氧气高炉块矿与烧结矿软熔过程交互作用

 以不同预还原度的块矿及块矿与烧结矿的混合矿为研究对象,利用单颗粒荷重软化试验装置,考察了氧气高炉及传统高炉还原气氛对块矿及混合炉料软熔性能的影响。研究发现,高还原势的氧气高炉条件下,含铁炉料还原度的提高导致其颗粒内部铁相数量增加,低熔点渣相数量减少,块矿的软熔性能与传统高炉条件相比有所改善。同时,通过对软熔过程相关数据及炉料颗粒微观结构的分析,发现氧气高炉条件下,块矿-烧结矿混合炉料在界面上发生了交互作用;由于铁相数量的增加及渣相的减少,不同渣相的接触时间被推迟,接触的渣量也减少,导致相对于传统高炉条件,氧气高炉条件下发生交互作用的温度升高,其作用强度减弱。     

Study on the interaction behaviour between lump and sinter under the condition of oxygen blast furnace

This research report describes the influence of the reducing atmosphere of oxygen blast furnace (OBF) and traditional blast furnace (TBF) on the softening and melting behaviour of lump and lump-sinter mixed burdens assessed by using the softening and melting test. The results reveal that in the OBF atmosphere, the softening and melting properties of lump ore is improved compared with that of the TBF, since the development of reduction degree increased the quantity of the iron phase in the burden particle, and decreased the quantity of slag phase with low melting temperature. In addition, the analysis on the microstructure of burden particles revealed that the interaction effect also occurred at the interface between lump and sinter particles in OBF case. Meanwhile, the scanning electron microscope images shows that the interface is still distinguishable when the samples of OBF case reached 60% contraction ratio (1379°C), whereas in the case of TBF, the interface almost disappeared above 40% contraction, and became completely undistinguishable at 60% contraction ratio (1290°C). This illustrates that, under the OBF condition, the starting temperature of interaction is raised, and the effect intensity is weakened.     

氧气高炉含铁炉料软熔特性研究

摘要：以烧结矿、球团矿及其混矿为研究对象,利用荷重软化滴落设备,分别探索了氧气高炉和传统高炉条件下烧结矿、球团矿、混合矿软熔特性。研究发现,与传统高炉气氛相比,在氧气高炉气氛下烧结矿、球团矿、混矿软化开始温度降低,软化结束温度升高,烧结矿滴落温度降低,球团矿与混矿滴落温度升高,并且熔滴区间减小甚至消失。通过对软熔过程相关数据分析,发现在氧气高炉气氛下混矿有一定的交互作用,提高了炉料透气性。     

Study on softening melting characteristics of iron bearing material in oxygen blast furnace

The softening melting characteristics of sinter, pellet and mixed ore in oxygen blast furnace and traditional blast furnace were studied by using load softening and dropping equipment. It is found that, compared with the traditional blast furnace under the softening starting temperature of sinter, pellet, and their mixture decreases, the softening ending temperature increases in oxygen blast furnace atmosphere. Under the condition of oxygen blast furnace, the dropping temperature of sinter decreases, the dropping temperature of pellets and their mixture increases, and dropping zone becomes narrow and even disappears. Through the analysis of the data of the soft melting process, it is found that the mixed ore has a certain interaction effect in the oxygen blast furnace atmosphere, which improves the gas permeability of the charge.     

基于软熔滴落性能的高炉合理炉料结构

 为全面掌握鞍钢的烧结矿碱度、天然块矿配加比例和不同炉料结构的软熔特性,得到可评价炉料结构的方法,通过实验室试验,系统研究了不同碱度烧结矿的冶金性能,不同碱度烧结矿与球团矿搭配、烧结矿与球团矿和天然块矿搭配的复合炉料结构高温特性。结果表明,随碱度提高,矿物组成渐趋合理,烧结矿的还原和粉化指标改善,在碱度为1.90～2.05时,单一烧结矿的软化熔融性能较好;在碱度为1.95～2.15时,透气性较好;当烧结矿与球团矿搭配,碱度为1.90～2.15时,软熔区间窄,[S]特性值低;在配加天然块矿后,复合炉料的软化区间变宽,熔融区间变窄,综合性能得到改善。基于研究结果,提出了适合鞍钢原料条件的炉料间交互反应性的评价指数,通过指数判断,高炉天然块矿的适宜配加比例为15%～20%。     

