260t复吹转炉单渣深脱磷工艺研究与实践

基于260 t复吹转炉进行单渣深脱磷工艺研究,优化了吹炼制度、造渣制度、温度制度等影响转炉脱磷效果的关键控制参数,并采取挡渣出钢、低磷合金及顶渣改质等控制回磷措施,实现复吹转炉单渣法出钢平均w(P)=75×10<'-6>,成品平均w(P)=98×10<-6>的目标.     

180t复吹转炉单渣法深脱磷工艺的研究

通过研究180 t复吹转炉单渣深脱磷工艺,确定实际铁水条件下吹炼制度、造渣制度、温度制度等影响转炉脱磷效果的关键控制参数,并通过优化出钢模式、采用低磷合金及顶渣改质等控制回磷措施,实现了复吹转炉单渣法出钢平均ω[P]为0.007 9%,成品平均ω[P]为0.008 4%的目标。     

120 t复吹转炉单渣法高拉碳工艺

 在复吹转炉铁水消耗1 050 kg/t(钢),铁水磷质量分数小于0.150%条件下,采用单渣法高拉碳工艺进行试验研究,实现了出钢碳质量分数大于0.40%,磷质量分数小于 0.020%。分析了高拉碳的操作控制难点是脱磷效率低、易喷溅和终点拉碳时机难以精确掌握。为此,对转炉操作抢位、氧压、底吹流量以及终点控制等方面进行了调整试验,试验结果表明：高枪位配合合适的底吹压力在提高脱磷效率的同时能有效控制喷溅;建立高碳出钢终点判断模型,能将碳命中率提高到90%以上。该工艺实施后,转炉终点游离氧保持在约100×10-6。     

顶底复吹转炉高效脱磷研究

在无铁水炉外预处理脱磷工艺条件下,于一座转炉内冶炼优质高碳钢,通过实验室研究及生产工艺优化,成功开发了复吹转炉采用单渣法高拉碳工艺冶炼优质低磷高碳钢新技术,解决了低磷、高碳出钢的工艺技术难题。采用新工艺后,优质高碳钢出钢平均磷的质量分数由0.015%下降为0.011%。出钢平均碳的质量分数由0.097%提高到0.44%。     

鞍钢转炉双渣深脱磷工艺研究与实践

 在100t顶吹、180t复吹及260t复吹转炉上研究了双渣法深脱磷规律。通过工业性试验,研究不同吹炼时期冶炼特点,分析吹炼过程需要控制的原料及工艺制度等关键措施,研究结果表明：控制倒炉温度、碱度、渣中w（(FeO)）及熔渣流动性等因素均是取得良好脱磷效果的重要保证。应用双渣法深脱磷生产试验取得了100t顶吹转炉出钢w（［P］）平均达到63×10-6,180t复吹转炉w（［P］）达到51×10-6,260t复吹转炉w（［P］）达到62×10-6的实绩。     

120吨复吹转炉冶炼低磷钢的生产实践

介绍了湘钢采用120 t复吹转炉生产低磷钢的新工艺,转炉终渣碱度控制在3.5-4.5,出钢温度控制在1605-1625℃,出钢w(O)控制在0.065％以上,可将转炉终点w(P)控制在0.011％以下,也可保证出钢后进一步脱磷效果.采用新工艺生产低磷钢,出钢后平均脱磷率51.2％,扒渣后平均返磷率34.6％,中间包w(...     

