Experimental study on application of steel slag magnetic tailings replacing part of sintering flux during sintering

Fundamental characteristics of magnetic separation tail slags were studied by chemical analysis, X-ray diffraction analysis, optical microscope analysis and other analysis methods. The microstructure and metallurgical properties of the sinter were studied, while magnetic separation tail slags were added into sintering material with 0, 2.5%, 5.0% and 10.0%, respectively. The results show that when the mass fraction of tail slags in the sintering material is less than 5.0%, with the increase of tail slags content, calcium ferrite content in the sinter tends to increase, the sinter yield elevates, strength and drum strength both improve. Then all these metallurgical performances tend to decrease, while the mass fraction of tail slags continues to increase. However, the vertical sintering speed and productivity of sintering decrease if the content of tail slags in sintering increases. The reducibility index of sinter and the low temperature reduction degradation index can be improved with the increase of the slag content. And these performances decrease when the mass fraction of tail slags is more than 5.0%. With the increase of tail slags content, the high free flow temperature and soften-melting temperature of sinter make softening temperature intervals expand, and worsen the softening-melting properties of sinter.