A thermochemical approach for calcium phosphate precipitation modeling in a pellet reactor

摘要: A common pathway for P-recovery from wastewater is phosphate precipitation as calcium phosphates. In this paper, a thermodynamic model proposed based on various models of activity coefficients taking into account phases which can crystallize in the range pH to be considered, i.e. both dicalcium dihydrate (DCPD) and amorphous (ACP) lower than 7.3 only ACP higher 7.3. The parameters include solubility products DCPD species. observed discrepancy liquid phase equilibrium constants reported literature leads determination an uncertainty zone describing domain. results obtained offer interesting possibilities further optimization process operating conditions, determining Ca/P molar ratio, order reduce effluent (thus avoiding post-treatment) and, consequently, maximize reactor efficiency.