低碱度脱磷渣在转炉少渣冶炼中的作用

以SGRS工艺为基础,研究了低碱度脱磷渣在转炉少渣冶炼中的作用.根据少渣冶炼物料平衡原理,脱磷阶段结束炉渣碱度控制越低,相当于转炉回收利用的Ca O量越多,能够实现的钢液去Si量也越多.同时实验结果表明,随着脱磷渣碱度的降低,炉渣的熔化性能逐渐改善,带来脱磷阶段结束转炉倒渣量不断增加以及脱磷渣金属铁含量不断降低的有益效果.当脱磷渣碱度在1.2~1.8范围时,脱磷渣半球点温度基本控制在1 380℃以内,脱磷渣中的游离Ca O质量分数控制在0.7%左右的较低水平,同时转炉脱磷阶段结束转炉倒渣量基本可控制在8 t(210 t转炉)或5 t(100 t转炉)以上.     

基于多功能转炉炼钢法的连续循环冶炼过程

为了研究脱碳渣在脱磷期的重新利用,基于多功能转炉炼钢法进行连续循环冶炼实验.实验发现：脱磷阶段渣中较低的FeO含量、吹炼5 min左右,[ C]≥2.8%的条件下,可实现转炉熔池内铁液[ P]≤0.025%的脱磷效果,并对低( FeO)含量炉渣的脱磷可行性进行热力学计算;随着循环的进行,石灰加入量逐渐降低,由65 kg·t-1降低至31 kg·t-1,转炉冶炼终点钢水[ P]量由0.018%降低至0.005%,2~4炉后达到平衡状态;在循环过程中,脱磷阶段结束倒出炉渣60~80 kg·t-1,整个循环结束一次性倒出剩余全部炉渣120~130 kg·t-1,平均渣量为83 kg·t-1左右,较普通工艺的120 kg·t-1渣量有大幅度减少.     

复吹转炉多功能法脱磷工艺

在不新增设备的前提下,通过优化转炉冶炼工艺,使用复吹转炉多功能法进行铁水脱磷,提高转炉脱磷率.根据现有转炉设备条件,通过热力学计算确定转炉前期脱磷温度范围,并在现场实验中掌握好倒渣时机、渣碱度、加料量和出钢温度,确定最佳脱磷工艺.分析实验结果,与常规冶炼相比,该脱磷工艺用原料量少,脱磷率稳定,且高达90%以上,在提高钢水质量的同时也降低了生产成本.     

转炉留渣-双渣操作前期脱磷影响因素

为实现转炉高效脱磷同时减少渣料(主要是石灰)消耗,对国内某钢厂的80 t转炉进行了留渣-双渣操作试验。通过引入经验公式对前期脱磷的影响因素进行了热力学计算,并与现场实验结果进行了对比,得出转炉吹炼前期脱磷较佳的工艺条件:炉渣碱度R控制在1.2~1.8左右,一次倒渣温度控制在1 325~1 355℃,渣中FeO质量分数控制在15~17%。统计生产数据表明,留渣-双渣操作比单渣操作,石灰加入量每吨钢减少6.9 kg。     

京唐公司转炉双联冶炼工艺及技术指标

阐述了京唐公司转炉双联工艺及其优势,重点就转炉双联法与常规冶炼主要技术指标进行了对比分析,分析结果显示：采用转炉双联冶炼法时脱磷率为92.86%,采用常规冶炼法转炉脱磷率为88.4%,转炉双联工艺脱磷效果明显。脱磷炉终渣中平均TFe含量是8.27%,脱碳炉终渣中平均TFe含量是18.92%,常规转炉终渣中平均TFe含量是18.98%,转炉双联冶炼过程不仅铁损低,而且金属料消耗少。辅原料消耗上转炉双联法白灰和轻烧白云石的用量比传统冶炼法分别减少9.7 g/t钢、9.3 g/t钢。转炉双联法和常规冶炼法终点钢水平均碳氧积分别为0.0023和0.0024,控制水平较好。     

