Phosphate removal in a fluidized bed—I. Identification of physical processes

The main processes concerning the precipitation of calcium phosphate in a fluidized bed were studied. Primary nucleation and molecular growth occur at the bottom of the bed, where the incoming phosphate is mixed with the reactants, producing fine particles which partly aggregate with the grains of the bed and further leave the reactor with the liquid effluent. This aggregation seems to be the most important process for phosphate removal, while molecular growth of the grains seems to be of secondary importance.