Precipitation and Crystallization of Struvite from  Synthetic Wastewater under Stoichiometric Conditions

Kozik, A.; Hutnik, N.; Piotrowski, Krzysztof; Mazieńczuk, A.; Matynia, A.

doi:10.4236/aces.2013.34b004

Cited by 31 publications

(18 citation statements)

References 7 publications

(16 reference statements)

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“…Compared to maximal sizes of struvite crystals produced from "pure" aqueous solutions of phosphate(V) ions (300 m and more) [11], [12] it is not a satisfying value. Fraction of the smallest product particles, of sizes below 5 m was 22.8 vol.…”

Section: A Crystal Size Distributionmentioning

confidence: 96%

“…Under stoichiometric conditions (molar ratio PO 4 3-: Mg 2+ as 1 : 1) smaller particles (mean size L m 15.5 m) and of moderate homogeneity (CV 76.0%) were produced [10]. Dominant size of these particles was L d 26.1 m, and their fraction in a product was slightly more than 4 mass %.…”

Section: A Crystal Size Distributionmentioning

confidence: 97%

“…One can assume, that these differences resulted from presence and -mainly -from specific concentrations of impurities in a given process system. Net effect of impurities is usually disadvantageous [14], [15]. From SABW product of lower quality was obtained than from phosphorus mineral fertilizer industry wastewater.…”

Section: A Crystal Size Distributionmentioning

confidence: 99%

“…The composition was identified using X-ray tests (X-ray diffractometer) and confirmed with thermal analysis methods (DTA, TG, DTG) [10], [13].…”

Section: B Chemical Compositionmentioning

confidence: 99%

See 3 more Smart Citations

Recovery of Struvite from Synthetic Animal Wastewater by Continuous Reaction Crystallization Process

Kozik¹,

Hutnik²,

Wierzbowska³

et al. 2016

IJCEA

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Abstract-Experimental results concerning continuous process of phosphate(V) ions recovery from synthetic animal breeding wastewater were presented. It was concluded, that phosphate(V) ions precipitated as sparingly soluble salts: amorphous calcium phosphate(V) (above 70% in a product) and struvite (below 30%). Solid product contained also impurities, mainly in the form of co-precipitated sparingly soluble metal hydroxides. Product size did not exceed 80 m. Its mean size varied from ca. 15 to ca. 18 m. Population homogeneity was moderate, with high agglomeration effects. Excess of magnesium ions in relation to phosphate(V) ions concentration (molar ratio 1.2 : 1) in a feed influenced process course and its results advantageously. Struvite content in a product increased more than 20%. Product size also enlarged -mean size was ca. 17% larger.Index Terms-Struvite, synthetic animal breeding wastewater, continuous reaction crystallization, DT MSMPR crystallizer, product quality, phosphorus recycling. I. INTRODUCTIONAnimal breeding wastewaters, especially liquid manure, are recently regarded as inexpensive and easily accessible secondary sources of phosphorus compounds [1]. Depending on a given wastewater origin, its collection method and even storage conditions the phosphorus content varies from 0.2 to 0.4 mass % on the average. Recovery of phosphate(V) ions from animal breeding wastewater is a complex process, difficult in practical implementation [2], [3], mainly because of its chemical composition. Main problem is high nitrogen, potassium and calcium contents, similar to phosphorus content [4], as well as presence of other impurities (especially: zinc, manganese, boron, copper and iron). These can catalyse or inhibit nucleation of struvite, calcium phosphates(V) and other sparingly soluble salts or/and hydroxides, as well as influence further nuclei growth, thus product quality [5].Struvite (MgNH 4 PO 4 •6H 2 O, MAP) precipitates after contacting magnesium (e.g. magnesium chloride) and ammonium ions with aqueous solution containing phosphate(V) ions and alkalisation of the resulting mixture (7 [7]. Presence of calcium ions in a process system results that the product is a mixture of struvite and calcium phosphates(V) [8]. It essentially restricts its possible application as a mineral fertilizer [9].The research results concerning continuous struvite reaction crystallization process from synthetic animal breeding wastewater (SABW), of chemical composition similar to liquid cattle manure, are compared [1], [4]. Concentration of phosphate(V) ions in this solution was 0.208 mass %. Crystallizer was provided with a feed assuming molar ratio PO 4 3-: Mg 2+ as 1 : 1 (stoichiometric conditions) and 1 : 1.2 (magnesium ions excess related to phosphate(V) ions concentration in struvite synthesis reaction). Process ran at pH 9 in temperature 298 K. Mean residence time of suspension in a crystallizer was 3600 s. Chemical and phase compositions of the resulting products, solids size distributions, as well as their statistical...

