| 摘要 |
<p>PURPOSE:To certainly and inexpensively treat at Cr<6+>-containing waste liquid, by reacting a calcium bisulfite-containing waste liquid, which is obtained by treating sulfur dioxide gas obtained by burning sulfur with lime milk, with the Cr<6+>-containing waste liquid and neutralizing the reaction liquid to apply flocculation/sedimentation treatment thereto. CONSTITUTION:The gas 21 generated from a coke oven is treated in a desulfurizing tower 22, and the recovered sulfur 25 is burnt in a combustion furnace 26 to form sulfur dioxide gas 27 which is, in turn, sent into a SO2 absorbing tower 28 and lime milk 29 is added to said sulfur dioxide gas to be reacted therewith to obtain a calcium bisulfite-containing waste liquid 30 which is, in turn, sent into a reducing agent tank 35. A Cr<6+>-containing waste liquid 1 is sent into a chromium reducing tank 2 and sulfuric acid 4 from a sulfuric acid tank 3 is added to the waste liquid 1 to adjust the pH thereof to 2-3 and the calcium bisulfite-containing waste liquid 30 is added to the resulting solution to perform reducing reaction. The solution 8 after the reducing reaction is finished is sent to a neutralizing tank 9 and lime milk 11 is added to said solution 8 to neutralize the same to pH 8 while the pH adjusted solution is sent to a flocculation/sedimentation tank 13 to remove a precipitate 14 while the supernatant liquid 15 is discharged.</p> |
