• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.30-31
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• 2015

Usually, carbonation of concrete causes pH reduction and corrosion of steel, it leads to decrease of durability. However, CaCO₃, as results of reaction with hydrates products and CO₂, can contribute to improvement of compressive strength. Based on this theory, using carbonation depth, the researches about CO₂ absorption of plain concrete and concrete containing CO₂ reactive materials has been performed. But, the researches has limitation about using one material, therefore, for this study, considering various CO₂ reactive materials, experiment has been proceeded. With water to binder ratio 50%, after initial curing for 2days, accelerated carbonation was performed for 28days, and carbonation depth and compressive strength were measured. As results of carbonation depth, specimen containing desulfurized slag, zeolite showed the highest CO₂ absorption, in case of compressive strength, specimens with MgO were indicated as highest compressive strength.

• Journal of the Society of Disaster Information
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• v.9 no.2
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• pp.128-136
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• 2013

The current contractor for use in performance compared to the performance study of industrial byproducts. Due to the stagnation of the construction business and the rise of raw materials, the contractor of the cost savings and environmental issues, and present a variety of ways for research actively being. Through special about the compressive strength characteristics of the mixed concrete, carbonation resistance and chloride penetration resistance of this study, previous studies have been a lot of progress, industrial byproducts, fly ash and blast furnace slag concrete structures were applied to evaluate.

• Clean Technology
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• v.20 no.1
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• pp.64-71
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• 2014

We have investigated the effects of various additives on Eco coal gasification under $CO_2$ atmosphere. The temperature ranges from $750{\sim}900^{\circ}C$ and the gasification experimental was carried out with Eco coal adding 7 wt% $K_2CO_3$, $Na_2CO_3$, $CaCO_3$, Dolomite, and non-additive under $N_2$ and $CO_2$ gas mixture. At $850^{\circ}C$, we observed that the reaction rate increased when the concentration of $CO_2$ increased. However, we also observed that the increment of reaction rate was small at more than 70% of the concentration of $CO_2$. The additives activity was ranked as 7 wt% $Na_2CO_3$ > 7 wt% $K_2CO_3$ > non-additive > 7 wt% Dolomite > 7 wt% $CaCO_3$ at $850^{\circ}C$. At the temperatures of $750^{\circ}C$, $800^{\circ}C$, $850^{\circ}C$, and $900^{\circ}C$, when the temperature increased, the gasification rate increased. The gasification was suitably described by the volumetric reaction model. Using volumetric reaction model, the activation energy of Eco coal including 7 wt% $Na_2CO_3$ gasification was 83 kJ/mol, which was the lowest value among all the alkaline additives.

• Journal of the Korea Institute of Building Construction
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• v.19 no.5
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• pp.383-389
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• 2019

The supply of natural aggregate for concrete has been difficult, and the amount of construction waste has been continuously increasing. Therefore, the necessity of using recycled aggregate made of construction waste as aggregate is rised. Therefore, many studies on the characteristics of concrete using recycled aggregate have been made and positive studies have been reported mainly in recent studies. A study on the chlorides binding effect of the mortar with recycled coarse aggregate has been reported. However, due to the user's perception of waste, most of the recycled aggregate currently produced is used only for low value-added products. In order to improve the recognition of recycled aggregate and the user's perception of recycled aggregate concrete, long-term monitoring of the structure with 100% recycled aggregate was conducted to confirm the applicability of the recycled aggregate concrete.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1145-1146
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• 2006

분산 형 전원 및 석탄 가스화와 연계한 복합 발전이 가능한 용융탄산염 연료전지(MCFC : Molten Carbonate Fuel Cell)는 천연가스, 석탄가스 등 다양한 연료를 사용할 수 있고, 공해요인이 적고, 높은 에너지 변환효율을 가지고 있어 전력사업 분야에 적용 가능성이 가장 큰 새로운 발전방식이다. 국내에서도 1993년부터 선도기술개발 사업의 하나로 시작하여 현재 250 kW급 발전시스템 개발 연구가 진행되고 있다. 250 kW개발 전 수행한 100 kW급 MCFC 발전 시스템 개발 연구에서는 6,000cm2 급 단위전지 90장으로 구성된 50 kW급 MCFC 스택 2기 로 구성된 100 kW MCFC 스택과 이를 운전 평가를 위한 시스템을 완성하였다. 2005년부터 스택운전에 필요한 시스템 내 단위기기들에 대한 시운전을 진행 한 후 장착된 100 kW MCFC 스택 운전에서는 시스템 단위 기기의 고장으로 전 부하운전을 실시하지 못했지만 상압 상태에서 AC 50 kW 전력을 계통과 연계 운전 시험을 진행하였다. 향후 100 kW MCFC 시스템 보완후 재 운전 시험을 진행할 예정이다. 한편 병행하여 진행되는 250 kW 열병합 발전 시스템 개발에서는 시스템 상세설계 및 신형 분리판을 이용한 새로운 형태의 스택을 개발 운전시험을 진행하고 있다. 여기에서는 MCFC 발전 시스템의 개요와 시스템의 운전을 위한 운전 모드 그리고 스택 운전 내용을 요약하여 소개하고자 한다.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.11-17
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• 2012

