Determination of Fe3O4 Content and Total Nonhydraulic Minerals in Steel Slag

The nonhydraulic minerals (Fe3O4, RO phase, Fe) in slag are important indicators for evaluating the pozzolanic activity and detecting the quality of the slag activation processing technology. Fe3O4 is an important characteristic mineral among the nonhydraulic minerals. In order to accurately assess the pozzolanic activity of steel slag powder and to monitor the quality of the activation process of steel slag powder for separate nonhydraulic minerals, it is imperative to precisely determine the nonhydraulic mineral content within the steel slag. Further refinement and enhancement are required for both the HNO3 dissolution method used in determining Fe3O4 content in steel slag, as well as for the EDTA-DEA-TEA (ethylenediamine tetraacetate sodium-diethylamine-triethanolamine) dissolution method employed in determining total nonhydraulic minerals, due to potential deviations caused by challenging impurity separations. The results show that the content of Fe3O4 is determined by 10%HNO3-20%NaOH-chemical analysis method, which solves the problem that the impurities of refractory materials (quartz, corundum, mullite) and amorphous phase affects the content determination in HNO3 dissolution method. The total amount of nonhydraulic minerals (Fe3O4, RO phase, Fe) was determined by the EDTA-NaOH-TEA dissolution method, which solved the problem that the incomplete dissolution of C2F in the EDTA-DEA-TEA dissolution method affected the content determination. The maximum error between the content determination value and the theoretical calculation value of the two methods is less than 0.50%. The improved Fe3O4 and total nonhydraulic mineral quantification methods are feasible and reliable.