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 describe the reaction of LIME and soil to changes in the PLASTICITY, SWELL, SHRINKAGE or COMPRESSIVE STRENGTH of the soil.
Abstract: THE USE OF HYDRATED LIME, CA/OH/2, FOR MODIFYING, UPGRADING, AND STABILIZING SOILS IS INCREASING GREATLY. THIS MEANS HIGHWAY LABORATORIES HAVE HAD THEIR WORK LOADS INCREASED, AND IN MANY INSTANCES, MORE THAN DOUBLED FOR A PARTICULAR JOB. BEFORE THE ADVENT OF THE USE OF LIME, THE LABORATORY WAS FINISHED WITH TESTING WHEN A SOIL WAS CLASSIFIED AS UNSUITABLE. NOW THE SAME SOIL IS TESTED AND RETESTED TO FIND THE PERCENTAGE OF LIME REQUIRED TO BRING THE SOIL WITHIN SPECIFICATIONS. IN MOST CASES THE PERCENTAGE IS DETERMINED BY COMPRESSIVE TESTS, ATTERBERG LIMITS TESTS, OR BOTH. THE REACTION OF LIME AND SOIL CAN BE DESCRIBED AS A SERIES OF CHEMICAL REACTIONS. THE RESULTS OF THESE REACTIONS ARE EXPRESSED AS A CHANGE IN THE PLASTICITY, SWELL, SHRINKAGE OR COMPRESSIVE STRENGTH OF THE SOIL. THEREFORE, A QUICK OR SIMPLE TEST IS NEEDED TO SHOW THE AMOUNT OF LIME REQUIRED TO REACT CHEMICALLY WITH A SOIL TO BRING ABOUT THESE PHYSICAL CHANGES TO AN OPTIMUM DEGREE. LABORATORY TESTS, INVOLVING MINERALOGICAL, PHYSICAL AND CHEMICAL CHARACTERISTICS OF UNTREATED AND LIME-TREATED SOILS HAVE PROVEN THAT PH TESTS CAN BE USED TO DETERMINE THE OPTIMUM LIME REQUIREMENTS OF A SOIL. /AUTHOR/
337 citations
TL;DR: This experimental study demonstrates that 1 ton of fly-ash could sequester up to 26 kg of CO(2), i.e. 38.18 ton ofFly-ash per ton ofCO(2) sequestered, and confirms the possibility to use this alkaline residue for CO( 2) mitigation.
320 citations
TL;DR: In this paper, an environmentally benign process was developed for the production of biodiesel from jatropha curcas oil using a heterogeneous solid super base catalyst, calcium oxide, and the results showed that the base strength of calcium oxide was more than 26.5 after dipping in ammonium carbonate solution followed by calcination.
317 citations
TL;DR: In this article, the active phase of calcium oxide was investigated by characterizing the catalyst collected after achieving the conversion of edible soybean oil into its methyl ester at reflux of methanol in a glass batch reactor.
Abstract: For developing a process of biodiesel production with environmental benignity, much interest has been focused on solid base catalysts such as calcium oxide for transesterification of vegetable oils with methanol. In this paper, the active phase of calcium oxide was investigated by characterizing the catalyst collected after achieving the conversion of edible soybean oil into its methyl ester at reflux of methanol in a glass batch reactor. Calcium oxide combined with the by-produced glycerol, so that calcium diglyceroxide was a major constituent of the collected catalyst. The absence of calcium methoxide was clear from the spectrum of solid-state 13C-NMR. The chemical change of calcium oxide was not observed, when the yield of FAME reached 30%. The collected catalyst was not as active as the fresh one (calcium oxide), but was reused without any deactivation. In order to identify the active phase of the collected catalyst, we prepared calcium diglyceroxide by immersion of calcium oxide with refluxing methanol in the presence of glycerol. Calcium diglyceroxide prepared as the reference sample was as active as the collected catalyst in the transesterification, and was tolerant to air-exposure.
294 citations
TL;DR: The use of CaO demonstrates a superior potential for the activation of ground granulated blast furnace slag (GGBFS), and it produces a higher mechanical strength than calcium hydroxide [Ca(OH)2] as discussed by the authors.
293 citations