Size effect of struvite crystals on their linear growth rate in phosphate(V) and aluminum(III) or iron(III) ions-containing in phosphorus recycling aqueous solutions

摘要

Struvite was crystallized from the title soln. to det. the kinetic parameters of the ideal mixed suspension, mixed product removal MSMPR model. Rojkowski exponential size-dependent growth model was used for the calculation. Nuclei population d., their growth rates, and crystal linear growth rates were detd. from product crystal size distributions. At Al-3(+) or Fe3+ contents 10-100 mg/kg or 2-10 mg/kg, resp., in the soln. feeding the crystallizer, pH 9 or 11 and the mean residence time of suspension in the crystallizer tau 900 or 3600 s, the linear growth rate of struvite crystals in presence of Al-3(+) varied from 6.82.10(-9) to 1.90.10(-8) m/s, whereas in presence of Fe3+ it was within the 6.1640(-9)-1.4940(-8) m/s range. Nucleation rate varied within the 2.89-10(12)-1.98-10(15) 1/(s.m(3)) and 4.30.10(14)-1.61.10(16) 1/(s.m(3)), resp. Al-3(+) ions affected struvite reaction crystn. more advantageously than Fe3+ ions. The MSMPR model test results were compared with the kinetic data of struvite crystallization from real wastewater from the P fertilizer industry.