• Resources Recycling
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• v.32 no.6
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• pp.18-24
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• 2023

This study undertook initial investigations into the carbonation of chlorine bypass dust, aiming to apply it as a raw material for cement and as an admixture for concrete. Various experimental methods, including XRD(X-ray diffraction), XRF(X-ray fluorescence), and particle size distribution analyses, were employed to verify the physical and chemical properties of chlorine bypass dust, with and without water washing. The mineral carbonation extent of chlorine bypass dust was examined by considering the dust type, stirring temperature, and experiment duration. Notably, a higher degree of mineral carbonation was observed in water-washed bypass dust than its non-water-washed counterpart, indicating an elevated calcium content in the former. Furthermore, an augmented stirring temperature positively impacted the initial stages of mineral carbonation. However, divergent outcomes were observed over time, contingent upon the specific characteristics of dust types under consideration.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.439-450
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• 2020

Global warming caused by the emission of greenhouse gases into the atmosphere is being treated as a major problem for the human life, and mineral carbonation is drawing attention as one of many countermeasures against this situation. In this study, mineral carbonation experiments using autoclaved lightweight concrete (ALC) were performed under various conditions to determine its potential as a carbonation material. ALC can be regarded as a promising material for carbonation because it contains about 27 wt.% of CaO, a major component of mineral carbonation. The CaCO3 content produced as a result of the carbonation of ALC calculated on the assumption that all of the CaO content participates in mineral carbonation is about 40 wt.%. The optimum conditions for the mineral carbonation reaction from ALC are the solid-liquid ratio of 0.01 and the reaction time of 180 minutes when calcite is considered as a single product, or 0.06 and 180 minutes when mixture of calcite and vaterite can be considered. The coexistence of vaterite with calcite at solid-liquid ratio of 0.06 or higher was interpreted to be the case where vaterite formed in the later stage and did not change to calcite until the reaction was completed.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.137-150
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• 2011

$CO_{2}$ mineral carbonation technology, fixation technology of $CO_{2}$ as carbonates, is considered to be an alternative to the $CO_{2}$ geological storage technology, which can perform small- or medium-scale $CO_{2}$ storage. We provide the current R&D status of the mineral carbonation with special emphasis on the technical and economical feasibility of $CO_{2}$ mineral carbonation taken into consideration of the domestic geological and industrial environment. Given that the domestic industry produces relatively large amount of the industrial by-products, it is expected that the technology play a pivotal role on the $CO_{2}$ reduction countermeasure, reaching the potential storage capacity to 12Mt-$CO_{2}$/yr. The economics of the overall process should be improved via the development of advanced technologies on the pretreatment of raw materials, method/solvents for metal extraction, enhanced kinetics of carbonation reactions, heat integration, and the production of highly value-added carbonates.

• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.205-217
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• 2017

Mineral carbonation by indirect method has been studied by serpentinite as cation source. Through the carbonation of $CO_2$ and alkaline earth ions (calcium and magnesium) from serpentinite, the pure carbonates including $MgCO_3$ and $CaCO_3$ were synthesized. The extraction solvent used to extract magnesium (Mg) was ammonium sulfate ($(NH_4)_2SO_4$), and the investigated experimental factors were the concentration of $(NH_4)_2SO_4$, reaction temperature, and ratio of serpentinite to the extraction solvent. From this study, the Mg extraction efficiency of approximately 80 wt% was obtained under the conditions of 2 M $(NH_4)_2SO_4$, $300^{\circ}C$, and a ratio of 5 g of serpentinite/75 mL of extraction solvent. The Mg extraction efficiency was proportional to the concentration and reaction temperature. $NH_3$ produced from the Mg extraction of serpentinite was used as a pH swing agent for carbonation to increase the pH value. About 1.78 M of $NH_3$ as the form of $NH_4{^+}$ was recovered after Mg extraction from serpentinite. And, the main step in Mg extraction process of serpentinite was estimated by geochemical modeling.

• Journal of the Mineralogical Society of Korea
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• v.27 no.1
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• pp.17-30
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• 2014

Waste cement generated from recycling processes of waste concrete is a potential raw material for mineral carbonation. For the $CO_2$ sequestration utilizing waste cement, this study was conducted to obtain basic information on the aqueous carbonation methods and the characteristics of carbonate mineral formation. Cement paste was made with W:C= 6:4 and stored for 28 days in water bath. Leaching tests using two additives (NaCl and $MgCl_2$) and two aqueous carbonation experiments (direct and indirect aqueous carbonation) were conducted. The maximum leaching of $Ca^{2+}$ ion was occurred at 1.0 M NaCl and 0.5 M $MgCl_2$ solution rather than higher tested concentration. The concentration of extracted $Ca^{2+}$ ion in $MgCl_2$ solution was more than 10 times greater than in NaCl solution. Portlandite ($Ca(OH)_2$) was completely changed to carbonate minerals in the fine cement paste (< 0.15 mm) within one hour and the carbonation of CSH (calcium silicate hydrate) was also progressed by direct aqueous carbonation method. The both additives, however, were not highly effective in direct aqueous carbonation method. 100% pure calcite minerals were formed by indirect carbonation method with NaCl and $MgCl_2$ additives. pH control using alkaline solution was important for the carbonation in the leaching solution produced from $MgCl_2$ additive and carbonation rate was slow due to the effect of $Mg^{2+}$ ions in solution. The type and crystallinity of calcium carbonate mineral were affected by aqueous carbonation method and additive type.

