MAGNESIUM SULFITE HEXAHYDRATE SUPERSATURATED SOLUTIONS STABILITY

Wet purification of crude MgSO3 . 6 H2O obtained at flue gases desulph urization is based on its dissolution, separation of solid ash followe d by crystallization of a clear supersaturated solution. The stability of supersaturated solutions during ash separation represents a requis ite condition for realization of this process. The stability of agitat ed supersaturated solutions containing from 5 to 8 wt% of MgSO3 is ass essed in the temperature range from 80-degrees to 95-degrees-C based o n experimentally determined induction period of crystallization, t(ind ), and desupersaturation curves. Time necessary for complete dissoluti on of MgSO3 . 6 H2O at the studied conditions, t(D), is also determine d. A plot of (t(ind) - t(D)) versus solution initial supersaturation f acilitates selection of suitable processing conditions for the wet pur ification.