Slag Melting Characteristic of Slag Forming and Slag Splashing for BOF Less Slag Smelting

 The slag melting characteristic of slag forming and slag splashing for 300 t BOF less slag process is researched by combining the methods of the slag chemical composition, the melting point determination and the petrographic analysis. The results show that the melting point of final slag for less slag smelting is 20 ℃ lower than that for conventional smelting. According to results of the petrographic analysis, the C3S (3CaO·SiO2) and C2S (2CaO·SiO2) content for less slag smelting are lower than those for conventional smelting, while the RO (FeO, MgO, MnO, etc) phase and C4AF (4CaO·Al2O3·Fe2O3) phase are higher than those for conventional smelting. According to results of the chemical analysis, the (CaO) content and slag basicity for less slag smelting are higher than those for conventional smelting, while (FeO) and (MgO) content in slag for less slag smelting are almost equal to those for conventional smelting. The reason why slag melting point for less slag smelting is lower than that for conventional smelting is that the quantity of added fluorite for less slag smelting is more than that for conventional smelting. According to the analysis results the slag melting point is determined by the C3S, C2S, RO phase and C4AF content. According to the results of slag melting characteristic before and after slag splashing for less slag smelting, the present adjusting slag process has little effect. It is important to adjust the composition of BOF final slag. The (FeO) content in slag is to be reduced at the slag splashing and adjusting slag process for less slag smelting.     

溅渣层形成和对炉衬保护机理的研究

通过对溅渣转炉残砖的成分和矿相分析,讨论了高ＦｅＯ炉渣溅渣形成的溅渣层化学成分变化和岩相结构特点;分析提出溅渣层的形成机理和对炉衬的保护作用。实验研究证明,溅渣结合层的化学成分与终渣有明显的差别。结构     

转炉溅渣护炉的炉渣控制及炉衬侵蚀机理

利用副枪在转炉吹炼过程中取样、测温和对炉衬残砖的化学成分、岩相、流动温度的测定结果,研究了宝钢转炉溅渣护炉炉渣的控制及炉衬侵蚀机理。结果表明：转炉终渣ＭｇＯ含量应控制在１０ ％ 左右、溅渣层的熔损主要发生在炉温较高的吹炼后期,而镁碳砖的侵蚀是由于炉渣渗入镁碳砖的气孔和裂缝中,使其脱碳和渣化,在高温下流入渣层所致。     

转炉溅渣护炉炉渣物性研究

针对转炉后吹和正常吹炼终渣∑FeO变化较大的特点,对炉渣的成分,熔化性温度和岩相结构进行研究,研究结果为转炉溅渣护炉终渣成分的调整提供了一些依据。     

转炉溅渣护炉改质剂的开发研究

影响转炉溅渣护炉效果的关键因素是终渣成分的控制,采用改质剂对转炉终渣成分进行调整,降低渣中FeO含量和炉渣温度,提高MgO含量和炉渣熔点及粘度,有利于改善炉渣与炉衬的粘结效果,并提高溅渣层的耐蚀性能,缩短溅渣起孕时间,在一定程度上抑制炉渣中铁的氧化物与炉衬中石墨的反应.     

溅渣护炉工艺探讨

从炉渣对炉衬和溅渣层的侵蚀机理入手,提出了兼顾冶金和溅渣双重效果的直接造渣工艺,探讨了终渣碱度、MgO、FeO含量等的调整范围,分析了溅渣操作中枪位、时间等的控制和炉底上涨的原因,以期更好地运用溅渣护炉技术。     

