Premium
Coprecipitation of CaCO 3 and CaSO 4
Author(s) -
Sudmalis Michael,
Sheikholeslami Roya
Publication year - 2000
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450780106
Subject(s) - coprecipitation , precipitation , salt (chemistry) , crystallization , chemistry , gypsum , kinetics , inorganic chemistry , mineralogy , materials science , metallurgy , meteorology , organic chemistry , physics , quantum mechanics
Coprecipitation characteristics of CaCO 3 and CaSO 4 were studied under various operating conditions. The investigations were carried out in temperature‐controlled batch tests. Coprecipitation results were compared with our experimental results of a single salt crystallization. It was found that the induction period and kinetics of coprecipitation of these two salts follow that of pure CaCO 3 . However, thermodynamic concentrations of Ca in coprecipitation followed that of pure CaSO 4 at all times. The relationship between the thermodynamic concentrations of Ca for pure CaCO 3 and CaSO 4 solutions depended on the pH of the CaCO 3 solution. CaSO 4 precipitated in form of gypsum and had a needle shape structure; CaCO 3 had a spiral growth and precipitated in form of calcite. The precipitate structure was affected by the co‐existence of salts; the co‐precipitation resulted in CaCO 3 crystals interwoven by CaSO 4 crystals. This tends to result in a co‐precipitate that is stronger than pure CaSO 4 and weaker than pure CaCO 3 precipitate.