Adsorption of Organic Phosphonates on Calcium Sulfate Dihydrate Crystals

CORROSION ◽  
1981 ◽  
Vol 37 (2) ◽  
pp. 120-122 ◽  
Author(s):  
Jasbir S. Gill ◽  
George H. Nancollas
Keyword(s):  
Phosphonic Acid ◽  
Calcium Sulfate ◽  
Crystal Habit ◽  
Active Growth ◽  
Surface Sites ◽  
Calcium Sulfate Dihydrate ◽  
Kinetics Of ◽  
Habit Modification ◽  
Heated Metal ◽  
Kinetics Of Crystal Growth

Abstract 14C labeled ethylenediaminetetra (methylene phosphonic acid) and triethylenediaminetetra (methylene phosphonic acid) have been used to study their adsorption on calcium sulfate dihydrate crystals radiometrically under different conditions. Kinetics of crystal growth of calcium sulfate dihydrate crystals was studied both in solution and on heated metal surface. The growth of gypsum has been shown to follow an equation second order in supersaturation. The heterogeneity of surface sites is responsible for crystal habit modification in the presence of impurities. Blocking of the active growth sites by the inhibitors results in inhibiting the scale formation.

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.

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

Thermal dehydration of calcium sulfate dihydrate: physico-geometrical kinetic modeling and the influence of self-generated water vapor

2020 ◽  
Vol 22 (39) ◽  
pp. 22436-22450
Author(s):  
Shun Iwasaki ◽  
Nobuyoshi Koga
Keyword(s):  
Water Vapor ◽  
Kinetic Modeling ◽  
Calcium Sulfate ◽  
Reaction Pathway ◽  
The Self ◽  
Thermal Dehydration ◽  
Calcium Sulfate Dihydrate ◽  
Kinetics Of

The reaction pathway and kinetics of thermal dehydration is regulated by the self-generated water vapor.

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