转炉优化配料与冶炼静态控制模型

在分析转炉炉料结构优化及 BP 预报模型特点的基础上,针对某厂50 t 转炉生产条件,构建了由优化配料、静态预测、过程控制、脱氧合金化和成本计算等模块构成转炉冶炼静态控制系统。以机理模型为基础、采用增量模型校正的优化配料模块,用以精确计算入炉料结构;以 BP 神经网络为基础构建了静态预测模块,对转炉冶炼终点碳和温度进行预测;以操作经验为基础构建了过程控制模块,动态给出冶炼过程控制的枪位曲线、加料时机和加入量;基于终点预测和全氧计算模型构建了脱氧及合金化模块,进而对转炉冶炼成本进行计算,构建了成本计算模块。通过本系统的开发,建立了全过程指导的炉料结构优化与冶炼静态控制,为现场生产提供了指导。     

CO2对脱磷转炉物料和能量的影响

基于CO2在高温条件下的反应特性,建立了CO2用于脱磷炉冶炼的物料和能量分析模型,验证CO2用于脱磷炉冶炼过程参与氧化反应的可行性。在此基础上,基于某厂脱磷炉的实际冶炼工况,研究喷吹CO2对脱磷转炉温度、煤气等的影响。研究发现：当废钢比为8%和CO2利用率为85%时,CO2的喷吹比例可控制在28%以内,氧耗可降低16%,炉气中CO比例可提高约12%；同时随着CO2利用率的提高,脱磷炉的半钢温度逐渐降低,氧耗逐渐降低。     

基于神经网络的转炉冶炼终点磷和硫含量预报模型

通过研究转炉冶炼终点磷、硫含量的影响因素.确定了影响冶炼终点的控制变量,根据人工神经网络技术,对常用BP算法进行改进,建立了基于神经网络的转炉冶炼终点双节点输出模型,实现了对终点钢水磷、硫含量同时进行预报,选取现场实际生产数据为样本,对模型进行训练,使模型对磷、硫含量的预报误差在±0.003%的命中率均达到了85%以上,预报精度达到了炼钢工艺的要求。     

转炉留渣脱磷工艺实践

介绍了某炼钢厂40t顶吹转炉的留渣操作工艺。从转炉脱磷的热力学和动力学理论两方面进行了分析,并针对性地制定了转炉吹炼过程去磷的有效措施,包括采用转炉留渣操作提高前期去磷效果、提高炉渣碱度等。实践证明,实施留渣操作对转炉冶炼时的脱磷十分有利,脱磷率由80.1%提高到89.9%,还可以降低石灰及钢铁料消耗,提高炉龄,取得了显著的经济效益。     

富硼渣MgO-B_2O_3-SiO_2-FeO体系表面张力计算

基于熔渣结构离子与分子共存理论和Butler方程建立MgO-B_2O_3-SiO_2-FeO体系表面张力计算模型,计算该体系及其子体系的表面张力,考察熔渣组元和温度对表面张力的影响。研究结果表明:本模型计算的相关体系熔渣表面张力与文献实验值吻合较好,模型平均相对误差为11.85%。含B_2O_3体系熔渣中,B_2O_3组元能够显著降低熔渣表面张力,纯氧化物表面张力与形成氧化物的阳离子静电势及氧化物中离子键分数有关。MgO-B_2O_3-SiO_2-FeO体系表面张力随B_2O_3含量增加和温度升高而显著降低,随着MgO/SiO_2质量比的增加而逐渐增大;当B_2O_3质量分数为17%~19%时,表面张力随FeO含量的变化规律发生改变,当B_2O_3含量较低时,熔渣表面张力随着FeO含量的增加而增大,当B_2O_3含量较高时,表面张力随着FeO含量的增加而降低。     

