Effect Of Calcium Ferrite On The Quality Of High Basicity Sinter

Calcium ferrite is the main binder phase of high basicity sinter,which has good strength and reducibility.Its content and morphology play an important role in the quality of sinter.In recent years,the large use of import iron ores and the instability of raw materials have a great influence on the content and morphology of calcium ferrite in sinter,which leads to some problems in the quality of sinter.The formation conditions of different forms of calcium ferrite were studied by means of polarizing microscope and electron probe microanalysis.The quantitative relationship between the content and form of calcium ferrite in high basicity sinter and its metallurgical properties was systematically analyzed.The influence mechanism of different forms of calcium ferrite on sinter quality was found out.Through the research on the site sinter,it is found that with the increase of basicity first and then decrease,the total content of calcium ferrite in sinter first decreases,then increases,and finally decreases,and the content of needle columnar calcium ferrite also decreases,then increases,and finally decreases;RDI > 3.15 mm of sinter also decreases first,then increases,and finally decreases.The tumbler strength increases gradually,but the reducibility changes little.Combined with the research results of sinter in the field,the sinters with different basicity,different constant temperature time and different temperature were prepared in the laboratory by using chemical purity.The results show that with the increase of basicity from 1.8 to 5.2,the overall microstructure of sinter changes from erosion porphyry structure to interlaced erosion structure,and then to interlaced erosion erosion erosion structure.The total content of calcium ferrite increased gradually and reached the maximum of 57.5% when the basicity was5.2;The content of acicular calcium ferrite first increased and then decreased,especially when the alkalinity was 3.2,the content of acicular calcium ferrite was the most,which was 17.5%.RDI > 3.15 mm increases from 65.52% to 76.18% when basicity is 3.2,and then decreases to70.36%.The reducibility of sinter becomes better gradually.With the increase of sintering constant temperature time from 2 min to 10 min,the microstructure of sinter changes from interweaved erosion structure to interweaved erosion erosion structure,and finally develops into erosion structure.The total amount of calcium ferrite decreased slightly,and its morphology changed from acicular to columnar,plate columnar and heteromorphic.The RDI >3.15 mm of sinter gradually decreases from 75.34% to 63.74%,and its reducibility is almost unchanged.During the ore-forming process of sinter,the total content of calcium ferrite first increases and then decreases in the heating stage,and the content of needle columnar calcium ferrite first increases and then decreases;The microstructure changes are melt structure,interweave erosion structure interweave structure,interweave erosion structure porphyry structure and porphyry structure.In the cooling stage,the total content of calcium ferrite in sinter first increases,and then tends to remain unchanged;The change of microstructure is erosion structure,interweaved erosion structure erosion structure,erosion structure porphyry structure.It provides a theoretical basis for further optimizing ore blending scheme and improving sinter quality.Figure 43;Table 28;Reference 78...