In contrast to the strong acids, the dissolution onset in the system with phosphoric acid is not observed in the first 2 h at a proton dosage of 82 µmol/g CAC . The thermodynamically modeled pH evolution with H 3 PO 4 differs significantly from that of the other acids (Figure ). The first pH plateau at 4.6 linked to the formation of Al(OH) 3 is much shorter due to the weaker acidity of phosphoric acid, as stated above.