Process for preparing salt.

Process for preparing salt, comprising the steps of: (i) preparing an aqueous salt solution containing at least 100 g / L of sodium chloride and at least 0.01 ppm of polyvalent cations by dissolving a sodium chloride source in the industrial water, (ii) adding to the aqueous salt solution an effective amount of at least one positive component increases retention, (iii) subsequently subjecting the solution to a nanofiltration step, whereby the solution is separated into a retentate which it is enriched in the polyvalent cations and a permeate which is the purified aqueous salt, and (iv) concentrating the permeate to produce salt.