转炉渣与镁质耐火材料的润湿机制

 采用静滴法研究了2种情况下转炉渣与炉衬耐火材料的润湿性。当转炉渣与耐火材料直接接触时,转炉渣不熔化,当用刚玉坩埚将两者隔开时,界面处发生反应性润湿,动态接触角随温度升高而单调减小,铺展面积随时间成线性增加。渣中FeO含量由于镁碳砖基板表面的碳及中间产物CO的还原而降低,导致炉渣熔化性温度升高而未熔化。液态熔渣沿镁碳砖表面的气孔和裂纹向基体内扩散、渗透,渣中铁氧化物与镁碳砖机体内的MgO反应生成含高熔点相的黄色渗透层,起到保护炉衬的作用,从而解释了炉渣与耐火材料的粘附机制,为优化溅渣护炉工艺,合理调整炉渣成分和选择耐火材料等工艺操作提供理论依据。     

Wear and Dissolution of MgO–C Refractory Lining in Belly and Top Cone Regions of BOF Vessel

The MgO–carbon bricks of varying carbon concentration are used as refractory lining material in BOF. Laser profiling of the lining is done at regular intervals to keep track of refractory wear in different parts of vessels. The main factors which affect the kinetics of dissolution of graphite flakes lying between the MgO grains in the belly region are attack by CO₂ in gas and FeO in slag, and temperature. FeO can easily penetrate the MgO grains along grain boundaries and reach those places where graphite flakes are present. Kinetic models of refractory wear are analyzed on the basis of data obtained from actual laser profile measurements. The bricks salvaged from the top cone region at the end of the campaign have been subjected to scanning electron microscope (SEM) and electron probe micro analyzer (EPMA) investigations. The possible cause of wear in top cone region is also the oxidation of carbon in the brick by CO₂ gas and direct attack by FeO thrown from the jet impact region.     

减轻低碳低磷钢冶炼炉衬侵蚀及炉渣成分优化

通过实验室管式高温炉蘸渣试验和理论计算,研究了转炉冶炼低碳低磷钢的终渣(FeO)含量、(MgO)含量和碱度对炉渣物化性能和溅渣护炉炉衬保护的影响.试验优化前,终炉渣(FeO)质量分数为31.5％,(MgO)质量分数为8％,通过调整炉渣碱度,炉渣的固相率依然接近0％,炉渣溅渣后难以残留在炉壁上,不能对炉衬起到保护的效果....     

转炉溅渣护炉成渣途径的探讨

在分析了渣中ＭｇＯ含量对转炉ＭｇＯ－Ｃ砖的侵蚀和炉渣熔点影响的基础上,探讨了溅渣护炉的成渣方式：在造渣过程分批向渣中加入含ＭｇＯ的调质剂如白云石,并通过实践操作讲座了渣中ＭｇＯ的调质剂如白云石,并通过实践操作讲座了潭中ＭｇＯ含量对造渣过程的影响以及相应的溅渣护炉的成渣途径。     

攀钢半钢吹炼条件下的溅渣护炉

攀钢转炉采用溅渣护炉提高炉龄已经取得了很好的成绩。本文主要报告Ｖ．Ｔｉ氧化物对炉渣熔点，粘度和ＭｇＯ饱和溶解度影响的研究结果，并提出了有关溅渣护炉渣系参数的建议。     

转炉炉渣中MgO含量的控制实践

 通过对炉渣中MgO饱和度的计算及MgO含量对溅渣护炉和脱磷的影响分析,得出炉渣中MgO含量过高是造成脱磷能力降低的主要原因。采取降低炉渣中全铁含量、优化配镁方案、改进加料模式等措施,降低了炉渣的饱和度和过饱和度,满足了溅渣护炉对炉渣中MgO含量的要求的前提下提高了低磷钢的一次做成率。     

转炉溅渣护炉调质剂的开发研究

影响溅渣护炉效果的终渣成分的控制,主要是控制终渣中ＦｅＯ％、ＭｇＯ％和Ｒ。通过试验室小型热态模拟实验,测定了溅渣的侵蚀量,炉渣半球熔点,并分析炉渣的显微结构,探讨了溅渣层的侵蚀机理,提出了溅渣护炉的终渣成分大致分别为ＭｇＯ＝８％－１０％,ＦｅＯ＝１０％－１３％,Ｒ＝３．５左右。     