基于BP神经网络的高炉熔渣黏度预测

建立一种BP神经网络模型来预测多元组分CaO-SiO2-Al2O3-MgO系高炉熔渣的黏度,并对其测量值进行实验验证。结果表明,采用BP神经网络模型对高炉渣黏度预测的总平均误差为2.36%,较好地解决了预测结果与实验结果之间的非线性关系,且预测结果与实验结果相吻合。     

Upgrading and dephosphorization of Western Australian iron ore using reduction roasting by adding sodium carbonate

The technology of direct reduction by adding sodium carbonate (Na₂CO₃) and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na₂CO₃ reacts with gangue minerals (SiO₂ and Al₂O₃), forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na₂CO₃ also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product (metal iron powder) after briquetting can be used as the burden for steelmaking by an electric arc furnace to replace scrap steel.     

A model for estimating the rate constant between CO2-CO gas and molten slag containing iron oxides using optical basicity

A simple model for estimating the rate constant between CO₂-CO gas and molten slag containing iron oxides was developed using optical basicity only. In this model, the temperature dependence of the rate constant can be described by the Arrhenius law, and the activation energy can be expressed with a linear function of the slag??s optical basicity. The model was applied to some molten slag systems, such as FeO, FeO-CaO, FeO-SiO₂, FeO-Na₂O, FeO-CaO-SiO₂, FeO-SiO₂-P₂O₅, FeO-SiO₂-Na₂O, and FeO-CaO-SiO₂-P₂O₅. A comparison between the predicted results and measured data showed that the model worked well.     

FeO的制备及其室温下稳定性研究

采用草酸亚铁在高纯Ar气条件下加热分解制备FeO,借助于XRD图谱探讨保护气氛对FeO制备的影响以及FeO在常温下存放的稳定性。结果表明,Ar气保护流量低于400mL/min时,产物相除FeO相外,还分别含有Fe3O4、Fe相,甚至有Fe2O3相杂质;较佳的Ar气保护流量为400mL/min,此时制备的FeO纯度高,其他杂质较少。新制备的FeO样品在干燥、潮湿和室内自然环境中保存,90d内未发生明显相的变化。     

莱钢高炉合理渣系的研究

为使莱钢高炉冶炼中具有合理渣系,保障高炉长期稳定运行,对其炉渣二元碱度及MgO、Al2O3、FeO含量对炉渣黏度的影响进行研究。结果表明,为保证较低的黏度,高炉渣保持二元碱度约为1.15、w(MgO)为8%~10%较适宜;当高炉渣Al2O3含量达到一定值时,其黏度会明显提高,高炉渣中Al2O3含量最好应控制在15%以内;高炉渣黏度随着FeO含量的增加而显著降低,初渣中较高FeO含量可改善其流动性能。     

热轧高强钢氧化动力学和氧化铁皮结构控制

通过实验室氧化增重实验和热模拟实验系统研究了不同时间和温度条件下高强钢(610L)的氧化动力学行为和FeO的转变行为,推导出了变温条件氧化动力学模型,在此基础上可实现热轧高强钢的厚度演变规律研究;测定了高强钢610L的氧化铁皮的等温转变曲线,指出FeO等温转变包含两个转变过程,即第一个转变过程为析出先共析Fe3O4,第二个转变过程发生共析反应(FeO→Fe+Fe3O4),同时给出610L钢FeO层发生先共析转变和共析转变的“鼻温”范围分别为350~500℃和350~450℃,为控制氧化铁皮结构提供了理论依据.     

