To obtain a solid containing a heavy metal whose eluted concentration is limited within the range of a reference value and at a low cost by adding, and mixing water-granulated fine powder containing gypsum, produced at a blast furnace, to generate waste incineration ash together with water, then extruding the mixture and molding it using a molding machine.
Water-granuated fine powder containing gypsum, produced at a blast furnace, is added to and mixed with general waste incineration ash together with water, and the mixture is extruded and molded using a molding machine. In addition to the water-granulated fine powder originating from the blast furnace, a molten steel mill slag or a fibrous material such as sawdust is added and mixed depending on occasion. Further, to continue a hydration reaction, a recovered water at water temperatures of 60-80°C used for slow- cooling a molten slag from a blast furnace is sprayed onto the top part of a stack of the moldings while curing the moldings by steam. About 1-10wt.% of the molding thus treated is added as such or in the form of a crushed product adjusted to the grain size of 5-0mm, to and mixed with a natural broken stone or the steel mill slag for the use as a road macadam.
KATO NORIYUKI
OKUMURA HIROAKI
NIPPON STEEL CORP