<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">Experimental tests covering the production of struvite MgNH4PO4·6H2O from water solutions containing 1.0 mass % of phosphate(V) ions using magnesium and ammonium ions in stoichiometric proportions were carried out in a crystallizer of 1.2 dm3 working volume. The process temperature was 298 K. Struvite crystals of mean size <italic>L</italic>m from ca. 14 to ca. 38 μm were produced depending on the process environment's pH (9-11) and the mean residence time of suspension in a crystallizer, τ (900-3600 s). In such defined process conditions the linear growth rate of struvite crystals changed from 1.45·10-8 m/s (pH 9, τ 900 s) to 2.06·10-9 m/s (pH 11, τ 3600 s) while the nucleation rate from 5.1·107 to 3.2·109 1/(sm3). Crystal product of the most advantageous granular characteristics was produced at pH 9 and the mean residence time 3600 s. Within this product population the largest sizes reached above 200 μm while the number of crystals smaller than 3 mm was kept below 6%.</abstract>

Experimental tests covering the production of struvite MgNH4PO4·6H2O from water solutions containing 1.0 mass % of phosphate(V) ions using magnesium and ammonium ions in stoichiometric proportions were carried out in a crystallizer of 1.2 dm3 working volume. The process temperature was 298 K. Struvite crystals of mean size Lm from ca. 14 to ca. 38 μm were produced depending on the process environment's pH (9-11) and the mean residence time of suspension in a crystallizer, τ (900-3600 s). In such defined process conditions the linear growth rate of struvite crystals changed from 1.45·10-8 m/s (pH 9, τ 900 s) to 2.06·10-9 m/s (pH 11, τ 3600 s) while the nucleation rate from 5.1·107 to 3.2·109 1/(sm3). Crystal product of the most advantageous granular characteristics was produced at pH 9 and the mean residence time 3600 s. Within this product population the largest sizes reached above 200 μm while the number of crystals smaller than 3 mm was kept below 6%.

Reaction crystallization of struvite in a continuous DTM type crystallizer with a compressed air driven jet pump

Faculty of Chemistry, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland

Department of Chemical & Process Engineering, Silesian University of Technology, ks. M. Strzody 7, 44-101 Gliwice, Poland

Polish Journal of Chemical Technology

Experimental tests covering the production of struvite MgNH4PO4·6H2O from water solutions containing 1.0 mass % of phosphate(V) ions using magnesium and...

Reaction crystallization of struvite in a continuous DTM type crystallizer with a compressed air driven jet pump

Published Online: Jun 16, 2011

Page range: 46 - 53

DOI: https://doi.org/10.2478/v10026-011-0023-8

Keywords
continuous DTM crystallizer, jet pump, compressed air, reaction crystallization, phosphates(V) removal, struvite, crystal size distribution, SIG kinetic model

This content is open access.

Reaction crystallization of struvite in a continuous DTM type crystallizer with a compressed air driven jet pump

Published Online: Jun 16, 2011

Page range: 46 - 53

DOI: https://doi.org/10.2478/v10026-011-0023-8

Keywordscontinuous DTM crystallizer, jet pump, compressed air, reaction crystallization, phosphates(V) removal, struvite, crystal size distribution, SIG kinetic model

This content is open access.

Keywords
continuous DTM crystallizer, jet pump, compressed air, reaction crystallization, phosphates(V) removal, struvite, crystal size distribution, SIG kinetic model