METHOD OF PURIFYING WASTE WATER FROM FLUORIDES Russian patent published in 2024 - IPC C02F1/58 C02F1/52 

FIELD: water treatment.

SUBSTANCE: invention relates to treatment of industrial waste water from fluoride ions by sedimentation and can be used for treatment of waste water from production of mineral fertilizers or aluminium metal. Method of purifying waste water from fluoride ions consists in treating them with a calcium-containing reagent until reaching pH 9-11 and then separating the liquid and solid phases by settling. Calcium-containing reagent used is calcium carbonate, preliminary thermally treated at temperature of 100-120 °C. Precipitation is carried out at a ratio of calcium : fluorine equal to (1.0-1.5):1. In order to separate the solid and liquid phases, deposition is carried out using a sodium salt of acrylic acid, which is a medium-molecular low-charge anionic flocculant in dosage of 5-20 mg/dm³.

EFFECT: providing a highly efficient method of purifying waste water from fluoride ions with content of more than 100 g/dm³.

1 cl, 6 ex