scholarly journals THE MECHANISM OF THE HYDRATION OF CALCIUM OXIDE

1955 ◽  
Vol 33 (5) ◽  
pp. 881-886 ◽  
Author(s):  
Fraser W. Birss ◽  
T. Thorvaldson
Keyword(s):  
Calcium Carbonate ◽  
Calcium Oxide ◽  
Vapor Phase ◽  
Calcium Ions ◽  
Constant Weight ◽  
Burnt Lime ◽  
Three Samples ◽  
Lime Solution ◽  
Solution Mechanism ◽  
Phase Process

Three samples of calcium oxide, designated as A, B, and C, were prepared from calcium carbonate labelled with calcium-45. A was heated to constant weight at 700 °C.; B was heated an additional three hours at 1400 to 1550 °C.; and C was heated six hours at the same temperature. The samples were hydrated in a supersaturated lime solution at 21 °C., the development of activity and the changes in concentration of the solution being determined. The activity entering the solution accounted, according to theory, for the following percentages of the samples passing through the solution during the hydration: A, 27%; B, 57%; C, 94%. These results indicate that sample C ("dead-burnt" lime) hydrated by a "through-solution" mechanism, but that A and B either hydrated partly according to some other mechanism, such as a vapor phase process in the pores of the particles of lime, or the calcium ions failed to reach the bulk of the hydrating liquid before precipitation as calcium hydroxide.

Nitrification and Autotrophic Denitrification in Calcium Alginate Beads

1987 ◽  
Vol 19 (1-2) ◽  
pp. 175-182 ◽  
Author(s):  
Z. Lewandowski ◽  
R. Bakke ◽  
W. G. Characklis
Keyword(s):  
Calcium Carbonate ◽  
Calcium Ions ◽  
Continuous Flow ◽  
Calcium Alginate ◽  
Microbial Respiration ◽  
Flow System ◽  
Alginate Beads ◽  
Alginate Gel ◽  
Gel Beads ◽  
Calcium Alginate Gel

Immobilization of nitrifiers and autotrophic denitrifiers (Thiobacillus denitrificans) within calcium alginate gel was demonstrated. Calcium carbonate reagent was immobilized along with bacteria as the stabilizing agent. Protons released as a result of microbial respiration reacted with calcium carbonate producing calcium ions which internally stabilized the calcium alginate gel. The microbially active gel beads were mechanically stable and active for three months in a continuous flow system without addition of calcium.

scholarly journals High-efficiency catalytic performance over mesoporous Ni/beta zeolite for the synthesis of quinoline from glycerol and aniline

RSC Advances ◽  
2017 ◽  
Vol 7 (16) ◽  
pp. 9551-9561 ◽  
Author(s):  
An Li ◽  
Chen Huang ◽  
Cai-Wu Luo ◽  
Wen-Jun Yi ◽  
Zi-Sheng Chao
Keyword(s):  
Catalytic Activity ◽  
Vapor Phase ◽  
High Efficiency ◽  
Zeolite Catalyst ◽  
Catalytic Performance ◽  
Beta Zeolite ◽  
Phase Process

Quinoline was synthesized via the typical Skraup approach with a vapor-phase process. The mesoporous Ni/beta zeolite catalyst exhibited high-efficiency catalytic activity and an enhanced ability of anti-deactivation.

scholarly journals First-principles study of calcium-based sulfur fixers and their products

2021 ◽  
pp. 350-350
Author(s):  
Guoyan Chen ◽  
Jianing Chen ◽  
Anchao Zhang ◽  
Haoxin Deng ◽  
Yanyang Mei ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Power Plant ◽  
Thermodynamic Properties ◽  
Calcium Oxide ◽  
First Principles ◽  
Calcium Sulfate ◽  
Density Functional ◽  
Stable State ◽  
Generalized Gradient ◽  
Calcium Sulphoaluminate

