Enhancement of the quality of marketable iron ore products of Kryvyi Rih iron ore basin

The main indicators of the iron ore quality are the content of iron, silica, phosphorus and other components. It is ascertained that the quality of ore depends on its grain-size composition. The article proves that when crushing 16-0 mm fraction ore to 5-0 mm, Fe content is reclassified by sizes due to liberation of both martite and hematite at this grain size. To reduce energy consumption during grinding, it is recommended to install high pressure grinding rolls for crushing the 16-1 mm fraction and consider this operation as the first stage of grinding. Martite liberation in the -1.0+0.0 mm material shows that significant predominance (87.0 vs. 13.0%) of free grains over aggregates is observed in the -0.071+0.05 mm fraction material. Free martite aggregates make 57.12% in the -0.16+0.071 mm material. Complete (100%) liberation of martite is observed in the -0.05 mm material. Sieve analysis of the A56 sinter ore sample crushed to 5-0 mm in the industrial roll crusher enables ascertaining that the greatest increase in recovery (Fe tot = 60.05%) of sinter ore occurs at the -0.16+0.071 mm grain size.