ABSORBING REMOVAL OF SULFUR OXIDE FROM EXHAUST GAS BY USING CALCIUM IONN CONTAINING RED MUDDY SLURRY

摘要

A process for the removal of sulfur oxides from exhaust gases by absorbing with a slurry of red mud containing calcium ion which comprises the steps of: (1) contacting an exhaust gas containing sulfur oxides of not higher than about 100 DEG C. with a slurry of red mud containing calcium ion led from the next step (2) to take up sulfur oxides in the gas until pH of the slurry becomes in the range of 4.3 to less than 6 while maintaining the molar fraction of SO4-- to total SO2 in the slurry within the said pH range at 0.05 to 0.7; and then, (2) contacting the treated gas with a fresh slurry of red mud containing calcium ion to further take up sulfur oxides in the gas while maintaining the concentration of NaHSO3 in the slurry at not more than about 8 g/l.