Method for manufacturing furan-2,5-dicarboxylic acid (FDCA) from a solid salt

The present invention pertains to a method for manufacturing furan-2, 5-dicarboxylic acid (FDCA) by converting a furan-2,5- dicarboxylate salt (MFDC) into furan-2, 5-dicarboxylic acid (FDCA), comprising the steps of - combining solid MFDC with an inorganic acid (HY), to form a reaction mixture comprising solid FDCA in a concentration of 1-15 wt. % in a solution of a salt resulting from the cation of the furan-2, 5-dicarboxylate salt and the anion of the inorganic acid (MY solution), - removing solid FDCA from the reaction mixture in a solid/liquid separation step, and - providing at least 40 vol.% of the MY solution resulting from the solid/liquid separation step to the step of combining MFDC with HY. The step of providing part of the MY salt solution resulting from the solid/liquid separation step to the step of combining MFDC with HY makes it possible to obtain a stable and economic process which results in an FDCA product with good quality, and obtained in high yield.