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.

Thermally stabilized segmented copolyester adhesive

Abstract: Thermally stabilized thermoplastic segmented copolyester of recurring short chain ester units and long chain ester units joined through ester linkages, having a melt index of less than 150 and a melting point of at least 90° C., an inherent viscosity in the range of 1.0 to 1.7 and an acid number not greater than 3, stabilized with 0.05 to 3.0 percent by weight, based on the weight of copolyester, of an alkaline earth oxide. Improved stabilizing effect can be achieved when 0.25 to 2.5 percent by weight, based on the weight of copolyester, of the alkaline earth oxide is used in conjunction with 0.25 to 2.5 percent by weight, based on the weight of copolyester, of a substantially linear polycarbodiimide. Additional optional materials that can be added with the stabilizer, based on the weight of copolyester, include: 0.25 to 5.0 percent by weight of a compound taken from the group consisting of hindered phenols, nitrogen-containing hindered phenols and hindered secondary amines; 0.25 to 5.0 percent by weight of a thioalkylpropionate ester of 12 to 18 carbon atoms; 0.25 to 5.0 percent by weight of a phosphorous acid ester; or mixtures thereof. A useful stabilized adhesive composition comprises (A) 1 to 99 percent by weight of segmented copolyester, (B) 1 to 99 percent by weight of a compatible low molecular weight thermoplastic resin, and (C) 0.1 to 4.0 percent by weight, based on the weight of copolyester and resin of the alkaline earth oxide, preferably calcium oxide, stabilizer.

Process for producing super-activated carbon

Abstract: A process of preparing super activated carbon includes such steps as mixing hydroxide of alkali metal with carbon material, activating in a sealed furnace to obtain coarse product and tail gas, washing the coarse product with water, drying to obtain finished product, washing said tail gas with solvent, adding calcium oxide (or hydroxide), stirring while reacting to transform the carbonate of alkali metal to hydroxide and calcium, depositing, washing to obtain calcium carbonate, and cyclic use of said hydroxide.

Property changes induced in clay soils when using lime stabilization

Abstract: Lime is being used increasingly to modify and stabilize soils for numerous engineering applications such AS Embankments, road subgrade and sub-base stabilization and foundations for small buildings. It is therefore important that engineers using this technique are aware of the nature of the changes imparted to soils by the addition of lime, and of the modifications which are brought about in the physical and mechanical properties of soils by lime treatment (soil strength, permeability, frost resistance and plasticity). This paper reviews the current state of knowledge regarding the way in which lime modifies the properties of soils, and reports on the observed changes on a Devonian red marl when mixed with lime and cured in different environments. The results of the work suggest that more effective stabilization may be achieved, even at normal ambient temperatures, by the use of further chemical additives in addition to lime. (TRRL)

The mechanism of vapor phase hydration of calcium oxide: implications for CO2 capture.

Abstract: Lime-based sorbents are used for fuel- and flue-gas capture, thereby representing an economic and effective way to reduce CO2 emissions. Their use involves cyclic carbonation/calcination which results in a significant conversion reduction with increasing number of cycles. To reactivate spent CaO, vapor phase hydration is typically performed. However, little is known about the ultimate mechanism of such a hydration process. Here, we show that the vapor phase hydration of CaO formed after calcination of calcite (CaCO3) single crystals is a pseudomorphic, topotactic process, which progresses via an intermediate disordered phase prior to the final formation of oriented Ca(OH)2 nanocrystals. The strong structural control during this solid-state phase transition implies that the microstructural features of the CaO parent phase predetermine the final structural and physicochemical (reactivity and attrition) features of the product hydroxide. The higher molar volume of the product can create an impervious shell a...

Novel Optimized Process for Utilization of CaO-Based Sorbent for Capturing CO2 and SO2 Sequentially

Abstract: Calcium oxide (CaO) based sorbents, used for CO2 capture in calcination/carbonation cycles, reduce in activity with increasing numbers of cycles, thus reducing the economic benefits of this capture...