MODIFYING OF STAINLESS SLAG

PROBLEM TO BE SOLVED: To inexpensively prevent generation of chromium (VI) from stainless slag and safely reuse it to a material of construction, etc., by mixing a metal sulfate or an FeO-based substance as a modifier with molten stainless slag. SOLUTION: Modified stainless slag not generating chromium (VI) is obtained by mixing 0.5-10wt.% of a metal sulfate or an FeO-based substance based on the whole weight after the modification with molten stainless slag. As the sulfate, calcium sulfate, magnesium sulfate, iron sulfate, aluminum sulfate, etc., is exemplified. As the FeO-based substance, a substance abundantly containing FeO such as converter dust or mill scale is used. As the mixing method of the modifier, charging of sulfate into a converter or an electric furnace, adding and mixing during falling of waste slag, etc., can be adopted. By this method, convertion of a chromium ion in the slag to hexavalent is inhibited and the slag after cooling can effectively be utilized as a road material or a material of construction.