梅山150t复吹转炉溅渣护炉技术应用探讨

结合梅山转炉溅渣护炉的实践,从炉渣的特点、溅渣层的形成及保护炉衬机理、溅渣护炉工艺及参数选择等方面加以分析,对进一步提高梅山复吹转炉溅渣护炉的效果及溅渣护炉技术应用中的相关问题进行探讨。     

复吹转炉成渣过程对脱磷的影响

复吹转炉成渣过程是指冶炼过程中炉渣的碱度、氧化性和温度等因素的变化,成渣过程决定炉渣脱磷的效果。炉渣脱磷效果受热力学和动力学条件的影响,化渣脱磷期以改善动力学条件为主,脱碳升温期以改善热力学条件为主。     

复吹转炉补炉技术的改进实践

介绍了济钢炼钢厂"铁块补炉法"技术的改进情况,包括护炉前的炉渣调整、渣补护炉的操作步骤及要点等。采用优化后的"铁块补炉法"技术后,转炉护炉时间缩短至50 min,节约了30%的补炉料,吨钢成本降低0.65元。     

复吹转炉底枪布置优化探讨

通过复吹转炉底枪布置优化试验研究,结果表明底枪采用合适支数,特别是采取非对称集中布置方式,更有利于加强熔池搅拌强度.三明钢厂100 t复吹转炉底枪在国内首次采用非对称集中布置方案,实践应用结果表明冶炼终点各项技术指标得到很大的改善.     

复吹转炉双渣深脱磷工艺实践

为了提出适合南钢的操作原则和控制目标,根据转炉脱磷反应基本热力学原理和复吹转炉双渣脱磷工艺特点,针对南钢铁水条件,分析了铁水硅含量、温度、磷含量对脱磷的影响并提出合理的冶炼方案.南钢120t复吹转炉双渣深脱磷工艺实践表明,通过优化造渣、供氧、一次倒渣及终点控制等工艺操作,能取得转炉终点钢液磷的质量分数 ≤ 40×10^-6和脱磷率达97.3%的脱磷效果.按照优化后的方案进行冶炼能满足南钢超低磷钢的生产需要.     

Model study of mixing and mass transfer rates of slag-metal in top and bottom blown converters

Water model experiments have been conducted to clarify mixing rates of molten steel and mass transfer rates between slag and metal in LD and Q-BOP furnaces using six different circular tuyere arrangements. Splashing and ‘spitting’ were also examined with a view to finding a quiet bath with minimum mixing time and maximum mass transfer rate. Froude’s similarity criterion was fulfilled to determine gas flow rate and bath depth. Complete mixing time of water determined by tracer technique had been 0.9 second to 1.8 seconds for Q-BOP as compared to 6 seconds to 13 seconds for LD. This shows that the stirring intensity in Q-BOP is remarkably larger than that of LD. A simple relationship τ = 5.9(Q/N) ^−0.49 was obtained with gas flow rateQ and number of tuyereN. This indicates that flow rate of gas per tuyere should be intensified to realize better mixing. Mass transfer coefficient K_Ba for bottom blowing was found to be almost double that for top blowing. Of all the tuyere configurations studied for Q-BOP’s, a half circular tuyere arrangement was found to be the best considering all aspects of mixing, mass transfer, and bath agitation.     

复吹转炉双渣脱磷工艺实践

为解决帘线钢因磷偏析而造成的拧股断裂,根据现有的设备及生产组织情况,在中天120 t转炉上进行双渣工艺试验,通过对加料制度、顶枪操作、底吹等工艺制度进行研究,分析前期倒渣温度、碱度、FeO等对脱磷影响。结果表明,前期倒渣温度控制在1 320～1 400 ℃、炉渣碱度控制在1.8～2.0的工艺控制下,转炉终点脱磷率达到92.8%,平均出钢磷质量分数由0.011%降低至0.008 5%,平均终点碳质量分数由0.13%提高至0.205%。     

底吹搅拌对复吹转炉脱磷工艺的作用分析

 在分析讨论复吹转炉冶炼过程脱磷反应规律、常规转炉冶炼过程脱磷弊端的基础上,探讨了转炉冶炼过程脱磷时机选择与合理控制机制。基于转炉脱磷热力学与动力学条件分析得出,底吹搅拌能兼顾渣-钢界面搅拌和控制脱磷温度,是提高脱磷效率的主要动力学手段。通过水模试验模拟渣-钢之间的传质现象得出,转炉底吹元件数量和底吹强度的不同组合与渣-钢界面间的有效传质存在合适的匹配关系,随着转炉底吹强度增加,底吹元件个数应适当增加。转炉长寿命复吹效果不但取决于合理的供气元件选型、数量、布置及供气模式,更要依靠科学的底吹维护工艺制度。     

