Kye-Hong Cho

요 약 칼슘실리케이트 시멘트(Calcium silicate cement, CSC)는 친환경 저탄소 시멘트로써 최근에 많은 연구가 진행되고 있다. 하지만 이산 화탄소 반응 활성화와 시료 handling을 위하여 사전경화 단계를 진행하여야하는 어려움이

Titanium's importance as a mineral resource is increasing, but the Korean industry depends on imports. Ilmenite is the principal titanium ore. However, research and development from raw materials have not been investigated yet in detail. Hence, measures to secure a stable titanium supply chain are urgently needed. Accordingly, through beneficiation technology, we evaluated the possibility of technological application for the efficient recovery of valuable minerals. As a result of the experiments, we confirmed that mineral particles existed as fine particles due to weathering, making recovery through classification difficult. Consequently, applying beneficiation technologies, i.e., specific gravity separation, magnetic separation, and flotation, makes it possible to recover valuable minerals such as hematite and rutile. However, there are limitations in

한국석회석신소재연구소 연구개발부 고염소 시멘트는 CaO-Al 2 O 3-CaCl 2 가 결합된 CCA(calcium chloro aluminate)수경성 광물상이 다량 함유되어 있는 특수 시멘트로 보통 포틀랜드 시멘트 대비 Cl 성분이 과량 함유되어 있는 특징을 나타낸다. 석회석, 점토질 물질, 실리카질 물질 및 Cl이 과량 함유되어 있는 시멘트 킬른 더스트 등을 활용해 제조할 수 있으며, 조강특성이 우수해 자원순환 관 점에서 활용성이 우수한 시멘트이다. 다만, 시멘트 내 Cl이 과량 함유되어 있을 경우 경화과정에서 Cl 이온 용출에 따 라 철근부식, 시멘트 경화체의 내구성 저하 등의 문제가 발생될 수 있어 제조특성과 관련된 기초연구만 소수 진행된 상황이며, 실질적인 활용성 예측을 위한 수화반응 연구는 거의 진행되지 않는 상황이다. 이에 본 연구에서는 고염소 시 멘트의 수화반응을 거시적으로 연구하여, 활용성을 예측하고자 하였다. 실험결과, CCA가 과량 함유되어 있는 고염소 시멘트 일수록 수화초기 Al계 수화물인 ettrinigte가 다량 생성되며, 수화과정 중 용출된 Cl 이온이 monosulfate와 결합 하여 friedel's salt를 형성하는 것을 확인할 수 있었다.

In this study, soda lime was prepared from slaked lime to expand the scope of limestone use. To evaluate carbon dioxide absorption, an extruder-type and disc-type pelletizers were used to make the soda lime using bentonite as an additive. Regardless of the pelletizing process, the peak of CaCO 3 was confirmed in soda lime due to its reaction with carbon dioxide. Furthermore, it was confirmed that both calcite and aragonite were present together. The soda lime prepared using the disc-type pelletizer showed a larger specific surface area than that prepared using the extruder-type pelletizer did, and the specific surface area improved on adding bentonite. The carbon dioxide absorption rate increased under the sample condition with an enhanced specific surface area.

The cement industry, which is an energy-intensive and high carbon dioxide emission industry, requires strategy for carbon neutrality and sustainable development. Most domestic cement companies are generating electricity by waste heat recovery system to improve energy efficiency during cement processes; however, few studies exist on recycling of energy related to this. Certain countries with high cement production researched on modifying the conventional waste heat recovery system to maximize waste heat recovery using various methods such as applying the Rankine cycle depending on the temperature, comparing working fluids, applying two or more Rankine cycles, and combining with other industries. In this study, we reviewed the research direction for energy efficiency improvement by summarizing waste heat recovery and utilization methods in the domestic and overseas cement industries.

Calcium silicate based cement (CSC) is a low-carbon cement that emits less CO 2 by up to 70% compared to ordinary Portland cement during its manufacture. Most developed countries have commercialized CSC, whereas Korea is still investigating the manufacturing characteristics and basic properties of CSC. This paper provides a review of methods for manufacturing CSC using domestic raw materials and discusses the possibility of CSC localization based on an evaluation of the basic physical properties of manufactured CSC. The experimental results of this study indicate that the primary mineral components of CSC were CS, C 3 S 2 C 2 S, and unreacted SiO 2. This suggests the possibility of manufacturing CSC using domestic raw materials that exhibit mineral compositions similar to that of theoretical CSC. The compressive strength of CSC mortar is less than 1MPa at the age of 7 d under wet curing. This implies that hydration does not affect the property development of CSC mortar. Meanwhile, during carbonation curing, the compressive strength is 56 MPa or higher after 7 d, which indicates excellent