Study on Oxidation of Calcium Sulfite in Dual Alkali Flue Gas Desulfurization System

The main effects of operating parameters (sulfite concentration, airflow flux, pH, temperature, the stirrer speed, solid particle content the presence and absence of manganese ion as catalyst) on macroscopic reaction oxidation rate was investigated. A mathematical model in theoretical study was also established to include the effect of the intrinsic reaction, the dissolution of calcium sulfite and diffusion of oxygen. By varying the main operating parameters, the optimum conditions was founded at: T = 50 °C; initial pH = 5.0; airflow flux: 450 ml/min; stirrer speed: 450 r/min; solid particle content: 10%; oxidation time: 2 h. In absence of manganese ion as catalyst the oxidation reaction rate was of 60%. In the same conditions of presence of manganese ion as catalyst, the oxidation rate increased significantly, the analysis XRD of composition of gypsum has been carrying out. Scanning electron microscope (SEM) of different products has been also done.