• 제목/요약/키워드: 알루미나 시멘트

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Development of Fly Ash/slag Cement Using Alkali-activated Reaction(2) - Reaction products and microstructure - (알칼리 활성반응을 이용한 플라이 애쉬/슬래그 시멘트 개발(2) - 반응생성물과 미세구조 -)

  • Park, Sang-Sook;Kang, Hwa-Young;Han, Kwan-Su
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.7
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    • pp.810-819
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    • 2007
  • Investigation of alkali activation of fly ash and blast furnace slag was carried out using waterglass and sodium hydroxide. XRD, FTIR, $^{29}Si$ and $^{27}Al$ NMR, TGA and SEM were used to observed the reaction products and microstructure of the fly ash/slag cement (FSC) pastes. The reaction products were amorphous or low-ordered calcium silicate hydrate and aluminosilicate gel produced from alkali activation of blast furnace slag and fly ash, respectively. On the basis of this investigation, waterglass solution with a modulus(Ms) of 1.0 and 1.2 is recommended for alkali activation of fly ash and blast furnace slag. Morphology of FSC pastes alkali-activated with Ms of 1.0 and 1.2 shows a more solid and continuous matrix due to restructuring of gel-like reaction products from alkali-activated fly ash and blast furnace slag together with another hydrolysis product(i.e., silica gel) from water glass.

A Study on the Pore Structure of Hardened Alumina Cement Pste by Water Vapor Sorption ($H_2O$ 증착법에 의한 알루미나 시멘트 경화체의 기공구조 연구)

  • 임용무;장복기
    • Journal of the Korean Ceramic Society
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    • v.30 no.4
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    • pp.273-278
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    • 1993
  • Using water vapor (de)sorption isotherm, pore structure analyses were performed for hardened cement pastes by a combination of the "MP-method" for the micropores and the "corrected modelless method" for the wide pores. This work was carried out to investigate the pore structure and to understand the microstructural basis of alumina cement developing much higher strength than Portland cement. Alumina cement shows extremely low microporosity and its wide pores are also composed mainlyof pores with very small radii. And the pore structure analysis results are consistent with the high strength property of alumina cement.y of alumina cement.

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The characteristics of alumina cement utilized for binder of glass insulators in braket (브래킷 유리애자의 접합재로 이용되는 알루미나 시멘트의 특성)

  • Shong, Kil-Mok;Jung, Jin-Soo;Han, Woon-Ki;Kim, Young-Seok;Ryu, Young-Tae;Jun, Yong-Joo
    • Proceedings of the KIEE Conference
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    • 2008.09a
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    • pp.261-262
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    • 2008
  • Damaged glass insulator that is utilized the high-speed railroad in domestic try to find the cause. This paper is investigated on the characteristics of alumina cement as the binder of class insulator. The components of glass insulator ore stub(tin), rod(tin), shed(tempered glass), and alumina cement. If composition of alumina cement is not unified, crack of alumina cement generated. As these results, cracked marks of cement is appeared and composition of alumina cement is not unified. Therefore, it is estimated that main element of long-term degradation is a alumina cement.

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Slagging Effect of Combustion Gas containing Sulfur on Refractories (내화물에 대한 황함유 연소가스의 영향)

  • 임응극;이영희
    • Journal of the Korean Ceramic Society
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    • v.11 no.4
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    • pp.5-18
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    • 1974
  • 본 연구에 있어서는 연료유의 연소에 의한 내화물의 부식을 연구하기 위하여 시멘트소성용 회전가마, 보일러 및 판유리제조용 탱크가마에 쓰이는 여러 내화물을 짤라서 그 가운데에 구멍을 파고 중유재의 주성분인 V2O5, Na2CO3, Fe2O3, Fe 및 황산철을 미리 그 구멍속에 넣어 응용 확산시킨 다음 이들을 그들의 상용온도인 145$0^{\circ}C$로 황 함유량이 다른 연류유로 소성하여 얻은 결과는 다음과 같다. 일반적으로 5산화 바나듐-알루미나, 고알루미나질 및 염기성 내화물; 산화나트륨-고알루미나질, 실리마나이트질 및 염기성 내화물은 2%미만의 황 함유 연류유소성에 의하여 부식이 적고 3.5%이상의 황하유 연료유소성시는 황에 의하여 대개가 침식을 당하였다. 무수 아황산 분위기속에서 규산알루미늄 및 구석계의 내화점토질내화물은 산화철이 환원되어 색이 연해지고 고알루미나질 벽돌은 색이 짙어지는 경향이 있고 산화철은 황산철로 변하여 풍화의 원인이 되어 침식을 당하게 되었고, 소성시간이 길면 길수록 부식은 증가하고 황산소다보다 탄산소다에 의하여 훨씬 더 많이 부식을 당하였다.

