| 摘要 |
<p>PURPOSE:To purify waste gas contg. heavy metal to an extremely high extent using a compact and simple removing device comprising primarily of water washing by arranging trickling nozzles in multiple stages and providing a mist separating section at the top of the device. CONSTITUTION:Waste gas contg. heavy metal such as waste gas contg. chromium (VI), generated in the electrostatic coating process of a rust inhibitor on a metallic base body, etc. is introduced into a washing tower 1 from an introducing port 4 at the bottom of the tower 1. Heavy metals such as chromium (VI) in the waste gas are removed by spraying washing water from trickling nozzles 6, 7 at the space section 5. Further, remaining chromium (VI), etc. is removed in the form of mist at the mist separator part 8 at the top of the tower, and the gas freed of almost all harmful substances is discharged from the top 9 of the tower. The water after washing is stored in a liquid reservoir 3 and used repeatedly for washing through an external circulation line 2, but the frothing of the liquid due to increase of concn. of chromium (VI) is inhibited by the addition of an antifoaming agent from an intermediate tank 11. When the concn. of chromium (VI) attains a fixed value, by detecting the concn. of the chromium (VI) in the circulating liquid measured by a conductivity meter 12, the washing water is exchanged with fresh water.</p> |