Softening and Melting Behavior of Mixed Burden for Oxygen Blast Furnace

 The behaviors of mixed burden in the cohesive zone of oxygen blast furnace were studied by softening and melting tests, and the influence of reducing gas and burden basicity on the softening and melting behaviors of mixed burden was also investigated. The results indicated that the softening range became wide, however, the melting range narrowed sharply in the atmosphere of oxygen blast furnace. The permeability of burden in the oxygen blast furnace was obviously improved comparing with the conventional blast furnace. In addition, the content of sulphur in the dripping iron of oxygen blast furnace was much lower than that of conventional blast furnace, however, the content of carbon increased. An optimum basicity of burden, which could lead to the appearance of the narrower melting range and better permeability of burden, was obtained in the atmosphere of oxygen blast furnace.     

不同球团矿和块矿配加条件下炉料冶金性能

 针对铁矿石品种多、质量波动大,导致高炉炉料结构稳定性下降的问题,通过实验室试验,系统研究了含铁矿石的冶金性能以及烧结矿与不同种类天然块矿和球团矿搭配的混合炉料结构高温性能。结果表明,烧结矿的还原性能和熔滴性能优于酸性球团矿和进口块矿,但是低温还原粉化现象十分严重,低温还原粉化指数RDI_{>3.15 mm}仅为70%,哈皮块矿的滴落温度过低,只有1 353 ℃,南非块矿压差过大(6 820 Pa),不利于高炉稳定顺行;里奥球和萨玛科球冶金性能优良,可以适当地提高其比例来弥补烧结产能不足的缺陷;在低烧结比(55%)条件下,不同球团搭配使用时,炉料的软化区间、熔融区间变窄,最大压差Δp_m降低,综合性能得到明显改善。最佳的混合炉料结构为55%烧结矿+20%里奥球+5%萨玛科球+20%哈皮块矿;配加纽混块矿的炉料结构,软熔区间窄,最大压值Δp_m和总特性值S低,软熔滴落性能较好。     

高炉块状带透气性试验分析

通过试验研究了在不同球团矿配比、不同烧结矿粒度和不同料层厚度条件下,高炉块状带透气性指数的变化规律。粒度小于10 mm的烧结矿会使高炉块状带的透气性急剧变差;在保持料层炉料粒度组成不变的情况下,如果料层厚度增加,则高炉块状带的透气性降低;随着球团矿配比的增加,料层压差呈先升高后趋于稳定的状态,高炉块状带透气性升高。     

Study of the High Temperature Metallurgical Properties of On-Site Samples with Vanadium–Titanium Magnetite

In China, two typical vanadium–titanium magnetite ores were used as raw materials in iron making. In order to obtain the differences in the high temperature metallurgical properties of these ores, the phase and microstructure of on-site sinter, pellet, slag and laboratorial non-dripped slag were analyzed by XRD and SEM–EDS. The results show that the phases of two typical sinter and pellet have no significant changes, but the microstructures are different. The softening start temperature and softening zone of high chromium vanadium–titanium magnetite (HCVTM) burden are higher than ordinary vanadium–titanium magnetite (VTM) burden. The melting start temperature of HCVTM burden is higher and melting–dripping zone is smaller than VTM burden, which is beneficial to the blast furnace smelting. In addition, the calculation results using Factsage 7.0 are in accord with the experimental results. The primary crystal field of slag of HCVTM is the melilite, and the liquidus temperature is 1409.81 °C; the primary crystal field of slag of VTM is CaTiO₃, and the liquidus temperature is 1418.51 °C.     

