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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 paper, the chemical composition evolution of inclusions modified with calcium addition in the engineering steel bath (SAE 8620) along the time was evaluated, forming different types of calcium aluminates, as anticipated.
Abstract: Calcium (or calcium alloys) is very important in the metallurgy of many kinds of steel. This element is added to promote deoxidation, desulfurization, control of shape of the inclusions and to improve steel castability in continuous casting. Despite of the importance of calcium utilization in metallurgy, the knowledge concerning kinetic and thermodynamic behavior of calcium is still being topic of study. The aims of this work are: 1) to evaluate the chemical composition evolution of inclusions modified with calcium addition in the engineering steel bath (SAE 8620) along the time; and 2) to consolidate a methodology for inclusion study in laboratorial scale. Heats were carried out in an electric resistive furnace with capacity of 8 kg of steel. The raw materials used were: high purity iron, iron-alloys, aluminium and CaSi. In the chemical analysis the routine alloys elements of steelmaking, as well as the oxygen and total calcium content were considered. In the inclusion analysis, the following were considered: chemical composition, morphology, phase distribution and size via SEM/EDS. The chemical modification of inclusions with calcium was observed, forming different types of calcium aluminates, as anticipated. Due to the presence of sulphur, the calcium and manganese sulphites formation associated with calcium aluminates is observed.
TL;DR: In this paper, a room temperature solid states (RTSS) approach was introduced to fabricate the precursors of barium calcium aluminates (BCA) using crystalline hydrates.
TL;DR: In this paper, the sintering characteristic and leaching property of calcium aluminates in the CaO-Al2O3-SiO2 system with different FeO additions were investigated.
Abstract: The sintering characteristic and leaching property of calcium aluminates in the CaO-Al2O3-SiO2 system with different FeO additions were investigated. FeO decreases the melting temperature of clinker, and makes the clinker not self-pulverizable. As FeO addition increases from 0 to 4%, the main phases of clinkers sintering at 1350 °C are 12CaO•7Al2O3 and 2CaO•SiO2 as well as some CaO•Al2O3 when the mass ratio of Al2O3 to SiO2 is 5.0 and the molar ratio of CaO to Al2O3 is 1.4. The interplanar spacing of 12CaO•7Al2O3 in the clinker increases with the increase of FeO addition, and the proportion of CaO•Al2O3 in the clinker decreases with the increase of FeO addition. FeO does not affect the Al2O3 leaching rate of clinker obviously, but increases the molar ratio of caustic Na2O to Al2O3 in the leached liquor.
Patent•
09 Aug 2018TL;DR: In this paper, a method for obtaining calcium aluminates for metallurgical use from non-saline aluminium slags by means of reactive grinding and thermal treatment is described.
Abstract: The present invention relates to a method for obtaining calcium aluminates for metallurgical use from non-saline aluminium slags by means of reactive grinding and thermal treatment.
01 May 1979
TL;DR: In this paper, the relationship between impurities and microstructure and the properties of sodium beta alumina solid electrolytes was investigated using high-resolution transmission electron microscopy and measurement of the response of the electrolyte to ac signals between 10 hertz and 10 megahertz.
Abstract: About ten years ago sodium beta aluminas were identified as useful solid electrolytes for high-energy-density sodium/sulfur storage batteries. The ionic conductivity, the mechanical strength, and the lifetime of the electrolytes in operating cells was found to depend significantly on a number of factors. These factors included impurities and microstructure of the electrolytes. Because of the important economical benefits that could result from the use of long-life, high-energy-density batteries in load leveling, a study was conducted at Cornell to determine the relationship between the impurities and microstructure and the properties of sodium beta alumina solid electrolytes. Part of this study involved an investigation of certain aspects of the electrolyte fabrication, since the sintering process by which the electrolyte is made determines to a large extent the microstructure and impurity distribution. The methods used in this study include high-resolution transmission electron microscopy and measurement of the response of the electrolyte to ac signals between 10 hertz and 10 megahertz (complex admittance). Specifically, the importance of transient liquids during the sintering process was clarified. The effects on ionic conductivity of the presence of silicon (as silicates), calcium (as calcium aluminates), and zinc (in solid solution) were quantified. The importance of the microstructure and,more » in particular, the role of the grain boundaries in the sodium ion conduction process were elucidated. 89 figures, 7 tables.« less