| 摘要 |
PURPOSE:To realize the removal of fluorine from drained water containing fluorine without consequent generation of a large amount of sludge by adding hydrochloric acid to drained water containing fluorine to make it acid based on hydrochloric acid, then adding calcium salt and ferric chloride, and adding an alkali agent and a polymer coagulant sequentially. CONSTITUTION:When removing fluorine from a circulating water (fluorine concentration: 45mg/liter) through a dust collector for a converter gas, as a water to be treated, hydrochloric acid is added to the water in a reaction tank 1 to adjust the pH value. At the same time, calcium chloride and ferric chloride are added to the water and it is left held as it is for about 5 minutes with the concurrent stirring action of the water. Next, the water to be treated is sent to a neutralization tank 2 where calcium hydroxide is added as an alkali agent to adjust the pH value (neutralization). After that, the water is sent to a coagulation tank 3 where a polymer coagulant is added form a flock, then is sent to a sedimentation pond 4 to separated the flock by sedimentation. Consequently, the water to be treated whose fluorine concentration of treated water is reduced to 8mg/liter after separation by sedimentation is obtained and this water to be treated is discharged. |
