| 摘要 |
<p>PROBLEM TO BE SOLVED: To perform the high purification of gypsum recovered from a desulfurizing apparatus relatively simply and efficiently. SOLUTION: When gypsum is recovered as a by-product by bringing sulfur oxide in a waste combustion gas 1 into contact with an absorbing solution containing a calcium based absorbent in an absorbing tower 2 for absorption treatment and oxidizing the absorbing solution, in which the sulfur oxide is absorbed, in a circulation tank 7, high purification of the gypsum 14 is efficiently performed by supplying an acidic gypsum cleaning water 18 on a dehydrated cake layer, which consists essentially of the gypsum 14 and is formed in a certain degree. to dissolve and remove unreacted limestone or heavy metals existing as a solid in the gypsum 14.</p> |
