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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TL;DR: In this article, the authors investigated the reaction kinetics of CaO.6Al2O3 in contact with an aluminosilicate blast furnace hearth refractory.
Abstract: Blast furnace hearth refractories are a key component in achieving long furnace lives. These refractories can be degraded by among other things reactions with coke ash products. Recent studies have shown that these coke ash products could be calcium aluminate based. To understand and characterize the effects of these calcium aluminates on hearth refractories a study has been carried out that investigates the reaction kinetics of CaO.Al2O3, CaO.2Al2O3 and CaO.6Al2O3 in contact with an aluminosilicate blast furnace hearth refractory. The experimental program covered the temperature range 1 450° to 1 550°C. The temperatures were chosen to represent the hot face temperatures of the hearth refractories. From this study it was found that the rate of reaction with the aluminosilicate refractory and CaO.6Al2O3 was much slower than that of CaO.Al2O3 and CaO.2Al2O3. The prevailing kinetics of the aluminosilicate refractory with CaO.Al2O3 and CaO.2Al2O3 was found to be consistent with the linear rate law. The slow rate of reaction of the refractory with CaO.6Al2O3 prohibited identification of the prevailing kinetic regime. In characterizing the reaction interface between the aluminosilicate and the calcium aluminates it was found that there was significant reaction between the refractory and CaO.Al2O3 and CaO.2Al2O3 but little reaction with the CaO.6Al2O3. The reaction layers formed at the interface between the couples were found to consist of CaO.2Al2O3, CaO.6Al2O3, corundum (Al2O3), plagioclase (CaO.Al2O3.2SiO2) and melilite (2CaO.Al2O3.SiO2). The formation of a layer with these phases could result in spalling/wear of the hearth refractory.
11 citations
TL;DR: In order to know the types of inclusions in BOF crude steel and their evolution during Al deoxidation, steel samples are taken from industry and aluminum experiments are carried out in laboratory as discussed by the authors.
Abstract: In order to know the types of inclusions in BOF crude steel and their evolution during Al deoxidation, steel samples are taken from industry and deoxidation with aluminum experiments are carried out in laboratory. The results show that the BOF crude steel is an important source of inclusions. A lot of (Fe, Mn)O inclusions and some BOF slag droplets (mainly calcium silicates) were found in BOF crude steel. During Al deoxidation, alumina clusters could be formed because of homogeneous nucleation, while some singular alumina particles can also be generated on (Fe, Mn)O inclusions due to heterogeneous nucleation. Besides, (Fe, Mn)O would be reduced by dissolved Al into alumina completely. The unstable oxides in calcium silicates will be reduced by dissolved Al in liquid steel to form calcium aluminates. The study results are very helpful to understand the origin and evolution of different types of inclusions in industry.
10 citations
01 Jan 2006
TL;DR: In this paper, the effect and its mechanism of calcium carbonate on the cement based materials were studied and the relationship between fineness of limestone and early stress, long-term stress of the mortar were investigated respectively.
Abstract: The effect and its mechanism of calcium carbonate on the cement based materials were studied in this paperThe relationship between fineness of limestone and early stress,long-term stress of the mortar were investigated respectivelyResult show that the hydration of cement is accelerated by limestone flour at early agesWhile the later stress is enhanced chiefly by activity of limestone as calcium aluminates monocarbonate are formedSo the stress and durability of the cement based materials are increased
10 citations
TL;DR: In this paper, micro-sized MgCO3 and Al(OH)3 were used as inorganic porogenic agents for increasing porosity in alumina bubble lightweight castables.
10 citations
10 citations