Influence of the magnetite concentrate properties on sintering performance of magnetite-hematite-goethite iron ore blends and sinter quality

摘要

The proportion of fine magnetite concentrates in iron ore blends is expected to grow in future due to decreasing availability of high-grade iron ore resources and increasing utilisation of the lowgrades. Different magnetite concentrates were usually found to possess distinct physicochemical properties, which will largely affect the sintering performance of iron ore blends and consequently the quality of sinter products. In this work, sintering performance of two typical magnetite concentrates (MC-1# and MC-2#) from China and Australia, respectively, were compared through mini-pot (_100×500 mm) sintering tests in terms of their effects on the sintering performance of magnetite-hematite-goethite iron ore blends and the quality of sinters. The effects of magnetite concentrates properties including chemical compositions, particle size distribution and oxidisability were investigated and further discussed in association with the metallurgical properties of sinters and formation characteristics of liquid phase at high temperature zone in sinter bed. The results show the substitution of the MC-2# for the MC-1# in ore blend generally results in deterioration of both sinter strength and metallurgical performance. The mineralogical study of sinters reveals that the addition of the MC-2# tends to promote formation of high-Si sinter melt and low-strength sinter matrix, which can be attributed to its inferior oxidisability compared with the MC-1#. The oxidisability of magnetite concentrates can be used as a key indicator to reflect the formation ability of SFCA phases, which may in advance provide some predictive information about the sintering performance of different magnetite concentrates.