to those of bentonite from the Yangnam-Yeongil area.

• 자원환경지질
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• 제16권3호
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• pp.149-161
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• 1983

경상도(慶尙道) 지역(地域)의 삼기층중(三紀層中)에 배태(胚胎)되어진 산성백토(酸性白土)는 주(主)로 Ca-몽모리로나이트로 구성되며 이의 조성비(組成比)는 95%까지에 이른다. 이에 수반되는 광물(鑛物)은 크리스토발라이트, 석영(石英), 장석(長石), 삼정석광물(三井石鑛物) 및 비결정질(非結晶質)이 있다. 시차열분석(示差熱分析), 적외선 및 전자현미경에 의한 이들의 기본적인 특성(特性)을 기재하였고 물리적성질(物理的性質)을 섭성한계(涉性限界) 및 양이온교환능을 측정기재하였다. 이들 자원(資源)의 이용가능한 용도범위를 고찰하였다.

• Membrane and Water Treatment
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• 제10권4호
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• pp.259-264
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• 2019

Cost effective clay adsorptive microfiltration membranes were synthesized to remove Cr (III) from high polluted water. Raw and calcined bentonite were mixed in order to decrease the shrinkage and also increase the porosity; then, 20 wt% of carbonate was added and the samples, named B (without carbonate) and B-Ca20 (with 20 wt% calcium carbonate) were uniaxially pressed and after sufficient drying, fired at $1100^{\circ}C$ for 3 hours. Then, physical and mechanical properties of the samples, their phase analyses and microstructure and also their ability for Cr(III) removal from high polluted water (including 1000 ppm Cr (III) ions) were studied. Results showed that the addition of calcium carbonate lead the porosity to increase to 33.5% while contrary to organic pore formers like starch, due to the formation of wollastonite, the mechanical strength not only didn't collapse but also improved to 36.77 MPa. Besides, sample B-Ca20, due to the presence of wollastonite and anorthite, could remove 99.97% of Cr (III) ions. Hence, a very economic and cost effective combination of membrane filtration and adsorption technology was achieved for water treatment which made microfiltration membranes act even better than nanofiltration ones without using any adsorptive nano particles.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.32-33
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• 2016

In this work, pozzolanic activities of various waste materials were compared with those of well-known pozzolanic materials. Uncondensed and densified silica fume, two ASTM class F fly ashes with different calcium contents, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property were chosen for comparison. Drop in electrical conductivity at 40℃ saturated lime solution was measured for each materials. The amount of Ca(OH)₂ decomposed from cement paste at 450~500℃ was also measured used to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by various waste materials.

• 한국식품영양과학회지
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• 제28권1호
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• pp.53-60
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• 1999

Possibility of utilization of fig as a source of vinegar was tested. Alcohol fermentation was conducted by inoculation of Saccharomyces bayanus into fig juice. After 5 days of fermentation at 27oC, fig wine with alcohol content of 13.6%. Then fig vinegar was produced by cultivation of Acetobacter sp. E which was isolated from fig vinegar. Optimum concentration of alcohol, starter content and fermentation temperature for the acid production were 8~9%, 5% and 27~30oC, respectively. More acetic acid was produced by adding 0.5% of yeast extract and 0.01% of Ca pantothenate. Adjustment pH of culture broth with acetic acid and shaking cultivation method were not effective in higher yield of acid production. Addition of sulfite up to 50 ppm did not inhibit for acetic acid fermentation. Addition of 1% bentonite or 1% kakishibu was more effective for the clarification of fig vinegar than any other clarifying agents tested. During aging and racking, acidity, absorbance and tannin content of fig vinegar decreased, while redness and yellowness increased. Aged and racked fig vinegar showed higher sensory score than non aged one in the aspects of color and overall acceptability.

