• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.116-126
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• 2015

The present study utilized a shuttle mechanism of wet chemical absorption using MEA. In addition, industrial by-products containing a large amount of inorganic alkali substances were utilized for wet carbonization process. Chemical pretreatment of industrial by-products extracted calcium ions. ICP result of calcium ion was obtained up to 17,900 ppm(17.9%) by acidic substance. And also, In this work, 94% of recovery rate was obtained using wet MEA absorption process from $CO_2$ flow at the ambient condition. Through the liquid carbonation process, a sludge was fixed with rate of 0.175 mg of $CO_2$ per mg of sludge. It was found from XRD results that the structure of final product was composed of a calcite structure which is general structure of $CaCO_3$.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.34-38
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• 2019

A cement industrial by-product was used as a Ca source for the carbonation process. It was confirmed that the most of cement industrial by-products was composed of CaO and KCl through ICP and XRD analyses. The optimal extractant type and concentration was 1.5 M of hydrochloric acid, and the solid/liquid ratio was 0.1 g/mL. It was assumed that the cation extraction efficiency was dependent of the pair ions and their binding formation and also the solubility from extraction efficiency results by varing extractants. After extraction process, it was also confirmed that the cation could be selectively separated from the solution with respect to the kind of additives and the injection order. When NaOH was injected into the solution to control pH values ranging from 9.5 and 13, impurities and $Ca(OH)_2$ were precipitated, whereas the separated K ion was precipitated in the form of KCl under the injected $C_2H_5OH$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.49-58
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• 2008

Generally, steel corrosion occurs in concrete structures due to carbonation in down-town area and underground site and it propagates to degradation of structural performance. In general diagnosis and inspection, only carbonation depth in sound concrete is evaluated but unsound concrete such as joint and cracked area may occur easily in a concrete member due to construction process. In this study, field survey of carbonation for RC columns in down-town area is performed and carbonation depth in joint and cracked concrete including sound area is measured. Probability of durable failure with time is calculated through probability variables such as concrete cover depth and carbonation depth which are obtained from field survey. In addition, service life of the structures is predicted based on the intended probability of durable failure in domestic concrete specification. It is evaluated that in a RC column, various service life is predicted due to local condition and it is rapidly decreased with insufficient cover depth and growth of crack width. It is also evaluated that obtaining cover depth and quality of concrete is very important because the probability of durable failure is closely related with C.O.V. of cover depth.

• 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.232-238
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• 2016

In this study, a liquid carbonation method was applied for producing precipitate calcium carbonate by liquid-liquid reaction. Also a shuttle mechanism of wet chemical absorption using MEA was utilized. The high concentration $CO_2$(A) and exhaust gas(B) was used for collecting carbon dioxide in the 30% MEA aqueous solution, and $CO_2$ was fixed with rate of 0.35 mg of $CO_2$ per mg of sludge through the liquid carbonation process. It was found from SEM data that calcium carbonate was mainly made up with spherical vaerite with the mixing of a small quantity of calcite.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.188-189
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• 2020

In the field of architecture, concrete and steel bars are the most common and popular combinations. The relationship between the two in a structure is a complementary good that increases in utility when consuming both materials at the same time. However, the combination of the two, which has been perceived as semi-permanent, often faces repairs or reconstruction without its lifespan reaching decades. There are a number of deterioration factors at work for the reason for this phenomenon. Among them, the neutralization of concrete in particular refers to the process in which calcium hydroxide inside concrete reacts with carbon dioxide and loses alkalinity, which creates a corrosive environment for rebars inside concrete, causing serious damage to concrete. In this study, we intend to use a multi-physical analysis program using finite element analysis method to analyze the degree of carbonation according to the internal temperature and concentration of carbon dioxide in concrete, thereby contributing to the prediction of long-term neutralization of concrete and the research related to measures for neutralization of concrete.

