Li NAN Wuhan University of Science and Technology WUST
Hydration behavior of the spinel containing high alumina cement prepared from high titania blast furnace slag via smelting reduction method is studied. Cooling condition has considerable effect on
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Magnesium aluminate spinel is an excellent eco-friendly refractory compound that has high melting point (2105°C) 1 moderate thermal expansion rate (8.4 9 10 À6 / o C at 1000°C) no deleterious
Get PriceThe Hydration of Magnesium Oxide from the Vapor Phase
Dehydration/hydration of MgO/H2O chemical thermal storage system. Spinel-containing alumina-based refractory castables. Rafael Salomão Victor C. Pandolfelli. Magnesia sinter hydration–dehydration behavior in refractory castables. Ceramics International 2008 34 (8) . DOI 10.1016/j.ceramint.2007.06.009.
Get Price(PDF) Formation and Densification Behavior of Magnesium
It is also a general phenomenon that powders with more amount of spinel phase undergo better sintering as compared with the mixture of alumina and magnesia precursors as the latter one is associated with considerable amounts of volume expansion during spinel phase formation. 12 In alumina matrix CaO usually plays two types of roles during the
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o14) change of properties and hydration kinetics of ca and ca2 by prolonged milling.. 20 o15) thermomechanical behavior of high-alumina refractory castables containing
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Magnesium aluminate spinel is an excellent eco-friendly refractory compound that has high melting point (2105°C) 1 moderate thermal expansion rate (8.4 9 10 À6 / o C at 1000°C) no deleterious
Get PriceAluminous cements containing magnesium aluminate spinel
Jan 01 2001 · High quality castable compositions could be prepared from a mixture of 90 wt. well graded magnesia aggregate 10 wt. of aluminous cements containing MA spinel in the presence of 0.1 wt. Li 2 CO 3 as a strength modifier. Such castable compositions are easily cast into desired shapes without prefiring.
Get PriceHydration of γ-Alumina in Water and Its Effects on Surface
It appears that γ-alumina which is widely used as a model oxide in sorption experiments thanks mainly to its high specific surface area and to the presence of aluminol groups on its surface is progressively transformed to bayerite (β-Al(OH) 3). This transformation was characterized by an induction period of about 4 days corresponding to
Get PriceHydration of γ-Alumina in Water and Its Effects on Surface
It appears that γ-alumina which is widely used as a model oxide in sorption experiments thanks mainly to its high specific surface area and to the presence of aluminol groups on its surface is progressively transformed to bayerite (β-Al(OH) 3). This transformation was characterized by an induction period of about 4 days corresponding to
Get PriceThermomechanical Behaviour of High Alumina Refractory
The thermomechanical behavior of a high-alumina refractory that contains 10 wt of synthetic spinel has been studied. Results have been correlated with the microstructural and mineralogical
Get PriceZinc Stabilization Efficiency of Aluminate Spinel
The feasibility of immobilizing zinc in contaminated soil was investigated by observing the role of zinc reacting with aluminum-rich materials under thermal conditions. To observe the process of zinc incorporation mixtures of ZnO with alumina precursors (γ-Al2O3 and α-Al2O3) were fired at 750–1450 °C. Both precursors crystallochemically incorporated zinc into the ZnAl2O4 spinel structure
Get PricePorogenic Behavior of Water in High-Alumina Castable
Direct casting is a processing method that can produce large parts of complex geometry. It uses dispersions of ceramic particles in water and a hydraulic binder for consolidation. Studies on castable structures have reported the generation of a significant fraction of pores due to the presence of water. This effect occurs because drying preserves part of the interparticle pores originally
Get PriceKey Engineering Materials Vol. 768 p. 6 Scientific
Abstract This research was studied the effect of 15 nm SiO 2 on the hydration behavior hydration process and microstructure of spinel-containing high alumina cement (HAC) which is from high titanium blast furnace slag via smelting reduction method of Ti-Si-Fe making process. The results showed that with the increase of nano-SiO 2 the heat released rate of hydration and the maximum peak
Get PriceIn situ Spinel Expansion Design by Colloidal Alumina
Regarding the reactive aluminas (nano alumina powder hydratable alumina and colloidal alumina) the composition containing colloidal alumina performed remarkably better leading to the lowest in situ spinel expansion level as a consequence of its high sinterability. The use of nano scaled alumina suspensions was the most suitable alternative
Get Price(PDF) Development of spinel sol bonded high pure alumina
Similarly when spinel nanoparticles are present in the high pure alumina castable composition by using spinel sol as a sole binder 36 improved sintered density and strength both at room as
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Aug 30 2017 · Hydratable alumina (HA) is a calcium-free and high-refractoriness binder for alumina-based suspensions. Although recent studies have improved its dispersion mixing and drying behaviours a drawback related to its loss of strength between 250 and 900°C remains unexplored. Pores generated after decomposition of HA curing products are usually an explanation for the effect however no
Get PriceMicrostructure of Hydrated Magnesia and MgAl2O4 Spinel
Tests were performed to investigate the microstructure of MgAl2O4 spinel layer between magnesia and alumina after high temperature thermal treatment (1500 °C and 1600°C). The first test involved fused magnesia and alumina sol. Hydration of magnesia powders was studied in a controlled condition that soaked in aqueous solution at 80 °C for up to 1h and 2h.
