Research of metallurgical properties of fluxed sinter from iron ore raw materials of Stoilenskoye deposit

In recent years, much attention has been paid to the study of sinter raw materials and, first of all, to the improvement of their metallurgical properties in order to improve the efficiency of blast furnace processing. Complex studies were conducted on the AKM-312 sinter machine of the NLMK Sinter Plant to determine the metallurgical properties of the agglomeration cake along the bed height on the sinter machine after its almost complete cooling. With the agglomerate cake height of 460 mm, 3 samples were taken: layer 1 (top) – 410–290 mm, layer 2 (middle) – 290–170 mm and layer 3 (bottom) – 170–50 mm, and their chemical and granulometric compositions, strength in the initial state and during reduction-heat treatment, recoverability and fusibility were determined. Significant heterogeneity of the metallurgical properties of the agglomeration cake along the bed height was revealed. It is caused by the non-uniformity of the mix in terms of granulometric composition and bulk density in different parts of the bed, segregation of the mix by size and distribution of carbon along the bed height, increase in the amount of melt from top to bottom of the bed and imperfect mode of mix ignition. A decrease in the mass content of Fetotal, Fe2+, FeO, S and an increase in the oxides of Ca, Mg, Si, Al, Mn from top to bottom of the bed were established, mainly due to the corresponding increase in the mix size. An improvement in the indicators of cold strength X(+5), mass content of the fraction of agglomerate cake ≤5 mm and hot strength RDI-1+6.3 of sintered material from top to bottom and deterioration of the indicators: abrasion X(–0.5), RDI-1–3.15, RDI-1–0.5, and the content of classes +40, –40, +25 mm were revealed. The recoverability index Rf at a tem-perature of 950°C worsens, as a result of the increase in the amount of melt from top to bottom of the bed. The results of the research are planned to be used to improve the mode of loading the mix into the sinter machine and its ignition.