转炉双渣冶炼安全留渣及其工艺

针对梅山铁水中含磷量较高的问题，阐述留渣操作的重要性，提出安全留渣的条件并确定其工艺。     

80t顶吹转炉双渣冶炼工艺实践

通过对80 t顶吹转炉双渣法深脱磷工艺的实践探索,提出了倒炉时间、温度、碱度、渣中TFe含量及渣的流动性等关键因素的合理范围,为开发低磷品种钢奠定了坚实的基础。     

150 t转炉双渣冶炼技术的工艺实践

简要介绍了唐钢150 t转炉双渣冶炼技术工艺试验的研究分析,结合不同吹炼时期冶炼特点,确立了操作控制的关键措施,对倒炉温度、碱度、炉渣中的FeO和MgO含量及熔渣流动性等因素的合理控制,是取得良好脱磷效果的重要保证,运用控制轻烧白云石加入造渣的双渣生产试验使唐钢取得了良好的经济效益。     

150t转炉留渣+双渣冶炼技术的优化

分析原留渣+双渣冶炼中存在的问题,介绍在提高前期脱磷的稳定性、稳定留渣量、采用留渣单渣操作、构建铁水分级系统下的留渣模式等方面实施的优化与改进措施,钢铁料耗达1 045 kg/t,造渣料耗小于59 kg/t。     

优化转炉冶炼工艺研究

通过对重轨钢冶炼工艺进行优化设计,在终点碳不严格要求的情况下,提高转炉-倒前顶吹氧气流量及底吹气体流量,可减少点吹次数,减少冶炼时间.结果表明:点吹降到1次以下,冶炼时间缩短5 min,达到35.6 min;终点温度平均提高34℃,钢包内钢水温度提高10℃;脱磷率提高5%,终点w[P]平均降低0.005%;采用该工艺生产的重轨钢质量和成品轨质量性能满足标准.     

转炉少渣冶炼工艺的实践

为解决氧气顶吹转炉渣料、钢铁料消耗高,终点控制不稳定等问题,开发出一种转炉少渣冶炼工艺技术。生产实践表明,该工艺与常规单渣冶炼工艺相比,降低了生产成本,提高了脱磷效率,改善了钢水的纯净度,为生产超纯净钢奠定了基础。     

转炉双渣留渣工艺研究

介绍了转炉留渣双渣工艺操作过程,以及在生产过程中遇到的操作难点和解决方法。实践表明,实施该工艺可降低石灰消耗,提高脱磷效率,实现少渣炼钢等显著效果。     

转炉双渣留渣工艺实践

介绍了唐钢热轧部转炉双渣留渣的生产实践情况,讨论了脱磷阶段吹炼氧压、一倒温度、炉渣碱度、炉渣氧化铁含量以及倒渣时机对脱磷率的影响规律。研究表明,通过对倒渣时的炉渣物性进行控制,实现了降低辅料和钢铁料消耗的目的。     

基于转炉双渣冶炼工艺的锰矿直接还原合金化研究

以提高转炉双渣冶炼条件下锰矿直接还原合金化过程中锰的收得率为目的,进行了热力学理论分析,开展了实验室渣钢平衡试验和中试试验,在此基础上得出了基本结论;通过转炉工业化试验,验证了前期结论的可信性,同时得出在特定的双渣冶炼条件下,转炉锰矿直接还原过程中锰的收得率可稳定在35％～45％,具有经济上的优势,且对转炉冶炼效果有益,同时从总体上达到节能降耗、减少温室气体排放的效果.     

复吹转炉双渣法脱磷冶炼工艺一次倒炉温度最优化选择

从碳-磷选择性氧化、脱磷反应平衡、转炉熔池磷分配比与脱磷渣熔点的角度分析了复吹转炉双渣法冶炼工艺一次倒炉温度的选择。提出一次倒炉温度最佳控制范围为1 350~1 400℃,并进行了工业试验,结果表明:将一次倒炉温度控制在1 350~1 400℃,一次倒炉平均脱磷率、脱磷渣平均w(P2O5)分别达到63.11%、3.10%。并对1 350~1 400℃区间内试验炉次一次倒炉熔渣碱度、氧化性与一次倒炉脱磷效果的关系做了进一步研究,发现:碱度为1.8~2.0、w(T.Fe)=14%~17%的脱磷渣系更有利于获得一次倒炉的最佳脱磷效果。     

Influence of ladle slag additions on BOF process under production conditions

Abstract

The influence of recycled ladle slag on the basic oxygen furnace (BOF) process under production conditions was investigated in plant trials. More specifically, 25 heats with ladle slag additions and 23 heats without ladle slag additions were studied. Both steel and slag samples were collected, from which the chemical compositions were determined. In addition, several process parameters were monitored. Overall, it was found that recirculation of ladle slag during normal production conditions works fine. On the positive side, it was seen that the steel quality concerning the phosphorus and sulphur contents of liquid steel has, in accordance with previous studies, not been affected by the ladle slag additions. Furthermore, no major differences in the slag composition occur when the recycling of ladle slag to BOF is performed. Finally, in comparison to previous studies, the increased tendency for slopping when adding ladle slag could be eliminated with a change in the lance schedule. However, on the negative side, it was seen that the addition of ladle slag leads to an increased blowing time due to lower iron ore additions. Moreover, the slag weight at tapping increased due to an increased weight of added slag formers.     

转炉钢渣炉内改质的研究进展及展望

以转炉炉内改质降低渣中自由CaO含量为技术背景,提出从源头上加快石灰溶解,减少残余石灰尺寸,并结合炉渣改质消解渣中自由CaO.通过文献分析得出如下结论:提高石灰活性对加快石灰溶解的作用有限;相比于石灰石造渣,采用未完全煅烧的石灰石也具有十分可行的应用前景,所含石灰石最佳比例还有待研究确定;向转炉渣中协同添加SiO2和Al2O3更具优势,氧化性气氛也有利于自由CaO的消解,降温过程中自由CaO消解的动力学参数需进一步研究.     

