| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for treating an exhaust gas from a sulfuric acid manufacturing process, by which sodium sulfite contained in an absorption waste liquid is oxidized easily without air blowing in the final absorption process of the sulfuric acid manufacturing process to reduce treatment costs when a non-reacted sulfur dioxide gas in the sulfuric acid manufacturing process is treated. <P>SOLUTION: The non-reacted sulfur dioxide gas in the sulfuric acid manufacturing process is made to react on a caustic soda aqueous solution in the final absorption process to produce the absorption waste liquid containing mainly Na<SB>2</SB>SO<SB>3</SB>and NaHSO<SB>3</SB>. The absorption waste liquid is then supplied to a cleaning/cooling process for a smelting exhaust gas, in which the waste liquid is made to come into contact with high-temperature sulfur dioxide and oxygen to reclaim sulfur dioxide and to oxidize Na<SB>2</SB>SO<SB>3</SB>(the above sodium sulfite) into Na<SB>2</SB>SO<SB>4</SB>. A circulation liquid is extracted from the cleaning/cooling process as a waste acid to be used for manufacturing gypsum dihydrate composed of large crystalline grains. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
