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Title: The seeded growth of calcium sulfate dihydrate crystals in NaCl solutions up to 6 m and 90 C

Abstract

The kinetics of calcium sulfate crystal growth is of importance in various fields, such as geochemistry, desalination technology, petroleum industry, and water and wastewater treatment. The seeded crystal growth rate of calcium sulfate dihydrate was measured as a function of supersaturation in NaCl electrolyte solutions from 0 to 6 m at temperatures of 25, 50, 70, and 90 C. The growth followed a second-order parabolic rate law with activation energies greater than 53 kJ/mol which suggested the surface reaction as the rate-limiting step. It was observed that the rate constant and the activation energy are solution composition dependent. The rate constant increases with NaCl concentration up to 3 molal and then begins to fall slightly. The activation energy dropped from 61 kJ/mol in the pure Ca-SO[sub 4]H[sub 2]O system to 53 kJ/mol in 3.0 m NaCl solutions. The electrolyte effect was similar to the crystal solubility behavior in aqueous electrolyte solutions resulting from the variation of the mean activity coefficient of the crystal with ionic strength. The rate constant is proportional to the crystal solubility and inversely proportional to the edge work or the interfacial tension as expected in the classic BCF model.

Authors:
; ;  [1]
  1. Rice Univ., Houston, TX (United States). Dept. of Environmental Science and Engineering
Publication Date:
OSTI Identifier:
7207449
Resource Type:
Journal Article
Journal Name:
Journal of Colloid and Interface Science; (United States)
Additional Journal Information:
Journal Volume: 163:2; Journal ID: ISSN 0021-9797
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GYPSUM; CRYSTAL GROWTH; AQUEOUS SOLUTIONS; BRINES; DEPOSITION; FOULING; SAMPLE PREPARATION; SODIUM CHLORIDES; ALKALI METAL COMPOUNDS; CHLORIDES; CHLORINE COMPOUNDS; DISPERSIONS; HALIDES; HALOGEN COMPOUNDS; MINERALS; MIXTURES; SODIUM COMPOUNDS; SOLUTIONS; SULFATE MINERALS; 360602* - Other Materials- Structure & Phase Studies

Citation Formats

He, S, Oddo, J E, and Tomson, M B. The seeded growth of calcium sulfate dihydrate crystals in NaCl solutions up to 6 m and 90 C. United States: N. p., 1994. Web. doi:10.1006/jcis.1994.1116.
He, S, Oddo, J E, & Tomson, M B. The seeded growth of calcium sulfate dihydrate crystals in NaCl solutions up to 6 m and 90 C. United States. https://doi.org/10.1006/jcis.1994.1116
He, S, Oddo, J E, and Tomson, M B. 1994. "The seeded growth of calcium sulfate dihydrate crystals in NaCl solutions up to 6 m and 90 C". United States. https://doi.org/10.1006/jcis.1994.1116.
@article{osti_7207449,
title = {The seeded growth of calcium sulfate dihydrate crystals in NaCl solutions up to 6 m and 90 C},
author = {He, S and Oddo, J E and Tomson, M B},
abstractNote = {The kinetics of calcium sulfate crystal growth is of importance in various fields, such as geochemistry, desalination technology, petroleum industry, and water and wastewater treatment. The seeded crystal growth rate of calcium sulfate dihydrate was measured as a function of supersaturation in NaCl electrolyte solutions from 0 to 6 m at temperatures of 25, 50, 70, and 90 C. The growth followed a second-order parabolic rate law with activation energies greater than 53 kJ/mol which suggested the surface reaction as the rate-limiting step. It was observed that the rate constant and the activation energy are solution composition dependent. The rate constant increases with NaCl concentration up to 3 molal and then begins to fall slightly. The activation energy dropped from 61 kJ/mol in the pure Ca-SO[sub 4]H[sub 2]O system to 53 kJ/mol in 3.0 m NaCl solutions. The electrolyte effect was similar to the crystal solubility behavior in aqueous electrolyte solutions resulting from the variation of the mean activity coefficient of the crystal with ionic strength. The rate constant is proportional to the crystal solubility and inversely proportional to the edge work or the interfacial tension as expected in the classic BCF model.},
doi = {10.1006/jcis.1994.1116},
url = {https://www.osti.gov/biblio/7207449}, journal = {Journal of Colloid and Interface Science; (United States)},
issn = {0021-9797},
number = ,
volume = 163:2,
place = {United States},
year = {1994},
month = {3}
}