Calcium-based sulfur-fixing agent, as the main sulfur-fixing product, is widely used in power plant boiler systems. In order to further study the thermodynamic properties and reaction characteristics of calcium-based sulfur fixing agent and its products, the method of combining power plant experiment with theory was used. The electronic structure, thermodynamic properties and density of states of quicklime, limestone, calcium sulfate and calcium sulphoaluminate have been calculated based on the first-principles ultra-soft pseudopotential plane wave method of density functional theory. The generalized gradient approximation algorithm isused to optimize the structure of various minerals to achieve the most stable state. The results show that the enthalpy, entropy, specific heat capacity at constant pressure and Gibbs free energy of calcium sulfonate vary greatly from 25K to 1000K, while the change of calcium oxide is small, and that of calcium carbonate and calcium sulfate are between them. It shows that calcium sulphoaluminate has strong stability and more energy is needed to destroy the molecular structure of calcium sulphoaluminate. Calcium oxide is the most unstable and requires less energy to react; Calcium carbonate and calcium sulfate are in between. The variation range of calcium sulfate is greater than that of calcium carbonate, indicating that the stability of calcium sulfate is higher than that of calcium carbonate. The experimental results show that the desulfurization efficiency of generating calcium sulphoaluminate is much higher than that of only generating calcium sulfate, indicating that calcium sulphoaluminate is very stable, which is consistent with the calculated results.

Synthesis of lithium-doped Na-β″-alumina composite electrolytes by a vapor phase process

2020 ◽  
Vol 46 (3) ◽  
pp. 3009-3014 ◽  
Author(s):  
Chao Zhang ◽  
Ling Zhang ◽  
Xiaoxu Zhang ◽  
Peiyu Zheng ◽  
Fengyou Li
Keyword(s):  
Vapor Phase ◽  
Composite Electrolytes ◽  
Alumina Composite ◽  
Phase Process

Preparation of Plate-Shaped Calcium Carbonate and its Application in the Coating Paper

2011 ◽  
Vol 236-238 ◽  
pp. 1124-1127
Author(s):  
Sen Wang ◽  
Xin Ping Li ◽  
Er Lin Mao ◽  
Zhuo Yuan Cheng
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Calcium Oxide ◽  
High Performance ◽  
Air Permeability ◽  
Paper Coating ◽  
Reaction Conditions ◽  
Printing Ink

This paper deals with the preparation of Plate-shaped Calcium Carbonate and Its Application in the Paper Coating. calcium oxide and carbon dioxide were used as major materials to preparetion the Plate-shaped Calcium Carbonate, The best reaction conditions as follows: w(CaO)：w（H2O）=1：5, V（CO2）：V（atmosphere）=1：2. Then use the Plate-shaped Calcium Carbonate in spreading. The results show that the Plate-shaped Calcium Carbonate is a high-performance product that can obviously enhance the paper’s smoothness, whiteness, air permeability, printing ink absorbance.

Filling of Carbon Nanotubes with Selenium by Vapor Phase Process

2006 ◽  
Vol 6 (1) ◽  
pp. 82-86 ◽  
Author(s):  
Jérôme Chancolon ◽  
Françoise Archaimbault ◽  
Alain Pineau ◽  
Sylvie Bonnamy
Keyword(s):  
Carbon Nanotubes ◽  
Vapor Phase ◽  
Capillary Condensation ◽  
Phase Method ◽  
X Ray Diffraction ◽  
Filling Rate ◽  
X Ray ◽  
Full Control ◽  
Trigonal Structure ◽  
Phase Process

A vapor phase method was developed to fill different kinds of nanotubes (including multiwall and singlewall nanotubes), which inner diameters range from 200 down to 1.5 nm. Experiments were performed with selenium in a sealed reactor in order to control the selenium partial pressure. This process allows a full control of the nanotube filling (partial or complete), i.e., either a selective diameter filling or a full filling rate. The weight gain of all the samples was plotted for different reaction temperature as a function of selenium pressure. Experimental isotherms are characteristic of capillary condensation of selenium, which occurs at first in the smallest nanotube inner diameters. X-ray diffraction data show that selenium confined in nanotubes with diameters larger than 3 nm keeps its trigonal structure.

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