| 摘要 |
PROBLEM TO BE SOLVED: To reduce the content of selenium and heavy metals contained in a dechlorination water-washing solution for cement kiln extraction dust to a level of not higher than 0.1 mg/l which is a fluent standard according to Water Pollution Control Act. SOLUTION: A cement kiln extraction dust treatment method includes the following processes. The method includes (1) the first process of adding water to cement kiln extraction dust to form a slurry before executing solid/liquid separation, (2) the second process of controlling the pH of a liquid phase (raw water) obtained after solid/liquid separation in the first process to 5-10, adding a chelating agent for removing heavy metals, adding a ferric salt compound before controlling the pH of the liquid phase to 5-10 again and adding a polymer flocculating agent to execute solid/liquid separation, (3) the third process of adding a first ferrous salt compound to the liquid phase obtained after solid/liquid separation in the second process and controlling the pH to 8-12 before adding a polymer flocculating agent to execute solid/liquid separation, and (4) the fourth process of adding a ferric salt compound to the liquid phase obtained after solid/liquid separation in the third process and controlling the pH to 8-12 before adding a polymer flocculating agent for executing solid/liquid separation. COPYRIGHT: (C)2009,JPO&INPIT
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