• Journal of the Mineralogical Society of Korea
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• v.13 no.1
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• pp.22-36
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• 2000

중원지역 지열수의 CO2 가스의 용축과 수반된 탄산염 침전물의 광물학적 특성을 밝히기 위하여 탄산염 침전물에 대해 광물학적 및 지구화학적 분석방법을 적용하여 보았다. 이들은 매년 수 mm의 두께로 저수조내에 침전되며 미세한 층상으로 결정화되어 있고, 검은 갈색의 얇은 층들이 반복적으로 존재하고 있다. 침전물은 비교적 순수한 방해석으로 되어 있으며 1M HCl로 처리하여 잔류물을 XRD 분석한 결과는 카올린 광물 및 일라이트질 광물이 확인되었다. 전자현미분석에 의하면 검은 갈색층은 주로 방해석과 Fe나 Mn 산화광물의 집합체이며 소량의 점토광물도 함께 섞여 있는 것으로 추정된다. Fe의 경우에는 주로 방해석내 Ca자리를 치환하여 존재하며 일부 산화광물로 함께 침전된 것으로 보인다. 반면에 Mn의 경우는 일부는 Fe처럼 방해석결정구조 내에서 Ca를 치환하면서 존재하기도 하지만 주로 산화물의 형태로 존재하는 것으로 보인다. 후방산란전자상(BSEI) 관찰에 의하면 Fe와 Mn 모두 매우 미세한 입자의 산화광물들로 밀집해 있는 부분이 관찰되기도 한다. 중원지역 탄산수로부터 방해석이 침전되는 과정은 CO2 가스가 방출되면서 pH가 증가하면서 방해석 및 Fe, Mn 산화물이 과포화상태가 되어 침전되는 것으로서 해석할 수 있다. 또한 지하 심부를 순환하면서 활발한 물-암석반응의 결과로 Si나 Al 및 기타 이온들의 함량이 상대적으로 높았던 탄산수가 pH가 높아지면서 카올린 광물이나 일라이트질 광물, 석영등의 규산염 광물들이 함께 침전하였을 것이다. 그러나 방해석의 침전과정이 이루어지는 과정 동안에, 온천공으로부터 채수되는 탄산수의 양이 수요에 따라 매우 불규칙해서 탄산수의 수요가 많은 경우 탄산수가 지속적으로 과잉 채수되면 주변 천층지하수가 탄산수에 혼합되어 Fe, Mn 등의 농도를 상대적으로 낮추게 되어 산화물형태로 침전되기가 어려워져서 거의 순수한 방해석만이 침전하게 된다. 결과적으로 거의 순수한 방해석 층에 검붉은 층이 불규칙하게 반복되고 있는 중원지역 탄산염침전물은 침전작용이 일어나는 대부분의 기간 동안 지속적으로 주변 전층지하수의 유입이 일어났음을 지시하고 있다. 또한 Fe, Mn 등의 함량이 높은 탄산수로부터의 침전은 매우 짧은 기간동안 단속적으로 일어났음을 지시한다.

• Mineral and Industry
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• v.22 no.1
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• pp.71-85
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• 2009

• 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.

• Journal of the Korea Institute of Building Construction
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• v.24 no.1
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• pp.1-10
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• 2024

In-situ carbonation technology represents a form of mineral carbonation that integrates CO₂ into the fabrication process of cementitious construction materials, capturing CO₂ as calcium carbonate(CaCO₃) through a reaction between calcium ions(Ca²⁺) and CO₂ released during cement hydration. This investigation examines the application of in-situ carbonation technology to a variety of floor dry cement mortar formulations commonly used in local construction projects. It assesses the effects of varying the CO₂ injection flow rate and total volume of CO₂ injected. Additionally, the study evaluates the impact of reducing the quantity of cement used as a binder on the final product's quality.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.18-24
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• 2016

Mineral carbonation is a technology for permanently storing carbon dioxide by reacting with metal oxides containing calcium and magnesium. In this study, we used sea water and alkaline industrial by-product such as paper sludge ash (PSA) for the storage of carbon dioxide through direct carbonation. We found the optimum conditions of both sea water content (mixing ratio of sea water and PSA) and reaction time required in the direct carbonation through various experiments using sea water and PSA. In addition, we compared the amounts of carbon dioxide storage with the cases when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA. The amount of carbon dioxide storage was calculated by using both solid weight increase through the carbonation reaction and the contents of carbonate salts from thermal gravimetric analysis. PSA particle used in this study contained 67.2% of calcium. The optimum sea water content and reaction time in the carbonation reaction using sea water and PSA were 5 mL/g and 2 hours, respectively, under the conditions of 0.05 L/min flow rate of carbon dioxide injected at $25^{\circ}C$ and 1 atm. The amounts of carbon dioxide stored when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA were 113 and $101kg\;CO_2/(ton\;PSA)$, respectively. The solid obtained through the carbonation reaction using sea water and PSA was composed of mainly calcium carbonate in the form of calcite and a small amount of magnesium carbonate. The solid obtained by using ultra-pure water, also, was found to be carbonate salt in the form of calcite.