Study On Desulfurization Performance Of Bayer Red Mud

The red mud,is produced in the process of alumina production of large industrial solid waste,with high alkaline and high content of iron and aluminum,and the stockpiling has serious environmental risk for groundwater and soil.Sulfur dioxide is the main reason for the formation of regional acid rain.At present,the cost of ammonia desulfurization and calcium desulfurization is higher,and there are two pollution risks.Based on the idea of "waste disposal",this paper puts forward the removal of sulfur dioxide from flue gas by using the basic components in red mud.The study of red mud desulfurization has been reported,the results show that the effect of desulfurization effect is well,but the mechanism of red mud desulfurization needs further study.Therefore,this article through the design of desulfurization reactor,simulation of sulfur dioxide in flue gas by using Bayer red mud removal,studied the effect by desulfurization parameters and mechanism of desulfurization on desulfurization process,combined with scanning electron microscopy(SEM),X ray diffraction(XRD)and X ray photoelectron spectroscopy(XPS)etc.technical means,mechanism of micro morphology,the phase composition of red mud desulfurization before and after the change and Fe in the process of desulfurization,desulfurization after exploring the harmless and resourceful treatment.The results show that:(1),The optimum conditions of desulfurization parameters were obtained by orthogonal test and range analysis.The main factors affecting the desulfurization efficiency were the ratio of liquid to solid,SO2 concentration and temperature.The water absorption of SO2 has little contribution.The best reaction conditions of low concentration of SO2 absorbed by red mud slurry for gas flow rate is 1.5 L/min,temperature 25,liquid-solid ratio is 20:1,Oxygen content is the oxygen content in air,and SO2 inlet concentration was 1000 mg/m3.(2),Results from the study of liquid desulfurization mechanism of red mud and red mud slurry:good desulfurization effect,the emission requirements in per gram of red mud can contain sulfur 362mg;red mud slurry to desulfurization in acidic conditions,slurry pH value dropped to about 1.5.Solid alkaline substances play a major role in the desulfurization process of desulfurization;the presence of oxygen under anaerobic,oxygen plays an important role in the desulfurization process,the oxide ions cannot anoxic sulfite into sulfate ion;red mud slurry in the lower pH,iron ion concentration is high,pH=4 in Desulfurization in the process of slurry iron ion dissolution,and in the pH=1.58 when the iron ion concentration reached 133.88 mg/L;iron ions in the slurry by improving the oxidation solution,improve the oxidation rate of SO32-,accelerate the absorption and dissolution of SO2 in slurry;iron ion can redox reaction with sulfur dioxide,Fe3+ played a catalytic the role of oxidation in the desulfurization process,and is mainly for SO32→SO42-this balance right effect.The sulfate ion excess slurry to inhibit desulfurization;red mud phase analysis shows that in the process of desulfurization of solid alkaline substance has been dissolved,desulfurization is the main product of calcium sulfate and tamarugite,which is characterized by pale yellow solid tamarugite impurities;desulfurization before and after XPS analysis demonstrated that the red mud occurred catalytic oxidation desulfurization of iron in the process,and after desulfurization red mud showed that iron mainly exists in the form of Fe2O3 and FeSO4.(3),After the desulfurization,the red mud scanning electron microscopy(SEM)showed that the red mud became loose and the particles became finer after the desulfurization.The BET surface area of red mud after desulfurization became from 7.4142m2/g to 23.7977m2/g.After the red mud desulfurization and its specific surface area becomes larger,thinner structure became loose,granular,solid proof in the reaction in the red mud;XRF element analysis showed that the red mud good desulfurization effect,risk characteristics of red mud after desulfurization is not polluted by heavy metals.1 volume red mud is mixed with 5 volume red mud,so that the pH value of two red mud is adjusted to neutral,and finally harmless to red mud.