低硅含镁含钛球团矿的成矿基础研究

发布时间：2018-01-20 05:32

本文关键词： 球团矿低硅含镁含钛成矿带式焙烧机　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：钢铁工业能耗约占我国工业总能耗的15%,其中铁前工序能耗占到吨钢能耗的70%以上,而降低铁前工序能耗的关键在于做好精料工作。球团矿相比于烧结矿存在诸多优势,如能耗低、铁品位高、还原性能好、粒度均匀等。近年来,随着铁矿资源的劣化以及高炉长寿的需要,球团矿的功能角色不断多样化:为了应对高铝渣流动性能差、MgO含量高恶化烧结矿强度等问题,发展了镁质球团技术;为了高炉护炉需要,发展了钛球技术。但是在球团矿中同时添加MgO和TiO_2,尤其是针对低硅含铁原料条件下,生产低硅含镁含钛球团矿的技术尚属空白。本论文以首钢京唐钢铁公司504m2带式焙烧机为依托,针对首钢京唐球团生产用低硅磁铁矿粉资源、含镁添加剂资源和含钛矿粉资源,开展低硅含镁含钛球团矿生产技术的基础研究,具有非常重要的科学意义和实用价值。首先,对单一低硅磁铁矿粉的造球性能、生球质量、球团矿冶金性能以及改变不同SiO_2含量对球团矿还原膨胀率的影响进行了研究。低硅磁铁矿粉的SiO_2含量是1.52%,加入0.5%膨润土制备球团矿时,球团矿SiO_2含量是1.8%,焙烧球团内液相很少,还原后球团矿中出现了非常明显的铁晶须,球团矿的还原膨胀率高达76%,属于恶性膨胀,不能够直接入炉;随着球团矿SiO_2含量的提高还原膨胀率降低,当SiO_2含量在3.4%以上时,球团矿的还原膨胀率低于20%,达到18.7%,但是提高SiO_2含量会增大高炉渣量,造成高炉燃料比升高,所以球团矿在降低SiO_2含量的同时控制一定的还原膨胀率是关键。其次,研究了不同MgO含量和使用不同含镁添加剂对低硅球团矿冶金性能的影响、不同焙烧温度对低硅含镁球团矿质量的影响,以及低硅含镁球团矿还原动力学及其对综合炉料冶金性能的影响。随着MgO含量的提高,低硅球团矿的抗压强度明显下降,需要提高焙烧温度来进行补偿。焙烧温度低时,存在未反应的MgO,随着焙烧温度的提高,球团内部形成较均匀的镁铁矿,球团矿抗压强度能达到2800N/P以上;球团矿的MgO提高到3.4%以上时还原膨胀率可以降到16.5%;配加MgO可以明显改善球团矿的还原度和熔滴性能;配加镁橄榄石、氧化镁粉和蛇纹石能控制低硅球团矿的还原膨胀率,其中氧化镁粉的SiO_2含量低,MgO含量高,更有利于降低球团矿SiO_2含量和控制还原膨胀率;MgO含量适宜、焙烧温度较高的低硅含镁球团矿还原时主要被固相扩散控制,铁离子扩散受限,产生的铁晶须少,还原膨胀率低。然后,研究了 TiO_2对低硅球团矿抗压强度和冶金性能的影响,研究了MgO和TiO_2的协同作用对低硅球团矿质量的影响及机理。球团矿直接加入TiO_2时,形成钛磁铁矿有利于改善还原膨胀率,但不利于球团矿的还原性,而在加入TiO_2的同时加入MgO,可以改善含钛球团矿的还原性和熔滴性能;球团加入MgO和TiO_2时可形成镁铁矿和钛磁铁矿,有效控制球团矿的还原膨胀率,降低SiO_2含量,MgO和TiO_2含量分别提高至1.7%和1.2%时,球团矿的SiO_2含量可降低至2.8%;物相结构中磁铁矿和钛铁矿含量高的含钛矿粉对球团抗压强度影响相对较小,且有利于控制球团矿还原膨胀率;配加含钛矿粉后,低硅含镁球团矿的焙烧温度需要提高10℃左右。最后,进行了大型带式焙烧机生产低硅含镁含钛球团矿的工业试验研究,以及高炉应用低硅含镁含钛球团矿的效果分析。低硅含镁含钛球团矿的焙烧温度比低硅含镁球团矿的要高一些,焙烧温度适当提高后,球团矿的抗压强度和冶金性能可以满足大型高炉入炉要求;低硅含镁含钛球团矿SiO_2含量从3.5%降低至2.82%,MgO从自然含量提高至1.72%,TiO_2从自然含量提高到1.2%,球团矿还原膨胀率控制在20%以下,球团矿还原度和熔滴性能大幅度改善;在5500m3超大型高炉上应用了低硅含钛含镁球团矿,高炉渣量和燃料比分别降低了 12.6kg/tHM和5.3kg/tHM,利用系数提高,高炉生产取得了良好的技术经济指标
[Abstract]:The iron and steel industry of China's industrial energy consumption accounts for about 15% of the total energy consumption of iron, which before the process of energy consumption accounted for more than 70% of the energy consumption per ton of steel, and reduce the key process before iron consumption is to do the fine material. The pellets compared to many advantages such as low energy consumption of sintering ore, iron, high grade, the performance is good, particle size uniform. In recent years, with the deterioration of iron ore resources and the need of BF, the functional role of pellet continuous diversification: in response to the high aluminum slag flowability, sintering ore strength deterioration of the high content of MgO, the development of magnesia pellet technology; for the protection of blast furnace, the development of titanium ball technology but. At the same time, add MgO and TiO_2 in the pellet, especially in the condition of low silicon iron containing raw materials, the production of low silicon containing magnesium containing titanium pellet is still blank. In this paper, Shougang Jingtang Steel Corp 504m2 belt type roasting machine based on With low silicon magnetite resources production of Shougang Jingtang pellet, magnesium containing additives containing titanium ore resources and resources, to carry out basic research of low silicon containing magnesium production technology of titanium containing pellets, which has very important scientific significance and practical value. Firstly, the single low silica magnetite pellet properties, ball quality, pellet the metallurgical properties and the change of different SiO_2 content on pellet swelling rate were studied. The content of SiO_2 of low silicon magnetite powder is 1.52%, adding 0.5% bentonite pellet preparation, pellet SiO_2 content is 1.8%, the roasting pellet in liquid phase is very few, the appearance of the obvious iron whisker after reduction the pellet, the pellet reduction swelling rate as high as 76%, which belongs to the malignant expansion, can not be directly into the furnace; with the increase of the content of SiO_2 pellet reduction swelling rate decreased when the SiO_2 content is more than 