Abstract: The desulfurization effect and mechanism of treatment of low concentration SO2 by red mud slurry were studied by means of a laboratory-scale bubbling reactor, XRD and so on.The results show that the red mud liquid can contain sulfur 362.7 mg/g within the National Discharge Standard when the solid-liquid ratio is 1∶20.and red mud can purify SO2 under acidic conditions with the red mud pH of reaction termination dropping to 1.58.The solid matter in slurry desulfurization process has played a greater role in desulfurization the desulfurization,and the mechanism of red mud could be divided into basic physical desulfurization phase and iron ion catalytic oxidation desulfurization phase.When the red mud for pH ≤4, the dissolution of iron ion by mud slurry in acidic conditions has promote the absorption of SO2, and the effect of promoting is catalytic oxidation.Meanwhile, the final product by the reaction of SO2 and red mud mainly is calcium sulfate and sodium alum.

Key words: bayer red mud;SO2;Fe3+;mechanism;desulphurization