IMCT模型和KTH模型在S50C钢脱硫实践中的应用

脱硫是LF精炼的主要任务之一,基于酒钢S50C中高碳钢的开发,对S50C钢LF精炼过程硫容量、硫分配比的计算方法进行了研究。主要利用IMCT模型和KTH模型对LF精炼渣的渣-钢硫分配比进行计算,并通过工业试验对计算结果进行验证。结果表明,IMCT模型和KTH模型的计算值均能表现从LF到站到LF出站的过程中脱硫反应向着平衡的方向发展,但是KTH模型的计算结果更为准确。因此,对IMCT模型进行了修正,修正后的模型也能较为准确地计算出LF精炼末期硫分配比。最后计算了CaF_2含量对硫容量的影响,结果显示CaF_2含量对平衡硫容量的影响较小。     

IMCT模型和KTH模型在S50C钢脱硫实践中的应用

摘要：脱硫是LF精炼的主要任务之一，基于酒钢S50C中高碳钢的开发，对S50C钢LF精炼过程硫容量、硫分配比的计算方法进行了研究。主要利用IMCT模型和KTH模型对LF精炼渣的渣 钢硫分配比进行计算，并通过工业试验对计算结果进行验证。结果表明，IMCT模型和KTH模型的计算值均能表现从LF到站到LF出站的过程中脱硫反应向着平衡的方向发展，但是KTH模型的计算结果更为准确。因此，对IMCT模型进行了修正，修正后的模型也能较为准确地计算出LF精炼末期硫分配比。最后计算了CaF2含量对硫容量的影响，结果显示CaF2含量对平衡硫容量的影响较小。     

碳饱和铁水与CaO—SiO2—VxOy熔渣平衡体系间各组元的分配

在1450～1580℃范围内,对钒、硅及磷、硫等元素在碳饱和铁水与CaO-SiO_2-V_xO_y渣系间的分配进行了实验研究。结果表明:随着渣碱度B(CaO/SiO_2)的增加,钒、硅及磷、硫的分配比将增大;而提高温度将降低钒、硅在渣-铁间的分配比。应用光学碱度的概念表征熔渣的碱度,考察了在不同光学碱度及不同温度下,该渣系容钒、容磷和容硫的能力,表明光学碱度增加,渣中的钒容量,磷容量及硫容量随之增大,且它们都具有较好的线性关系。升高温度,将有利于增大渣的硫容量,但容钒、容磷能力显著降低。     

硫分配比在LF精炼渣成分优化中的应用

选取Ohta和Suito的经验公式和光学碱度模型计算不同组成成分的四元渣系(Al2O3-CaO-MgO-SiO2)的硫容量与平衡状态下的硫分配比,分析渣中各组元成分变化和钢水温度变化对硫分配比的影响.通过计算首都钢铁集团公司某炼钢厂LF精炼渣的硫容量与硫分配比,来验证计算模型,优化精炼渣成分,以期获得最佳的脱硫效果.     

炉渣组分对CaO-Al2O3-SiO2-TiO2-MgO-Na2O渣系与铁液间硫分配比的影响

针对高碱度高氧化铝的CaO-Al2O3-SiO2-TiO2-MgO-Na2O六元渣系,通过在1 773 K温度下测定其与铁液间的硫分配比,研究该渣系的脱硫性能.利用偏最小二乘法回归分析,建立了可较好预测硫分配比的回归方程,利用回归方程分析了炉渣碱度(mCao/msiO2)、MgO、TiO2、Al2O3以及Na2O对硫分配比的影响.结果表明,当炉渣碱度大于2.9时,炉渣硫分配比均在140以上,表明该渣系具有较强的脱硫能力.在实验范围内,硫分配比随炉渣碱度的增加而提高.当碱度一定时,MgO对硫分配比的影响不大,TiO2、Al2O3均使硫分配比降低,其中Al2O3降低硫分配比较为明显.硫分配比随Na2O增加而增加,少量的Na2O即可明显提高炉渣的脱硫能力.     

MgO含量对CaO-Al_2O_3-SiO_2-MgO精炼渣脱硫能力的影响

利用Factsage软件和KTH模型计算并分析了不同MgO含量时四元渣系CaO-Al2O3-SiO2-MgO的硫容量以及钢液(1 600 ℃)溶解铝质量分数为0.03 %时渣钢间硫平衡分配比的影响.得出控制炉渣成分为w(MgO)<8 %,w(CaO)=54 %～59 %,w(Al2O3)=25 %～30 %,w(SiO2)=6 %～10 %时,渣钢间硫平衡分配比能达到500以上,能满足快速冶炼超低硫钢的要求.     

