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 article, the reaction conditions, such as the concentration of the Ca2+ ion, ageing time and power of the ultrasonic device show important roles in the size, morphology and growth process of the final products.
Abstract: Calcium hydroxide nanostructures have been synthesised by the reaction of calcium acetate with sodium hydroxide or tetramethylammonium hydroxide by a sonochemical method. Reaction conditions, such as the concentration of the Ca2+ ion, ageing time and power of the ultrasonic device show important roles in the size, morphology and growth process of the final products. The calcium oxide nanoparticles have been obtained by heating of calcium hydroxide nanostructures at 600°C. The calcium hydroxide and calcium oxide nanostructures were characterised by transmission electron microscopy, scanning electron microscopy and X-ray powder diffraction.
54 citations
TL;DR: In this paper, a series of calcium oxide promoted cobalt catalysts were prepared by incipient wetness impregnation, and the influence of the calcium oxide on the dispersion, reducibility and cobalt particle size of the catalysts was studied by different techniques, including N 2 adsorption, X-ray diffraction, temperature-programmed reduction, temperatureprogrammed desorption and oxygen titration.
Abstract: A series of calcium oxide promoted cobalt catalysts were prepared by incipient wetness impregnation. The influence of the calcium oxide on the dispersion, reducibility and cobalt particle size of the catalysts was studied by different techniques, including N 2 adsorption, X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption and oxygen titration. It was found that calcium oxide improved the cobalt oxide reducibility, especially for the reduction of CoO to Co 0 . Since the interaction between cobalt oxide and the calcium oxide promoted support was suppressed, larger Co 3 O 4 particles were formed on the surface. The catalytic activity for Fischer–Tropsch synthesis was evaluated in a continuous stirred tank reactor (CSTR). A positive correlation was observed between CO conversion, C 5 + selectivity and calcium oxide content. Furthermore, methane selectivity decreased with increasing calcium oxide content. These could be attributed to the enhanced reducibility that provides abundant active sites.
54 citations
TL;DR: In this paper, the structures of surface-modified layers of Ca 2+ )-implanted Ti-6 mass%Al-4 mass%V and Ti-56 mass%Ni were characterized using Auger electron spectroscopy with argon-ion-sputtering and X-ray photoelectron spectrography.
Abstract: The structures of surface-modified layers of calcium-ion (Ca 2+ )-implanted Ti-6 mass%Al-4 mass%V and Ti-56 mass%Ni were characterized using Auger electron spectroscopy with argon-ion-sputtering and X-ray photoelectron spectroscopy. Calcium ions were implanted in Ti-6Al-4V and Ti-56Ni in the amount of 10 22 ions/m 2 with an acceleration energy of 2.88 fJ (18 keV). The surface oxide layers of these alloys grew to approximately 12 nm as a result of the Ca 2+ -implantation. The oxide layers contained hydroxide. The outermost layer of the surface oxide was 3-nm-thick calcium oxy-hydroxide. A large part of the surface-modified layer, existing inside the calcium oxide, consisted of a mixture of titanium oxide, aluminum oxide and calcium oxide in Ca 2+ -implanted Ti-6Al-4V, and a mixture of titanium oxide, nickel oxide and calcium oxide in Ca 2+ -implanted Ti-56Ni. In Ca 2+ -implanted Ti-6Al-4V, Ca 2+ -free oxide layers existed in the deepest region and this layer consisted of a mixture of titanium oxide with aluminum oxide, whereas this layer was absent in Ca 2+ -implanted Ti-56Ni.
54 citations
TL;DR: In this paper, a study on three groups of Australian arid zone soils indicates that cement is a more effective stabilizing agent than lime, while Sandy soils rich in gypsum and bassanite do not respond to stabilization.
Abstract: Summary Tests on three groups of Australian arid zone soils indicate that cement is a more effective stabilizing agent than lime. Sandy soils rich in gypsum and bassanite do not respond to stabilization. The cement stabilized clayey soils must be adequately protected against increase in moisture content.
54 citations
Patent•
19 Nov 2004TL;DR: In this article, a low density foamed cement composition of the invention comprises fly ash comprising calcium oxide or calcium hydroxide, water present in an amount sufficient to form a slurry, a foaming and foam stabilizing surfactant or a mixture of surfactants, and sufficient gas to foam the mixture.
Abstract: Methods of cementing and low density foamed cement compositions therefor are disclosed. A low density foamed cement composition of the invention comprises fly ash comprising calcium oxide or calcium hydroxide, water present in an amount sufficient to form a slurry, a foaming and foam stabilizing surfactant or a mixture of surfactants present in an amount sufficient to facilitate foam and stabilize the foamed cement composition, and sufficient gas to foam the foamed cement composition.
53 citations