• 한국초지조사료학회지
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• 제15권4호
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• pp.245-252
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• 1995

To select a carrier as Rhizobiwn inoculants for alfalfa, severeal Rhizobium inoculants were produced by adding or not sub-materials($CaCO_3$ and sucrose) to main materials(organic or inorganic materials). The root nodule bacteria, Rhizobium meliloti 1061 distributed from KAIST, and Vemal alfalfa was used in this experiment. The Rhizobium populations and inoculation effects of the Rhizobium inoculants produced in several materials were scrutinized at laboratory and greenhouse in Livestock Experiment Station, RDA from 1993 to 1994. Moisture contents of the caniers were varied from 32 to 50% on dry weight basis according to material characteristics and the pH ranges of these were varied from pH 4.56 to 10.06 according to raw material characteristics and preparations. Initial Rhizobium numbers of the carriers were higher in organic material-inoculants than in inorganic, and among the inoculants, the inoculant made of Bentonite+Vermiculite(l:3 w/w) was excellent because of high rhizobium population($7.8~8.3\times10^8/g$ inoculant) and high rhizobium reappearance of inoculant in severed different production time. The root nodules of the alfalfa inoculated with different inoculants were fast formed in the fermented sawdust with cattle dung (FSC) inoculant, and bentonite(B)+vermiculite(V) than others. Plant length of alfalfa was differentiated on 15 days after inoculation but was not nearly different between higher inoculants than rhizobium number $10^7/g$ inoculant. Total dry matter of alfalfa was yielded by 20.65, 20.34mg per pot in FSC + sucrose 0.5% and B + V + sucrose 1% inoculants respectively that were higher inoculation effect by 17 times compared with non-inoculation, 1.2 mg per pot.

• Nuclear Engineering and Technology
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• 제40권7호
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• pp.593-606
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• 2008

In this study, data on radionuclide migration and retardation processes in the engineered and natural barriers of High-Level Radioactive Waste (HLW) repository have been reviewed and compiled for use in the performance assessment of a HLW disposal system in Korea. The status of the database on radionuclide migration and retardation that is being developed in Korea is investigated and summarized in this study. The solubilities of major actinides such as D, Th, Am, Np, and Pu both in Korean bentonite porewater and in deep Korean groundwater are calculated by using the geochemical code PHREEQC (Ver. 2.0) based on the KAERI-TDB(Korea Atomic Energy Research Institute-Thermochemical Database), which is under development. Databases for the diffusion coefficients ($D^b_e$ values) and distribution coefficients ($K^b_d$ values) of some radionuclides in the compacted Korean Ca-bentonite are developed based upon domestic experimental results. Databases for the rock matrix diffusion coefficients ($D^r_e$ values) and distribution coefficients ($K^r_d$ values) of some radionuclides for Korean granite rock and deep groundwater are also developed based upon domestic experimental results. Finally, data related to colloids such as the characteristics of natural groundwater colloids and the pseudo-colloid formation constants ($K_{pc}$ values) are provided for the consideration of colloid effects in the performance assessment.

• 한국광물학회지
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• 제16권1호
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• pp.33-47
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• 2003

국내산 벤토나이트의 유변학적 특성과 그 규제 요인을 파악하기 위해서 각종 응용광물학적분석과 체표면적, 입도분포, 팽윤도 및 점성도를 측정하였다. 비교적 저품위(몬모릴로나이트 함량:30∼75 wt%)를 이루는 국내산 Ca-형 벤토나이트들은 2∼4 $\mu\textrm{m}$의 입도를 갖고 대부분 반자형의 엽상 결정체를 이룬다. 현탁액 상에서 벤토나이트 광물성분들의 입도 분포는 대체로 10∼100 $\mu\textrm{m}$ 범위에서 높은 빈도를 보이고 전체적으로는 다소 복잡한 이중적인 분포양상을 나타낸다. 이 같은 양상은 제올라이트질 벤토나이트에서 보다 심하게 나타난다. 이 벤토나이트들의 EGME 체표면적은 $269∼735\m^2$/g의 값의 범위를 갖는 것으로 측정되었다 이 체표면적 값은 몬모릴로나이트의 함량, 수분함량 및 CEC 수치와 대체로 정비례하는 관계를 나타낸다. 제올라이트질 벤토나이트가 제올라이트를 함유하지 않는 것보다 전반적으로 약간 높은 체표면적 갈을 갖는다. 국내산 벤토나이트들은 전반적으로 낮은 팽윤도와 점성도를 나타낸다. 2∼5 wt%의 $Na_2$$CO_3$첨가에 의해서 유발된 국내산 벤토나이트들의 팽윤도 향상 최대치는 몬모릴로나이트의 함량과 불순물, 특히 제올라이트의 함유정도에 따라 250∼500%수준인 것으로 측정되었다. Na치환능력이 강한 제올라이트를 함유하는 벤토나이트의 팽윤도 향상에는 좀더 많은 양의 $Na_2$$CO_3$가 소요된다 점성도에 있어서는 장석의 함량이 높고 상대적으로 낮은 입도와 결정도를 갖는 벤토나이트들이 비교적 높은 수치를 보이는 경향이 있다. 또한 현탁액의 pH가 상대적으로 높은 수치를 보이는 시료들이 대체로 점성도가 높은 것으로 나타난다. 그렇지만 벤토나이트의 주요한 유변학적 특성들인 팽윤도와 점성도는 몬모릴로나이트의 함량이나 평균 분산입도와는 뚜렷한 일률적인 상관관계를 보이지 않는 것으로 나타난다. 이에 비해서 팽윤도는 벤토나이트의 광물조성, 표면전하 특성, 입도 및 형상 등의 물리화학적 성향을 포괄하는 체표면적 수치와 대략적으로 반비례적인 관계를 보인다 따라서 벤토나이트 현탁액에서의 유변학적 특성은 몬모릴로나이트의 표면전하 특성, 형태, 입도 및 조직 등의 차이에 의해서 달라지는 점토 입자들의 응집특성 및 취합결정체의 형상에 주로 규제되고, 제올라이트와 같은 미세한 불순 광물성분들의 영향도 부수적으로 관여되는 복합적인 성향인 것으로 해석된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.938-946
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• 2008

