Patent ID: 8906117

Claim:
A process for the combined regeneration of at least two soluble salts contained in a residue of an industrial process comprising polyvalent metals, said process comprising: (a) bringing into contact with the residue an amount of a reactive aqueous solution to dissolve the at least two salts which are to be regenerated to form an aqueous suspension; (b) subjecting the resulting aqueous suspension to a separation to obtain an aqueous production solution on the one hand and insoluble impurities on the other hand, which are removed; (c) successively subjecting the aqueous production solution to at least two selective crystallization steps to produce, separately, crystals of the at least two soluble salts which are to be regenerated, which are washed, dried and regenerated separately; and (d) adjusting the concentration of at least one of the soluble salts to be regenerated in the aqueous production solution, at the moment when said aqueous production solution is subjected to crystallization of the at least one of the soluble salts to be regenerated, to obtain the selective crystallization of this salt, by addition of a controlled amount of the at least one of the soluble salts to be regenerated to the aqueous production solution upstream of said crystallization in step (c).