Patent ID: 6235203
Filing Date: 2001-05-22
Classification: B01D,C02F,Y10S

Abstract:
A crystallization process for removing fluoride from waste water, comprising the following steps of:(a) introducing fluoride-containing waste water into a fluidized bed crystallizer provided with a carrier;(b) adding a water soluble sodium reagent and a water soluble aluminum reagent into the fluidized bed crystallizer to form crystallized cryolite (Na.sub.3 AlF.sub.6) onto the carrier with which the fluoride in the waste water can be removed, wherein the molar ratio of aluminum to fluorine is between 0.8.about.1:6, and the molar ratio of sodium to fluorine is larger than 0.5; and(c) discharging the treated waste water from the fluidized bed crystallizer to obtain a primary treated water.