| At present,overcapacity is still a prominent problem in iron and steel industry.Due to the sustained rise in the price of iron ore,production costs began to spiral every year and steel enterprises were facing much more survival pressure than ever before.Therefore,it is necessary for steel enterprises to do some research to improve the quality of sinter,aiming at reducing costs and improving industrial competitiveness.In order to improve the quality of sinter,it is essential to clarify the characteristics of ore structures,spatial distributions,formation mechanism of ore phase and the changing rule of ore phase in the process of reduction.However,the sinter structures are complex.The traditional two-dimensional analysis method still has some shortcomings.In order to improve these shortcomings and reflect the characteristics of the two sinter ore comprehensively,intuitively and accurately,the three-dimensional reconstruction method is used in this paper to obtain the three-dimensional mine phase diagrams of vanadium-titanium sinter and ordinary sinter.And the effects of the structures and their contents on sinter metallurgical properties are also compared in the paper.Firstly,qualitative analysis of vanadium and titanium sinter and ordinary sinter are carried out by XRD.The three-dimensional mine phase diagrams of vanadium-titanium sinter and ordinary sinter are obtained by three-dimensional reconstruction method.Using adaptive threshold segmentation to split image of each mine phase and comparing the distribution and connection of the two sinter structures in 3D.The single mine phase was divided by color threshold division,and the partial three-dimensional structures of the two sinter were further compared.The morphology and quantitative analysis of elements in each mine phase of the two types of sinter were observed by means of Philips nanoSEM400 field emission scanning electron microscopy(SEM-EDS).Then,the microhardness of vanadium and titanium sinter and ordinary sinter were measured by Vickers indentation method.The microhardness values,the initiation anddevelopment of indentation cracks in different ore phases were compared and analyzed.The experiment result shows that the microhardness of vanadium and titanium sinter is higher than that of ordinary sinter,but some of the ore grain has a plurality of long cracks.The perovskite and titanium hematite are fragile and have poor fracture toughness.Reducing the plate-like hematite and developing calcium ferrite and interwoven erosion structure are beneficial to improve the microhardness and then improve the quality of sinter.Finally,quantitative analysis of vanadium and titanium sinter and ordinary sinter are carried out by threshold segmentation method.The results show the calcium ferrite and magnetite in ordinary sinter are obviously higher than that of vanadium and titanium sinter,the content of hematite is lower than that of vanadium and titanium sinter,and the other mine phase and pores have little difference.And combined the high temperature reduction experiment results,with the mined content and structures in sinters to analyze sinter metallurgical performance and microstructure.It was found that there are a lot of regenerated titanium hematite and most of them exist in the shape of skeletal crystal and diamond in vanadium titanium sinter,which accounts for that vanadium and titanium sinter is easy to be reduced,the rate of low-temperature reduction disintegration is higher,and the strength is lower than ordinary sinter.This also provides a theoretical basis for improving the quality of sinter. |
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