| 摘要 |
<p>PURPOSE:To remove and recover efficiently heavy metals from waste water, by adding an iron component to a liquid contg. heavy metals according to need, and thickening the sulfide obtd. by adding sulfide ions thereto by using a magnetic field. CONSTITUTION:If a liquid is approximately neutral and contains an excess iron- component with respect to the content of heavy metals, said liquid is used as it is. If the liquid is strongly acidic or alkaline, the liquid is neutralized to about 5-8pH and if the iron component is not enough, a water soluble iron component of about 10 times of the total molar concn. of the predicted heavy metals is added to the liquid. H2S is passed through such liquid or an ammonium sulfide soln. is added thereto under stirring to form the black precipitate of iron sulfide. The formation of the other heavy metal sulfides has been completed when the formation of said precipitate is completed. Since the magnetism is weak right after the reaction, the liquid is allowed to rest for about 5 days or to heat and cool. Thereafter, when the strong magnetic field is applied to the liquid, iron sulfide flocculates along the magnetic field and therefore this part is separated and the heavy metal parts contg. iron are removed and recovered.</p> |
