• Resources Recycling
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• v.12 no.1
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• pp.41-47
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• 2003

In order to improve the hydration resistance of lime in the air at room temperature, carbonation and hydration experiments have been conducted. Carbonation of the surface of lime by about 6 wt％ was needed to suppress the hydration of lime used in steel-making. The effect of recirculation of rotary kiln exhaust gas for the carbonation of lime on the combustion temperature and NOx concentration was analyzed by thermodynamics. From the thermodynamic calculation results, it was frond that the equi-librium combustion temperature and NOx concentration decreased with increasing volume percentage of exhaust gas.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.2
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• pp.57-71
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• 1985

The characteristics of compaction and unconfined compressive strength were investigated by mixing with lime to all soils adjusted by given percentages of two kinds of clays to sand to obtain the most effective distribution of grain size and the optimum lime content for soil stabilization. In addition, unconfined compressive strength and durability tested by adding of sodium metasilicate, sodium sulfate, sodium carbonate, sodium gydroxide and magnesium oxide to lime-soil mixture mixed with 8 percent lime to adjusted soil having the mixing percentage of 60 percent of cohesive black clay and 40 percent of sand by weight to get the effect and the optimum content of chemicals. The results obtained were as follows; 1.With the addition of more lime, the optimum moisture content was increased, and the maximum dry density was decreased, whereas the more the amount of clay and the less was the maximum drt density. 2. In the soil having more fine grain size the unconfined compressive strength was larger in the earlier stage of curing period, in accordance with the longer period, the mixing percentages of sand to clay showing the maximum unconfined compressive strength, on the basis of 28-day strength, were 60% : 40% (black clay) and 40% : 60% (brown clay) respectively. 3. The reason why the soil adjusted with black clay was remarkably bigger in the unconfined compressive strength than ones adjusted with brown clay for all specimen of lime-soil mixture was the difference in the kind of clay, the amount of chemical compositions the value of pH. Black clay was mainly composed of halloysite that reacted with lime satisfactorily, whereas the main composition of brown clay was kaolinite that was less effect in the enhance of unconfined compressive strength. Also the difference of unconfined compressive strength was because black clay was larger in the amount of composition of calcium oxide and magnesium oxide in the value of pH affecting directly on the unconfined compressive strength of lime-soil mixture than brown clay. 4. In the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40%, on the standard of 7-day strength, the effect of chemical was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium hydroxide and sodium metasilicate. 5. The optimum amount of chemical being applicable to the maximum unconfined compressive strength of lime-chemical-soil mixture was 1 percent by weight for air dry soil in the case of adding sodium carbonated and 0.75 percent on sodium hydroxide, the unconfined compressive strength was increased continuously with increase of the amount of chemical up to 2 percent of chemical content is the lime-chemical-soil mixture added sodium metasilicate, sodium sulfate and magnesium oxide. 6. It was considered that the chemical played and accelerant role of early revelation of strength because the rate of increase of unconfined compressive strength of all of lime-chemical-soil mixtures was largest on the 7-day cured specimen. 7. The effect of test on freezing and thawing after adding suitable amount of chemical on the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40% was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium metasilicate and sodium hydroxide.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.129-140
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• 2013

Bottom Ash is industrial by-product from a thermoelectric power plant. An immense quantities of bottom ash have increased each year, but most of them is reclaimed in ash landfill. In this study, in order to raise recycling rate of Bottom Ash, it is suggested to cure Bottom Ash (BA) mixtures mixed with cement, lime, Fly Ash (FA), and oyster shell (OS). Mixtures of 5~20 % mixing ratio had been cured for 1, 3, 7, 14, and 28 days using sealed curing and air-dry curing method. Unconfined compressive strength test was conducted to determine strength and deformation modulus ($E_{50}$) change for mixtures as mixing ratio and curing day, water contents of mixtures were measured after test. As a result, strength and $E_{50}$ were increased as mixing ratio and curing days, but values and tendencies of them appeared in different as kind of mixture, mixing ratio, curing method, and curing days. The results showed the addition of cement, lime, Fly Ash, and oyster soil in Bottom Ash could improved strength and $E_{50}$ and enlarge its field of being used.

