• Title/Summary/Keyword: 고반응성 생석회

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Applied-mineralogical Characterization for the Quick-lime Manufactured from Fine-grained Domestic Limestones (국내산 세립질 석회석으로부터 제조된 생석회에 대한 응용광물학적 특성 평가)

  • Noh, Jin-Hwan;Lee, Hyun-Chul
    • Journal of the Mineralogical Society of Korea
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    • v.22 no.3
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    • pp.261-277
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    • 2009
  • This study is aimed to emphasize the significance of ore selection in lime manufacturing through the evaluation of applied-mineralogical impact factors of crude ores controlling calcination characteristics for some domestic limestones used currently for lime manufacturing. To do this work, systematic characterization and determination were carried out for the limestone ores and their calcination products in a fixed calcining condition (target temperature: $1000^{\circ}C$, retention time: 30 minutes, 2, 4, 10, 16 hours), and the results were correlated and discussed. Selected high-Ca limestones in this study are as much as > 98 wt%, but they are somewhat diverse in crystallinity, texture, and impurity composition. Synthesized quicklimes are varied depending on such a difference in ore characters. The Pungchon limestone has relatively very low calcination rate, and the limestones from the Gabsan formation and the Jeongseon formation exhibit good quality in calcination rate and decrepitation. Among these samples, the limestone ore from the Jeongseon formation is evaluated to be the best for crude ore in manufacturing of highly-reactive quicklime. In addition, it is characteristic that the Gabsan limestone comparative rich in Fe-bearing mineral such as pyrite and goethite is more conspicuous in sintering effect.

Quality Evaluation of the High-purity Limestones for Lime Manufacturing Based on the Measurements of Shape Factor and Grain Boundary Frequency (형상계수 및 경계빈도수 측정에 의거한 생석회 제조용 고품위석회석의 품질 평가)

  • Noh, Jin-Hwan;Lee, Hyun-Chul
    • Journal of the Mineralogical Society of Korea
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    • v.22 no.4
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    • pp.371-383
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    • 2009
  • Crystallinity and textural relations, which are crucial in terms of the quality concept of high-purity limestone, have not been effectively applicable to the limestone evaluation as crude ore due to the difficulties in precise measurements. To overcome the above, as a new method of ore characterization, a measurement of shape factor and grain boundary frequency utilizing the image analysing system was adopted in this study. Some domestic limestones used for lime manufacturing were investigated by such a quality evaluation method, and its results are discussed and correlated each other samples. As the result, even though calcite contents of crude ore, i.e., limestone grade and its crystal size are similar, quality of manufactured lime is remarkably different depending on the degree of shape factor and grain boundary frequency. In other words, as the more irregular in crystal shape and the higher the grain boundary frequency, the manufactured quick lime became more superior in all terms of lime quality such as rate of calcination, porosity, reactivity, sintering and decrepitation effect. However, because the quick lime become easily overheated in case of relatively higher degree in shape factor and grain boundary effect, a technology minimizing heating time is necessary for the manufacturing of high quality lime. In limestone industry, such a ore characterization method will be much more reasonable than the conventional method by measurement of mean size, because the method may collectively comprise crystal shape and other textural factors which can not be numerically evaluated in the past.

Recovery of High Purity Calcium Nitrate from Blast Furnace Slag (고로수재슬래그로부터 고순도 질산칼슘 회수에 관한 연구)

  • Yoo Jeong Kun;Lee Man Seung;Kim Kyung Soo;Choi Seung Hoon
    • Resources Recycling
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    • v.13 no.2
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    • pp.33-38
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    • 2004
  • Concepts and experimental results for the unique utilization process which we could obtain the high purity calcium nitrate from blast furnace slag in the steel industry are described. Firstly we reacted the blast slag with nitric acid and separatively removed the insoluble silica by filtration. We adjust the pH of filtrate to 6∼8 with calcined lime, and then precipiated out the metal components like Fe, Al, Mg in the forms of hydroxides. Consequently concentration of the mother liquor and crystallization processes make us obtain the high purity (>98 wt%) calcium nitrate tetrahydrates, which is expected the valuable fertilizers.

A Study on Characterization of Expansion Agent in Mortar with Light Burned Dolomite By-Product (경소백운석(輕燒白雲石) 부산물(副産物)을 활용(活用)한 바닥 몰탈용 팽창재(膨脹材)의 특성검토(特性檢討))

  • Lee, Keon-Ho;Min, Sung-Eoi;Lee, Hyoung-Woo;Cho, Jin-Sang;Cho, Kye-Hong;Han, Choon
    • Resources Recycling
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    • v.21 no.6
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    • pp.12-22
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    • 2012
  • This study investigated a utilization technology of light burned dolomite. light burned dolomite ($CaMg(CO_3)_2$) generated in furnace (steel manufacturer) is an alternative to quick lime. Using light burned dolomite has an effect on reducing the consumption of fluorite slag MgO concentration in supersaturated solution by prolonging the life of softening effect. Armophous MgO, not containing periclase is formed by firing dolomite under $800^{\circ}C$. It has larger surface area and higher reactivity than periclase, and also shows better expansion effect than quicklime. Due to those effects, therefore, armophous MgO produced from light burned dolomite is used as an alternative expansion agent in mortar. In the experiment, characteristics of light burned dolomite were compared to those of existing expansion agents such as anhydrite and quicklime. Then, each expansion and shrinkage rates were measured over a period of about 3 months in both of 1m Jis mold at labscale and apartment mortar flooring at field scale. In the result, it was observed that light burned dolomite in mortar flooring more compensates for the expansion and shrinkage rates than the existing expansion agents, showing low expansion rate of below 0.05% and also decreases the crack.