• Advances in concrete construction
• /
• 제10권4호
• /
• pp.311-317
• /
• 2020

Performance of Sustainable materials continues through using of recycled waste construction materials to minimize the utilization of the natural resources. The cement industry is a major source of CO₂ in the atmosphere which is the main cause of global warming. Replacement of OPC with other sustainable cementitious materials has been the most interesting area of researches. This investigation focuses on the properties of alkali-activated mortar with the different replacement ratios of ceramic tile powder (CTP) by fine soil powder (FSP) (0 to 100)% and different molarities of sodium hydroxide concentrations. The experimental program was conducted by examining the compressive strength, water absorption, and water sorptivity. The results showed that the compressive strength of the specimens at age of (28, 56, and 90 days) increases with an increase in the amount of fine soil powder content and decreases at the age of 120 days. Also, minimum water absorption at the age of 90 days was found in the mixes containing 100% fine soil powder. However, fine soil powder replacement had a negative effect on the sorptivity and water absorption values at the age of 120 days. On the other hand, the 12M sodium hydroxide concentration was considered the optimum concentration compared to other concentrations.

• 펄프종이기술
• /
• 제37권5호통권113호
• /
• pp.41-49
• /
• 2005

This paper deals the effect of anthraquinone (AQ) on the contribution of sulphidity in kraft pulping of sapwood. The pulping conditions namely- active alkali concentration, pulpingtime, temperature and liquor ratio were varied in low ($15\%$) and high ($30\%$) sulphidity. $0.1\%$ AQ was added in the low and high sulphidity pulping with varying active alkali concentration and cooking time. At optimum conditions, low sulphidity kraft process produced about $44\%$ pulp yield with kappa number of about 23. But in high sulphidity kraft process kappa number was reduced to about 20 at the same yield. An addition of AQ reduced alkali requirement by $2\%$ on oven dried raw material and cooking time by 1 hour to produce pulp yield of about $44\%$ at kappa number 20. AQ is more effective in low sulphidity pulping than the high sulphidity pulping. The breaking length of kraft-AQ pulp was slightly higher than that of kraft pulp.

• 공업화학
• /
• 제33권1호
• /
• pp.109-112
• /
• 2022

Lime has been used for the neutralization of acidic waste because it is cheap and available in large quantities. The resulting sludge often contains a considerable amount of unreacted lime due to alkali overdosing, even during automatic neutralization processes, which mainly arises from the poor solubility of lime. The sludge cake from lime neutralization of Ilkwang Mine also contained high percentages of calcium and magnesium. The elemental content of the sludge cake was compared with those obtained from a simulation of the lime neutralization facility installed at Ilkwang Mine. A Goldsim^® model estimated the degree of lime overdosing to be 19.1% based on the fractions of ferrous oxide. The analysis suggests that resolubilization of aluminum hydroxide could occur in the settling basin, in which pH exceeded 10 due to the continued dissolution of the overdosed lime. The present study demonstrated that chemical analysis of sludge combined with process simulation could provide a reasonable estimate of mass balance and chemistry in a neutralization facility for acid mine drainage.

• 한국건설순환자원학회논문집
• /
• 제1권2호
• /
• pp.107-113
• /
• 2013

연구에서는 문제시 되는 순환자원의 종류를 상호 보완적으로 활용하여 문제를 해결하고자하는 연구이다. 즉, 고로슬래그 미분말(BS)의 잠재 수경성반응을 순환 잔 굵은 골재의 알칼리로 반응시키고, 부족분의 알칼리를 보통포틀랜드 시멘트(OPC)로 해결하면서 소석회 처리된 소각장애시(WA)의 치환율을 실험변수로하여 최적치를 구하고자 실험하였다. 실험결과 WA 치환율이 증가할수록 유동성과 공기량은 약간 저하하고, 염화물량은 증가하여 불리하였지만 압축 및 인장강도가 1% 에서 최대 값을 나타내어 폐기물 유효처리 관점까지도 고려하면 WA 1% 혼합이 최적인 것으로 분석되었다.

• 자원리싸이클링
• /
• 제12권2호
• /
• pp.3-10
• /
• 2003

PCB (Printed Circuit Board) 산업에서 배출되는 산성 염화동 폐액으로부터 농약원제로 사용이 가능한 고순도의 copper oxycloride를 제조하였다. PCB제조 산업은 구리 소재를 이용한 전자 부품 가공 산업으로서 제조 공정인 부식 과정에서 다량의 구리가 함유된 에칭 폐액이 발생한다. 환경과 경제적인 측면에서 폐액으로부터 구리성분을 재회수하는 기술의 개발은 매우 중요하다. 본 연구에서는 가성소다로 폐액을 중화하여 copper oxychloride를 회수하는 공정의 반응 조건을 확립하였다. 반응 온도 2$0^{\circ}C$-4$0^{\circ}C$, pH 5-7 사이에서 순수한 copper oxychloride제조가 가능하였고 이때 수득율은 95% 이상이었다. 생성물의 물리적 특성을 SEM, XRD, TGA, ICP 그리고 원자 흡수 분광기를 사용하여 분석하였다.

