Study On High Temperature Metallurgical Properties Of Comprehensive Burdens Under Different Ore Blending Conditions

This paper focus on the stability of BF production,combining the experimental study with actual production to carry out laboratory research.Setting the corresponding boundary conditions and parameter ranges according to the actual production situation during the study.Study on high temperature metallurgical properties of comprehensive burdens under different ore blending.Explored the mechanism of the change of the droplet properties by scanning electron microscope?SEM?,X-ray diffraction?XRD?,X-ray fluorescence analysis?XRF?,melting point tester device as well as Factsage thermodynamic software.The following conclusions are drawn:?1?Sinter S-1 and sinter S-2 owns fine reduction property,RI are 87.12%and89.33%respective;but the RDI_+3.15 are judt reach 61.43%and 70%;the droplet properties of sinters are better than other iron ores,the T_s of the sinter are 1339?and1369?;T_d of the sinter are 1436?and 1454?.The pressure drop peak value of the sinter are 15965 Pa and 15832 Pa which make great resistance on the gas flow.?2?Adding much lump ore into the BF burdens,the basicity of the BF burdens decrease from 1.44,1.52,1.60 to 1.36,1.45 and 1.53 separately,and cause the soften temperature decrease which increase the the position of the upper edge of the melting zone,the melting zone of the burden is shift up.The maxium soften temperature decrease 38?,the maxium melting temperature decrease 11?.?3?Increasing the sinter ratio could increase the basicity of the BF burdens to1.60,1.56 and 1.53 separately,the melting temperature and dripping temperature of the composite burden increase remarkably with the higher temperature along the upper/lower edge of the column melting zone.However,too much sinter in burden lead the ratio of CaO/SiO₂ increased,the high fusion point phase C2S is easily formed during slag formation and cause melting zone shift down and thicker,the melting zone increase 25?on maxium.?4?When using high basicity sinter S-2,according to the thermodynamic calculation results,the system CaO-SiO₂-Fe₂O₃ is propitious to form C2S,the T₁₀,T₄₀,T_s and T_d are higher than that BF burdens which add sinter S-1.However the soften interval and melting zone are increased 8-12?which deteriorated the permeability of the burden column,the maxium peak value of the pressure drop reach12994 Pa.?5?The chemical composition of slag is the primary cause for the difference of slag melting performance.At lower temperature,the slag contain higher Al₂O₃,that cause SiO₂ and Al₂O₃ in slag absorb the O^2-to generate the?SiO₄?^4-and?AlO₄?^5-,in the slag system of CaO-SiO₂-MgO-Al₂O₃-FeO,the area of the phase of Fe?s?+Monoxide+Slag-liq+Spinel is relatively larger,which lead fusion point of slag different due to contain much high fusion point mineral phase such as Spinel during the slag formation.?6?When the temperature get higher,the slag contain higher FeO,that provide free-moving Fe²⁺and O^2-in the Si-O network,and Al₂O₃ in slag absorb the O^2-to generate the?AlO₆?^5-and in the slag system of CaO-SiO₂-MgO-Al₂O₃-FeO,the area of the phase of Fe?s?+Monoxide+Slag-liq+Spinel is relatively small,the main mineral phase in slag are Feldspathic minerals,cause the fluidity properties different.