Process for the preparation of defluorinated tricalcium phosphate

摘要

Continuous process for the preparation of tricalcium phosphate containing more than 18 % by weight of phosphorus and at most 0.2 % by weight of fluorine by calcination of a mixture of natural calcium phosphate ore and of phosphoric acid, in which the CaO/P2O5 molar ratio is between 2.75 and 3.25, in more than two stages in fluidised bed reactors at temperatures of between 1100 DEG C and 1400 DEG C, in which the hydrofluoric acid partial pressure is at most equal to 5 ô 10<-3> bar in the final stage. <IMAGE>