• Proceedings of the Korean Environmental Health Society Conference
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• 2004.12a
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• pp.51-62
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• 2004

Lime based stabilization/solidification (S/S) can be an effective remediation alternative for the immobilization of arsenic (As) in contaminated soils and sludges. However, the exact immobilization mechanism has not been well established, Based on previous research, As immobilization could be attributed to sorption and/or inclusion in pozzolanic reaction products and/or the formation of calcium-arsenic (Ca-As) precipitates. In this study, suspensions of lime-As were studied in an attempt to elucidate the controlling mechanism of As immobilization in lime treated soils. Aqueous lime-As suspensions (slurries) with varying Ca/As molar ratios (1:1, 1.5:1, 2:1, 2.5:1 and 4:1) were prepared and soluble As concentrations were determined. X-ray diffraction (XRD) analyses were used to establish the resulting mineralogy of crystalline precipitate formation. Depending on the redox state of the As source, different As precipitates were identified. When As (III) was used, the main precipitate formation was Ca-As-O. With As(V) as the source, Ca4(OH)2(AsO4)2${\cdot}$4H2O formed at Ca/As molar ratios greater than 1:1. A significant increase in As (III) immobilization was observed at Ca/As molar ratios greater than 1:1. Similarly, a substantial increase in As (V) immobilization was noted at Ca/As molar ratios greater than or equal to 2.5: 1. This observation was also confirmed by XRD. The effectiveness of both As (III) and As(V) immobilization in these slurries appeared to increase with increasing Ca/As molar ratios.

• Congress of the korean instutite of fire investigation
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• 2011.04a
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• pp.102-116
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• 2011

With the spread of FMD and AI in the country livestock farmers have used lime(CaO) prevalently and due to incorrect storage lime served as a fire ignition source in a number of cases. As combined chemically with water, lime has exothermic reaction. Then In these experiments we want to know how exothermic reaction - caused by lime - acts as sources of fire ignition in any circumstances and conditions. So we have done experimental work of ignition temperature and ignition process in the artificial conditions as lime combined chemically with water. As a result, we have confirmed that lime could be flammable material sufficiently as a fire ignition source with the proper presence of heat and moisture conditions. If the lime served as sources of fire ignition, as identification techniques of fire scene, we must ascertain the existence of water, flammable material and Calcium Hydroxide($Ca(OH)_2$). We should take special precautions in order to prevent fire and educate the safe handling of lime to the manufacturer and agricultural cooperative's joint livestock farmers who product or use lime.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.215-216
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• 1999

연소시설, 소각시설 등에서 배출되는 아황산가스, 질소산화물, 염화수소, 불화수소 등의 산성가스를 경제적, 효율적으로 처리하는데 많은 관심의 대상이 되고 있는 건식 세정에는 석회석(CaCO$_3$, limestone), 생석회(CaO, lime), 소석회(Ca(OH)$_2$, hydrated lime) 등 calcium을 다량 함유하는 흡수제가 매우 효과적이라고 알려져 있다. 따라서 이러한 흡수제와 SO$_2$dml 화학반응에 관하여 많은 연구가 수행되어 왔으나, 대부분의 연구는 SO$_2$와 석회석이 고온에서 진행되는 화학반응에서 관한 것이다.(중략)

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.119-125
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• 1999

This research has been studied in terms of investigating the reaction behavior of pyrite with a cyclone reactor. The Mathematical model has developed pyrite oxidation and lime sulfation in this reactor. The model assumes a chemical control shrinking core behavior for the pyrite and a fluid film control shrinking core behavior for the lime. The model was solved and characterized numerically. Experiments have been performed to study the influence of reaction parameters such as reactor temperatures, pyrite particle sizes, air flow rates, feeding rates, and mixing ratio of pyrite and lime. The oxidation and sulfation products were characterized chemically and physically.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.206-214
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• 2016

This study aims to produce dolomitic hydraulic lime (D-NHL) using domestic low grade dolomitic limestone and to determine the effect of adding blast furnace slag (BFS) and gypsum as part of an investigation of the hydration properties of D-NHL to increase the mechanical properties. The main mineral phases of D-NHL as a hydraulic lime binder were $Ca(OH)_2$, $Mg(OH)_2$, $C_2S$, $C_3S$, and MgO residues. $Ca(OH)_2$ transformed into $CaCO_3$ in D-NHL paste over the period of 28 days, but the carbonation of $Mg(OH)_2$ and the hydration of $C_2S$ did not occur until hydration, after 28 days. Through an investigation of the hydration properties of D-NHL pastes mixed with BFS and gypsum, Al-based compounds such as calcium aluminate hydrates ($C_4AH_{13}$) and ettringite were observed at early hydration time. The compressive strength was improved due to the increased quantities of these hydration products. These results show that good performance results from the application of dolomitic hydraulic lime and that a high value product can be made from domestic waste materials.