Get PriceHydration of hydratable alumina in the presence of various
Jan 01 2006 · The hydration behavior of hydratable alumina in the presence of reactive magnesia has been investigated at room temperature. However in industrial practice deadburnt and fused magnesias rather than reactive magnesia are normally used for production of refractory castables.
Get Price(PDF) Spinel-Coated Graphite for Carbon Containing
J. Am. Ceram. Soc. 92 8 1895–1900 (2009) DOI 10.1111/j..2009.03133.x r 2009 The American Ceramic Society Journal Spinel-Coated Graphite for Carbon Containing Refractory Castables Sunanda Mukhopadhyay w Sarbasree Dutta Sheikh A. Ansar Sumita Das and Susmita Misra Department of Chemical Technology University of Calcutta Kolkata 700 009 India Oxidation
Get PriceImproved sol gel spinel (MgAl 2 O 4 ) coatings on graphite
An improved sol gel coating of magnesium aluminate spinel (MgAl 2 O 4) over flaky graphite was prepared by aluminium-sec-butoxide and magnesium nitrate.The mechanism of evolution of an extended thin film of spinel was investigated by Fourier transform infrared spectroscopy differential thermal analysis scanning electron microscopy and energy dispersive spectral analysis.
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also induce faster in situ spinel (MgAl 2O 4) formation in alumina-based formulations at high temperatures 9 12 . Consequently it is of utmost importance to find solutions to adjust MgO hydration features so that different sources of this oxide can be used as alternative binder additives for
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May 21 2015 · Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of
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Aug 16 2018 · These Mg- Al-containing crystals are embedded in the investigated 50-day hydrated cementitious matrices between alumina/hydrated alumina and magnesium hydroxide particles (Fig. 12a–c). A greater amount of hydration products i.e. newly formed thin-walled plates of MAH compound appeared in the 259-day cured material (Fig. 13 a–c).
Get Price(PDF) Spinel-Coated Graphite for Carbon Containing
J. Am. Ceram. Soc. 92 8 1895–1900 (2009) DOI 10.1111/j..2009.03133.x r 2009 The American Ceramic Society Journal Spinel-Coated Graphite for Carbon Containing Refractory Castables Sunanda Mukhopadhyay w Sarbasree Dutta Sheikh A. Ansar Sumita Das and Susmita Misra Department of Chemical Technology University of Calcutta Kolkata 700 009 India Oxidation
Get PriceMicrostructure of Hydrated Magnesia and MgAl2O4 Spinel
Tests were performed to investigate the microstructure of MgAl2O4 spinel layer between magnesia and alumina after high temperature thermal treatment (1500 °C and 1600°C). The first test involved fused magnesia and alumina sol. Hydration of magnesia powders was studied in a controlled condition that soaked in aqueous solution at 80 °C for up to 1h and 2h.
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Jan 01 2016 · Hydration behavior of spinel containing high alumina cement from high titania blast furnace slag 1. Introduction. Calcium aluminate cement (CAC) particularly high alumina cements (HAC) is a type of hydraulic binder 2. Experimental procedure. The
Get PriceRheological Behaviors of Calcium Aluminate Cement
Calcium aluminate cement (CAC) and hydratable alumina (HA) are the most widely used binders for refractory castables. Nevertheless CAC as the binder for refractory castable generates some low melting point phases when coupled with SiO2 which deteriorate the high temperature performance of refractory castables. Although hydratable alumina (HA) bonded castables overcome the drawbacks of CAC
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Han B Wang P Ke C. Hydration behavior of spinel containing high alumina cement from high titania blast furnace slag. Cem Concr Res. 201679 257–64. Article CAS Google Scholar
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Sep 01 2012 · The in situ magnesia hydration usually leads to a mechanical resistance decay as a function of time due to crack formation. In order to evaluate the microsilica role in this reaction Fig. 1 shows the castable splitting tensile strength during the curing time for the magnesia–alumina castables containing different CAC and microsilica contents. . Regardless of the binder content the
Get PriceKey Engineering Materials Vol. 768 p. 6 Scientific
Abstract This research was studied the effect of 15 nm SiO 2 on the hydration behavior hydration process and microstructure of spinel-containing high alumina cement (HAC) which is from high titanium blast furnace slag via smelting reduction method of Ti-Si-Fe making process. The results showed that with the increase of nano-SiO 2 the heat released rate of hydration and the maximum peak
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