铁精粉通过掺煤提高还原性的研究

Study on improving reducibility of iron concentrate powder by adding coal

随着近年环保和节能降耗政策的逐渐收紧,高炉炉料结构变化较大,主要是球团和烧结矿冶金性能相差较大,对高炉稳定性以及经济技术指标造成一定影响。实验研究了铁精粉和煤粉的配比及不同气氛、不同温度铁精粉所达到还原度,结果表明,铁精粉掺煤颗粒试样在还原温度和还原气氛相同的条件下,试样的还原度、金属化率都是随着掺煤量的增加而升高,说明煤中的C对铁精粉的还原性影响较大,当掺煤量为15%时,还原后试样的还原度、金属化率达到97%以上,继续添加煤粉对结果的影响不明显。还原后试样的Fe^(2+)含量随着掺煤量的增加而减少;在还原气氛和掺煤量相同、还原温度不同时,还原度、金属化率随着温度的升高而提高。在900℃进行冶金性能测试,还原度未能达到97%;在还原温度和掺煤量相同时,还原度、金属化率随着CO浓度的提高而升高;还原后试样表面出现孔洞和凹坑,表面形成致密铁层,有柱状铁晶须。试样能够打出主要成分是C的点,原因可能是高温还原过程中,煤粉从铁矿粉上脱落,结合不够紧密。实验为实际生产工艺过程中提供了准确的还原温度、还原气氛、掺煤量等数据,可节省能源、降低成本。

With the gradual tightening of environmental protection and energy-saving policies in recent years,the structure of blast furnace burden has undergone significant changes,mainly due to the significant difference in metallurgical properties between pellets and sintered ore,which has had a certain impact on the stability and economic and technical indicators of blast furnaces.The ratio of iron concentrate powder and coal powder,as well as the reduction degree achieved by iron concentrate powder under different atmospheres and temperatures were investigated.The results show that under the same reduction temperature and atmosphere,the reduction degree and metallization rate of the iron concentrate powder mixed with coal particles increase with the increase of coal content.This indicates that the C content in coal has a significant impact on the reduction degree of iron concentrate powder.When the coal content is 15%,the reduction degree of the reduced sample increases.The metallization rate reaches over 97%,and the continued addition of coal powder has no significant impact on the results.The Fe^(2+)content of the reduced sample decreases with the increase of coal content.When the reduction atmosphere and coal content are the same,the reduction temperature is different,the reduction degree and metallization rate increase with the increase of temperature.The reduction degree tests at 900℃is below 97%.When the reduction temperature and coal content are the same,the reduction degree and metallization rate increase with the increase of CO concentration.After reduction,holes and pits appear on the surface of the sample,forming a dense iron layer with columnar iron whiskers.The main component of the sample is C,which may be due to the coal powder falling off from the iron ore powder during the high-temperature reduction process,and the combination is not tight enough.The experiment provides accurate data such as reduction temperature,reduction atmosphere,and coal blending amount for the actual production process,which can save energy and reduce costs.