| 摘要 |
Sulfur-containing compounds, particularly sulfur dioxide, are removed from stack gas streams by wet scrubbing the gases wherein an alkaline earth metal sulfate and/or sulfite are formed. Example processes are lime/limestone and Double Alkali scrubbing processes. These processes produce sludge material containing primarily the alkaline earth metal sulfate which is disposed of only with significant difficulty. An improvement is described herein whereby the aqueous sludge is reduced in contact with sufficient coal to produce the corresponding sulfide and effluent gases from the reduction step having a sufficient heating value to be used to dry the mixture of sludge and coal prior to the reducing step. The alkaline earth metal carbonate and elemental sulfur are recovered from the sulfide.
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