COMPOSITE TREATMENT AGENT OF ACIDIC GAS AND HEAVY METAL, AND TREATMENT METHOD OF ACIDIC GAS AND HEAVY METAL

摘要

PROBLEM TO BE SOLVED: To sufficiently reduce alkalinity in fly ash in a wide addition amount range for solving a problem in a subsequent fly ash treatment step due to the excess and deficiency of an acidic gas treatment agent caused by the property change of wastes.SOLUTION: A composite treatment agent of an acidic gas and a heavy metal includes: powders containing calcium hydroxide, having a specific surface area of 20 m/g or more and having a median diameter (d50) of less than 30 μm; and a mixture of one or more compounds selected from among a chloride, a sulfate and a hydroxide. The chloride is preferably a copper chloride because of excellent in both material stability and blending stability. The sulfate is preferably magnesium sulfate, a sulfate-containing aluminum hydroxide, zinc sulfate or copper sulfate. The hydroxide is preferably magnesium hydroxide, aluminum hydroxide, an iron hydroxide, zinc hydroxide or copper hydroxide.SELECTED DRAWING: Figure 3