Liquidus temperatures in the calcium carbonate-calcium hydroxide-calcium oxide and calcium carbonate-calcium sulfate-calcium sulfide ternary systems. 1

1981 ◽  
Vol 20 (3) ◽  
pp. 441-443 ◽  
Author(s):  
M. C. Fuerstenau ◽  
C. M. Shen ◽  
B. R. Palmer
Keyword(s):  
Calcium Carbonate ◽  
Calcium Hydroxide ◽  
Calcium Oxide ◽  
Calcium Sulfate ◽  
Ternary Systems ◽  
Calcium Sulfide ◽  
Liquidus Temperatures

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.

Characterization of Calcium Carbonate, Calcium Oxide, and Calcium Hydroxide as Starting Point to the Improvement of Lime for Their Use in Construction

2009 ◽  
Vol 21 (11) ◽  
pp. 694-698 ◽  
Author(s):  
Miguel Galván-Ruiz ◽  
Juan Hernández ◽  
Leticia Baños ◽  
Joaquín Noriega-Montes ◽  
Mario E. Rodríguez-García
Keyword(s):  
Calcium Carbonate ◽  
Calcium Hydroxide ◽  
Calcium Oxide ◽  
Starting Point

CALCIUM CYCLE IN CHEMISTRY TEACHING AT THE LOWER SECONDARY SCHOOL

2019 ◽  
Author(s):  
Karel Kolar ◽  
◽  
Martin Bilek ◽  
Katerina Chroustova ◽  
Jiri Rychtera ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Calcium Carbonate ◽  
Hydrochloric Acid ◽  
Secondary School ◽  
Calcium Hydroxide ◽  
Calcium Chloride ◽  
Calcium Oxide ◽  
Lower Secondary School ◽  
Chemistry Teaching ◽  
Lower Secondary Education

The research is focused on the use of experimental calcium cycle in chemistry teaching at the lower secondary school. The cycle is based on four reactions: 1. thermal decomposition of calcium carbonate, 2. reaction of calcium oxide with water, 3. calcium hydroxide with hydrochloric acid, 4. reaction of calcium chloride with sodium carbonate. The calcium cycle was tested at lower secondary schools (and equal classes from comprehensive schools). Despite the difficulty of taking some steps, the cycle was accepted by both teachers and learners. Keywords: chemistry teaching, experimental cycle, calcium cycle, lower secondary education.

Controlled preparation of micro–nano hierarchical hollow calcium carbonate microspheres by pressurized-CO2 carbonization and their CaCO3:Eu3+ photoluminescence properties

CrystEngComm ◽  
2021 ◽  
Vol 23 (16) ◽  
pp. 3033-3042
Author(s):  
Liubin Shi ◽  
Mingde Tang ◽  
Yaseen Muhammad ◽  
Yong Tang ◽  
Lulu He ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Calcium Hydroxide ◽  
Hierarchical Structure ◽  
Ethylenediaminetetraacetic Acid ◽  
Disodium Salt ◽  
Hollow Microspheres ◽  
Photoluminescence Properties ◽  
Controlled Preparation

Herein, calcium carbonate hollow microspheres with a micro–nano hierarchical structure were successfully synthesized using disodium salt of ethylenediaminetetraacetic acid (EDTA-2Na) as an additive, by bubbling pressurized carbon dioxide and calcium hydroxide at 120 °C.

PREPARATION OF PRECIPITATED CALCIUMCARBONATE USING ADDITIVE AND WITHOUT ADDITIVE

2015 ◽  
Vol 77 (3) ◽  
Author(s):  
Anuar Othman ◽  
Nasharuddin Isa ◽  
Rohaya Othman
Keyword(s):  
Calcium Carbonate ◽  
Calcium Hydroxide ◽  
Mineral Composition ◽  
Hydrated Lime ◽  
Raw Material ◽  
Precipitated Calcium Carbonate ◽  
Uniform Size ◽  
The One

Precipitated calcium carbonate (PCC) chemically can be synthesized in the laboratory. In this study, hydrated lime or calcium hydroxide was used as raw material with sucrose as additive to produce PCC. The process was compared with the one without additive. PCC produced was observed based on morphology, mineral composition and size by using Fesem-Edx and LPSA, respectively. PCC products without additive demonstrated fine and more uniform size of calcite PCC as compared to the one with additive. Nevertheless, the process with additive produced more PCC product than without additive.

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