• 한국결정성장학회지
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• 제22권3호
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• pp.152-157
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• 2012

본 연구는 알칼리 활성화제로 NaOH와 물유리를 사용하고 리젝트애쉬와 고로슬래그를 혼합하여 지오폴리머를 제조하였다. 리젝트애쉬와 고로슬래그의 치환율과 물유리와 NaOH의 농도에 따른 압축강도를 측정하였다. 압축강도 측정결과로는 알칼리 활성화제로 NaOH 1 wt%, 물유리 3 wt%와 전량 고로슬래그를 사용한 경우 재령 28일차 강도가 38.91 MPa의 성능을 나타내었다. 압축강도 증진의 중요한 요인은 알칼리 활성화제의 비율과 리젝트애쉬와 고로슬래그의 치환율에 의한 것이었다.

• 한국세라믹학회지
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• 제49권2호
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• pp.161-166
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• 2012

The temperature-rasing sintering method was used in this study to fabricate the aggregates of uniform pore size and distribution containing reject ash occurred in the thermal power plant. The spheric green aggregates made of reject ash were put into the box furnace of 800~$1000^{\circ}C$, heated with a heating rate of 5~$15^{\circ}C$/min to 1200~$1275^{\circ}C$, sintered for 10 min and then discharged out of the furnace to the room temperature. The input temperature, heating rate and sintering temperature increased the bloating phenomenon of the specimen, and the sintering temperature among them was the most effective factor. The aggregate manufactured at $1275^{\circ}C$ had the specific gravity of about 1.0 and water absorption of 1~2%, and the pores of 500~1,000 ${\mu}m$ were uniformly distributed across the whole specimen. Especially, the aggregates fabricated using the temperature-rasing sintering method in this study showed an excellent bloating properties and uniform microstructure without black core phenomenon which is typical for the bloated ceramics synthesized by direct sintering method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.178-179
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• 2017

In this study, the fundamental properties of cement mortar in relation to the change of the replacement ratio of the RA(Reject-Ash) were analyzed by mixing RA to the mixed aggregate consisting of poorly graded fine rock aggregate and marine aggregate for quality improvement. It was found that replacing 5% of the mixed aggregate with RA could improve the quality of the aggregate to the degree of fine rock aggregates.

• 한국건설순환자원학회논문집
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• 제5권3호
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• pp.275-281
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• 2017

본 연구에서는 플라이애시(FA)의 정제가 시멘트 모르타르의 제반 품질에 미치는 영향을 고찰하고자 하였다. 본 연구에서 사용된 플라이애시는 원분플라이애시, 정제플라이애시, 리젝트애시 및 이들의 조합으로 5수준으로 선정하였고, 모르타르 배합비는 1: 1, 1 : 3 및 1 : 5의 3수준으로 계획하였다. 본 연구의 실험결과로 먼저 플로는 모든 배합비에서 원분인 Ra 사용시 Rf 보다 낮은 유동성을 나타내었다. 또한 Rj의 경우는 낮은 유동성을 보일 것으로 예상하였으나, Rf와 동등하거나 그 이상의 유동성을 나타내었다. 공기량의 경우 Rf와 Rj를 제외한 모든 배합이 목표 범위에 만족하지 못하였다. Ra를 사용한 배합의 경우 정제과정을 거친 Rf보다 약 41% 낮은 공기량을 나타내었으며, Rj의 경우 모르타르 내부 다공질의 이물질 등으로 인해 Rf 보다 약 19% 높은 공기량을 나타내었다. 압축강도의 경우 초기 3, 7일에서는 Plain인 OPC에 비해 낮은 압축강도를 나타내었으나, 28일 이후에는 양호한 품질인 Rf의 포졸란 반응으로 인해 여타의 FA 보다 높은 강도를 발휘하였으며, 배합비 1 : 1 및 1 : 3에서는 OPC보다 높은 강도를 확보할 수 있음을 확인하였다. 내동해성으로 정제되지 않은 FA를 사용한 경우 공기량 감소로 인해 내동해성에 취약한 것으로 분석되었다. 따라서 정제과정을 거친 양질의 FA 사용은 콘크리트의 경제적인 배합과 구조물의 안정성에도 긍정적인 기여를 할 것으로 판단되었다.

• 펄프종이기술
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• 제47권4호
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• pp.88-95
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• 2015

The main sources of recovered paper for newsprint are old newsprint (ONP) and old magazine (OMG). Recently, a lot of advertisement flyers are flowing into bales of ONP and portion of OMG is increasing in recovered paper because the consumption level of coated paper increases. In this study, nonionic surfactant and fatty acid were used as the de-inking agent for froth-flotation process of mixed recovered paper to investigate the effect of increased mixing ratio of OMG. De-inking efficiency of nonionic surfactant decreased as the mixing ratio of OMG increased; ink removal efficiency of froth-flotation is poor, however, the reject ratio increases due to ash from OMG. In comparison with nonionic surfactant, the ash from OMG had a little effect on reject ratio and optical properties of fatty acid applied flotation accept. If nonionic surfactant and fatty acid are added to pulper and flotation cell sequentially, excessive ash from OMG may not give an adverse effect on de-inking efficiency of mixed recovered paper.

• 펄프종이기술
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• 제35권3호
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• pp.1-12
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• 2003

The complexity of the papermaking system accelerates interactions between a large number of variables involved. The process operation, therefore, is subject to frequent perturbations by disturbance. Dynamic modelling is a useful tool for characterizing the transient behavior and selecting the best control strategies to reject disturbances. In this study we developed a dynamic simulation model of a fine paper production process, which consists of stock preparation, wire sections, white water circulations, and broke system. It focused on dynamic simulation in its role for developing control strategies and studying control loop dynamics related to filler loading for ash control. The results emphasized the importance of filler-loading position and length of control loop for rapid ash control and process stabilization.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.43-44
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• 2016

Recently there have been media reports of some domestic FA refinement factories that omit the refinement process and ship raw material directly, for production time and cost reduction purposes, resulting in a negative effect on concrete quality. Accordingly, it's expected to have a negative effect on concrete quality. So this study seeks to clarify the impact that FA quality has on concrete's engineering characteristics, using various FA from refined FA being circulated in the nation to reject ash discarded during the refinement process. The results showed that when FA is used, liquidity is enhanced than when only OPC is used in the combination, and when refined FA is used air quantity and intensity increases as well.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.483-490
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• 2005

At present around 50 companies have their own crushing plants, which manufacture rock into crushed sand, over around 350 different quarry throughout the nation. However, in most plants the stone dust sludge is left as it is in their plants so that they have difficulty to utilize. Furthermore, environmental pollution may be even caused due to dust generated when it is dried. Recycling is starting capturing the attention of the people working over the quarry due to the reasons described above. This research has studied in the quarters the usability as landfill liner of the stone dust sludge, which is industrial waste. We investigated what technological properties it would have after mixing the stone dust sludge with SM(sandy soil) first and then with blast furnace slag or reject ash, which is waste, and cement as the stabilizer. As the result of three tests; compacting test, strength test, and permeability test; to satisfy the regulatory guideline of the government that is the compress strength over 5 $kgf/cm^2$, the flexibility over 1 $kgf/cm^2$, and the permeability under $1.0{\times}10^{-7}cm/sec$ From this research, we could confirm that stone dust sludge would be used as waste landfill liner if it were mixed with other waste by the proper mixing ratio.