Basic steel-making slag mixed by fly ash - produces hydraulic setting properties which increase commercial value of slag

摘要

The fly ash is added to the molten slag and the mixt. is rapidly cooled or quenched, pref. with granulation. The fly ash is pref. added as a suspension in a fluid together with a gaseous agent reducing the major part of the iron and manganese oxides to metals. The reducing gas is pref. added via two coaxial pipes forming a tuyere, the inner pipe providing O2 and the outer pipe a reducing gas so the combined gas mixt. is reducing. Used e.g. to treat basic slags obtd. in the oxygen refining of haematite iron. By adding fly ash to the molten slag before quenching, the resulting granulate exhibits hydraulic setting properties so it can be used as a type of Portland cement.