The invention relates to a method for the industrial preparation of phosphoric acid from an aqueous suspension comprising water and particles of at least one phosphate material dispersed in the presence of at least one additive of the anionic polymer type. Phosphoric acid is obtained by treating this suspension with at least one strong acid. The polymer is obtained by polymerization reaction of at least one acid selected from acrylic acid, methacrylic acid and salts thereof.
The invention relates to the use of this anionic polymer as well as the method for improving the rheology of the suspension and the hydrodynamics of the reaction medium in which the reactions for the manufacture of phosphoric acid take place.