Thermodynamic Preparation Window of Alpha Calcium Sulfate Hemihydrate from Calcium Sulfate Dihydrate in Non-Electrolyte Glycerol–Water Solution under Mild Conditions

2011 ◽  
Vol 50 (23) ◽  
pp. 13561-13567 ◽  
Author(s):  
Baohong Guan ◽  
Guangming Jiang ◽  
Hailu Fu ◽  
Li Yang ◽  
Zhongbiao Wu
Keyword(s):  
Calcium Sulfate ◽  
Water Solution ◽  
Glycerol Water ◽  
Mild Conditions ◽  
Calcium Sulfate Dihydrate ◽  
Calcium Sulfate Hemihydrate

Trace NaCl and Na2EDTA Mediated Synthesis of α-Calcium Sulfate Hemihydrate in Glycerol–Water Solution

2016 ◽  
Vol 55 (34) ◽  
pp. 9189-9194 ◽  
Author(s):  
Caiyun Jia ◽  
Qiaoshan Chen ◽  
Xu Zhou ◽  
Hao Wang ◽  
Guangming Jiang ◽  
...  
Keyword(s):  
Calcium Sulfate ◽  
Water Solution ◽  
Glycerol Water ◽  
Calcium Sulfate Hemihydrate

Preparation of α-calcium sulfate hemihydrate from FGD gypsum in K, Mg-containing concentrated CaCl2 solution under mild conditions

Fuel ◽  
2009 ◽  
Vol 88 (7) ◽  
pp. 1286-1293 ◽  
Author(s):  
Baohong Guan ◽  
Liuchun Yang ◽  
Zhongbiao Wu ◽  
Zhuoxian Shen ◽  
Xianfa Ma ◽  
...  
Keyword(s):  
Calcium Sulfate ◽  
Fgd Gypsum ◽  
Mild Conditions ◽  
Calcium Sulfate Hemihydrate ◽  
Cacl2 Solution

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%.

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