To efficiently decrease the concentrations of a heavy metal and a sulfate ion in the washed filtrate which is generated when dust is treated and solid-liquid separation is performed and which contains potassium and chlorine as main components, by treating the washed filtrate at simple steps.
A method for treating dust includes: a step 32 of mixing heavy metal-containing dust 30 with water 31 to prepare slurry 33; a step 36 of blowing carbon dioxide gas 34 into the slurry 33 to adjust the pH of the slurry to 10-12; a step 38 of adding calcium chloride 37 to the pH-adjusted slurry 33 to precipitate the heavy metal in the form of the hydroxide or carbonate thereof and remove the sulfate ion; a standstill step 39 of leaving standing the calcium chloride-added slurry to further precipitate the remaining heavy metal dissolved in the water by a coprecipitation effect with the carbonate thereof; and a solid-liquid separation step 43 of separating the material left standing at the standstill step into the filtrate 41 and residues 42 by solid-liquid separation.
TENKAI YASUNARI
MURAMATSU HIDEKI
MIURA HARUKI
| JP2004269330A | 2004-09-30 | |||
| JPH01284381A | 1989-11-15 |