| 摘要 |
PURPOSE:To reduce the quantity of waste materials, by treating sludge under a specific condition using a vertical centrifugal separator. CONSTITUTION:The waste water 21 from a waste gas desulfurizing process is guided to a pH control process 1 and slaked lime 31 is added to said waste water to control pH and reacted with F and metal salt in waste water to convert the same to CaF2 and hydroxide being hardly soluble substances. Next, the waste water is guided to a flocculative sedimentation process 2 to receive the addition of a polymer flocculant 32 to form a solid substance and coarse floc both of which are, in turn, sedimented and separated. The flocculated sedimented sludge 23 is centrifugally separated into a filtrate and a solid by a vertical centrifugal separator in a dehydration process 3. By this method, gypsum being a by-product can be recovered and can be converted to valuables such as an auxiliary material for cement.
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