3.4%, the reduction of bentonite pellets The inflation rate is lower than 20%, reached 18.7%, but increased the content of SiO_2 will increase the amount of blast furnace slag, blast furnace caused by fuel ratio increased, so the pellets decreased the SiO_2 content in the control of certain reduction expansion rate is the key. Secondly, and the use of different MgO content of different magnesium containing additive effect on low silicon pellet metallurgical properties the effect of different calcination temperature on low silicon magnesium pellet quality, and low silicon containing magnesium pellet and its dynamics on metallurgical properties of burden. With the increasing of MgO content, the compressive strength of low silicon pellet decreased significantly, the need to improve the calcination temperature to compensate. The calcination temperature is low, there is the unreacted MgO, with the increase of calcination temperature, pellet formed inside the MAGNESIOFERRITE is uniform, the pellet compression strength can reach more than 2800N/P; improve the pellet MgO to above 3.4% when the reduction swelling rate Down to 16.5%; adding MgO can significantly improve the reduction degree of pellets and droplet properties; adding forsterite, the reduction swelling of magnesium oxide and serpentine can control the low silicon pellet, which SiO_2 content of magnesium oxide, the content of MgO is high, more conducive to reducing the expansion rate of pellet SiO_2 content and control the content of MgO; suitable, low silicon containing magnesium pellets with higher calcination temperature reduction is mainly solid diffusion control, iron ion diffusion limited, the iron whiskers less, reducing swelling rate is low. Then, the effects of TiO_2 on low silicon pellet compressive strength and metallurgical properties, studied the synergistic effects of MgO and TiO_2 the influence of low silicon pellet quality and mechanism. TiO_2 directly into pellets, the formation of titanium magnetite can improve the reduction swelling, but not conducive to the reduction of pellets, while adding TiO_2 into MgO, can improve Titanium containing pellet reducibility and droplet properties; adding MgO and TiO_2 pellets can be formed when magnesium iron and titanium magnetite, effectively control the reduction swelling of pellets, decrease the content of SiO_2, MgO and TiO_2 content were increased to 1.7% and 1.2%, SiO_2 content of the pellets can be reduced to 2.8% and titanium magnetite; the content of iron phase in high titanium slag on compressive strength of pellets is relatively small, and is helpful to control the pellet reduction swelling rate; adding titanium slag, calcination temperature of low silicon containing magnesium pellet need to raise around 10 degrees. Finally, the industrial experimental study on production of low silicon containing type roasting machine magnesium containing titanium pellet with large, low silicon blast furnace application and effect analysis of magnesium containing titanium containing pellets. Higher calcination temperature of low silicon containing magnesium titanium containing pellets than low silicon magnesium containing pellets, calcination temperature increasing, the pellets The compressive strength and metallurgical properties can meet the requirements of large blast furnace; low silicon magnesium containing titanium containing pellets of SiO_2 content decreased from 3.5% to 2.82%, MgO from the natural content increased to 1.72%, TiO_2 increased to 1.2% from the natural content, pellet expansion rate below 20%, the pellet reduction degree and droplet properties improved; in 5500m3 ultra large blast furnace with low silicon containing titanium magnesium containing pellets, slag volume and fuel ratio were reduced by 12.6kg/tHM and 5.3kg/tHM, improve the utilization coefficient of blast furnace production, and achieved good economic and technical index

【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TF046.6

【参考文献】