| Iron and steel plants are facing increasing pressure to reduce carbon emissions under the current "double carbon" policy.It is an effective way to improve the iron grade of sinter by adding iron ore concentrate,which also reduce the fuel consumption of blast furnace ironmaking and effectively reducing carbon emissions in the smelting process.Therefore,it is important to conduct research on sintering with adding the different types and ratios of iron ore concentrates.In this paper,the high-temperature basic characteristics of 8 kinds of fine ores(A1-A8)and 4 kinds of iron ore concentrates(B1-B4)commonly used in sintering were tested,which showed that the assimilative capacity of 12 kinds of iron ores was A4>A1>A8>A5>B3>A3>A7>B2>A6>A2>B4>B1,and the liquid phase fluidity index was A4>B2>A5> A3>B1=B3 >A6>B4>A1>A7>A2,and the size of the bonding phase strength was A2>A6>A3>B2>B3>B1>A4>B4>A8>A5>A1>A7.The study on the high-temperature basic characteristics of the blended ore after the addition of iron ore concentrate showed that the assimilation temperature of the blended ore increased to different degrees compared with the base group after the addition of different iron ore concentrates.All of them were above 1260℃.The liquid phase fluidity index of the blended ore increased to 9.8 after the addition of 5% B2,while the liquid phase fluidity index of the blended ore decreased with the addition of the other three iron ore concentrates.The liquid phase fluidity index decreased and then increased with the addition of B2 and increased with the addition of the other three types of iron ore concentrates;the assimilation temperature of blended ore increased gradually with the increase of the proportion of iron ore concentrates,and the liquid phase fluidity index decreased and then increased,and the bonding phase strength increased and then decreased.The sintering pot experimental results of the influences different iron ore concentrate types on sintering quality indexes show that: the effect is better when the proportion of iron ore concentrate B1 is 5%,and the solid combustion consumption decreases from 65.76 kg/t to 61.68 kg/t,and the tumble index increases from 62.65%to 66.71%.However,the proportion of iron ore concentrate should not be too high,and the permeability of sintering mixture deteriorates when the proportion of iron ore concentrate is further increased,and also play an adverse effect on the productivity,solid combustion consumption,tumble index.The results show that there is a correlation between the high-temperature base characteristics of blended ore and tumble index,and the highest tumble index is achieved when the assimilation temperature of blended ore is maintained at 1270-1280°C and the liquid phase fluidity index is maintained at 8.5-9.5.Based on the hightemperature base characteristics,the sintering indexes were effectively improved when a certain amount of suitable iron ore concentrate was added,and the best index was achieved with the scheme S-8(10% B1+5% B4),the sintering drum strength increased to 70.03%,the yield and utilization factor increased to 79.37% and 1.755 t/m2-h,respectively,and the solid combustion consumption decreased to 55.17 kg/t,which verified the feasibility of the sintering process.The feasibility of ore blending based on high temperature base characteristics was verified.The thermal strength of sintered ore before and after optimization of iron ore concentrate addition was studied.With the increase of temperature,the sintered ore binder phase gradually softens and the sintered ore thermal strength gradually decreases,and the effect of iron ore concentrate type on the sintered ore thermal strength was studied at a fixed proportion of iron ore concentrate.Based on the high temperature base characteristics of iron ore concentrate,the thermal strength of sintered ore after optimization of ore allocation showed that the thermal strength of S-8 scheme(10%B1+5%B4)was 62% higher than that of the benchmark group at 1000°C in neutral atmosphere;the thermal strength of S-8 scheme at 1000°C in reducing atmosphere was50% higher than that of the benchmark group.The sintered ore thermal strength is 50%higher than that of the benchmark group;with the increase of reduction time the sintered ore thermal strength gradually decreases,both of them have a sharp decrease in strength after 30 min,and at the same time the comparison reveals that the S-8 scheme sintered ore has better strength than the benchmark group,at 60 min the S-8 scheme sintered ore is 67% higher than that of the benchmark group. |
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