不同富氧阶段下烧结矿的矿相结构及软熔滴落性能

Mineral structure and softening dropping property of sinter under different oxygen-rich stages

为了深入探究不同富氧阶段下烧结矿的矿物组成及冶金性能,本文采用SEM-EDS和荷重软化熔滴设备研究在烧结前、中、后期采用富氧喷吹时烧结矿的矿相结构和软熔性能的变化规律和影响机理。试验结果表明:烧结矿的矿物组成主要包括赤铁矿、磁铁矿、铁酸钙、镁尖晶石和硅酸盐液相等;SEM观察和面扫结果表明,随着烧结过程富氧阶段的后移,SFCA(复合铁酸钙)的形态由板条状、针状向熔蚀状转变,与硅酸盐液相交织更加紧密,孔隙率下降,矿物结晶聚集性更强;XRD精修结果表明,随着富氧阶段的后移,铁酸钙在含铁矿物中的占比由76.04%下降到69.77%;不同富氧阶段得到烧结矿的软化开始温度(T 10)均在1180℃以上,软化区间为99~103℃,熔融区间为212~218℃,烧结矿的滴落质量从75.5 g变化为73.0 g最终升高到78.6 g,滴落速度在后期达到最大值0.85 g/min,原因是高熔点物质的减少和低熔点物质的形成;在烧结过程后期进行富氧喷吹时渣铁分离度高,铁的聚集性强,导致炉料的滴落性变强。

In order to deeply explore the mineral composition and metallurgical energy of sinter under different oxygen-rich stages,SEM-EDS and load-softening droplet equipment are used to study the change law and influence mechanism of the mineral structure and softening performance of sinter when oxygen-rich injection is used before,during and after the sintering process.The results show that the mineral composition of sinter mainly includes hematite,magnetite,calcium ferrite,magnesium spinel and silicate liquid phase.The results of SEM observation and surface scanning result show that,with the backward movement of the oxygen-rich stage in the sintering process,the type of SFCA(calcium ferrite complex)is changed from slat-like and needle-like to eroded,and it is more closely intertwined with the silicate liquid phase,the porosity decreases while and the mineral crystallization aggregation is stronger.The XRD refinement results show that the proportion of calcium ferrite in iron-bearing minerals is decreased from 76.04%to 69.77%with the backward movement of the oxygen-rich stage.The softening starting temperature(T 10)of the sinter obtained in different oxygen-rich stages is above 1180℃,the softening interval is 99~103℃,the melting interval is 212~218℃,the dripping mass of the sinter is changed from 75.5 g to 73.0 g and finally is increased to 78.6 g,and the dripping velocity reaches the maximum value of 0.85 g/min in the later stage,due to the decrease of high melting point and the formation of low melting point substances.In the later stage of the sintering process,the slag iron separation is high,and the iron aggregation is strong,resulting in a strong dripping of the charge.