Although 20 - 80 weight the iron of the iron gross which is included the oxidizer

摘要

PROBLEM TO BE SOLVED: To provide a means simply converting heavy metals in waste or contaminated soil to ferrite to insolubilize them. SOLUTION: An oxidizing agent is added to a ferrous salt soln. in an amt. necessary for changing 20-80wt.% of the total amt. of iron in the soln. from a ferrous compd. to a ferric compd. to obtain an iron salt soln. This iron salt soln. is added to a solid containing heavy metals in an amt. of at least 1% of iron by wt. of the solid and the pH of the soln. is made alkaline and the whole is kneaded to convert heavy metals in the solid to ferrite.