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.117-123
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• 1968

A simplest and best method to find out lime requirement for Korean soils is described. Twenty six top soil samples were collected from various localities and chemical characteristics were dertermined. Three different buffer curve methods were employed as the standard to find out the most reliable test for lime requirement. In addition, the lime requirement test by the Shoemaker's and Woodruff's as well as the O.R.D. kit method were compared with the most reliable buffer curve method. The results may be summarized as follows. 1. The regression equation of the most reliable lime requirement by buffer curve method, y, on percent base saturation of various soils, X, was y=9.69-0.106 X and the negative correlation coefficient r=-0.84 was statistically significant at 5% level. 2. Lime requirement test by the best, buffer curve, method was more well correlated with the sum of exchangeable hydrogen and exchangeable aluminum contents of the soil samples than the exchangeable hydrogen content only. 3. The ordinary buffer curve method for lime requirement is more reasonable than the lime requirement test by the buffer curve prepared after addition of 1 normal potassium chloride or calcium chloride solutions. 4. The lime requirement tests by the most reasonable buffer curve method, X, and by the Woodruff's, the Shoemaker's and O.R.D. kit were compared. The best method for laboratory lime requirement test was the Shoemaker's method and the O.R.D. kit method also was good enough for the field test and these two method are recommended as the unified method of lime requirement test in each soil testing laboratories throughout Korea.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.4
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• pp.174-178
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• 2008

Nano-crystalline slaked lime was synthesized using design of experiment. In order to synthesize slaked lime, calcium chloride $(CaCl_2)$ and urea were used as starting materials. Calcium chloride solution and urea solution were mixed and heated in vessel that calcium carbonate was precipitated during heating. Precipitates were filtered, washed several times using D.I.water and ethanol and finally dried in oven. Slaked lime $(Ca(OH)_2)$ has been fabricated by the hydration of calcined $CaCO_3$. Design of experiment (Taguchi method) was used to optimize parameter, to minimize noise factors of experiment and to statistically analyze the results. Slaked lime having about 50 nm in optimized crystallite size could be obtained by calcination of $CaCO_3$ at $1000^{\circ}C$ for 0.5 h and hydration with D.I water containing ethanol and oxalic acid.

• KIEAE Journal
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• v.6 no.2
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• pp.11-18
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• 2006

In this research, Conducting an engineering properties experiment, this study examined basic properties of regional Hwangto. The results of experiments are as followings. 1) This study confirmed that a result of examining lime order for Hwangto and comparison of stimulants, this study confirmed that 28 day's strength promotion is found in case of calcium hydroxide(Ca(OH)2) and calcium chloride(CaCl2) stimulant. Finally, it is known the fact that lime highly improves the weak strength of Hwangtoh. 2) As XRD analysis for proving the strength manifestation principle of Hwangto by regions, CSH figure and CASH figure appeared in each regional Hwangto in all the strength areas. This result could be appeared through hydraulicity from reaction of alkali stimulant and water, and pozzolan reaction(CSH figure) and $Str{\ddot{a}}tlingite$ reaction(CASH figure) by silica (SiO2) ingredient and calcium hydroxide (Ca(OH)2) among ingredients of clay, and alumina(Al2O3). 3) In result of strength analysis, It is knowned that the Gyeongsangdo Hwangto is stronger than the Jeollado Hwangto in reactivity.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.72-81
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• 2014

The main mineral phases of natural hydraulic lime (NHL) as a hydraulic lime binderare $Ca(OH)_2$, $C_2S$, $C_3S$, $C_3A$, and $SiO_2$ residues. Also, NHL has the characteristic of setting and hardening by a hydration reaction with water and by carbonation reactions with carbon dioxide from the air. In this study, in an effort to investigate changes of the mineral phases by NHL hydration and carbonation reactions, transitions of mineral phases and the microstructures of hardened pastes were analyzed by XRD, DSC, SEM, and by pore size distributions using domestic and foreign-sourced NHL pastes after curing at 1, 3, 7, and 28 days. On the basis of the analysis results, it was confirmed that domestic low-grade limestone can be used for the manufacturing of NHL. The main hydration mineral phases were $Ca(OH)_2$, $CaCO_3$, $C_2S$, and $SiO_2$ residues, while in the case of foreign-sourced NHL, a small amount of an aluminium hydration phase formed. Also, the $CaCO_3$ content after the carbonation reaction increased with an increase in the curing time. After hydration for 28 days, NHL containing considerable amounts of $C_2S$ and $C_3S$ showed higher carbonation ratios than others types.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.1-8
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• 2013

BACKGROUND: Many studies associated with cadmium (Cd) immobilization using lime fertilizer have been conducted for several decades. However, these studies did not suggest exact mechanism of Cd immobilization using lime fertilizer and evaluated effect of lime fertilizer on Cd phytoavailability in rice paddy soil under field condition. METHODS AND RESULTS: This study was conducted to determine exact mechanism of Cd immobilization using lime fertilizer and evaluate liming effect on Cd uptake of rice in contaminated paddy soil. $Ca(OH)_2$ was mixed with Cd contaminated arable soil at rates corresponding to 0, 1,000, 2,000, 4,000, and 8,000 mg/kg. The limed soil was moistened to paddy soil condition, and incubated at $25^{\circ}C$ for 4 weeks. $NH_4OAc$ extractable Cd concentration in soil decreased significantly with increasing $Ca(OH)_2$ rate, since $Ca(OH)_2$ markedly increased net negative charge of soil by pH increase, and decreased bioavailable Cd fractions (F1; exchangeable + acidic and reducible Cd fraction). Calculated solubility diagram indicated that Cd solubility was controlled by soil-Cd. $NH_4OAc$ extractable Cd and F1 concentration were negatively related to soil pH and negative charge. $Ca(OH)_2$ was applied at rates 0, 2, 4, and 8 Mg/ha and then cultivated rice in the paddy soil under field condition. Cadmium concentrations in grain, straw, and root of rice plant decreased significantly with increasing application rate of $Ca(OH)_2$. CONCLUSION(S): Alleviation of Cd phytoavailability with $Ca(OH)_2$ can be attributed primarily to Cd immobilization due to the increase in soil pH and negative charge rather than precipitation of $Cd(OH)_2$ or $CdCO_3$, and therefore, $Ca(OH)_2$ is effective for reducing Cd phytoavailability of rice in paddy soil.