PROCESS OF PURIFYING EXHAUST GAS

摘要

In order to improve the economy of the purification of exhaust gas in a process which comprises a dry separation of solids and a scrubbing of gas in two stages succeeding in the direction of flow, it is proposed to operate the first and second scrubbing stages with acid and weakly basic scrubbing liquids, respectively, and to subject those quantities of scrubbing liquid which have been withdrawn from the two scrubbing cycles to separate further processing. As a result, (a) a sludge which contains the heavy metals and fluorine compounds and constitutes the first residual product to be dumped, (b) a re-usable alkali chloride salt, and (c) condensate and residual solutions both of which can be recycled in the process are obtained from the scrubbing liquid used in the first scrubbing stage and (a) a second residual product which is to be dumped and essentially contains alkali sulfate, and (b) condensate and a residual solution, both of which can also be recycled in the process, are obtained from the scrubbing liquid used in the second scrubbing stage.