烧结矿碱度变化对软熔滴落性能影响的试验研究

介绍了改善烧结矿软熔滴落性能对强化高炉冶炼的重要性,并通过试验系统研究了烧结矿碱度变化对软熔滴落性能的影响。试验结果表明:对于高碱度烧结矿来说,随着碱度升高,开始软化温度、开始熔化温度均呈现下降趋势,滴落温度升高,软熔区间、熔化区间均变宽,初渣熔点升高,整体性能呈现变差趋势。     

高炉冶炼钒钛磁铁矿合理炉料结构的研究

合理的炉料结构是高炉冶炼钒钛磁铁矿最重要的内容之一.本文基于现场生产条件,在保证炉渣二元碱度、焦比、煤比等不变的条件下,进行不同碱度钒钛烧结矿和不同球团比例的综合炉料软熔滴落的试验,研究了高炉冶炼钒钛磁铁矿的合理炉料结构.结果表明,随着综合炉料中烧结矿碱度的提高和球团比例的增加,综合炉料的软化开始温度T4基本不变,软化终了温度T40升高,软化区间（T40-T4）变宽;综合炉料的熔化开始温度TS逐渐升高,熔化终了温度TD逐渐上升,熔化区间TD-Ts明显收窄,综合炉料的透气性能明显改善;同时初铁中V、Cr含量增加,V、Cr收得率明显提高.因此,在一定的范围内,提高综合炉料中钒钛烧结矿的碱度和球团比例,有利于高炉冶炼钒钛矿合理炉料结构的形成.     

矿焦混装对钒钛矿综合炉料软熔滴落的影响

 为提高高炉冶炼钒钛磁铁矿水平,系统研究了矿焦混装对高炉综合炉料软熔滴落性能和V、Cr在渣铁中迁移规律的影响,并进行了理论分析。试验过程中烧结矿和球团矿所占比例不变。研究表明,矿焦混装对高炉综合炉料的软化区间、熔化区间、滴落率和透气性等软熔滴落性能参数有显著影响。随着混装率提高,软化区间[t40－t4]稍微变宽;熔化区间[tD－tS]逐渐变窄,软熔带变薄且位置下移;熔滴性能总特征值明显减小,综合炉料透气性能显著改善;渣铁滴落率先增加后减少;V、Cr在初铁中的收得率先升高后降低。因此,一定程度的矿焦混装有利于改善钒钛磁铁矿高炉冶炼综合炉料的软熔滴落性能,其混装率以25%为宜。     

球团矿中MgO含量对炉料熔滴性能的影响

球团矿带入适宜的MgO可以提高炉渣的冶金性能,有利于高炉冶炼。为了探究球团矿MgO含量对高炉炉料性能的影响,在全球团冶炼的条件下,以高炉终渣成分为依据进行配料,利用高温熔滴炉检测球团矿不同w(MgO)时高炉初渣性质、炉料软熔滴落性能的变化情况。试验结果表明,随球团矿w(MgO)升高,初渣中未矿化的MgO明显增多,软化结束温度升高,软化温度区间变宽,炉料软化性能变差。当球团矿w(MgO)大于1.01%后初渣熔点升高,导致熔化特征温度升高,熔化带位置向高温区移动,熔化温度区间变窄,熔化带透气性提高;炉料的软熔带温度区间由229 ℃升高至269 ℃,软熔带增厚,炉料整体透气性变差。由于初渣中w((MgO))随之增加,初渣黏度升高,炉料最大压差和熔滴性能特征值增大。因此,在试验范围内,随球团矿w(MgO)升高,高炉炉料的软熔滴落性能恶化,渣铁分离变差,不利于高炉顺行。     

Microstructure evolution during softening and melting process in different reduction degrees

This paper concerns the degree of indirect reduction in a burden rising substantially in an oxygen blast furnace. It studies the pellet, sinter and a mixture of both in different cases. The paper concerns experiments on single particle load softening to investigate the microstructural evolution of different burdens during the softening and melting process. The results of the experiments show that the degree of reduction impacted the softening and melting behaviour. In the case of a low degree of reduction, a slag phase substrate and a myrmekitic iron structure were formed on the periphery area of the molten burden, whereas slag phase substrate and disperse island wüstite structure were formed in the centre area. Both peripheral and central areas had a slag phase substrate and myrmekitic iron texture. The slag–iron distribution had a structure in which the slag phase was cut in the metal iron phase. The content of 2FeO.SiO₂ as a low melting point phase in the slag decreased sharply, and this resulted in the increase in slag–iron separation temperature. The variation of the Ca/Si ratio in the interface between the pellet and the sinter indicated that enhancement of the reduction degree caused the initial temperature of the interaction in the mixed burden to rise and the interaction distance to decrease.     