酒钢SPCC钢的LF精炼脱硫

 通过热力学分析,建立了硫分配比与硫容量的关系,用热力学软件FactSage计算渣中Al2O3活度,用KTH模型计算渣的硫容量,对SPCC(一般用冷轧碳素钢薄板坯钢带)两个浇次10炉钢水在LF进站和出站时取钢、渣样以及测氧和温度,通过分析钢样和渣样成分以及生产检测数据,分析了温度、炉渣成分和钢水成分对LF精炼脱硫的影响规律。定义了硫分配比对钢液中溶解氧活度的急剧变化区(a［O］＜4×10-6),在该区内硫分配比对钢液中溶解氧活度十分敏感,钢液中氧活度的增大导致硫分配比的迅速减小,温度升高,a［O］升高,不仅抵消了升温对脱硫反应轻微的促进作用,反而使硫分配比随温度升高而减小。LF精炼过程Al-O反应未达渣-钢平衡,实际［O］活度介于平衡计算值与Al2O3活度为1的计算值之间,故渣钢硫分配比也介于二者之间。精炼渣二元碱度升高则硫分配比增加,wCaO/wAl2O3在1.6~2.0时脱硫效果较好,硫分配比并不随［Al］s含量的增加而增大,所以用增加w［Al］s来脱硫效果并不明显。钢中夹杂铝(w［Al］t-w［Al］s)降低到10×10-6以下,硫分配比明显升高。     

高碱度精炼渣脱硫分析及硫分配比预测模型

为考察管线钢生产所用高碱度、高曼内斯曼指数的精炼渣脱硫能力,通过工业试验,对精炼过程精炼渣脱硫进行了研究。结果表明,萤石的加入使精炼渣在碱度、曼内斯曼指数均高于一般管线钢生产推荐值的情况下,仍具有很高的脱硫能力和良好的熔化、流动性能。通过对KTH硫容量模型计算得到的硫分配比进行修正,得到适用于某钢厂管线钢生产的硫分配比预测模型。模型计算值与实测值吻合度高,绝对误差范围在±5%之间的占85%。     

超低碳弱脱氧钢炉渣硫容量和硫分配比探讨

首先简述了现有炉渣硫容量的预测模型,包括光学碱度模型和皇家工学院(kungliga tekniska h9gskolan,简称KTH)模型等,同时提出利用FactSage软件计算炉渣的硫容量,并与前两种模型进行对比。结果表明,这3种模型都能较好地预测RH顶渣的硫容量;利用FactSage软件对超低碳钢钢-渣间的硫分配比进行计算,计算结果与检测结果非常接近。因此,FactSage软件可以用来预测超低碳弱脱氧钢RH(Ruhrstahl-Hereaeus)顶渣的硫容量和钢-渣间的硫分配比,并指导生产实践。同时指出,对于超低碳钢的生产,增大RH顶渣中w(CaO)/w(Al_2O_3)比值,降低渣中(FeO+MnO)和SiO_2的质量分数,可以将钢液中硫质量分数控制在较低水平。     

齿轮钢20CrMoH脱硫的热力学研究

 采用LD LF RH CC的工艺路线,出钢采用Al脱氧,造高碱度低氧化性精炼渣,生产高品质汽车用齿轮钢20CrMoH。使用KTH模型和推导硫分配比公式对生产过程的硫容量和硫的分配比进行了计算,将预测与实测的硫分配比进行对比;并对整个精炼过程的脱硫效果进行了分析。     

Phosphorus Capacity of CaO-SiO2-Al2O3-MgO-FexO Slag

The CaO-SiO2-Al2O3-MgO-FexO slag occurs in the production process of Corex ironmaking technology.Most of its metallurgical properties,especially the phosphorus property,are different from the slag produced from blast furnace or converter.In order to explore the dephosphorization ability of CaO-SiO2-Al2O3-MgO-FexO slag,its phosphorus capacity was measured at 1 673 Kby gas-slag-metal equilibrium technique.An iron crucible was used as the reaction vessel,Ag alloy with 0.2% P was used as the metal phase which equilibrated with CaO-SiO2-Al2O3-MgO-FexO slag,and a constant flow of CO-CO2-N2 gas was used to provide oxygen partial pressure in the experiment.The effects of MgO,FexO and basicity on slag phosphorus capacity were investigated by single factor test.The results show that the phosphorus capacity rises firstly and then decreases with increasing MgO content under the condition of basicity 1.3,FexO content of 2% and Al2O3 content of 12%.The phosphorus value reaches maximum as the MgO content is 8%.When the basicity of slag is 1.1,MgO content is 10%,and Al2O3 is 12%,the phosphorus capacity increases with the increase of FexO content.The phosphorus capacity rises linearly when the basicity is increased from 1.1to 1.5.     