转炉钢渣物相组成及其显微形貌

利用XRF、XRD和SEM+EDS对本钢转炉钢渣的物相组成及其显微形貌进行研究.结果表明,该钢渣为高碱度钢渣,钢渣中的主要物相有硅酸二钙、硅酸三钙、铁酸二钙以及RO相,还有少量二氧化硅相和金属铁相.铁酸二钙相呈无规则状或絮状、RO相呈骨骼状或絮状分布于硅酸二钙相和硅酸三钙相的基体上. XRD不能完全检出钢渣中的所有物相,需配以SEM+EDS综合分析.     

转炉吹炼末期泡沫渣高度控制技术

重点介绍了一些先进钢厂在转炉吹炼末期泡沫渣高度的控制技术。温差法?微波法和声学法都被用于测量吹炼过程中的泡沫渣高度,不仅仅能够有效防止喷溅,而且能够降低吹炼终点的钢中氮含量。此外,讨论了首钢迁安钢铁有限责任公司利用温差法测量吹炼末期泡沫渣高度的可行性。     

铜精炼炉渣磨矿流程优化

采用闭路磨矿—压滤干排的方式处理铜精炼炉渣,会导致球磨机的台时能力降低。通过引入高频振动脱水筛,与旋流器和压滤机一起构成新的干排系统,使粗粒、细粒级进行了单独脱水,解决了球磨机排矿的脱水问题,实现了铜精炼炉渣的开路磨矿,既提高了球磨机的处理量,又降低了矿粉水分。     

烧结工序中转炉渣的优化利用

钢铁厂产生的矿渣中很大一部分来自氧气顶吹转炉(LD转炉)和吹氧转炉工序.LD工序的主要目的是将熔融的铁水和废钢转化为优质钢.在印度,每年产生的熔融钢渣超过400～450万t.总体看来,生产每吨钢会产生150～200 kg的钢渣,对这些钢渣的处理已经成为了严重的环境问题.金达尔钢公司是年产700万t的联合钢厂,每天产生钢渣3 200 t,其中2 000～2 500 t来自LD转炉.LD转炉渣中含有47.75%的CaO,22.0%的Fe以及8.22%MgO,由于CaO含量很高,LD转炉渣可直接替代烧结工序中的生石灰.目前在实验室范围已进行了一些研究,以确定烧结工序中所允许的LD转炉渣的最大投加量以及转炉渣的投加对烧结产率和性能的影响.实验中,LD转炉渣在烧结矿里的添加量从0依次到60 kg/t.随着添加率的增大,烧结料层温度的降低致使FeO含量降低,而烧结配矿中烧损的降低以及由于避免了石灰石煅烧过程带来的的重量损失,使得烧结产率上升.与此同时,LD转炉渣中缺少自由的CaO,使烧结矿强度及还原粉化指数变差,可参加反应的CaO的减少也导致了铁酸钙相减少,及残存Fe2O3自由相增加.试验结果最终得出:烧结矿中LD转炉渣的投加量为30～35 kg/t时,可获得预期的烧结矿性能.     

Free CaO stabilisation by mixing of BF slag and BOF slag in molten state

Reducing free CaO (f-CaO) in basic oxygen furnace (BOF) slag effectively and efficiently is the prerequisite to achieve the goal of BOF slag's volume stability. In this work, Taguchi experimental design method was used to explore the influencing factors effect on stabilising f-CaO by mixing BOF slag with blast furnace (BF) slag and probe into the relevant mechanism. The results show that, in the setting conditions of this work, the most influential factor on the stabilisation ratio of f-CaO is mass ratio between BF slag and BOF slag, and then mixing temperature and duration time as a queue. The reasonable conditions are obtained as follows: mass ratio of BF slag to BOF slag is 6:1, temperature of mixing is 1783?K and duration time for mixing is 20?min. The f-CaO stabilised mechanism on BF slag and BOF slag molten mixing was regarded as mutual coupling effects of stabilisation reactions and dilution.     

MgO solubility in BOF slag equilibrated with ambient air

The MgO solubility in the CaO‐MgO‐Fe₂O₃‐FeO‐SiO₂‐(MnO)‐(Al₂O₃) slag was measured under the condition of equilibrium with the ambient air at 1873 K as a fundamental study for precise slag coating control in BOF operation. The CaO/SiO₂ mass ratios of the main slag were 1, 1.5, 2, 3 and 4, and total iron content was in the range of 10 to 35 %. Moreover, 1 to 13 % of MnO and 2 to 12 % of Al₂O₃ were added to the melt to evaluate their effects on the MgO solubility. The effect of slag composition on the MgO solubility was discussed and quantified by means of a newly developed formula. As the basicity in slag increases, the MgO solubility decreases. The effect of iron oxide content is observed to be dependent on the basicity of slag. An increase in iron oxide content makes the MgO solubility higher for basic slag but lower for acidic slag. It is revealed that the MgO solubility in steelmaking slag is controlled by the complex anion formation reaction of iron oxide. Both Al₂O₃ and P₂O₅ increase the MgO solubility by diluting the basic oxides as SiO₂ does, while manganese oxide affects the MgO solubility in a similar manner as iron oxide. The MgO solubility can be described as a function of slag composition, X = (%CaO) + 0.45(%Fe₂O₃+ %FeO) + 0.55(%MnO), in the equation of (%MgO) = 0.00816X^2‐1.404X + 62.31. Based on the results, the guidance for addition of MgO‐containing material could be suggested for best slag coating practice.