| 摘要 |
<p>PURPOSE:To provide a method for treating fly ash from an incinerator and a melting furnace capable of separating heavy metals contained in the fly ash in a stabilized form. CONSTITUTION:First, two liters of distilled water is poured into a three-liter beaker and 100 grams of fly ash are added into slurry with a concurrent stirring action. Next, hydrochloric acid is added to this slurry and the slurry continues to be stirred for 10 minutes following the adjustment of the pH value. After that, the slurry is filtered into a residue and a filtrate, and an aqueous sodium hydroxide solution of concentration adjusted to 200g/liter is added to the filtrate thus obtained so that the pH value of the filtrate is neutralized to pH7. Further, the sodium hydrosulfide of concentration adjusted to 10g/liter is added, if necessary, to the filtrate so that the oxidation-reduction potential reaches-100mV. Thus a hydroxide sediment of heavy metal based on zinc and hydrosulfide sediments of other heavy metals are produced. Finally, a solution in which sediments are produced is filtered and separated into a zinc sediment and a neutralized filtrate.</p> |