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Influence of Various Oxide and Nonoxide Microfillers on the Thermomechanical Properties of Alumina Based Low-Cement-Castables (산화물 및 비산화물 Microfiller의 첨가가 저시멘트 알루미나 캐스타블의 특성에 미치는 영향)

  • 이승재;이상원
    • Journal of the Korean Ceramic Society
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    • v.32 no.9
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    • pp.977-988
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    • 1995
  • Several oxide (ZrO2, Al2TiO5, reactive Al2O3) and nonoxide (SiC, Si3N4, "ALON" (5AlN.9Al2O3)) additives were used as a microfiller for alumina based LCC (Low-Cement-Castable). High temperature prooperties (HMOR, softening under load) and the phase changes of developed LCC on various sintering temperatures were examined. In addition, thermal shock test and corrosion test were accomplished. Based on these data the effects of each microfiller on the properties of LCC were established comparing to those of the commercial LCC with amorphous silica as a microfiller. The castables, containing reactive alumina, ZrO2 and "ALON" (5AlN.9Al2O3) as a first portion, exhibited considerably higher HMOR-values over 100$0^{\circ}C$, better creep behavior, and thermal shock resistance than those of castables with amorphous silica. The LCC with 5% Al2TiO5 showed no corrosion against molten aluminum.nst molten aluminum.

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Studies on Alumina Cement from Alunite (I) (Synthesis of monocalcium aluminate) (명반석을 이용한 알루미나 시멘트의 제조(I) (Monocalcium Aluminate의 합성))

  • 한기성
    • Journal of the Korean Ceramic Society
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    • v.15 no.4
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    • pp.199-204
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    • 1978
  • In the present investigation, refined alumina obtained from alunite locally available was used as a aluminous source to synthesize monocalcium aluminate $(CA)_3$ the major mineral constituent of alumina cement. The influence of $SiO_2$ and $Fe_2O_3$ contents on the formation of monocalcium aluminate was studied by X-ray diffraction analysis mainly. About 0.8-1.0 of $Al_2O_3/C_3O$ mol ratio and less than 4 percent of $SiO_2$ were desirable for the effective formation of CA. The small amount of alkali and sulphur contents contained in refined alumina from alunite as the impurities were affected to form $C_4A_3S$ and $C_3S_2$, disadvantageous compounds for the alumina cement, therefore the impurities should be restricted in minimum content as possible.

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Material Properties of Grout Using Alumina Cement and Anhydrite (알루미나 시멘트와 무수석고를 이용한 그라우트의 재료적 특성)

  • Hong, Ki-Nam;Jung, Jin-Yeong;Han, Sang-Hoon
    • Journal of the Korean Society of Safety
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    • v.26 no.5
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    • pp.59-64
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    • 2011
  • This paper presents the research results performed to develope the shrinkage-free grout with high early strength. Alumina cement and anhydrite were utilized as the expensive tool to gain the shrinkage-free grout. The compressive strength, length change, and ettringite formation of the grout were investigated with compressive test, length change test, and X-ray diffraction. The more anhydrite was added into the grout, the larger the early expansion of the grout. In addition, the more anhydrite formated the more ettringite. From this study, It was conformed that the grout mixture with shrinkage-free property and high early strength is the mixture with the ratio of alumina cement and anhydrite of 40:60 by weight.

