Patent ID: 7329357

Claim:
A method for removing fluorine from wastewater, comprising: settling wastewater for settling heavy suspended solids and for permitting floating of light suspended solids on the surface of the wastewater, and subsequently removing the heavy and light suspended solids; removing metal ions in the wastewater by adjusting the pH value of the wastewater by adding a pH-adjusting agent into the wastewater in an amount such that the pH value of the wastewater ranges from 6 to 10 so as to precipitate metal hydroxides through reaction of the metal ions with hydroxide ions in the wastewater, and filtering the wastewater to remove the precipitate of the metal hydroxides from the wastewater; adding a fluorine reactive agent NaAlO 2 into the wastewater so as to form sodium ions and aluminum ions in the wastewater and so as to precipitate sodium aluminum fluoride by reaction of the sodium ions and the aluminum ions with fluorine ions in the wastewater; and removing the precipitate of sodium aluminum fluoride from the wastewater, wherein the precipitate of sodium aluminum fluoride has a formula of Na 3 AlF 6 .