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Effect of particle size on the transformation kinetics of flue gas desulfurization gypsum to α-calcium sulfate hemihydrate under hydrothermal conditions
- Source :
- Particuology. 40:98-104
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- The effect of particle size on the transformation kinetics of flue gas desulfurization (FGD) gypsum to α-calcium sulfate hemihydrate (α-HH) in calcium chloride (CaCl2) solutions was investigated to better guide value-added FGD gypsum use. Gypsum samples from different sources were sieved into several size groups, and their transformation rates were compared. The results showed that using FGD gypsum with a smaller particle size accelerated the transformation to α-HH. The size effect accelerated nucleation kinetics of α-HH rather than its crystal growth rate (that is, the thermodynamic driving force for the transformation changed little with particle size variation). Analysis using a kinetics model revealed that a smaller gypsum particle size lowered the overall activation energy barrier for the transformation. This is because the smaller gypsum particles had a larger relative specific surface area and thus provided more nucleation sites and crystalline defects to promote α-HH nucleation. A smaller particle size of FGD gypsum also gave a higher yield of fine α-HH particles because of the increased incidence of primary and secondary nucleation coupled with attrition. This paper indicates the transformation of FGD gypsum into α-HH could be effectively promoted by regulating FGD gypsum particle size.
- Subjects :
- Gypsum
Materials science
General Chemical Engineering
Kinetics
Nucleation
02 engineering and technology
Activation energy
engineering.material
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
0104 chemical sciences
Flue-gas desulfurization
chemistry.chemical_compound
chemistry
Chemical engineering
Specific surface area
engineering
General Materials Science
Particle size
Sulfate
0210 nano-technology
Subjects
Details
- ISSN :
- 16742001
- Volume :
- 40
- Database :
- OpenAIRE
- Journal :
- Particuology
- Accession number :
- edsair.doi...........a0ed75ef9b9af70ebb271298833efaa8