Effect of the CaO/SiO2 mass ratio and FeO content on the viscosity of CaO-SiO2-“FeO”-12wt%ZnO-3wt%Al2O3 slags

An effective process for recycling lead from hazardous waste cathode ray tubes (CRTs) funnel glass through traditional lead smelting has been presented previously. The viscous behavior of the molten high lead slag, which is affected by the addition of funnel glass, plays a critical role in determining the production efficiency. Therefore, the viscosities of the CaO-SiO₂-"FeO"-12wt%ZnO-3wt%Al₂O₃ slags were measured in the current study using the rotating spindle method. The slag viscosity decreases as the CaO/SiO₂ mass ratio is increased from 0.8 to 1.2 and also as the FeO content is increased from 8wt% to 20wt%. The breaking temperature of the slag is lowered substantially by the addition of FeO, whereas the influence of the CaO/SiO₂ mass ratio on the breaking temperature is complex. The structural analysis of quenched slags using Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy reveals that the silicate network structure is depolymerized with increasing CaO/SiO₂ mass ratio or increasing FeO content. The[FeO₆]-octahedra in the slag melt increase as the CaO/SiO₂ mass ratio or the FeO content increases. This increase can further decrease the degree of polymerization (DOP) of the slag. Furthermore, the activation energy for viscous flow decreases both with increasing CaO/SiO₂ mass ratio and increasing FeO content.     

Effect of FeO on the formation of spinel phases and chromium distribution in the CaO-SiO2-MgO-Al2O3-Cr2O3 system

Synthetic slag samples of the CaO-SiO₂-MgO-Al₂O₃-Cr₂O₃ system were obtained to clarify the effect of FeO on the formation of spinel phases and Cr distribution. X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS), as well as the thermodynamic software FactSage 6.2, were used for sample characterization. The results show that the addition of FeO can decrease the viscosity of molten slag and the precipitation temperatures of melilite and merwinite. The solidus temperature significantly decreases from 1400 to 1250°C with the increase of FeO content from 0wt% to 6wt%. The addition of FeO could enhance the content of Cr in spinel phases and reduce the content of Cr in soluble minerals, such as merwinite, melilite, and dicalcium silicate. Hence, the addition of FeO is conducive to decreasing Cr leaching.     

FeO影响CaO-SiO_2-MgO-Al_2O_3-Cr_2O_3体系中含铬尖晶石晶体析出的热力学分析

不锈钢渣中的铬以尖晶石矿物相状态赋存时不易溶出,有利于钢渣的资源化利用。本文基于熔体非平衡凝固理论,采用热力学数据库FactSage 7.0研究了FeO添加量对CaO-SiO_2-MgO-Al_2O_3-Cr_2O_3不锈钢渣体系中尖晶石晶体析出温度、析出量、化学组成及铬元素赋存状态的影响规律。模拟计算结果表明,尖晶石晶体为高温析出相,主要由MgCr_2O_4和FeCr_2O_4组成;随着FeO添加量不断增多,尖晶石晶体的析出温度逐渐降低,其最终析出量逐渐增加,析出物中FeCr_2O_4所占比例增加而MgCr_2O_4相对减少;铬元素的赋存状态未受FeO添加量变化影响,仍以尖晶石固溶体形式存在。     

高磷赤铁矿制备碳化铁的产物分离试验研究

利用高磷鲕状赤铁矿制备碳化铁,产物中含磷组分是影响碳化铁质量的关键因素。为了探究分离方式和添加剂对产物中含磷组分分离的影响,在1023K下分别用无添加、添加2%V2O5和添加5%Na2SO4的高磷鲕状赤铁矿制备碳化铁,将制得的产物球磨不同时间后采用磁选或离心+磁选的方式进行产物分离,最后分析产物中含磷组分的变化。结果表明,延长球磨时间可以提高产物的脱磷率,但球磨时间过长会降低产物的铁收得率,以球磨2h为宜;无添加剂时制备所得碳化铁试样球磨时间从1h延长至2h后,脱磷率从18.17%升至18.48%,再增加离心分离操作后,会进一步提升产物的脱磷率至23.04%;添加5%Na_2SO_4和2%V_2O_5均可破坏铁矿石的鲕状结构,有利于含Fe组分与脉石的分离,但添加Na_2SO_4会降低产物的碳化铁含量,而V_2O_5的添加则可同时促进碳化铁的生成以及提高产物的脱磷率,是一种较好的添加剂。