Effect Of Cr₂O₃ On The Metallurgical Properties Of Wantong Steel BF Slag

In recent years, due to the mussy source and uneven quality of iron ore in the process of iron making, a small amount of chromium appear in the BF slag, which is necessary to study the effect of chromium on the metallurgical properties of blast furnace slag systematically and to provide theoretical basis for improving the process of blast furnace. The BF slag of Wantong Steel Corp is been used in this study. The influence of Cr₂O₃, alkalinity, Mg O and Al₂O₃ on the mineral composition and metallurgical properties of BF slag is studied by X ray diffraction, mineral phase microscope and melt physical properties etc. The results show that: The mineral composition of Wantong steel BF slag is mainly melilite and a small amount of dicalcium silicate and magnesium aluminium spinel. The viscosity of slag is low in high temperature, and the slag has good stability. There's a sharp increase in the slag viscosity when the temperature is near the melting temperature, it illustrates that the slag is typical short slag. With the increasing of Cr₂O₃, the content of melilite in slag reduced and alumina spinel content increased, and there appeared a small amount of magnesia chrome spinel. The viscosity and melting temperature of the slag decreases slightly when Cr₂O₃ content in the slag is increased in a low content, and the desulphurizing capacity of slag has a slight increase. The viscosity and melting temperature of the slag will increase when the Cr₂O₃ content in the slag is increased in a high content, and the desulfurizing capacity of the slag is decreased obviously. In order to improve the fluidity and the desulfurization capacity of the slag, the Cr₂O₃ content in the slag should not more than 1.3%. The alkalinity and the content of Mg O and Al₂O₃ will not influence the metallurgical properties of BF slag obviously when there's a high content of Cr₂O₃. Considering the metallurgical properties of slag, the Cr₂O₃ content in the slag should less than 1.3%, the alkalinity should be 1.1, and the content of Mg O and Al₂O₃ should be controlled at 10.5% and less than 17% respectively.