| 摘要 |
<p>PURPOSE: To remove the selenium component contained in a stack gas and to make it harmless by cooling the stack gas below a specified temp., collecting the dust and converting the selenium contained in the dust in the stack gas to the insoluble compd. CONSTITUTION: A stack gas A is cooled to <=350 deg.C by a cooler, hence most of the selenium (Se) in the stack gas is condensed and stuck to the ash constituting the dust in the stack gas. The dust is separated by an electrostatic precipitator and recovered, and the whole separated dust is introduced en block into an Se treating device 25 by a conveyor 24. The introduced dust is repulped in the device 25, and the Se(IV) (mainly as selenite SeO3 <2-> ) is converted to iron selenite Fe2 (SeO3 )3 and insolubilzed. Consequently, the insolubilized dust slurry is separated from solid in a separator 26, and most of Se is separated as the ferrous selenite, insolubilized and mixed in a dust cake D discharged from the separator 26.</p> |
