Topic
Calcium oxide
About: Calcium oxide is a research topic. Over the lifetime, 7600 publications have been published within this topic receiving 66104 citations. The topic is also known as: caustic lime & quicklime.
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TL;DR: In this paper, the authors assessed the impact of increasing the CaO and B2O3 content on the tendency of the melts to crystallize and the impact on the glass network structure.
Abstract: In nuclear borosilicate glasses, when molybdenum is in too high concentration and when it combines with other elements such as alkali and alkaline-earth elements it may form crystalline molybdates, including sodium molybdate, Na2MoO4, during melt cooling. In a nuclear vitrification context, the origin of this phenomenon must be understood to control and to avoid the appearance of this water-soluble crystalline phase. The solubility limit of MoO3 was found to be 2.5 mol% in a simplified SiO2–B2O3–Na2O–CaO nuclear glass at about 1300°C. Higher MoO3 concentrations induced liquid phase separation followed by crystallization of Na2MoO4 and CaMoO4. This study assessed the impact of increasing the CaO and B2O3 content on the tendency of the melts to crystallize and the impact on the glass network structure. Structural analysis (95Mo MAS NMR and 11B MAS NMR) of several glass series and standard SiO2–Na2O–MoO3 or SiO2–CaO–MoO3 glass showed that the nature of the crystallized phases that may appear during cooling of the melt can be controlled by correlation of the proportion of Na+ cations remaining free in the glass network with the soda/lime environment of tetrahedral MoO42− entities.
51 citations
Patent•
21 Jan 2010TL;DR: A geopolymer composite binder is provided in this article, which includes at least one fly ash material having less than or equal to 15 wt% of calcium oxide, and a gelation enhancer.
Abstract: A geopolymer composite binder is provided herein, the composite binder including (i) at least one fly ash material having less than or equal to 15 wt% of calcium oxide; (ii) at least one gelation enhancer; and (iii) at least one hardening enhancer having a different composition from a composition of the at least one fly ash material.
51 citations
TL;DR: In this article, a modified calcium oxide (CaO) is proposed as an alkaline solid catalyst, which is chemically modified using bromooctane through a microwave approach to improve its catalytic ability.
51 citations
TL;DR: In this article, the role of organic additive concentration, calcination temperature and sonication on the particle size of the products were investigated, and the specific surface are (SSA) of samples was calculated by the XRD data and compared by the measured BET.
Abstract: Calcium carbonate nanoparticles were synthesized via so-called sol–gel citrate method using calcium nitrate as precursor in presence of different concentration of citric acid, selected to be 0.0, 0.5, 1.25 and 2.5 times of the concentration of the precursor, on calcining at 600 °C for 5 h. Stable phase of the calcite is formed in presence of citric acid. The roles of organic additive concentration, calcination temperature and sonication on the particle size of the products were investigated. Calcium oxide nanoparticles were prepared by facial calcination of the resulted product at 900 °C for 5 h. Calcium hydroxide nanoparticles, however, were synthesized on sonication of the product for 20 min in water at room temperature. Samples were characterized by XRD and FT-IR studies. Crystallite size of samples was calculated by XRD data and was measured by TEM analysis. The specific surface are (SSA) of samples was calculated by the XRD data and compared by the measured BET. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
51 citations
TL;DR: In this article, the influence of the CaO content and decomposition of calcium-containing minerals on the bulk density, pore structure, compressive strength, and crystalline structure of ceramic foams was systematically studied by adding calcium oxide, calcium carbonate, and gypsum.
51 citations