American Journal of Agricultural and Biological Sciences

Nucleation and Crystal Growth Rates of Struvite in DTM Type Crystallizer with a Jet-Pump of Descending Suspension Flow in a Mixing Chamber

Joanna Koralewska, Krzysztof Piotrowski, Boguslawa Wierzbowska and Andrzej Matynia

DOI : 10.3844/ajabssp.2007.260.266

American Journal of Agricultural and Biological Sciences

Volume 2, Issue 4

Pages 260-266

Abstract

The kinetic data concerning reaction-crystallization of struvite from diluted water solutions of Mg2+, NH4+ and PO43- ions in a continuous DTM-type liquid jet-pump crystallizer with internal circulation of suspension are presented and discussed. The measurements were performed with the assumption of minimal value of unit power of a jet-pump’s feeding stream, providing thus a minimal level of internal circulation intensity. Nucleation and linear growth rates of struvite crystals were calculated on the basis of population density distributions of product particles. A mathematically convenient kinetic model for MSMPR crystallizer, making allowance for a size-dependent growth (SDG) phenomenon, was adopted for description of a complex process of precipitation integrated with crystals growth. It was concluded, that in the concentration range of magnesium ions in a feeding solution [Mg2+]RM = 0.1-2.0 mass % and, in stoichiometric proportions, phosphate ions [PO43-]RM = 0.39-7.81 mass % as well as the ammonium ions [NH4+]RM = 0.074-1.48 mass %, the Rojkowski hyperbolic SDG kinetic model proved to be an equation the best statistically fitted to the own experimental data.

Copyright

© 2007 Joanna Koralewska, Krzysztof Piotrowski, Boguslawa Wierzbowska and Andrzej Matynia. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.