• Journal of Energy Engineering
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• v.12 no.2
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• pp.145-153
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• 2003

In order to develop the carbonation process as a core technology of zero emission coal power plant, study on characterization of methane steam reforming (MSR) which is main reaction of this process was carried out. The effects of gas hourly space velocity (GHSV), steam/carbon (S/C) ratio and pressure in the MSR using reforming catalyst were investigated. The equilibrium composition of the gases produced in the MSR were obtained below GHSV 7,000 hr$\^$-1/. The operating conditions of carbonation process using hybrid reaction (MSR+CO$_2$ adsorption using CaO) were 700∼800$^{\circ}C$ and S/C ratio of 2.5∼3. The equilibrium mixture of gases composed of 75∼78% H$_2$ and 8∼9％ CO$_2$ at atmospheric pressure and 60∼78% H$_2$ and 9∼l1% CO$_2$ at 1∼30 atm respectively under above operating conditions.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.11
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• pp.597-606
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• 2015

This work investigates the carbonation of KOH-dissolved methanol and ethanol solution systems carried out for $CO_2$ fixation. Potassium methyl carbonate (PMC) and potassium ethyl carbonate (PEC) were synthesized during the reaction in each solution as the solid powder, and they were characterized in detail. The amount of $CO_2$ chemically absorbed to produce the PMC and PEC precipitates were calculated to be 97.90% and 99.58% of their theoretical values, respectively. In addition, a substantial amount of $CO_2$ was physically absorbed in the solution during the carbonation. PMC precipitates were consisted of the pure PMC and $KHCO_3$ with the weight ratio of 5:5, respectively. PEC precipitates were also mixture of the pure PEC and $KHCO_3$ with the weight ratio of 8:2, respectively. When these two precipitates were dissolved in excess water, methanol and ethanol were regenerated remaining solid $KHCO_3$ in the solutions. Therefore, the process has the potential to be one of the efficient options of CCS and CCU technologies.

• Smart Structures and Systems
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• v.21 no.3
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• pp.305-320
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• 2018

The second half of the 20th century was marked with a significant raise in amount of railway bridges in Austria made of reinforced concrete. Today, many of these bridges are slowly approaching the end of their envisaged service life. Current methodology of assessment and evaluation of structural condition is based on visual inspections, which, due to its subjectivity, can lead to delayed interventions, irreparable damages and additional costs. Thus, to support engineers in the process of structural evaluation and prediction of the remaining service life, the Austrian Federal Railways (${\ddot{O}}$ BB) commissioned the formation of a concept for an anticipatory life cycle management of engineering structures. The part concerning concrete bridges consisted of forming a bridge management system (BMS) in a form of a web-based analysis tool, known as the LeCIE_tool. Contrary to most BMSs, where prediction of a condition is based on Markovian models, in the LeCIE_tool, the time-dependent deterioration mechanisms of chloride- and carbonation-induced corrosion are used as the most common deterioration processes in transportation infrastructure. Hence, the main aim of this article is to describe the background of the introduced tool, with a discussion on exposure classes and crucial parameters of chloride ingress and carbonation models. Moreover, the article presents a verification of the generated analysis tool through service life prediction on a dozen of bridges of the Austrian railway network, as well as a case study with a more detailed description and implementation of the concept applied.

• Journal of the Korea Institute of Building Construction
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• v.22 no.3
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• pp.251-258
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• 2022

In the cement industry, in order to reduce CO₂ emissions, technology for raw materials substitution and conversion, technology for improving process efficiency of utilizing low-carbon new heat sources, and technology for collecting and recycling process-generated CO₂ are being developed. In this study, we conducted a basic experiment to contribute to the development of CSC that can store CO₂ as carbonate minerals among process-generated CO₂ capture and recycling technologies. Three types of CSC clinker with different SiO₂/(CaO+SiO₂) molar ratios were prepared with the clinker raw material formulation, and the characteristics of the clinker were analyzed. As a result of analysis and observation of CSC clinker, wollastonite and rankinite were formed. In addition, as a result of the carbonation test of the CSC paste, it was confirmed that calcite was produced as a carbonation product. The lower the SiO₂/(CaO+SiO₂) molar ratio in the CSC clinker chemical composition, the lower the wollastonite production amount, and the higher the rankinite production amount. And the amount of calcite production increased with the progress of carbonation of the CSC paste specimen. It is judged that rankinite is more reactive in mineralizing CO₂ than wollastonite.