| 摘要 |
PURPOSE: To simply fix heavy metals in fly ash by adding water and piperazine- carbodithionic acid or a salt thereof to fly ash to knead them with the fly ash. CONSTITUTION: Either one of piperazine-N-carbodithionic acid and piperazine-N, N'-biscarbodithionic acid, a mixture of both acids or a salt of either one of them and water are added to fly ash to be kneaded therewith. At this time, alkali metal, alkaline earth metal and ammonium salts as the salts of those acids, can be used. The use amt. of either one of those acids or the salt thereof is different according to the content of heavy metals in fly ash to be treated or the form of heavy metals are not limited especially but set to about 0.01-5% by wt. of the fly ash. The amt. of water is not also limited but set to about 6-50% by wt. of the fly ash. In this case, when water is 5wt.% or less, the mixing with a chemical agent is not sufficient and, when water is 50wt.% or more, the fly ash becomes liquid and the disposal thereof becomes difficult. |
