Topic
Calcium aluminates
About: Calcium aluminates is a research topic. Over the lifetime, 490 publications have been published within this topic receiving 9200 citations.
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20 Apr 2011-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the effects of sulfur concentration in liquid iron on mineral layer development between coke and iron as coke dissolves in a 2 mass pct carbon-iron liquid have been investigated at 1773 K (1500 °C).
Abstract: The effects of sulfur concentration in liquid iron on mineral layer development between coke and iron as coke dissolves in a 2 mass pct carbon-iron liquid have been investigated at 1773 K (1500 °C). The initial sulfur in iron concentrations used ranged from 0.006 to 0.049 mass pct. Key findings include that the two-stage dissolution behavior exhibited in the carbon transfer from coke to iron, as reported in a previous study by the authors, at low initial sulfur in iron contents, was also apparent at the higher values used in this study. This two-stage behavior was attributed to a change in the mineral layer density as a result of changes in mineral morphology at the interface. In addition to confirming the two-stage behavior of the carbon-transfer kinetics at the higher sulfur concentration in iron levels, after a period of time, a solid calcium sulfide layer formed on the mineral layer. The sulfide layer formed after approximately 40 minutes, and the proportion of sulfide in the mineral layer increased with increased experimental time and initial sulfur concentration in iron. It was usually found at the iron side of the mineral layer and was associated with calcium-enriched calcium aluminates. Thermodynamic analysis of this layer confirmed that the sulfide is stabilized as the mineral layer is enriched by calcium.
22 citations
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TL;DR: In this paper, a novel type of supplementary cementitious material (SCM), produced by the calcination of aluminosilicate such as clays and micas in the presence of dolomite, is investigated.
22 citations
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TL;DR: In this paper, a novel route to simple processing of a layered and graded material (LGM) based on alumina/calcium-hexaluminate (CA 6 ) is described.
21 citations
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TL;DR: Several examples of the use of X-ray diffraction patterns in industrial chemical problems are mentioned in this paper, such as the identification of the constituents of bleaching powder, the explanation of the variable colours of certain precipitated iron oxide pigments as a consequence of the polymorphism of FeO(OH), identification of boiler scale constituents with known mineral species, a study of the crystallography of the hydrated calcium aluminates and of calcium sulphate sub-hydrate (hitherto known as hemihydrate), quantitative analysis of mixtures of polymorphous crystal forms
Abstract: Several examples of the use of X-ray diffraction patterns in industrial chemical problems are mentioned. The results include the identification of the constituents of bleaching powder, the explanation of the variable colours of certain precipitated iron oxide pigments as a consequence of the polymorphism of FeO(OH), the identification of boiler scale constituents with known mineral species, a study of the crystallography of the hydrated calcium aluminates and of calcium sulphate sub-hydrate (hitherto known as hemihydrate), the quantitative analysis of mixtures of polymorphous crystal forms, the determination of crystal size in the range below 10-5 cm., and the discovery of the molecular structure of plastics.
21 citations
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TL;DR: In this article, eight different oxygen carriers (OC) containing CuO (60 wt %) and different mass ratios of CaO to Al2O3 as the support were synthesized by wet-mixing followed by calcination at 1000 °C.
Abstract: Eight different oxygen carriers (OC) containing CuO (60 wt %) and different mass ratios of CaO to Al2O3 as the support were synthesized by wet-mixing followed by calcination at 1000 °C. The method of synthesis used involved the formation of calcium aluminum hydrate phases and ensured homogeneous mixing of the Ca2+ and Al3+ ions in the support at the molecular level. The performance of the OCs for up to 100 cycles of reduction and oxidation was evaluated in both a thermogravimetric analyzer (TGA) and a fluidized bed reactor, covering a temperature range of 800 to 950 °C. In these cycling experiments, complete conversion of the OC, from CuO to Cu and vice versa, was always achieved for all OCs. The reactivity of the materials was so high that no deactivation could be observed in the TGA, owing to mass transfer limitations. It was found that OCs prepared with a mass ratio of CaO to Al2O3 in the support >0.55 agglomerated in the fluidized bed, resulting in an apparent deactivation over 25 cycles for all tempe...
20 citations