Influence of sandblasting and primer on shear bond strength of resin cement to zirconia (샌드블라스팅과 프라이머가 지르코니아와 레진시멘트의 전단결합강도에 미치는 영향)

  • Lee, Jung-Haeng;Kim, Hyeong-Seob;Pae, Ah-Ran;Woo, Yi-Hyung
    • The Journal of Korean Academy of Prosthodontics
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    • v.49 no.1
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    • pp.49-56
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    • 2011
  • Purpose: The aim of this study was to evaluate the effect of mechanical, chemical surface treatments on the zirconia-to-resin cement shear bond strength (SBS). Materials and methods: Eighty zirconia discs (Lava, 3M ESPE) and eighty zirconia/alumina composite (Zirace, Acucera) were embedded in an epoxy resin base. Zirconia discs were randomly divided in to four treatment groups(10 for each manufacturer): $50\;{\mu}m$ $Al_2O_3$ sandblasting (S50), $110\;{\mu}m$ $Al_2O_3$ sandblasting (S110), $50\;{\mu}m$ $Al_2O_3$ and primer (Z-Prime Plus, Bisco Inc) (S50z) and $110\;{\mu}m$ $Al_2O_3$ and primer (Z-Prime Plus) (S110z). Two resin-based luting cements (Calibra, Panavia F) were used to build 2 mm diameter cylinders onto the zirconia. After 24 h of storage in water, SBS testing was evaluate using a universal testing machine. Bond strength data were analyzed with one-way ANOVA, two-way ANOVA test and post hoc comparison was done using Tukey test (${\alpha}$ = .05). Results: Groups using primer showed the high shear bond strength. The groups that did not use primer presented lower shear bond strengths. Conclusion: The use of primer (Z-Prime Plus, Bisco) had significantly higher shear bond strengths.

Influence of Material Factors on Estimation of Compressive Strength of Concrete by P Type Schmidt Rammer (P형 슈미트해머에 의한 콘크리트의 압축강도 추정에 미치는 재료요인의 영향)

  • Han Cheon-Goo;Lee Yong-Sung;Han Mn-Cheol
    • Journal of the Korea Concrete Institute
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    • v.16 no.4 s.82
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    • pp.459-465
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    • 2004
  • The present paper is intended to investigate the influence of materials such as cement, mineral admixture and aggregate, on the estimation of compressive strength by P type schmidt hammer. According to the results, the materials of concrete, such as the types of cement, the replacing ratio of mineral admixture, the kinds and maximum size of aggregate, hardly influence on non-destructive test by P type schmidt hammer except for alumina cement, hence, P type schmidt can be applicable to most of the concrete with a wide range. Since the correlativity between the rebound value of P type schmidt hammer and compressive strength is very favorable(above coefficient of correlation 0.96) regardless of materials, it is considered that compressive strength can be estimated comparatively exactly by P type schmidt hammer. The estimating formula of compressive strength by rebound value are derived from this experiment as following. $\cdot$Horizontal strike : Fc = 0.765RH - 5.74 (R=0.965) $\cdot$ Vertical strike Fc = 0.793RV - 8.66 (R=0.959)

Characteristics on Compressive Strength of Cement Paste with Content of LRM Neutralized by Nitric Acid and Sulfuric Acid (질산 및 황산에 의해 중화된 액상화 레드머드의 첨가량에 따른 시멘트 페이스트의 압축강도 특성)

  • Kang, Suk-Pyo;Lee, Hee-Ra;Kang, Hye-Ju;Lee, Byeong-Gi
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.333-340
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    • 2019
  • Red mud is an industrial by-product produced during the manufacturing aluminum hydroxide (Al(OH)3) and aluminum oxide(Al2O3) from Bauxite ores. In Korea, aproximately 2 tons of red mud in a sludge form with 50% moisture content is produced when 1ton of Al2O3 is produced through the Bayer process. Neutralization of red mud will help to reduce the environmental impact caused due to its storage and also lessen significantly the ongoing management of the deposits after closure. It will also open opportunities for re-use of the residue which to date have been prevented because of the high pH. Moreover, attention to liquefied red mud(LRM) that does not require heating and grinding process for recycling is needed. In this paper, characteristics of compressive strength for cement paste with content of LRM neutralized by nitric acid and sulfuric acid. The results showed that compressive strength of cement paste with neutralized LRM is higher than that of cement paste with LRM.