METHOD FOR DEFLUORINATION OF APATITE Russian patent published in 2012 - IPC C01F11/00 C01B25/32 C05B13/02 

FIELD: chemistry.

SUBSTANCE: invention relates to processing phosphate material and can be used in the technology of mineral fertilisers, feed grade and food phosphates. The method for defluorination of apatite involves adding acid to a mixture of apatite concentrate and water in a reactor. The acid used is phosphoric acid with concentration of 90% which is first heated to 145°C. The phosphoric acid is fed into the reactor to a mixture of apatite concentrate and water at temperature 170-180°C while stirring constantly. Pressure is then lowered to 1 atm and steam is released at pressure 14-16 atm. The gas-vapour phase then undergoes distillation and absorption. Separation of phases and defluorination products is carried out after distillation at reactor pressure 1 atm and temperature 20°C.

EFFECT: enabling removal of fluorine from the reaction mixture and obtaining fluorine-containing products - defluorinated calcium phosphates, defluorinated concentrate of rare-earth elements and strontium while ensuring ecological cleanness of the process.

5 cl, 2 ex