| 摘要 |
PROBLEM TO BE SOLVED: To safely and easily immobilize a heavy metal incorporated in a fly and while suppressing the generation of a harmful gas by adding dithiocarbamic acid or its salt and an amine compd. having at least more than one primary or secondary amino group to the fly ash together with water and kneading the mixture. SOLUTION: At the time of treating the fly ash obtained from an incineration plant, the dithiocarbamic acid or its salt and amine compd. having at least more than one primary or secondary amino group are added to the fly ash together with water and the mixture is kneaded. A composition used to this treatment, consisting of the dithiocarbamic acid or its salt and the specified amine compd., is high in chelating ability to heavy metals and able to suppress the generation of gas to a trace amount by immobilizing the heavy metals with its small amount addition even in the case of a highly alkaline fly ash. A dithiocarbamic acid, etc., having more than 4 nitrogen number are used as the dithiocarbamic acid or as its akaline salts, and the polyethylene polyamine is used as the specified amine compd. |
