Solution-Mediated Transformation Kinetics of Calcium Sulfate Dihydrate to α-Calcium Sulfate Hemihydrate in CaCl2 Solutions at Elevated Temperature

2013 ◽  
Vol 52 (48) ◽  
pp. 17134-17139 ◽  
Author(s):  
Hailu Fu ◽  
Guangming Jiang ◽  
Hao Wang ◽  
Zhongbiao Wu ◽  
Baohong Guan
Keyword(s):  
Elevated Temperature ◽  
Calcium Sulfate ◽  
Transformation Kinetics ◽  
Calcium Sulfate Dihydrate ◽  
Kinetics Of ◽  
Calcium Sulfate Hemihydrate

The Kinetics and Mechanism of Formation of Calcium Sulfate Scale Minerals—The Influence of Inhibitors

CORROSION ◽  
1979 ◽  
Vol 35 (7) ◽  
pp. 304-308 ◽  
Author(s):  
GEORGE H. NANCOLLAS ◽  
WESLEY WHITE ◽  
FELIX TSAI ◽  
LARRY MAS LOW
Keyword(s):  
Calcium Sulfate ◽  
Mechanism Of Formation ◽  
Seeded Growth ◽  
Langmuir Adsorption ◽  
Calcium Sulfate Dihydrate ◽  
Calcium Sulfate Scale ◽  
Rate Of Reaction ◽  
Growth Method ◽  
Kinetics Of ◽  
Calcium Sulfate Hemihydrate

Abstract A seeded growth method has been used to study the kinetics of crystallization of calcium sulfate dihydrate at various temperatures and at ionic strengths up to 0.6M. Under all conditions, the rate of reaction is proportional to the square of the relative supersaturation and is controlled by a surface process. The same kinetics are applicable for the growth of calcium sulfate hemihydrate at temperatures above 110 C. The organic phosphonates effectively retard scale formation, and diethylenetriaminepenta (methylenephosphonic acid), when present at a concentration as low as 10−7M, completely inhibits the growth of calicum sulfate hemihydrate at 120 C. By assuming that the inhibitor molecules are adsorbed on growth sites on the surface of the crystals, the inhibition can be interpreted in terms of a simple Langmuir adsorption isotherm.

Fabrication of Spherical Carbonate Apatite Using Calcium Sulfate as a Precursor by W/O Emulsion Method

2012 ◽  
Vol 529-530 ◽  
pp. 78-81 ◽  
Author(s):  
Shunsuke Nomura ◽  
Kanji Tsuru ◽  
Shigeki Matsuya ◽  
Ichiro Takahashi ◽  
Ishikawa Kunio
Keyword(s):  
Calcium Sulfate ◽  
Single Phase ◽  
Carbonate Content ◽  
Carbonate Apatite ◽  
X Ray Diffraction ◽  
Emulsion Method ◽  
Calcium Sulfate Dihydrate ◽  
Hydrogen Carbonate ◽  
Diffraction Patterns ◽  
Calcium Sulfate Hemihydrate

We fabricated spherical carbonate apatite from spherical calcium sulfate which was prepared by w/o emulsion method. Calcium sulfate hemihydrate slurry was dropped in oil under continuous stirring and was kept at room temperature for 60 min to obtain set spherical calcium sulfate dihydrate (CaSO42H2O) with approximately 1 mm in diameter. The spherical CaSO42H2O was hydrothermally-treated at 120°C for 24 hours in the presence of 0.4 mol.L-1 disodium hydrogen phosphate and sodium hydrogen carbonate aqueous solution. X-ray diffraction patterns assigned to apatite single phase could be detected from the obtained spheres. Carbonate content in apatitic structure was found to be approximately 6.5wt%.

Research on Crystallization Kinetics of Calcium Sulfate Dihydrate Prepared by Bittern under 20°C and 120r/min Condition

2014 ◽  
Vol 926-930 ◽  
pp. 210-213
Author(s):  
Bi Jun Luo ◽  
Hai Hong Wu ◽  
Yu Qi Wang ◽  
Qi Zhang
Keyword(s):  
Experimental Data ◽  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Residence Time ◽  
Calcium Sulfate ◽  
Nucleation Density ◽  
Growth Line ◽  
Calcium Sulfate Dihydrate ◽  
Kinetics Of

Crystallization kinetics experiment of calcium sulfate dehydrates, which is prepared by bittern under 20°C and 120r/min conditions, is carried out. According to the results of the experimental data, nucleation densityn0of gypsum crystals is proportional to the residence time, and the rate of crystal growth lineGis inversely proportional to the residence time. Meanwhile, the crystallization kinetics formula is derived to be:B0= 5.78×102G0.87.

scholarly journals The Effects of Inorganic Additives on the Nucleation and Growth Kinetics of Calcium Sulfate Dihydrate Crystals

2017 ◽  
Vol 17 (2) ◽  
pp. 582-589 ◽  
Author(s):  
Taher Rabizadeh ◽  
Tomasz M. Stawski ◽  
David J. Morgan ◽  
Caroline L. Peacock ◽  
Liane G. Benning
Keyword(s):  
Growth Kinetics ◽  
Calcium Sulfate ◽  
Nucleation And Growth ◽  
Calcium Sulfate Dihydrate ◽  
Kinetics Of
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