高比例酸性炉料对高炉操作的影响及应对措施

Effects of high proportion of acid burden on blast furnace operation and its countermeasures

随着环境保护压力的增加,中国钢铁公司的高炉炉料结构中酸性料(球团和块矿)配比显著提高,尤其在冬季取暖季的时候。但是,各钢铁公司的资源条件不同,采用高比例酸性炉料冶炼时,有的钢铁企业获得较好的生产指标,但也有钢铁企业操作指标不佳或难以实现高比例酸性料操作。基于此,以提高高炉酸性料比例和降低生产成本为目的,分析了高比例酸性料所带来的问题,并提出了应对高比例酸性炉料的技术措施。高比例酸性料对高炉冶炼的影响主要体现在块状带和软熔带。对块状带的影响主要有,粒度的差异导致空隙率降低;堆积性能的差异导致料面难以控制;还原产生的粉末影响高炉块状带的透气性。对软熔带的影响主要有,酸性料自身软熔温度较低;还原度较低导致矿石进入软熔带前FeO含量高,使得软熔带位置上移且变宽;软熔带焦窗长度变长,增加整个焦窗的压力损失。应对高比例酸性炉料的具体措施有,合理选择优质酸性炉料;制备碱性镁质球团;采用合理的布料制度尽量克服球团矿对料面的不利影响;高炉精细化用焦,充分发挥大块焦与小焦丁的特点与功能。能够改善块状带和软熔带透气性的技术措施都可以缓解高比例酸性料对高炉冶炼的不利影响,各生产企业可结合自身的资源情况和炉型特点,逐步采取技术措施去适应和改善高比例酸性炉料条件下的高炉操作指标。旨在为中国钢铁企业采用高比例酸性炉料进行炼铁生产时提供参考。

Recently the proportion of acid burden(pellet and lump ore)in blast furnace(BF)of Chinese iron and steel companies increased due to the environmental considerations,especiall in the winter heating season.However,under the high proportion of acid burden,the operation performances are different due to the different resources.Some BFs got better performances,and some BFs got worse performances.Aimed to improve the proportion of acid burden and reduce the ironmaking cost,the problems caused by high proportion of acid burden were analyzed,and some countermeasures were proposed.The effects of high proportion of acid burden on the BF operation are mainly reflected in lump zone and cohesive zone of BF.The effects on the lump zone include that prosity of burden decreases due to the size difference between acid ores and sinter,difficult contolling of the burden pile due to the different packing properties,and negative effect of the powder generated by reduced lump ores on the gas permeability.The effects on the cohesive zone include that the lower melting temperature of acid burden,lower reducibility and higher FeO content in reduced ore,resulting in a higher position and wider cohesive zone in BF,and the length of coke slit increases,resulting in the increased the pressure drop.The countermeasures for the high proportion of acid burden include that reasonable select high quality of acid ores,using MgO-bearing basic pellet,relieving the negative effect on the burden pile by reasonable charge methods,and mixed charge of pellet and coke nut,effectively use the functions of bulk coke and coke nut.All the measures that improve the permeability of lump zone and cohesive zone can relieve the negative effects of high proportion of acid burden on the BF operation.The ironmaking plants can gradually take the measures,combined with the resource and operation characteristics,to improve the BF performances.The contribution of the present work is to give some references when the high proportion of acid burden is used in the BF operation.