METHOD OF PROTECTING GROUND WATER FROM FLUORINE CONTAMINATION Russian patent published in 2025 - IPC E02D31/00 B09C1/00 

FIELD: ecology.

SUBSTANCE: invention relates to ecology and is intended to reduce the degree of contamination of ground water during infiltration of atmospheric precipitation through soil contaminated with fluorine. Method of protecting ground water from contamination with fluorine enables to retain water-soluble fluorine compounds – element of 1st hazard class, in a layer of phosphogypsum with thickness of 10-25 cm, placed at depth of 25 cm. Phosphogypsum – CaSO₄ ⋅ nH₂O is a by-product of production of mineral fertilizers, which has high fluorine-holding capacity. Method consists in creation of impervious barrier in soil by removal of topsoil and placement under its surface at depth of 25 cm of solid layer of sorbent in the form of phosphogypsum with thickness of 10-25 cm, after which removed topsoil is returned into place. Chemistry of the process consists in binding water-soluble fluorine compounds with calcium to form a sparingly soluble compound CaF₂ – fluorite, when infiltration water passes through a layer of phosphogypsum.

EFFECT: invention enables to prevent contamination of ground water with fluorine.

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