본 연구에서는 건축폐기물로 분류되는 레미콘회수수를 재활용함과 동시에 지구온난화의 주범 인 CO2의 자원화를 위한 시스템의 공정최적화를 진행하였다. 레미콘회수수를 이용한 액상탄산화 반응에 서 가장 중요한 공정은 Ca2+를 용출하는 공정이다. 일정량의 레미콘회수수를 이용해 고순도의 CaCO3을 생성하기 위해 Ca2+ 용출시 질산에 의해 낮아지는 pH 농도를 기준으로 실험을 진행하였으며, CO2는 발전기 배기가스를 이용해 MEA용액에 포집하였다. 본 연구를 통해 1톤의 레미콘회수수에서 최대 11 kg의 CaCO3를 합성할 수 있었다. 생성된 CaCO3 분석결과 제지용으로 사용 가능한 것을 확인하였다.

본 연구에서는 이산화탄소 고정화에 있어 이산화탄소 전환을 위해 MEA를 이용한 습식화학흡 수법의 셔틀메카니즘을 도입하였다. 또한 알칼리 무기물질을 다량 함유한 산업부산물을 습식탄산화법을 이용해 처리하고자 하였다. 즉, 산업부산물의 화학적 처리를 통해 칼슘이온을 용출하였다. 산성물질을 이용한 용출상징수를 ICP로 분석한 결과, 칼슘이온이 최대 17,900 ppm(1.79%)을 확보하였다. 또한 MEA를 이용한 습식 흡수공정을 통해 상온, 상압조건의 이산화탄소 분위기에서 94%의 전환률을 얻었 다. 슬러지의 액상탄산화를 통해 슬러지 mg 당 0.175 mg의 이산화탄소를 고정하였으며, 최종생성물의 XRD 분석결과 일반적인 탄산칼슘의 결정구조인 calcite 형상을 확인하였다.

In this study, a liquid carbonation method was applied for producing precipitate calcium carbonate by liquid-liquid reaction. We recycled the recycling water of ready-mixed concrete, one of construction waste for use source of carbonate ion. A supernatant separated from the recycling water of ready-mixed concrete, as a result of ICP analysis of a cation, Ca²+ was contained up to 1100 ppm. We used MEA as a CO₂ absorbent for the liquid carbonation. A precipitate CaCO₃ was produced at more than MEA 20 wt%. The precipitate CaCO₃ as a final product was separated and dried. The result of XRD was confirmed the generation of CaCO₃ to calcite structure.

Steel slag has been used as the alternative binder to replace Portland cement that furthermore used as in construction and/or for stabilization/solidification of heavy metals in mine soil. One of the treatments to modify the leaching behavior of the mine soil is by carbonation. The purpose of this study was to assess the potential of carbonation in various steel slags. Based on chemical and mineralogical characterization of four kinds of slag that were used in this study, it showed that all slags had high potential for reacting with CO2 that was in accordance with the high CaO and MgO content. CO2 sequestration by aqueous carbonation of several kinds of stainless steel slags with different liquid to solid ratio was investigated in this study. The effect of chemical properties and reaction time on the performance of the carbonation process was also investigated. Converter slag, blast furnace slag (BFS) and ladle furnace slag (LFS) were used. Carbonation experiment was conducted in a closed reactor under the conditions; 1bar, 400rpm and 25℃, with solid to liquid ratios of 0.4, 0.6 and 1.0. Carbonation kinetic test was relatively fast and completed within 5 hours. The CO2 consumption increased when the liquid to solid ratio increased because of the dilution effect. Our results showed that the higher CaO and MgO contents in the slag, the higher CO2 consumption was observed. Pohang converter slag and Dangjin LFS showed slightly different tendency. At L/S ratio 0.4, Pohang slag with higher CaO and MgO content had higher CO2 consumption than Dangjin LFS. As the water content increased, Dangjin LFS had higher CO2 consumption than Pohang converter slag that was caused by the texture of Dangjin LFS with smaller particle size than Pohang converter slag. However, both Pohang BFS and Dangjin BFS have poor capacity in CO2 sequestration.

Mineral carbonation, the return technology of Carbon dioxide into the Nature as a generating source, has been studied by advanced countries. Industrial by-products can be used as economical resource for mineral carbonation. This study is intended as an investigation of effluent recycling of liquid carbonation with carbon dioxide fixation using industrial by-products. The nitrogen and carbon dioxide was used by mixing the same as the exhaust gas concentration 15vol%. Carbon dioxide absorbent was used as Mono Ethanol Amine (MEA) concentration of 5~30wt% and then concentration of carbon dioxide absorption were analyzed. After carbonation reaction, Concentration of dissolved inorganic cations and conversion of carbonation were analyzed by ion chromatography, thermogravimetric, x-ray diffraction, scanning electron microscope(SEM). Effluent was recycled MEA and water using RO system. These results Confirmed potential of CO2 reduction and Utilization of carbonation using industrial by-products.

In this study, we examined the liquid carbonation reaction using recycled aggregates as an industrial by-products. This research deals with carbon fixation with a precipitation reaction utilizing 5 wt% and 30 wt% alkanolamine absorbents in an aqueous calcium oxide solution. Unlike carbon fixation operated at high temperature and pressure that consumes a lot of energy, we conducted experiments at moderate temperature (303.15 K) and pressure (1 atm). By adding calcium oxide solution into the carbon dioxide saturated solution, carbonated recycled aggregate was formed. To verify the physical properties of products, XRD analysis was performed and SEM images were obtained.