• 한국건설순환자원학회논문집
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• 제8권1호
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• pp.64-71
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• 2020

본 연구에서는 대표적인 건설재료인 시멘트를 대상으로 남북한의 시멘트 기준과 성능을 비교 분석하여 북한 시멘트 산업 및 기술 현황을 평가하는 것을 연구의 목적으로 문헌조사와 실험을 병행하였다. 문헌적 연구에서 북한의 시멘트 산업현황과 성능기준에 관한 자료를 통일부의 북한자료센터와 특수자료 취급기관 등을 통해서 수집하여 분석하였다. 이를 토대로 남북한 시멘트의 설비, 분류, 품질기준을 비교하였다. 실험적 연구에서 북한의 시멘트 품질에 관한 조사는 실제 북한의 시멘트를 중국을 통하여 소량 입수하여 물리화학 분석실험을 병행하였고 국내 시멘트와 비교분석을 하였다. 연구결과, 북한 시멘트는 한국 시멘트 보다 품질이 저하되는 것으로 나타났다. 북한 시멘트는 한국 시멘트 보다 C₃S가 낮고 C₂S가 높았으며, 특히 잔사 함량이 월등히 높게 나타났다. 또한 북한 시멘트는 한국의 시멘트보다 약 50% 정도의 압축강도 발현을 하지 못하였다. 이는 북한 시멘트 설비의 낙후 및 전력 문제로 인하여 충분한 온도로 클링커가 소성되지 않았기 때문인 것으로 사료된다.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.296-302
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• 1999

The state of the art of the 2-stage swirl calciner is to make 2-stage counter gas flow in a calciner with cooler hot air. Gas flow in the calciner increases retention time of raw mix particles. Simple structure of the 2-stage swirl calciner operated optimally the rotary cement kiln. In this study, in order to decide the entrance type of the cooler air of the optimal calciner model, an entrance cooler air velocity, the input points of raw mix were analyzed in many aspects with cold model experiment and computational fluidized dynamic simulation. It was found that the entrance type of cooler air fully splite 2-stage for the optimal condition of the cold model calciner. The operation conditions were that the input feeding, the cooler air velocity and the air velocity of throat were 0.33kg/$\textrm m$3$, 15m/s and 20m/s respectively. The performance of 150 t/d the pilot plant connected with the kiln rising duct was that volume capacity of the calciner is over 430 kg/$\textrm m$3$-h, decarbonation rate of raw mix apparently 90%, heat consumption 950 kcal/kg-cli and retention time of raw mix 2.4 sec. Its the best operating condition is cooler air velocity 18m/s, the gas velocity of throat 25m/s, feeding rate of raw mix 10t/h. The operating experience of the pilot plant confirmed the success of scale up for over 3000 t-cli/d.

• 자원리싸이클링
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• 제4권4호
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• pp.37-58
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• 1995

본 고에서는 소형 타이어 원형 그대로를 시멘트 kiln inlet 부분에 투입하였고, 그 부분의 가스온도와 시멘트 원료 온도는 각각 $1050^{\circ}C$, $800~850^{\circ}C$ 정도이다. 폐타이어를 4단 부유예열실에서 예열된 고온의 원료와 함께 kiln 입구부분에 투입하였다. 투입량은 폐타이어 열이용 실험 대상 kiln인 열소비량의 3, 5, 7%로 정하여 실험하였다. 폐타이어 열이용 전에 폐타이어의 성상을 분석하였으며, 열이용을 실험하는 동안에 투입수준별로 시멘트 소성공정에 미치는 영향, 즉 예열실 온도, 압력, 배가스량, 배가스성분, 코팅형성, 전력 사용량, 연료감소량, clinker 생산량 변화 등을 분석하였고, 품질에 미치는 영향에서는 시멘트 색도, 광물조성, 응결시간, 압축강도 등의 변화를 분석하였고, 환경오염 평가에서는 $SO_2$, NOx의 증감을 측정 분석하였다. 폐타이어 투입수준 5%일 때 비교적 시멘트 공정이 안정한 상태를 보였으며, 이때의 열량회수율도 50% 정도였고, 시멘트 품질은 사용전과 등등 수준이었다. $SO_2$, NOx는 증가하는 경향이었으나 규제치에는 훨씬 못미치는 수치였다.

• 한국세라믹학회지
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• 제53권2호
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• pp.194-199
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• 2016

Presently, for the cement industry, studies that seek to reduce $CO_2$, because of the development of the plastic industry and demand for reduction of energy use, have been actively conducted among them, studies attempting to use Gamma-$C_2S({\gamma}-C_2S)$ to fix $CO_2$ have been actively conducted. The ${\gamma}-C_2S$ compound has an important function in reacting to $CO_2$ and stiffening through carbonatization in the air. The ${\gamma}-C_2S$ compound, reacting to $CO_2$ in the air, generates $CaCO_2$ within the pore structure of cement materials and densifies the pore structure this leads to an improvement of the durability and to the characteristic of resistance against neutralization. Therefore, in this experiment, in order to synthesize ${\gamma}-C_2S$, limestone sludge and waste foundry sands are used these materials are plasticized for 30 or 60 minutes at $1450^{\circ}C$, and are prevented from being cooled in the temperature range of $30{\sim}1000^{\circ}C$ when they are about to be cooled. XRD analysis and XRF analysis are used to determine the effects of this process on ${\gamma}-C_2S$ synthesization, the temperature at which a thing is plasticized, and the conditions for cooling that obtain in the plasticized clinker also, in order to confirm the $CO_2$ capture function, analysis of the major hydration products is conducted through an analysis of carbonatization depth and compressive strength, and through MIP analysis and XRD Rietveld analysis. As a result of these analyses, it is found that when ${\gamma}-C_2S$ was synthesized, the clinker that was plasticized at $1450^{\circ}C$ for one hour demonstrated the highest yield rate the sample with which the ${\gamma}-C_2S$ was mixed generated $CaCO_3$ when it reacted with $CO_2$ therefore, carbonatization depth and porosity were reduced, and the compressive strength was increased.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.73-76
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• 1999

