Removal and recovery phosphorus from wastewater by converter slag-seeded crystallization of calcium phosphate
- Received Date: 03/12/2009
- Accepted Date: 29/09/2009
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Key words:
- phosphorous recovery /
- crystallization /
- converter slag /
- seed crystal /
- hydroxyapatite(HAP)
Abstract: With converter slag used as a seed crystal, the effects of the reaction conditions on induced crystallization of calcium phosphate for removal and recovery of phosphorus from wastewater were investigated by batch experiments. Results indicated that pH value of 9.5，Ca/P molar ratio of 2,seed concentration of 1.7 g/L, reaction time of 3 h seemed to be the favorable conditions.Under the optimal reaction conditions, carbonate concentration had a little effect on the precipitation of calcium phosphate, and the P removal efficiencies of the swine farm wastewater and the concentrated sludge supernate were 95.36% and 96.54%, respectively. After used for ten times, converter slag as a seed crystal material for phosphorus recovery was still satisfactory. Characteristics of the products were determined by such analytical techniques as scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS) and powder X-ray diffraction(XRD). The results showed that the main recovered product was hydroxyapatite.
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