Numerical Simulation of Desulfurization Behavior in Gas-Stirred Systems Based on Computation Fluid Dynamics–Simultaneous Reaction Model (CFD–SRM) Coupled Model

A computation fluid dynamics–simultaneous reaction model (CFD–SRM) coupled model has been proposed to describe the desulfurization behavior in a gas-stirred ladle. For the desulfurization thermodynamics, different models were investigated to determine sulfide capacity and oxygen activity. For the desulfurization kinetic, the effect of bubbly plume flow, as well as oxygen absorption and oxidation reactions in slag eyes are considered. The thermodynamic and kinetic modification coefficients are proposed to fit the measured data, respectively. Finally, the effects of slag basicity and gas flow rate on the desulfurization efficiency are investigated. The results show that as the interfacial reactions (Al₂O₃)-(FeO)-(SiO₂)-(MnO)-[S]-[O] simultaneous kinetic equilibrium is adopted to determine the oxygen activity, and the Young’s model with the modification coefficient R _th of 1.5 is adopted to determine slag sulfide capacity, the predicted sulfur distribution ratio LS agrees well with the measured data. With an increase of the gas blowing time, the predicted desulfurization rate gradually decreased, and when the modification parameter R _k is 0.8, the predicted sulfur content changing with time in ladle agrees well with the measured data. If the oxygen absorption and oxidation reactions in slag eyes are not considered in this model, then the sulfur removal rate in the ladle would be overestimated, and this trend would become more obvious with an increase of the gas flow rate and decrease of the slag layer height. With the slag basicity increasing, the total desulfurization ratio increases; however, the total desulfurization ratio changes weakly as the slag basicity exceeds 7. With the increase of the gas flow rate, the desulfurization ratio first increases and then decreases. When the gas flow rate is 200 NL/min, the desulfurization ratio reaches a maximum value in an 80-ton gas-stirred ladle.     

CaO-SiO2-Al2O3-MgO-FeO渣系FeO活度的计算模型

利用熔渣结构共存理论建立了CaO-SiO2-Al2O3-MgO-FeO渣系FeO活度的计算模型,并分析了1400℃时炉渣碱度、MgO和FeO含量对该渣系FeO活度的影响规律。结果表明：当CaO-SiO2-Al2O3-MgO-FeO渣系三元碱度为1.3,Al2O3含量为12wt%,FeO含量为2wt%条件下,随MgO含量的增加,炉渣FeO活度增大;当二元碱度为1.1,Al2O3含量为12wt%,MgO含量为10wt%时,FeO活度随随渣中FeO含量的增加呈线性增加;当渣中Al2O3、MgO和FeO含量分别为12wt%、10wt%和2wt%固定不变时,随着二元碱度的提高,炉渣FeO活度迅速增加。计算得到的上述规律和实测规律一致,说明了本模型用于分析FeO活度的正确性。     

Calculation and Analysis of Sulfide Capacities for CaO-Al2O3-SiO2-MgO-TiO2 Slags

The empirical models of sulfide capacity calculated by traditional optical basicity do not consider the charge compensation of alkaline metal ions to Al³⁺ in the molten slags, so that the deviations between the calculated values and measured ones of sulfide capacity are inevitable. The relation between sulfide capacity and the corrected optical basicity put forward by Mills considering the charge compensation was investigated. Combined with the relation between sulfide capacity and temperatures, a novel and accurate calculation model of sulfide capacity was proposed, which was applied to calculate the sulfide capacities of CaO-Al₂O₁-SiO₂-MgO and CaO-Al₂O₁-SiO₂-MgO-TiO₂ systems, where the sum of the CaO and MgO concentrations in the slags must be not lower than the Al₂O₃ concentration. It was also found that the calculated values were in a good agreement with the measured values, and the mean deviations were 2. 57% and 2. 65%, respectively.     

CaO-SiO2-MgO-Al2O3-BaO渣系脱硫能力研究

为了探究温度、碱度（R）、MgO质量分数和BaO质量分数对高炉渣脱硫能力影响,以酒钢现场高炉渣实际成分为基准,选取分析纯化学试剂配制实验渣样,采用双层石墨坩埚法研究了含钡渣系的脱硫能力,并考察BaO对脱硫动力学条件的影响。研究结果表明,增大高炉渣碱度,提高渣中MgO质量分数均能使硫分配比增加,炉渣脱硫能力增强。渣中BaO质量分数由0增加到4%,硫分配比先逐渐升高后略有降低,BaO质量分数为35%左右时硫分配比达到最大值。BaO质量分数增加使得熔渣中硫的传质系数增大,脱硫速率明显提升。     

Chemical behaviour of nitrogen in metallurgical slags

According to previous experimental work, nitride capacity C_N, in opposition to sulfide capacity C_S, decreases with increasing optical basicity of metallurgical slags. This tendency is also confirmed by the contradictory behaviour of the free energy changes of oxide-nitride and oxide-sulfide transformation reactions as a function of basicity. From the present metal-slag equilibrium studies, denitrogenation potentials P_N = %(N)/{%[N] · %[Al]} were obtained characterizing denitrogenation efficacy of slags at given compositions and temperatures. From these potentials, factors were derived which mark the effects of individual slag components. It was found that these factors feature the same basicity dependence as nitride capacities C_N and denitrogenation potentials P_N. The factors are increased, e.g., as less basic oxides are increasingly present in the slag phase in the order BaO → SrO → CaO → MgO.