现代高炉合理使用天然块矿的基础研究

由于对天然块矿的冶金性能认识不够全面和深入,影响了现代高炉使用块矿技术的发展.通过分析和实验,考察了世界主要产地的块矿的各种冶金性能.结果表明天然块矿除自身软熔特性较差外,其他冶金性能均能满足现代高炉冶炼的要求;在高炉高温区块矿会与烧结矿发生交互反应,能够明显改善块矿自身的软熔特性,且可利用这一交互反应性优化块矿搭配模式.     

济钢用铁矿石软熔滴落性能研究

利用RDL-02装置对济钢高炉现用烧结矿、球团矿及拟用烧结矿软熔滴落性能进行研究分析。研究结果表明：60烧结矿、120烧结矿各项软熔滴落性能相近,320烧结矿开始软化温度、开始熔化温度都比60烧结矿、120烧结矿高,最大压差为11608Pa,低于另2种矿,320烧结矿软熔性能略优于60烧结矿和120烧结矿,为高炉配料提供了科学依据。     

软熔过程中烧结矿和块矿的交互作用

 为更好地明晰块矿的软熔行为并优化其在高炉内的使用,以烧结矿和澳大利亚纽曼混合块矿为研究对象,分别就两者在软熔过程中的物理和化学交互作用进行了试验研究。通过使用中子CT扫描软熔试验试样, 发现1 450 ℃时烧结矿与纽曼混合块矿的混合炉料孔隙度要高于两者单一炉料,即两者间存在着物理交互作用;通过采用扫描电镜和电子探针分析发现,1 200～1 300 ℃温度范围内烧结矿中钙和镁扩散到了块矿中,两者发生了明显的化学交互作用。在物理和化学交互共同作用下,配加约20%纽曼混合块矿的混合炉料软熔行为得到了明显改善,且其性能相似或略好于同碱度的单一烧结矿炉料,这表明块矿和烧结矿混合后能在高炉内形成温度区间更窄、位置更低、透气性更好的软熔带。     

鼓风条件及块矿比例对炉料软熔性能的影响

为了研究不同鼓风条件下块矿比例对高炉含铁炉料软熔性能的影响,计算模拟了3种鼓风条件下的温度和气体含量并使用高温熔滴炉研究了块矿比例对含铁炉料软熔性能的影响,进而进行综合炉料结构优化的分析。结果表明,富氧、加湿鼓风条件下,氢气含量增加,能有效降低炉内最大压差,窄化熔融区间,改善炉内透气性;富氧、加湿鼓风条件下,块矿比例的增加虽然会导致炉内最大压差和软熔区间的增大,但是最大压差的绝对值仍远小于基准条件下的最大压差值,软熔带宽度也小于基准条件下的宽度。可以得知,在富氧和加湿鼓风条件下适当增加块矿比例,综合炉料软熔性能仍然优于基准条件,且能降低高炉生产成本,对于炉料结构是一种有效的优化措施。     

邯钢高炉低烧比炉料结构的优化

鉴于环保压力的影响,高炉应减少烧结矿的使用,多使用相对清洁的球团矿和块矿进行高炉冶炼。为配合酸性炉料的大比例加入,需要提高烧结矿的碱度。然而,随着烧结矿碱度的提高,高炉炉内压差升高,透气性恶化,高炉相应生产质量指标难以提升。为了避免烧结矿碱度过高所带来的问题,提出了新的技术思路,即将烧结矿中碱性熔剂取出直接加入高炉,选择适宜的球团矿种类、适宜碱度的烧结矿配加一定量的石灰石与一定比例块矿组成高炉炉料结构。研究结果表明,与综合炉料中直接加入碱度为2.3的烧结矿相比,外配石灰石的方式所组成的综合炉料熔滴性能更优,炉料透气性得到了改善。在熔滴性能满足高炉要求的情况下,通过外配石灰石的方式,炉料结构中烧结矿比例可以降低至47%左右。     

MgO对烧结工艺及烧结矿冶金性能的影响

研究了MgO对烧结工艺及烧结矿冶金性能的影响.研究结果表明,在烧结过程中不加或少加MgO,可提高烧结生产效率,获得冷态强度高、软熔带温度区间窄的烧结矿,从而提高高炉软熔带的透气性、降低料柱全压差.为保证高炉渣对MgO含量的要求,以及确保烧结矿低的低温还原粉化率,提出了合理添加MgO的新工艺.