In recent, concrete material like specific cement and additives having many functions hsa been developed. In road pavement, ultra high early strength cement or organic material are used to open the road early, but there are many restrictions like workable time and special equipment. We aim to developed specific concrete which 1 day strength is over 300kgf/$\textrm{cm}^2$ to open the road within one day and workable time is maintained over 1 hour that can make the concrete ready mixed concrete. In this study, we are convinced if the ratio of hauyne clinker or its additive is increased early strength property is progressed and if the ratio of non hydrous gypsum is increased longtime strength is progressed. The concrete strength is 290-310 kgf/$\textrm{cm}^2$ at 1 day, 570-640 kgf/$\textrm{cm}^2$ at 28 day and the workable time is maintained over 30 minutes. As the results of this experiments We find out the possibility to developed the 1 day usable ready mixed concrete with high early strength.

• 한국세라믹학회지
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• 제38권1호
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• pp.68-73
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• 2001

Active belite cement clinker 합성을 위하여 안정제로 borax (3 wt%)를 사용하였으며, 1300, 1350, 140$0^{\circ}C$에서 소성하고, 각각의 소성온도에서 아세톤 급냉, 공냉, 로냉의 3가지 방법으로 냉각속도를 달리하여 합성하였다. 클링커의 특성분석은 TG-DTA, XRD, FT-IR, SEM-EDS로 조사 분석하였으며, free-CaO 함량은 KSL 5120의 ethylene glycol법으로 정량하였다. Borax(3 wt%)를 첨가한 시료의 시차열분석에서 ${\gamma}$상으로의 전이는 관찰되지 않았으며, 각각의 소성온도와 냉각속도에 따른 free-CaO 분석에서 0.07~0.14%의 범위로 낮게 나타났으며, borax가 첨가되지 않은 시료는 140$0^{\circ}C$에서 소성하고 급냉시켰지만 ${\gamma}$상으로 전이되어 dusting 현상을 나타내었다. Borax(3 wt%) 첨가된 시료의 SEM 미세구조는 140$0^{\circ}C$에서 소성하고 급냉시켰지만 ${\gamma}$상으로 전이되어 dusting 현상을 나타내었다. Borax(3 wt%) 첨가된 시료의 SEM 미세구조는 140$0^{\circ}C$에서 소성된 모든 시료와 135$0^{\circ}C$에서 소성하고 급냉과 공냉시킨 시료는 type I belite, type III belite($\alpha$상) 구조를 나타낸다. 135$0^{\circ}C$에서 소성하고 로냉한 시료와 130$0^{\circ}C$에서 소성된 모든 시료는 type II belite($\beta$상) 구조를 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.215-216
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• 2012

Emissions of CO₂ occur during the production of cement manufacturing process. During the production of clinker, limestone is mainly calcium carbonate, is heated to produce lime and CO₂ as a by-product. It has a major problem, CO₂ uptake is not considered in concrete carbonation, just focus in CO₂ emission. This study is to develop a simulation model for CO₂ uptakes in concrete structures based on carbonation reduction coefficient considering finishing materials. CO₂ uptakes unit of concrete cubic meter is calculated by CO₂ emissions unit of concrete materials and usage of concrete materials in mix proportion. From the simulation result, CO₂ uptake ratios is 2.04 percent in carbonation models of concrete structure during 40 years.

• 분석과학
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• 제26권5호
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• pp.340-351
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• 2013

The chemical element and structural characterization of different types of cements and its brick stones are been investigated under forensic aspects using X-ray florescence (XRF) and X-ray diffraction (XRD) spectrometer. The XRF provides rapid compositional data for controlling almost all stages of raw materials, clinker and cement. The decisive advantage of XRD methods is based on the unique character of the diffraction patterns of crystalline substances, the ability to distinguish between elements and their oxides, and the possibility to identify chemical compounds, polymeric forms, and mixed crystals by non-destructive examination. Therefore, combination of these examinations is useful and able to apply for the forensic analysis in comparison of cements and brick stones. There are more study remained to determine the viability of method for forensic analysis of brick stones and the limits of the discrimination that can be achieved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.155-160
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• 1998

In this study, the estimation method of adiabatic temperature rise of concrete was developed by using hydration heat generation of mineral compounds of clinker and pozzolans. Specific heat considered the effects of mix proportion and temperature was calculated with experimental data. The adiabatic temperature rise calculated by developed method were compared with experiments in which many types of cement and admixtures were used. As the results of this study, it was found that the developed method could calculate adiabatic temperature rise of concrete accurately without the experiment.

• 한국세라믹학회지
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• 제35권12호
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• pp.1241-1248
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• 1998

$\beta$-C2S and C4A3 were synthesized separately and potassium oxalate was added to each system. The ad-ditive caused calcium ions in solution to decrease at early time in hydration and promoted hydration reac-tion. And then clinker which is mainly composed of $\beta$-C2S and C4A3 was synthesized at 130$0^{\circ}C$ After ad-ding potassium oxalate to it behavior of hydration was observed. It showed that the additive promoted et-tringtie formation at early time and C-S-H formation as time went on.