PROBLEM TO BE SOLVED: To solve such problems that a heavy metal treatment agent except lead elutes, or the use amount of the treatment agent increases in the heavy metal-insolubilizing treatment of heavy metal-containing materials, particularly in the presence of organic acids. SOLUTION: The elution of not only a particularly harmful lead but also other heavy metals such as zinc can be suppressed low even in the coexistence with organic acids and the like by adding a small amount of secondary amine carbodithioate, alkali metal hydroxide and/or alkali earth metal hydroxide to the heavy metal-containing material, and controlling the P alkalinity of the material to be (200 g-CaCO3/kg-heavy metal-containing material) or more. COPYRIGHT: (C)2013,JPO&INPIT
