“…In the first communication of this series, we have demonstrated successful application of the ion-exchange isothermal supersaturation (IXISS) effect for designing highly efficient and ecologically clean ion-exchange technology for manufacturing chlorine-free potassium fertilizers (Muraviev et al, 1997a). The IXISS phenomenon, discovered for the first time by Muraviev (Muraviev, 1979), is observed in a number of ion-exchange systems where ion-exchange separation is accompanied by simultaneous concentration of the target substance in the interstitial space of ion-exchange column up to and beyond the level exceeding its solubility at a given temperature (Muraviev et al, 1979;Muraviev and Saurin, 1980;Khamizov et al, 1996;Tikhonov, 1995;Muraviev et al, 1997b). The present communication is dedicated to the development of IXISS-based clean ion-exchange technology for recovery of high-purity magnesium compounds from seawater, which can be considered as a competitive alternative to the existing large-scale magnesium-from-seawater industrial processes.…”