• Explosives and Blasting
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• v.29 no.2
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• pp.13-31
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• 2011

Air deck charge blast methods have been applied to improve the fragmentation in open cut bench blastings for mining developments. However, during large scale bench blasting operations, there exist some problems such as boulder productions due to explosive charge concentration. Especially, in case of lime stone mining, when air deck method is applied, there has been unintentionally concentrated on charging because the inside holes are often broken by erosion and decomposition. In this study, compared with general blasting, air deck blasting has been focused in lime stone mining. In other to maximize its efficiency, inside hole was examined by endoscope in advance and deck charge using air tube was applied to the section in which concentration might be taken place. Blasting efficiency, fragmentation, charging reduction rate, and total working hours (from charging to blasting) were the main object for comparing, and as a result, air deck was more efficient then the general blasting in all aspects except total working hours.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.287-292
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• 2001

This paper investigates the properties of high fluidity concrete incorporating lime stone powder and fly ash. Lime stone powder(LSP) and fly ash(FA) contents are varied with. According to test results, as LSP and FA contents increase, fluidity, air content and placeability shows a declining tendency. For the temperature history, both LSP and FA have favorable effects on reducing hydration heat, moreover, LSP reduces hydration heat more than FA. LSP shows undesirable strength loss as its content increases. FA also decreases the strength at early age, but it enhances later age strength. Accordingly LSP is expected to improve the quality at fresh concrete and reduce hydration heat, while it causes strength loss.

• 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.

• KIEAE Journal
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• v.11 no.4
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• pp.95-101
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• 2011

Earth has been used as a building material not only our country but also many foreign countries in the world. In foreign countries, we can often find the high-storied earthen houses which have been maintained for over several hundred years, which means the fact that earth differs in durability according to the methods of utilizing earth. So, the purpose of this study is to progress the fundamental research for utilizing earth as a wall material. Also, the another purpose of this study is to utilize the optimum micro-filler effect which adjusts the grain size of earth and the lime composite which promotes chemical combining power, and so examine whether earth material ensures its high compressive strength. This study applied both of rammed earth method and pour earth method among earth architecture methods. This study investigated compressive strength, slump, and air content according to unit binder weight. On the basis of such experimental results, this study derived the following conclusions. 1) Optimum micro-filler mixtures reduce a lot of fine particles contained in earth. If optimum micro-filler mixtures are used as aggregates, they develop lower W/B and relatively higher strength than general earth. 2) In this study, which uses optimum micro-filler earth mixtures and lime composite, rammed earth method develops 29MPa and pour earth method develops 28MPa in 28 days compressive strength. Such strengths can be utilized in building walls.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.4
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• pp.44-51
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• 2012

In this study, hardened loess bodies, which did not compose of cement or any chemical binder, were made and tested to evaluate the physical properties such as slump, air content, and compressive strength. Addition of a natural binding material to mixture of loess and lime showed better performance in physical properties. However a lime among natural binding materials is considered as a superior binder to improve the properties of the hardened bodies. According to the experimental results, mixing proportion with 45% of W/B ratio, $285kg/m^3$ of water content, and 60% lime substitution ratio was recommended to acquire the good performance of physical properties for the hardened loess bodies.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.1-7
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• 2024

Objectives: The study was performed to investigate characteristics of hazardous factors regarding chemical(liquid lime) tank dredging workers by case survey. Methods: Field data such as working condition, MSDS and respirators applied to chemical tank dredging work were analyzed and the work environmental factors of noise and indoor air quality were measured to compare existing data with actual work situations. Results: No health hazards to workers due to working conditions were confirmed during dredging work inside the chemical storage tank. All air quality measurement data during dredging work satisfied the management standards, and there were no by-products. During dredging work, there was a significant change in noise depending on the type of work, but considering the noise reduction rate(NRR) of the earplugs worn by workers, there was no actual health hazard due to noise exposure. Conclusions: A fit test for respirator and the expiration date of the safety helmet should be observed to ensure an appropriate level of safety and health for dredging workers in the chemical storage tank.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.87-98
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• 2011

Clay bricks with lime mortar are recently popular since they are eco- and environment-friendly construction material being capable of air flow and moisture movement. However, there is little study on those of clay brick an lime mortar while relatively many researches on the structural characteristics of concrete bricks with cement mortar are available in Korea. Furthermore, the current Korean Building Code of masonry structures was established on the base of the Foreign Codes which does not reflect Korean masonry construction circumstance, such as material characteristics and section properties. To overcome these problems, experiments of masonry structures constructed using clay bricks with lime mortar were carried out to evaluate their structural characteristics such as, prism compressive strength, adhesive strength and diagonal tensile(shear) strength. Also this research compares the mechanical characteristics between clay bricks with lime mortar and concrete bricks with cement mortar to provide information that will be used for revisions of the domestic standards for masonry structures. As masonry structures constructed with clay bricks and lime mortar show different aspects over the ones constructed with concrete bricks and cement mortar, we suggest estimation equation of prism compressive strength and diagonal tensile strength on masonry structures constructed with clay bricks and lime mortar.