• Computers and Concrete
• /
• 제29권 5호
• /
• pp.335-346
• /
• 2022

Geopolymers are an important alternative material supporting recycling, sustainability, and waste management. Durability properties are among the most critical parameters to be investigated; in this study, the durability of manufactured geopolymer samples under the attack of 10% magnesium sulfate and 10% sodium sulfate solution was investigated. 180 cycles of freezing and thawing were also tested. The experimentally obtained results investigate the durability of geopolymer mortar prepared with fly ash (class F) and alkali activator. Three different quarry dust wastes replaced the river sand aggregate: limestone, marble, and basalt powder as fine filler aggregate in three different replacement ratios of 25%, 50%, and 75% to produce ten series of geopolymer composites. The geopolymer samples' visual appearance, weight changes, UPV, and strength properties were studied for up to 12 months at different time intervals of exposure to sulfate solutions to investigate sulfate resistance. In addition, Scanning Electron Microscopy (SEM), EDS, and XRD were used to study the microstructure of the samples. It was beneficial to include quarry waste as a filler aggregate in durability and mechanical properties. The compact matrix was demonstrated by microstructural analysis of the manufactured specimens. The geopolymer mortars immersed in sodium sulfate showed less strength reduction and deterioration than magnesium sulfate, indicating that magnesium sulfate is more aggressive than sodium sulfate. Therefore, it is concluded that using waste dust interrogation with partial replacement of river sand with fly ash-based geopolymers has satisfactory results in terms of durability properties of freeze-thaw and sulfate resistance.

• 펄프종이기술
• /
• 제30권2호
• /
• pp.85-95
• /
• 1998

Traditionally, Hanji had been made only with the bast fiber of paper mulberry (Broussonetia kazinoki). Nowadays, Hanji has been made mainly in the mixed forms of paper mulberry bast fiber and waste paper, and consequently it has raised many problems using them. This study was carried out to investigate the characteristics of Hanji mixed with paper mulberry bast part and whole stalk pulps. Hanjis made from the solfomethylated pulp were shown higher brightness and sheet strengths than those from alkali and alkali-hydrogen peroxide pulps. The brightness of solfomethylated pulp was found to be high enough not to need additional bleaching. The sheet formations were improved as the increase of whole stalk pulp contents, while the sheet strengths were decreased. In the physical properties of the Hanji mixed with bast part and whole stalk pulps, the handsheet strengths were decreased as the increase of the whole stalk pulp contents. The tensile strength and folding endurance of the Hanji containing 40∼60% of whole stalk pulps were higher as compared to the others.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.195-196
• /
• 2023

In this study, the mechanical properties, alkali-silica reaction(ASR) expansion and residual mechanical properties after ASR of waste glass fine aggregate(GS) mortar according to mineral mixture were evaluated. As a result, it was found that the mineral mixture reduces the ASR expansion. However, mechanical properties and residual mechanical properties have decreased.

• 자원리싸이클링
• /
• 제28권6호
• /
• pp.54-63
• /
• 2019

본 연구에서는 폐유리를 골재로 재활용하고자 폐유리와 산화 그래핀을 사용한 시멘트 모르타르의 압축강도 및 길이 변화율 등을 검토하였다. 3일 및 7일 압축강도는 일반 모래 대체용 폐유리 사용량이 증가할수록 상승하였다. 특히, 폐유리 사용량이 10~50% 범위일 경우, 압축강도는 큰 폭으로 상승하는 경향을 나타내었다. 더불어 폐유리 50% 조건에서도 산화 그래핀의 첨가량이 증가됨에 따라 압축강도가 상승하였으며, 0.2%를 첨가하였을 때, 압축강도는 42.6 N/㎟ 이었다. 폐유리의 사용량이 증가됨에 따라 모르타르의 길이 변화율은 증가하였으나, 50% 이상에서는 길이변화율이 감소하는 경향도 나타내었다. 폐유리 사용량 50% 모르타르에서는 산화 그래핀 첨가량이 증가할수록 길이 변화율이 감소하는 경향을 나타내었으며, 이는 산화 그래핀의 시멘트 수화반응 촉진작용과 이온이동 억제효과로 추정되었다.

• 유기물자원화
• /
• 제24권4호
• /
• pp.5-9
• /
• 2016

현대의 집적된 산업 사회에서 자정능력을 초과하여 발생하는 막대한 양의 유기성폐자원은 수질, 토양, 대기 등 총체적인 환경오염을 유발하는 처리 곤란 물질로 전락하였고, 화석연료의 지속적인 사용에 따른 온실가스의 방출은 지구온난화를 촉진시켰다. 개발된 회분식 공정을 적용하는 음식물쓰레기 수소발효에서, 세계 최초로 수소 전환율과 초기 및 운전 pH와의 관계를 수학적으로 표현하였고, 동시에 최적화하였다. 최적 초기 및 운전 pH는 각각 7.50, 6.01이었다. 축산폐수를 음식물쓰레기의 수소발효에 보조기질로 첨가 시 pH 제어를 위해 요구되는 알칼리량을 감소시킴과 동시에 수소발생률도 크게 증대시킬 수 있음을 관찰할 수 있었다.