| abstract |
A dryer (2) which is separated from a cleavage plant (2) by a solids sluice (3) is heated to more than 200 ° C by circulating an outlet steam stream which is heated by heat exchange with the exhaust gas from the cleavage plant (1), whereby both the moisture content and the crystal water are released. - is operated, whereby in the connected cleavage plant (1), water vapor-free acid anhydride (SO2) is recovered from the dehydrated salt, while the metal oxide is recovered or added for new use. The acid anhydride can be condensed and marketed because of its purity. |