复吹转炉炉底控制技术应用实践

介绍了复吹转炉炉底上涨的影响因素,通过造渣工艺制度控制冶炼过程温度控制及溅渣工艺控制等技术应用,从而有效地预防了炉底上涨,使复吹转炉冶炼效果得到改善。     

Model study of turbulence structure in a bottom blown bath with top slag using conditional sampling

Water model experiments were carried out to study the effect of top slag on the turbulence structure in a molten steel bath agitated by bottom gas injection. Water and silicone oil were used as models of molten steel and slag, respectively. Air was injected through a single-hole bottom nozzle so that the reverse emulsification of the silicone oil occurred at the silicone oil-water interface. Silicone oil droplets thus generated were carried deeply into the lower water layer. Turbulence measurements were made using a two-channel laser Doppler velocimeter (LDV) in the presence and absence of the top oil layer. A conditional sampling method called the four-quadrant classification method was applied to detect large scale coherent motions in the vertical bubbling jet as well as in the recirculation region. The structure and intensity of turbulence inside the bubbling jet were strongly affected by bubbles. In the absence of the top oil layer, higher momentum fluid motions directed from the centerline of the bubbling jet to the sidewall of the vessel were mainly responsible for the turbulence production in the bubbling jet, while lower momentum fluid motions directed from the sidewall toward the centerline governed the turbulence production in the recirculation region. On the other hand, in the presence of the top oil layer, the coherent motion in the bubbling jet was also affected slightly by the top layer except for the center of the bubbling jet, whereas any distinguished coherent motion was not observed in the recirculation region, and hence, turbulence production was weak there.     

Water model experiment on the liquid flow behavior in a bottom blown bath with top layer

Water model experiments were performed to study the effect of top slag on the mean flow and turbulence characteristics in a steel bath agitated by bottom gas injection. The slag was modeled by silicone oil with a density of 0.968 g/cm³ and a kinematic viscosity 100 times larger than that of water at 25 °C. Velocity measurements were made using a two-dimensional (2-D) laser Doppler velocimeter (LDV) in the absence of swirl motions. The output signals of the LDV system were processed on a personal computer to obtain the axial and radial mean velocity components, the root-mean-square (rms) values of the axial and radial turbulence fluctuations, the Reynolds shear stress, and the turbulence production for two cases with and without top slag. The bubbling jet (or the bubble dispersion) region was localized near the centerline of the bath by the presence of the top oil layer. The mean flow and turbulence motions in the recirculation region located outside the bubbling jet region were also suppressed significantly by the top layer. This result could be attributed to the entrainment of top slag into steel in a real system.     

Experiments on the mass transfer between two immiscible phases by a top and bottom blown converter model

The mass transfer of caprylic acid between water and oil was studied at a top and bottom blown converter model. A model law was deduced from the experiments. It was observed that the oil phase presents itself nearly completely in droplet form at higher blowing rates. This observation allowed the determination of the mass transfer coefficient at 2.26 · 10^?4 [ms^?1]. A value of equal magnitude can be calculated of spheres being flown around. The rotational speed of the bath corresponds to earlier measurements.     

90 t 复吹转炉底吹工艺优化与应用

对三明钢厂 90 t 复吹转炉底枪布置进行物理模拟试验,结果表明,底枪沿耳轴方向非对称布置的熔池混匀时间比底枪采用对称布置要缩短28%.生产应用结果表明,底枪布置优化后复吹转炉冶炼技术指标有了很大的改善,终点钢中氧质量分数平均下降0.016%,终点碳与氧值的乘积平均下降6×10-4,锰质量分数平均提高0.029%,终渣T.Fe质量分数平均下降2.21%.