Difference in BOF Slag Splashing in US and China

Slag splashing is a relatively new technique thathas been used successfully to enhance refractory lifein BOF′s.During the last ten years,slag splashinghas been used by many steel works in the US[1— 3 ] .Recently,slag splashing has also been applied tomore than twenty steel works in China. Althoughthese steel works are successful to varying extentswith slag splashing,some differences are exhibitedbetween the US and Chinese steel works because ofdifferent conditions in their BOF steelmaki…     

转炉留渣操作炉渣喷溅临界条件的研究

对转炉留渣操作炉渣喷溅的临界条件进行了热力学和及动力学的研究，得出了炉渣喷溅临界温度的计算公式，利用计算机定量分析了ａ（ＦｅＯ）对安全留渣操作临界温度的影响，从理论上分析了实施留渣操作应采取的工艺措施，为实施具有显著效益的转炉留渣操作提供了可靠的依据。     

转炉溅渣层与镁碳砖炉衬的结合机理

通过对生产现场带有溅渣层的转炉炉衬残砖和试验室小型坩埚溅渣试验结果进行矿相显微结构分析、研究，确定了溅渣层的矿相组成、溅渣层与ＭｇＯ－Ｃ砖结合区域的矿相结构及坩埚溅渣层自上而下的矿相分布规律，并根据矿相结构分析中观察到的烧结层、结合层和溅渣层３个区域，提出了溅渣层与镁碳砖炉衬的结合机理为化学结合、机械镶嵌与化学烧结结合及冷凝结合３种形式。     

High Temperature Properties of BOF Slag and its Behaviour in the Blast Furnace

Slag formation in the bosh and raceway is an important issue in the blast furnace process. SSAB works in Luleå operate with 100 % olivine pellets. A small amount of basic fluxes is added from the top, slag and limestone are used. To improve the control of slag formation, a concept with injection of BOF slag was evaluated and tested in the LKAB experimental blast furnace (EBF). In this paper, the behaviour of BOF slag as a slag former, when it is top‐charged or tuyere‐injected, is evaluated based on the results from a laboratory study including reduction tests, softening and melting tests, XRD analyses and SEM analyses. Samples taken from the EBF during excavation, and with a burden probe during operation, are examined. The evaluations show that the melting point of BOF slag is quite low and will not be increased, because of the partial reduction that occurs in the BF shaft. When carbon is present at high temperatures, reduction proceeds and a high basicity slag with a high melting point, consisting of di‐ and tricalcium silicates, is formed. When pellets with a basicity of B2 ~ 1 are used, a slag with similar properties can be formed as a result of interaction with the BOF slag. BOF slag in combination with olivine pellets with a low basicity generates a slag with intermediate basicity and the reduction of iron oxides in the slag has a small effect on the melting temperature. The BOF slag decreases the melting point of coal and coke ashes.     

济钢超低碳、超低磷钢转炉溅渣护炉工艺

随着超低碳、超低磷钢种冶炼的增多,济钢复吹转炉终点氧含量大幅提高,严重侵蚀了转炉炉衬。从高氧化性炉渣对炉衬的侵蚀机理入手,提出了兼顾溅渣层和炉底的溅渣工艺,介绍了超低碳、超低磷钢溅渣护炉工艺参数的优化及取得的效果。     

转炉溅渣护炉技术

溅渣工艺是用高压和大流量氮气通过氧枪将渣喷溅涂挂到全部转炉炉衬上。此技术使炉衬寿命延长，喷补料消耗降低，增加生产率，明显地降低操作成本。     

转炉溅渣护炉对钢水质量的影响

转炉采用溅渣护炉时溅渣层在下一炉冶炼过程熔入炉渣、能够促进石灰溶解、加速成渣过程。吹炼终点时溅渣怀未溅渣次钢中氧、磷、硫、氮平均含量基本相同,溅渣护炉对钢的质量没有影响。