The crystallization of Calcium sulfate dihydrate produced by the reaction between pure Ca(OH) 2 suspension and H 2 SO 4 solution was investigated at different pH values, temperatures and citric acid concentrations. Crystal size distributions, filtration rates and zeta potentials of gypsum were determined as a function of citric acid concentrations at pH 3.5 and 65°C. The influence of citric acid on the morphology of gypsum was also investigated and discussed. The average particle size of gypsum was reached to maximum in the presence of approximately 2500 ppm citric acid concentration, where the minimum cake resistance and maximum filtration rate were obtained. In the presence of citric acid, various crystal morphologies such as tabular, platelike, double-taper leaf-like and flower-like, etc., were obtained. The change of morphology is related to the preferential adsorption of citric acid on different crystallographic faces.
The effect of Fe 2+, Fe 3+ , and Cr 3+ ions on crystallization of calcium sulfate dihydrate (gypsum) produced by the reaction between calcium hydroxide suspension and sulphuric acid solution was investigated at 3.5 pH and 65°C in the absence and presence of 2500 ppm citric acid concentration. Crystal size distributions, filtration rates, and morphology of gypsum were determined and discussed as a function of ion concentration. Average particle size of gypsum was not affected significantly by the presence of Fe 2+, Fe 3+, and Cr 3+ ions individually. Variation of gypsum morphology depending on ion concentration affected the filtration characteristics. The presence of Fe 3+ or Cr 3+ ions besides 2500 ppm citric acid influenced both average particle size and filtration characteristics. The effect of citric acid on gypsum morphology was suppressed at high Fe 3+ and Cr 3+ ion concentrations. The change of morphology is related to the complex formation between Fe 3+ or Cr 3+ ions and citric acid at high ion concentrations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.