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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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Patent
Tze-Chi Jao1
07 Dec 1987
TL;DR: In this article, it has been found experimentally that by first adding at least 25% of the total water in a single aliquot that crystalline calcium carbon formation is suppressed.
Abstract: In an overbased sulfonate process calcium hydroxide is formed in situ by first adding 25% of the total water and then adding the remainder of the water uniformly to the calcium oxide over the entire hydration and carbonation time rather than incrementally. It has been found experimentally that by first adding at least 25% of the total water in a single aliquot that crystalline calcium carbon formation is suppressed. A 300 TBN product is formed with an H 2 O/CaO molar ratio of 0.4 and a 3 hour hydration time. A 400 TBN product is formed with an H 2 O/CaO molar ratio of 0.8 and 3 hour hydration time. Improved storage stability is achieved by eliminating crystalline calcium carbonate formation. Crystalline calcium carbonate has been related to engine wear.

20 citations

Journal ArticleDOI
TL;DR: In this paper, the composition of an electrolyte was selected and optimized to induce the formation of hydroxyapatite during PEO treatment on an AZ31 alloy for application in bioabsorbable implants.
Abstract: In this work, the composition of an electrolyte was selected and optimized to induce the formation of hydroxyapatite during Plasma electrolytic oxidation (PEO) treatment on an AZ31 alloy for application in bioabsorbable implants. In detail, the PEO process, called PEO-BIO (Plasma Electrolytic Oxidation-Biocompatible), was performed using a silicate-phosphate-based electrolyte with the addition of calcium oxide in direct-current mode using high current densities and short treatment times. For comparison, a known PEO process for producing anticorrosive coatings, called standard, was applied on the same alloy. The coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and XPS analyses. The corrosion performance was evaluated in simulated body fluid (SBF) at 37 °C. The coating produced on the PEO-BIO sample was porous and thicker than the standard PEO one, with zones enriched in Ca and P. The XRD analysis showed the formation of hydroxyapatite and calcium oxides in addition to magnesium-silicon oxide and magnesium oxide in the PEO-BIO sample. The corrosion resistance of PEO-BIO sample was comparable with that of a traditional PEO treated sample, and higher than that of the untreated alloy.

20 citations

Journal Article
TL;DR: In this paper, the authors investigate the effect of SODIUM ADDITIVE on the reaction between SOIL and CEMENT in a mixture of MONO-MINERAL SOILS/QUARTZ and KAOLINITE.
Abstract: THE NATURE OF REACTIONS ACCOMPANYING THE STABILIZATION OF SOIL WITH LIME AND CEMENT AND THE MECHANISMS INVOLVED IN THE ALTERATION OF SOIL-CEMENT /OR SOIL-LIME/ REACTION BY CHEMICAL ADDITIVES WERE STUDIED WITH TWO SOIL MINERALS. MIXTURES OF MONO-MINERAL SOILS AND 10 PERCENT CEMENTING COMPOUNDS, WITH OR WITHOUT SODIUM ADDITIVES, WERE EXAMINED AFTER COMPACTION AND VARIOUS CURING PERIODS BY A NUMBER OF ANALYTICAL TECHNIQUES, INCLUDING FLAME PHOTOMETRY, COLORIMETRY, X-RAY DIFFRACTION, AND DIFFERENTIAL THERMAL ANALYSIS. BOTH MONO-MINERAL SOILS /QUARTZ AND KAOLINITE/ REACTED WITH THE THREE CALCIUM STABILIZERS /HYDRATED LIME, TRICALCIUM SILICATE AND TYPE I PORTLAND CEMENT/. ADDITION OF SODIUM ADDITIVES GREATLY INTENSIFIED THE REACTION BETWEEN THE SOIL AND THE STABILIZER AND INCREASED THE ABUNDANCE OF REACTION PRODUCTS. REACTIVITY OF KAOLINITE WITH ANY ONE OF THE CEMENTING COMPOUNDS WAS HIGHER THAN THAT OF QUARTZ. THE PRINCIPAL REACTION PRODUCTS PRODUCED IN QUARTZ MIXTURES WERE HYDROUS CALCIUM SILICATES OF VARIOUS COMPOSITIONS WITH CAO TO SIO2 RATIO VARYING FROM 0.2 TO 1, AND IN KAOLINITE MIXES WERE HYDROUS CALCIUM SILICATES, HYDROUS CALCIUM ALUMINATES AND A MIXED CALCIUM ALUMINOSILICATE. SODIUM FROM THE ADDITIVE ASSOCIATED WITH SOLUBLE COMPOUNDS EARLY IN CURE AND LATER WITH INSOLUBLE MIXED SODIUM-CALCIUM SILICATES OR ALUMINATES. /AUTHOR/

20 citations

Patent
10 Jul 1985
TL;DR: A coating composition useful for increasing the corrosion resistance of a surface is provided in this paper, which comprises a coating material and an anti-corrosive agent comprised of a calcined mixture consisting essentially of magnesium oxide and zinc oxide with or without calcium oxide.
Abstract: A coating composition useful for increasing the corrosion resistance of a surface is provided The composition comprises a coating material and an anti-corrosive agent comprised of a calcined mixture consisting essentially of magnesium oxide and zinc oxide with or without calcium oxide The composition may also include a defined compound which can improve the corrosion resistance, and filler

20 citations

Journal ArticleDOI
TL;DR: The speciation of inorganic arsenic compounds produced in pulverized coal combustion was investigated in a bench-scale study conducted under fuel-lean combustion conditions as discussed by the authors, and it was concluded that the formation of arsenic(V) in combustion systems requires either the oxidation of As2O3, which appears to be a kinetically limite, or the doping of the silica particles with small amounts of calcium.
Abstract: The speciation of inorganic arsenic compounds produced in pulverized coal combustion was investigated in a bench-scale study conducted under fuel-lean combustion conditions. Results suggest that at temperatures of 850–1100 K, and in the absence of particulate, arsenic initially condenses as As2O3 rather than the thermodynamically favored As2O5. Synthetic fly ash in the form of uniform 0.25 μm spherical silica particles produced by sol-gel methods, added to the experimental system to simulate the presence of combustion-derived fly ash, did not affect arsenic speciation, nor did doping of the silica particles with small amounts of calcium. As(V) was only observed at these temperatures when calcium was added to the system as calcium acetate, producing a reactive calcium oxide fume and leading to the formation of calcium arsenate. From these results, it was concluded that the formation of arsenic(V) in combustion systems requires either the oxidation of As2O3, which appears to be a kinetically limite...

20 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023101
2022186
2021116
2020234
2019350
2018432