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Section: A Crystal Size Distributionmentioning

confidence: 96%

Section: A Crystal Size Distributionmentioning

confidence: 97%

Section: A Crystal Size Distributionmentioning

confidence: 99%

“…The composition was identified using X-ray tests (X-ray diffractometer) and confirmed with thermal analysis methods (DTA, TG, DTG) [10], [13].…”

Section: B Chemical Compositionmentioning

confidence: 99%

See 2 more Smart Citations

Recovery of Struvite from Synthetic Animal Wastewater by Continuous Reaction Crystallization Process

Kozik¹,

Hutnik²,

Wierzbowska³

et al. 2016

IJCEA

Self Cite

View full text Add to dashboard Cite

show abstract

“…The course of the process and its results are affected by many process variables (e.g., feed solution composition, component concentrations) (Doyle and Parsons, 2002;Le Corre et al, 2009;Kozik et al, 2013;Hutnik et al, 2013a;Karabegovic et al, 2013;Rahman et al, 2014), technological aspects (e.g., pH, mean residence time of the suspension in the crystallizer, molar ratio of substrates) (Parsons, 2001;Matynia et al, 2006;Le Corre et al, 2007a;Kozik et al, 2014a) and even constructional parameters (e.g. mixing and/or circulation method, mixing intensity and efficiency) (Ali and Schneider, 2006;Bhuiyan et al, 2008;Le Corre et al, 2009;Marti et al, 2010;Mazienczuk et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Effect of Continuous Crystallizer Performance on Struvite Crystals Produced in Reaction Crystallization From Solutions Containing Phosphate(v) and Zinc(ii) Ions

Hutnik

Wierzbowska

Piotrowski

et al. 2016

Braz. J. Chem. Eng.

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-Continuous reaction crystallization of struvite from aqueous solutions containing phosphate(V) (1.0 mass %) and zinc(II) ions (from 0.1 to 2.0 mg kg -1 ) in a continuous DT MSMPR crystallizer was investigated. The influence of pH (9 -11) and mean residence time (900 -3600 s) on the product characteristics and its chemical composition was tested. Struvite crystals of mean size 22-41 m were produced. An increase in Zn 2+ concentration decreased the mean crystal size and homogeneity. An elevation of the pH also decreased the struvite crystal size. Augmenting the mean residence time influenced product quality advantageously. Coexistence of struvite and Zn(OH) 2 in the product was confirmed analytically.

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Continuous reactive crystallization of pharmaceuticals using impinging jet mixers

et al. 2016

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For reactive crystallization of pharmaceuticals that show rapid reaction rate, low solubility of active pharmaceutical ingredient, hence large supersaturation, it was found in a recent study that a process design that integrates an impinging jet mixer and a batch stirred tank, the former to achieve intensive micromixing prior to reaction and crystal nucleation and the later to immediately disperse the formed nuclei or small particles to minimise aggregation but promote crystal growth, has produced high quality crystals. The current investigation studies the hypothesis that due to the short processing time of reactive crystallization, the impinging jet mixer -stirred tank design can be made to operate in continuous mode. The new design combines an impinging jet mixer for feed introduction and reaction, and a continuous stirred tank reactor (CSTR) and a tubular reactor for crystal growth. Study on reactive crystallization of sodium cefuroxime (an antibiotic), using firstly in a 1L CSTR then scaled to 50L CSTR, found that the new design has produced crystals of higher crystallinity, narrower particle size, and improved product stability, than the conventional batch crystallizer.

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Precipitation and Crystallization of Struvite from Synthetic Wastewater under Stoichiometric Conditions

Cited by 31 publications

References 7 publications

Recovery of Struvite from Synthetic Animal Wastewater by Continuous Reaction Crystallization Process

Recovery of Struvite from Synthetic Animal Wastewater by Continuous Reaction Crystallization Process

Effect of Continuous Crystallizer Performance on Struvite Crystals Produced in Reaction Crystallization From Solutions Containing Phosphate(v) and Zinc(ii) Ions

Continuous reactive crystallization of pharmaceuticals using impinging jet mixers

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