This study focused on application of various $CO_2$ philic adsorbents with amine to improve $CO_2$ uptake in mortar. TGA, phenolphthalein method, FT-IR XRD, and FE-SEM analysis methods were used to evaluate $CO_2$ capture in mortar. When $CO_2$ philic adsorbents was used, $CO_2$absorption efficiency was improved maximum of 58.5%. Carbonation depth was increased 3 times compared with original mortar. Chemical reactions between bicarbonate ion, $CO_2$, $CO_2$ philic adsorbents aqueous solution, and $Ca^{2+}$ ions dissolved from cement formed $CaCO_3$ in the mortar. Therefore, impregnation of the $CO_2$ philic adsorbent on the surface of the mortar can increase the adsorbed $CO_2$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.39-46
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• 2020

Carbonation is a deterioration which degrades structural and material performance by permitting CO₂ and corrosion of embedded steel. Service life evaluation through deterministic method is conventional, however the researches with probabilistic approach on service life considering loading and cold joint effect on carbonation have been performed very limitedly. In this study, probabilistic service life evaluation was carried out through MCS (Monte Carlo Simulation) which adopted random variables such as cover depth, CO₂ diffusion coefficient, exterior CO₂ concentration, and internal carbonatable materials. Probabilistic service life was derived by changing mean value and COV (Coefficient of variation) from 100 % to 300 % and 0.1 ~ 0.2, respectively. From the analysis, maximum reduction ratio (47.7%) and minimum reduction ratio (11.4%) of service life were obtained in cover depth and diffusion coefficient, respectively. In the loading conditions of 30~60% for compressive and tensile stress, GGBFS concrete was effective to reduce cold joint effect on carbonation. In the tensile condition, service life decreased linearly regardless of material types. Additionally service life rapidly decreased due to micro crack propagation in the all cases when 60% loading was considered in compressive condition.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.217-227
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• 2023

Crystalline calcium carbonate (CaCO₃) occurs in various geological and aqueous environments as calcite, aragonite, and vaterite. These minerals also have practical applications in engineered settings. Synthetic methods of calcium carbonate have been developed for scientific research and technical applications. For example, these methods have become widely adopted for studying the formation of CaCO₃ minerals and (geo-)chemical processes involving these minerals in natural and engineered systems. Furthermore, these methods have the potential to be applied in various technical and biomedical fields. Water-based synthesis is particularly important for simulating the formation of calcium carbonate minerals in natural aqueous environments. This review paper describes the procedures and experimental conditions for water-based synthetic methods of each calcium carbonate polymorph, compares the morphological and structural features of the resulting crystals, and analyzes the crystallization mechanisms.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.141-155
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• 2017

In the present paper, we investigated the development status of precipitated calcium carbonate (PCC) production using steel slag, which is one of mineral carbonation (MC) technologies, from the standpoint of $CO_2$ utilization. Principle, feature, and global and domestic development status of the mineral carbonation technology were discussed together with the overview of the production method and market of PCC. Mineral carbonation is known as stable and environmentally-friendly technology enabling economical treatment of industrials wastes. Typically, PCC is produced by the reaction of $CO_2$ with supernatant solution after Ca extraction from steel slag followed by the separation of solid and liquid. The development status of MC using steel slag is at the pilot stage (Slag2PCC at Aalto University), and there remains the process economics improvement for commercialization. Key technologies for the further development are efficient extraction of Ca ions from steel slag including impurities removal, valorization of PCC via shape and size control, usage development and value-addition of residual slag, and optimization of reaction conditions for continuous process setup, etc.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.239-246
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• 2016

In this study, recycling sludge water of Ready-mixed concrete, and was carried out to optimize the system for recycling of the $CO_2$. The most important process in the liquid phase using a carbonation reaction can be recovered ready-mixed concrete is a process for the $Ca^{2+}$ release. $Ca^{2+}$ concentration of the experiment relative to the pH being lowered by the acidic substance during elution was performed. $CO_2$ was trapped in the MEA solution using a generator flue gas. In ready-mixed concrete can be synthesized $CaCO_3$ up to 11kg/1ton. The resulting $CaCO_3$ analysis results show that it is possible to use paper industry.