The invention relates to a collector for the separation by flotation of carbonates contained in non-sulfurous minerals, particularly phosphoric rock, comprising at least one phosphoric ester of formula (I) wherein, R1 represents H, CH3 or C2H5, R2 represents a linear or branched alkyl or alkenyl group containing between 4 and 10 carbon atoms, R3 represents H or a suitable cation, selected from an alkali metal, an alkaline earth metal, ammonium, alkyl ammonium, alkanol ammonium or glucammonium, k represents a number comprised between 1 and 2, and n represents a number comprised between 0 and 4.