US 11,286,189 B2 · Treatment of fluoride-containing wastewater

Abstract

The invention relates to a method for treating fluoride-containing, in particular HF containing wastewater to remove fluoride and to a corresponding apparatus. In the new method calcium carbonate is reacted in a reaction step at an acidic pH≤4 with the fluoride in the wastewater to form calcium fluoride particles. Then, in a subsequent filtration step said calcium fluoride particles are separated by a porous membrane from the treated wastewater. The inventive apparatus comprises at least one reaction container/tank for reacting calcium carbonate at an acidic pH≤4 with fluoride in the wastewater to form calcium fluoride particles, as well as at least one porous membrane, in particular at least one porous ceramic membrane for separating calcium fluoride particles from the treated wastewater in a filtration step.

Claims13

Dependent claims

Method for treating HF-containing wastewater to remove fluoride in a crystalline process, wherein

at an acidic pH≤4 calcium carbonate (CaCO3) is reacted in a reaction step with the fluoride in the wastewater to form crystalline calcium fluoride (CaF2) particles, and
in a subsequent filtration step said CaF2 crystalline particles are separated by a porous ceramic membrane from the wastewater,
the CaCO3 in the process performing three distinct functions:
(1) neutralization of acidity by carbonate;
(2) providing calcium for CaF2 crystallization;
and (3) providing seed material for crystallization.

3 more elements

Dependencies are inferred from the claim text.

Treatment of fluoride-containing wastewater

Life of this patent

Treatment of fluoride-containing wastewater

Life of this patent

Abstract

Claims13