DRYING AND SEPARATING PROCESS AND PLANT

摘要

PCT No. PCT/AT93/00182 Sec. 371 Date Aug. 9, 1995 Sec. 102(e) Date Aug. 9, 1995 PCT Filed Dec. 2, 1993 PCT Pub. No. WO94/13580 PCT Pub. Date Jun. 23, 1994A process and plant for drying and then separating moist salts, such as magnesium sulfite, in which the moist magnesium sulfite is heated to a temperature greater than or equal to about 200 DEG C. in a dryer and the passed through a solid materials lock into a separating plant. The dryer is heated by a circulating stream of exhaust vapors which is heated in a heat exchanger by exhaust gas generated in the separating plant so that the water of crystallization of the magnesium sulfite as well as residual humidity is eliminated during the drying process. Vapor-free acid anhydride, usually sulphur dioxide, is prepared in the separating plant from the dehydrated salt and a metal oxide, e.g., MgO, is recovered or otherwise used. The acid anhydride may be liquified and has a large degree of purity.