This study is on sealing leakage holes where are in landfills to make clay cakes with clay particles, which have a negative surface charge using the method of electrophoresis. Generally, electrophoresis is the motion of charged particles in a colloid under the influence of an electric field; particles with a positive charge go to the cathode and negative to the anode. In this study in order to develop the prevention system of leakages of the leachate in landfills, one-dimensional electrophoresis tests were conducted for determining the properties of the motion of the electrophoresis and cutoff using the method of electrophoresis depending on various the effect factors such as types of clays, concentrations of the clays, and applied electric field. In case of the experiments of determining the optimum clays, Na and Ca-Bentonite, Na and Ca-Montmorillonite, which have greater zeta-potential, cation, exchange capacity as well as ability of cutoff, and Micro-cement inducing cementation were chosen and then the effect of those clays was investigated. Moreover, the properties of the motion and settling of the clays were investigated following electric field varied from 0 to 1V/cm at different concentration of the clays in order to determine both the properties of the motion of the clays and the efficiency of electric field when applying different direct current. Ultimately, the ability of cutoff was examined through measuring the permeability of the clay cakes derived from the one-dimensional electrophoresis tests.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.586-591
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• 2001

This research investigated the feasibility of the accelerated carbonation of cement waste forms with carbon dioxide in a supercritical state. Hydraulic cement has been used as a main solidification matrix for the immobilization of radioactive and/or hazardous wastes. As a result of the hydration reaction for major compounds of portland cement, portlandite (Ca(OH)$_2$) is present in the hydrated cement waste form. The chemical durability of a cement form is expected to increase by converting portlandite to the less soluble calcite (CaCO$_3$). For a faster reaction of portlandite with carbon dioxide, SCCD (supercritical carbon dioxide) rather than gaseous $CO_2$, in ambient pressure is used. The cement forms fabricated with an addition of slated lime or Na-bentonite were cured under ambient conditions for 28days and then treated with SCCD in an autoclave maintained at 34$^{\circ}C$ and 80atm. After SCCD treatment, the physicochemical properties of cement matrices were analyzed to evaluate the effectiveness of accelerated carbonation reaction. Conversion of parts of portlandite to calcite by the carbonation reaction with SCCD was verified by XRD (X-ray diffraction) analysis and the composition of portlandite and calcite was estimated using thermogravimetric (TG) data. After SCCD treatment, tile cement density slightly increased by about 1.5% regardless of the SCCD treatment time. The leaching behavior of cement, tested in accordance with an ISO leach test method at 7$0^{\circ}C$ for over 300 days, showed a proportional relationship to the square root of the leaching time, so the major leaching mechanism of cement matrix was diffusion controlled. The cumulative fraction leached (CFL) of calcium decreased by more than 50% after SCCD treatment. It might be concluded that the enhancement of the characteristics of a cement matrix by an accelerated carbonation reaction with SCCD is possible to some extent.